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May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503135613.htm
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Bornean rajah scops owl rediscovered after 125 years
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The Bornean subspecies of Rajah scops owl (
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"It was a pretty rapid progression of emotions when I first saw the owl -- absolute shock and excitement that we'd found this mythical bird, then pure anxiety that I had to document it as fast as I could," Boyce said. "Based on size, eye color and habitat, I knew it was the Bornean Rajah scops owl. What's more, taking into account this bird's specific plumage characters, known speciation patterns within the Otus genus and phylogeographic patterns of montane birds in Borneo and Sumatra, Scops owls weigh approximately 100 grams (about 4 ounces), equivalent to four AA batteries. Both subspecies of Rajah scops owl are native to southeast Asia -- The serendipitous discovery occurred in May 2016 as part of a 10-year study of avian life-history evolution at Mount Kinabalu in seven study plots at elevations from 1,500-1,900 meters (about 5,000-6,200 feet). The project was led by T.E. Martin, assistant unit leader and research wildlife biologist with the Montana Cooperative Wildlife Research Unit at the University of Montana. While nest-searching in May 2016, technician Keegan Tranquillo notified Boyce, then a doctoral student at the University of Montana, after spotting a roosting scops owl larger and with different plumage than the regularly encountered Mountain scops owl (O. spilocephalus luciae)."Unfortunately, we are only good at conserving what we know and what we name," Boyce said. "If this rare bird is endemic only to Borneo and is its own species, conservation action is more likely. Our sole sighting during this intensive study confirms this owl lives in mature montane forests, likely above or below the survey area. Those elevations are already threatened by habitat loss due to climate change, deforestation and palm oil development. To protect this bird, we need a firm understanding of its habitat and ecology."Almost all data on this species is of the Sumatran subspecies. Properly resolving the ecology, distribution and taxonomic standing of
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Animals
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503113933.htm
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Newly identified giant saber-toothed cat roamed North America 5-9 million years ago
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A giant saber-toothed cat lived in North America between 5 million and 9 million years ago, weighing up to 900 pounds and hunting prey that likely weighed 1,000 to 2,000 pounds, scientists reported today in a new study.
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The researchers completed a painstaking comparison of seven uncategorized fossil specimens with previously identified fossils and bone samples from around the world to describe the new species. Their finding makes a case for the use of the elbow portion of the humerus -- in addition to teeth -- to identify fossils of large saber-toothed cats whose massive forearms enabled them to subdue their prey.The newly identified cat weighed an average of around 600 or so pounds and could have managed to kill prey weighing up to 6,000 pounds, the scientists estimate, suggesting that their findings provide evidence for another giant cat, one of the largest in Earth history."We believe these were animals that were routinely taking down bison-sized animals," said study co-author Jonathan Calede, an assistant professor of evolution, ecology and organismal biology at The Ohio State University's Marion campus. "This was by far the largest cat alive at that time."Calede completed the study with John Orcutt, assistant professor of biology at Gonzaga University, who initiated the project. Orcutt found a large upper arm bone specimen that had been labeled as a cat in the University of Oregon Museum of Natural and Cultural History collection when he was a graduate student, and collaborated with Calede on the years-long effort to figure out what kind of cat it could be.They have determined that the new species is an ancient relative of the best-known saber-toothed cat Smilodon, the famous fossil found in the La Brea Tar Pits in California that went extinct about 10,000 years ago.The Oregon specimen was excavated on the traditional lands of the Cayuse, a tribe joined with the Umatilla and Walla Walla in the Confederated Tribes of the Umatilla Indian Reservation. In recognition of its origin, Calede and Orcutt collaborated with the Tamástslikt Cultural Institute to name the new species Machairodus lahayishupup. Machairodus is a genus of large saber-toothed cats that lived in Africa, Eurasia and North America, and in the Old Cayuse language, Laháyis Húpup means "ancient wild cat."The study is published today (May 3, 2021) in the Orcutt and Calede found similar uncategorized upper arm fossil specimens at the Idaho Museum of Natural History, where a big cat forearm was accompanied by teeth -- generally considered the gold standard for identifying new species -- as well as at the University of California Museum of Paleontology and Texas Memorial Museum."One of the big stories of all of this is that we ended up uncovering specimen after specimen of this giant cat in museums in western North America," Orcutt said. "They were clearly big cats. We started with a few assumptions based on their age, in the 5 1/2 to 9 million-year-old range, and based on their size, because these things were huge."What we didn't have then, that we have now, is the test of whether the size and anatomy of those bones tells us anything -- and it turns out that yes, they do."The largest of the seven Machairodus lahayishupup humerus fossils available for the analysis was more than 18 inches long and 1.7 inches in diameter. By comparison, the average modern adult male lion's humerus is about 13 inches long.The researchers hypothesized that if an isolated forearm bone were useful in telling species apart, that would be true among the big cat species alive today. Calede and Orcutt visited numerous museums in the U.S., Canada and France to photograph forearm specimens of lions, pumas, panthers, jaguars and tigers, as well as fossils of previously identified extinct big cats.Calede used software to place landmark points on each digitized sample that, when drawn together, would create a model of each elbow."We found we could quantify the differences on a fairly fine scale," Calede said. "This told us we could use the elbow shape to tell apart species of modern big cats."Then we took the tool to the fossil record -- these giant elbows scattered in museums all had a characteristic in common. This told us they all belonged to the same species. Their unique shape and size told us they were also very different from everything that is already known. In other words, these bones belong to one species and that species is a new species."The researchers calculated estimates of the new species' body size based on the association between humerus size and body mass in modern big cats, and speculated about the cat's prey based on its size and animals known to have lived in the region at that time: rhinoceros were particularly abundant, as well as giant camels and giant ground sloths.The teeth from the Idaho Museum of Natural History came from the lower part of the jaw and did not include the saber-shaped canines, but provided additional evidence that the fossil belonged to the Machairodus genus, which gave its name to the machairodontines -- the technical name for a saber-toothed cat, Orcutt said."We're quite confident it's a saber-toothed cat and we're quite confident it's a new species of the Machairodus genus," he said. "The problem is, in part because we haven't necessarily had a clear image in the past of how many species were out there, our understanding of how all these saber-toothed cats are related to each other is a little fuzzy, particularly early in their evolution."Establishing that the humerus alone can be analyzed to identify a fossil cat has important implications for the field -- saber-toothed cats' "big, beefy" forearm bones are the most common specimens of fossil cats found in excavations, he said.Only a reconstruction of the evolutionary history of saber-toothed cats can determine where this new species fits in, but Orcutt and Calede believe Machairodus lahayishupup existed early in the evolution of the group.A discovery that this giant cat in North America existed at the same time similar animals lived around the world also raises another evolutionary question, Calede said."It's been known that there were giant cats in Europe, Asia and Africa, and now we have our own giant saber-toothed cat in North America during this period as well," he said. "There's a very interesting pattern of either repeated independent evolution on every continent of this giant body size in what remains a pretty hyperspecialized way of hunting, or we have this ancestral giant saber-toothed cat that dispersed to all of those continents."It's an interesting paleontological question."
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Animals
| 2,021 |
May 3, 2021
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https://www.sciencedaily.com/releases/2021/05/210503104801.htm
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Dogs' aggressive behavior towards humans is often caused by fear
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A study encompassing some 9,000 dogs conducted at the University of Helsinki demonstrated that fearfulness, age, breed, the company of other members of the same species and the owner's previous experience of dogs were associated with aggressive behaviour towards humans. The findings can potentially provide tools for understanding and preventing aggressive behaviour.
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Aggressive behaviour in dogs can include growling, barking, snapping and biting. These gestures are part of normal canine communication, and they also occur in non-aggressive situations, such as during play. However, aggressive behaviour can be excessive, making the dog a health threat to both humans and other animals."Understanding the factors underlying aggressive behaviour is important. In what kinds of circumstances does aggressive behaviour occur and what is the dog's motive for such behaviour? In normal family dogs, aggressive behaviour is often unwanted, while some dogs with official duties are expected to have the capacity for aggressiveness. At the same time, aggressiveness can be caused by welfare issues, such as chronic pain," says doctoral researcher Salla Mikkola from the University of Helsinki.The canine gene research group active at the University of Helsinki surveyed connections between aggressive behaviour and several potential risk factors with the help of a dataset encompassing more than 9,000 dogs, a sample from a larger dataset from a behavioural survey dataset of nearly 14,000 dogs. The study investigated aggressiveness towards both dog owners and unfamiliar human beings. Dogs were classified as aggressive if they growled often and/or had attempted to snap at or bite a human at least occasionally in the situations described in the survey."Dogs' fearfulness had a strong link to aggressive behaviour, with fearful dogs many times more likely to behave aggressively. Moreover, older dogs were more likely to behave aggressively than younger ones. One of the potential reasons behind this can be pain caused by a disease. Impairment of the senses can contribute to making it more difficult to notice people approaching, and dogs' responses to sudden situations can be aggressive," Mikkola adds.Small dogs are more likely to behave aggressively than mid-sized and large dogs, but their aggressive behaviour is not necessarily considered as threatening as that of large dogs. Consequently, their behaviour is not addressed. In addition, the study found that male dogs were more aggressive than females. However, sterilisation had no effect on aggressive behaviour.The first dogs of dog owners were more likely to behave aggressively compared to dogs whose owners had previous experience of dogs. The study also indicated that dogs that spend time in the company of other dogs behave less aggressively than dogs that live without other dogs in the household. While this phenomenon has been observed in prior research, the causality remains unclear."In the case of dogs prone to aggressive behaviour in the first instance, owners may not necessarily wish to take a risk of conflicts with another dog," Mikkola muses.Differences in the aggressiveness of various dog breeds can point to a genetic cause."In our dataset, the Long-Haired Collie, Poodle (Toy, Miniature and Medium) and Miniature Schnauzer were the most aggressive breeds. Previous studies have shown fearfulness in Long-Haired Collies, while the other two breeds have been found to express aggressive behaviour towards unfamiliar people. As expected, the popular breeds of Labrador Retriever and Golden Retriever were at the other extreme. People who are considering getting a dog should familiarise themselves with the background and needs of the breed. As for breeders, they should also pay attention to the character of dam candidates, since both fearfulness and aggressive behaviour are inherited," says Professor Hannes Lohi from the University of Helsinki.
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Animals
| 2,021 |
April 30, 2021
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https://www.sciencedaily.com/releases/2021/04/210430165850.htm
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Branching worm with dividing internal organs growing in sea sponge
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The marine worm Ramisyllis multicaudata, which lives within the internal canals of a sponge, is one of only two such species possessing a branching body, with one head and multiple posterior ends. An international research team led by the Universities of Göttingen and Madrid is the first to describe the internal anatomy of this intriguing animal. The researchers discovered that the complex body of this worm spreads extensively in the canals of their host sponges. In addition, they describe the anatomical details and nervous system of its unusual reproductive units, the stolons, which form their own brain when detached for fertilization, allowing them to navigate their environment. The results were published in the
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The research team found the host sponges and their guest worms in a remote area in Darwin, Australia, where these animals live. They collected samples, some of which are now located in the collections of the Biodiversity Museum at the University of Göttingen. For their analysis, they combined techniques such as histology, electronic optical microscopy, immunohistochemistry, confocal laser microscopy, and X-ray computed microtomography. This made it possible to obtain three-dimensional images both of the worms' different internal organs and of the interior of the sponges that they inhabit. The scientists show that when the body of these animals divides, so do all their internal organs, something that has never been observed before.Furthermore, the three-dimensional models developed during this research have made it possible to find a new anatomical structure exclusive to these animals, which is formed by muscular bridges that cross between the different organs whenever their body has to form a new branch. These muscular bridges are essential because they confirm that the bifurcation process does not occur in the early stages of life, but once the worms are adults and then throughout their lives. In addition, researchers propose that this unique "fingerprint" of muscle bridges makes it theoretically possible to distinguish the original branch from the new one in each bifurcation of the complex body network.In addition, this new study investigates the anatomy of the reproductive units (stolons) that develop in the posterior ends of the body when these animals are about to reproduce, and that are characteristic of the family to which they belong (Syllidae). The results show that these stolons form a new brain and have their own eyes. This allows them to navigate their environment when they are detached from the body for fertilization. This brain is connected to the rest of the nervous system by a ring of nerves that surrounds the intestine."Our research solves some of the puzzles that these curious animals have posed ever since the first branched annelid was discovered at the end of the 19th century," explains senior author Dr Maite Aguado, University of Göttingen. "However, there is still a long way to go to fully understand how these fascinating animals live in the wild. For example, this study has concluded that the intestine of these animals could be functional, yet no trace of food has ever been seen inside them and so it is still a mystery how they can feed their huge branched bodies. Other questions raised in this study are how blood circulation and nerve impulses are affected by the branches of the body." This research lays the foundations for understanding how these creatures live and how their incredible branched body came to evolve.
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Animals
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429142646.htm
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Eastern and Western house mice took parallel evolutionary paths after colonizing US
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The European house mouse has invaded nearly every corner of the Americas since it was introduced by colonizers a few hundred years ago, and now lives practically everywhere humans store their food.
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Yet in that relatively short time span -- 400 to 600 mouse generations -- populations on the East and West Coasts have changed their body size and nest building behavior in nearly identical ways to adapt to similar environmental conditions, according to a new study by biologists at the University of California, Berkeley.To make these adaptations -- at least in the case of body size -- mice in the Western United States evolved many of the same genetic changes as their cousins in the East, showing that evolution often works on the same genes in different populations when those populations are confronted with similar environmental conditions.The study represents one of the first times scientists have tracked down the genetic changes underlying a complex adaptive trait in mammals, though similar studies have been conducted with laboratory insects, such as fruit flies, and in fish."The big take-home message from this paper is that there is some predictability to evolution, both at the organismal level and at the genetic level," said study leader Michael Nachman, UC Berkeley professor of integrative biology and director of the campus's Museum of Vertebrate Zoology. "We have shown that the same genes have been recruited independently in two different areas, all over very short evolutionary time. This is a good example of rapid evolutionary change over short times for a complex adaptive trait."The findings also have implications for mammals other than rodent pests."The mice we are studying are a reasonable model for thinking about human evolution as well, since humans have been in the Americas about as many generations as house mice," Nachman said. "We found genes involved in mouse body size that had previously been implicated in metabolism and things like obesity in humans, so there also are parallels between humans and mice."Nachman and his colleagues were able to prove that these traits have a genetic cause -- they resulted from nature, not nurture -- by raising mice from different environments in the lab under the same environmental conditions. House mice from New York and Alberta, Canada, always produced bigger nests than mice from Florida and Arizona, even when nesting at the same temperature, while the northern mice were always bigger than the southern mice, despite being raised in similar conditions."We and many other people have studied natural populations for a long time and you can document differences among natural populations," he said. "But in this case, we went one step further and took those animals into the lab and reared them for multiple generations so we could ask whether the differences we see in nature are due to the environment or due to genetics. By having a combination of animals in the wild and animals in the lab, we can tease out the genetic component to the traits that we are studying."The study appeared today in the journal Nachman and his team have been studying house mice in North and South America for several years to determine how they have adapted to different environments -- physiologically and genetically -- since arriving as stowaways aboard ships from Europe. His goal has been to link changes in physiology and instinctual behavior to changes in specific genes, to understand how multiple genes interact to create changes in complicated adaptations.To date, most studies linking genetic change -- genotype -- to physiological change -- phenotype -- have involved relatively simple characteristics, such as changes in fur color with environment, or development of insecticide resistance.House mice -- Mus musculus domesticus, the ancestor of all laboratory mice used today -- seemed a good subject since they exist in a wide variety of habitats throughout the Americas, including in the Andes at elevations above 4,000 meters (13,000 feet). Over the years, Nachman and his colleagues have collected hundreds of individual mice from Tierra del Fuego at the tip of South America to southern Canada and upstate New York, and from different elevations in Ecuador and Bolivia, and sequenced all the genes in their genomes.Nachman said that he couldn't help but notice that in the wild, northern mice -- from Edmonton, Alberta, and Saratoga Springs, New York -- tended to be larger than southern mice from Tucson, Arizona, and Gainesville, Florida, though it wasn't always clear given that the mice differed in age, diet and health. Larger body size is a well-known adaptation to colder weather, referred to as Bergmann's rule after the 19th century German biologist Carl Bergmann."Mice from 45 degrees north latitude are about 50% bigger than mice from the equator," Nachman said. "A mouse from the equator is about 12 grams; a mouse from upstate New York is about 18 grams. That is a big difference. If we were talking about humans, that would be a 100-pound versus 150-pound person, on average."Northern mice also build bigger nests: about twice the size of southern mice.To determine the genetic relationships among these mouse populations, his team collected 10 mice from 5 different sites in the West, about equally spaced from Tucson to Edmonton, sequenced their genes and compared them to the genes of mice his team had collected earlier along the East Coast from Gainesville to Saratoga Springs. He found that, though Northeastern mice and Northwestern mice had both developed larger bodies and built larger nests, they were not closely related. New York mice were more closely related to other Eastern mice than to Alberta mice, while Alberta mice were more closely related to other Western mice than to New York mice.If Eastern and Western mice are two distinct populations that independently adapted to cold weather using the same strategy -- larger size and larger nests -- did their genes also change?To find out, he and his colleagues established lab colonies with 41 individual mice from the extreme areas sampled: Edmonton (EDM) in the north and Tucson (TUC) in the south. Raising them in identical indoor conditions, the northern mice over five generations retained their larger body size and larger nest building behavior, showing that the behavioral and physiological changes were in fact encoded in their genetics. Three years ago, Nachman conducted similar experiments with mice from Saratoga Springs (SAR) and Gainesville (GAI), and found similar results from these Eastern populations."By bringing them into the common lab environment and keeping them there at a comfy room temperature for a few generations, we can conclude that any differences we see have a genetic basis," he said.They then conducted a genome-wide association study to identify which variant or allele of each gene in the genome had changed frequency along with the change in body mass. They're still tracking the genetic causes of nest building.The researchers identified eight mutations in five genes associated with increased body size in the Edmonton mice."We found that of all those genes that we identified for body size, four of the five genes show strong signatures of natural selection in both the East and West," he said. "That suggests that we found some genes that are contributing to this pattern, known as Bergmann's Rule, which is actually one of the most widespread geographic patterns in the evolution of warm-blooded animals. We are starting to get at its genetic basis in this study."Combining these data with the results from Nachman's previous study of house mice in New York and Florida, the researchers found a total of 16 genes that showed parallel evolution along the north-south gradient on both coasts, many of which are involved in regulating body temperature. For example, the gene Trpm2, which causes mice to avoid very high temperatures, showed genetic changes in southern populations.While mice in the East and West exhibited evidence of independent evolution in many of the same genes, each region also harbored genetic adaptations not seen in the other region. In the West, for example, fur color varied with soil color: northern mice were a darker shade, consistent with trying to blend in on damper, darker soil. Eastern mice did not show such variation.Nachman is continuing to study house mouse variation, and hopes eventually to employ CRISPR genome editing to alter genes in his mouse populations to confirm their involvement in traits such as body size."We'd like to edit some of these genes and see if we can take a mouse from Canada and turn it into a mouse that looks like a Tucson mouse, or vice versa," he said.The work was funded by the National Institutes of Health (RO1 GM074245, R01 GM127468). The NIH and The Jackson Laboratory also support Nachman's development of new house mouse strains -- SAR, GAI, EDM, TUC and a fifth strain, MAN, from Manaus, Brazil -- that researchers can use in place of the inbred lab mouse -- the most popular strain is called C57BL/6 -- if they want greater genetic variation in their mouse studies.
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Animals
| 2,021 |
April 29, 2021
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https://www.sciencedaily.com/releases/2021/04/210429123340.htm
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Fasting lowers blood pressure by reshaping the gut microbiota
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Nearly half of adults in the United States have hypertension, a condition that raises the risk for heart disease and stroke, which are leading causes of death in the U. S.
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At Baylor College of Medicine, Dr. David J. Durgan and his colleagues are dedicated to better understand hypertension, in particular the emerging evidence suggesting that disruption of the gut microbiota, known as gut dysbiosis, can have adverse effects on blood pressure."Previous studies from our lab have shown that the composition of the gut microbiota in animal models of hypertension, such as the SHRSP (spontaneously hypertensive stroke-prone rat) model, is different from that in animals with normal blood pressure," said Durgan, assistant professor of anesthesiology at Baylor.The researchers also have shown that transplanting dysbiotic gut microbiota from a hypertensive animal into a normotensive (having a healthy blood pressure) one results in the recipient developing high blood pressure."This result told us that gut dysbiosis is not just a consequence of hypertension, but is actually involved in causing it," Durgan said. "This ground work led to the current study in which we proposed to answer two questions. First, can we manipulate the dysbiotic microbiota to either prevent or relieve hypertension? Second, how are the gut microbes influencing the animal's blood pressure?"To answer the first question, Durgan and his colleagues drew on previous research showing that fasting was both one of the major drivers of the composition of the gut microbiota and a promoter of beneficial cardiovascular effects. These studies, however, had not provided evidence connecting the microbiota and blood pressure.Working with the SHRSP model of spontaneous hypertension and normal rats, the researchers set up two groups. One group had SHRSP and normal rats that were fed every other day, while the other group, called control, had SHRSP and normal rats with unrestricted food availability.Nine weeks after the experiment began, the researchers observed that, as expected, the rats in the SHRSP control had higher blood pressure when compared to the normal control rats. Interestingly, in the group that fasted every other day, the SHRSP rats had significantly reduced blood pressure when compared with the SHRSP rats that had not fasted."Next, we investigated whether the microbiota was involved in the reduction of blood pressure we observed in the SHRSP rats that had fasted," Durgan said.The researchers transplanted the microbiota of the rats that had either fasted or fed without restrictions into germ-free rats, which have no microbiota of their own.Durgan and his colleagues were excited to see that the germ-free rats that received the microbiota of normally fed SHRSP rats had higher blood pressure than the germ-free rats receiving microbiota from normal control rats, just like their corresponding microbiota donors."It was particularly interesting to see that the germ-free rats that received microbiota from the fasting SHRSP rats had significantly lower the blood pressure than the rats that had received microbiota from SHRSP control rats," Durgan said. "These results demonstrated that the alterations to the microbiota induced by fasting were sufficient to mediate the blood pressure-lowering effect of intermitting fasting."The team proceeded to investigate the second question of their project. How does the gut microbiota regulate blood pressure?"We applied whole genome shotgun sequence analysis of the microbiota as well as untargeted metabolomics analysis of plasma and gastrointestinal luminal content. Among the changes we observed, alterations in products of bile acid metabolism stood out as potential mediators of blood pressure regulation," Durgan said.The team discovered that the SHRSP hypertensive animals that were fed normally had lower bile acids in circulation than normotensive animals. On the other hand, SHRSP animals that followed an intermittent feeding schedule had more bile acids in the circulation."Supporting this finding, we found that supplementing animals with cholic acid, a primary bile acid, also significantly reduced blood pressure in the SHRSP model of hypertension," Durgan said.Taken together, the study shows for the first time that intermittent fasting can be beneficial in terms of reducing hypertension by reshaping the composition of gut microbiota in an animal model. The work also provides evidence that gut dysbiosis contributes to hypertension by altering bile acid signaling."This study is important to understand that fasting can have its effects on the host through microbiota manipulation," Durgan said. "This is an attractive idea because it can potentially have clinical applications. Many of the bacteria in the gut microbiota are involved in the production of compounds that have been shown to have beneficial effects as they make it into the circulation and contribute to the regulation of the host's physiology. Fasting schedules could one day help regulate the activity of gut microbial populations to naturally provide health benefits."
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Animals
| 2,021 |
April 30, 2021
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https://www.sciencedaily.com/releases/2021/04/210430093209.htm
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Wasps are valuable for ecosystems, economy and human health (just like bees)
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Wasps deserve to be just as highly valued as other insects, like bees, due to their roles as predators, pollinators, and more, according to a new review paper led by UCL and University of East Anglia researchers.
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The study, published in Lead author Professor Seirian Sumner (UCL Centre for Biodiversity & Environment Research, UCL Biosciences) said: "Wasps are one of those insects we love to hate -- and yet bees, which also sting, are prized for pollinating our crops and making honey. In a previous study, we found that the hatred of wasps is largely due to widespread ignorance about the role of wasps in ecosystems, and how they can be beneficial to humans."Wasps are understudied relative to other insects like bees, so we are only now starting to properly understand the value and importance of their ecosystem services. Here, we have reviewed the best evidence there is, and found that wasps could be just as valuable as other beloved insects like bees, if only we gave them more of a chance."Wasps are top predators of other insects. Predation by insects -- as biocontrol to protect crops -- is worth at least $416 billion (US) per year worldwide. Yet, this figure almost completely overlooks the contributions of hunting wasp predation. The review highlights how wasps' role as predators makes them valuable for agriculture. Wasps regulate populations of arthropods, like aphids and caterpillars that damage crops. Solitary wasp species tend to be specialists, which may be suited to managing a specific pest, while social wasps are generalist predators, and may be especially useful as a local source of control for a range of crop-eating pests.The researchers say that wasps could be used as sustainable forms of pest control in developing countries, especially tropical ones, where farmers could bring in populations of a local wasp species with minimal risk to the natural environment. Professor Sumner and colleagues recently published a study finding that common wasp species are effective predators that can manage pests on two high-value crops, maize and sugarcane, in Brazil.The review also highlights the pollination services provided by wasps. Pollination by insects is vital for agriculture, and its economic importance has been valued at greater than $250 billion (US) per year worldwide.The researchers found evidence of wasps visiting 960 plant species. This included 164 species that are completely dependent on wasps for pollination, such as some orchid species that have evolved adaptations to attract the wasps they rely on, such as an appearance that mimics the back end of a female wasp. Many wasps are also generalist pollinators that visit a wide variety of plants, so the researchers say they could serve as 'backup pollinators' if a plant loses its local primary pollinator.The review also describes other uses for wasps such as wasp-derived medications, as their venom and saliva have antibiotic properties, while yellowjacket wasp venom has shown promise in treating cancer. Wasps may even be a valuable food source, as their larvae are already harvested in some tropical countries for food.Co-author Dr Alessandro Cini (UCL Centre for Biodiversity & Environment Research, UCL Bioscience and University of Florence) said: "The value of wasps in supporting our crops remains poorly understood; we hope that by rehabilitating their bad reputation, we can collectively get the most value out of these fascinating creatures."The paper's first author, Ryan Brock (University of East Anglia) said: "Alongside other insects, many wasp species are declining from factors such as climate change and habitat loss. As such, there is urgent need to address their conservation and ensure that habitats continue to benefit from the far-reaching ecosystem services that wasps provide."The research was supported by the Natural Environment Research Council and a Marie Curie fellowship from the European Commission.
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Animals
| 2,021 |
April 28, 2021
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https://www.sciencedaily.com/releases/2021/04/210428113813.htm
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Human antibiotic use threatens endangered wild chimpanzees
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It's well established that infectious disease is the greatest threat to the endangered chimpanzees made famous by the field studies of Jane Goodall at Gombe National Park in Tanzania. Now, new research led by scientists at Emory University shows that nearly half of the fecal samples from wild chimpanzees contain bacteria that is resistant to a major class of antibiotics commonly used by people in the vicinity of the park.
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The journal "Our results suggest that antibiotic-resistant bacteria is actually spreading from people to non-human primates by making its way into the local watershed," says Thomas Gillespie, senior author of the study and associate professor in Emory's Department of Environmental Sciences and Rollins School of Public Health. "People are bathing and washing in the streams, contaminating the water with drug-resistant bacteria where wild chimpanzees and baboons drink."The researchers tested for genes conferring resistance to sulfonamides -- drugs often used by people in the region to treat diarrheal diseases -- in fecal samples from humans, domestic animals, chimpanzees and baboons in and around Gombe National Park. They also tested stream water used by these groups.Sulfonamide resistance appeared in 74 percent of the human samples overall, 48 percent of chimpanzee samples, 34 percent of baboon samples, and 17 percent of the domestic animal samples. Sulfonamide also showed up in 19 percent of the samples taken from streams shared by people, domestic animals and wildlife.The researchers also tested all the groups in the study for genes conferring resistance to tetracycline -- another class of antibiotics that is used much less frequently by people in the vicinity, likely due to its greater expense and the fact that it is less available in the area. As expected, very few of the fecal samples from any of the groups, and none of the water samples from the streams, showed evidence of tetracycline resistance.First author of the study is Michelle Parsons, who did the work as an Emory doctoral student in Environmental Sciences. Parsons has since graduated and works at the Centers for Disease Control and Prevention (CDC). Co-authors include researchers from the Jane Goodall Institute, the CDC, the University of Minnesota and Franklin and Marshall College.Gillespie is a disease ecologist who helped pioneer the "One Health" approach to protect humans, ecosystems and biodiversity. His projects in Africa, including the collaboration with the Jane Goodall Institute in Tanzania, are focused on helping farmers subsisting amid fragmented forests co-exist with primates and other wildlife in ways that minimize the risk of pathogen exchange between species, known as "spillover." The virus that causes AIDS, for example, spilled over from chimpanzees to people."It's important to consider both sides of the story -- human health and well-being, as well as conservation of chimpanzees and other species," Gillespie says.Human encroachment has taken a toll on the great apes, due to fragmented habitat and the exchange of pathogens. Today, the number of chimpanzees in Gombe National Park are down to about 95.Diarrheal diseases are common in the area and people often turn to cheap sulfonamide antibiotics that are available without a prescription at small stores that act as informal pharmacies, selling drugs, soap and other necessities. Wild chimpanzees also suffer from wasting diseases that can be related to bacterial and other enteric pathogens that affect their ability to maintain calorie intake and absorb nutrients."The majority of people in our sampling harbored bacteria resistant to the sulfonamide medication they are taking," Gillespie says. "In those cases, they're spending their money on a drug that is not helping them get better. Overuse of such drugs creates the potential for more lethal, antibiotic-resistant 'super bugs' to emerge."The research findings will now support the development of interventions. More guidance is needed locally regarding the proper use of antibiotics, Gillespie says. He adds that it is also important to improve hygiene for wash-related activities in area streams, as well as to improve disposal of human waste materials."By misusing antibiotics, people can actually harm not only themselves, but also the species they share an environment with," Gillespie says. "After drug-resistant bacteria jump into chimpanzees, it can further evolve with the chimpanzees and then spill back into humans. We need to be thinking about infectious diseases within evolutionary and ecological frameworks, something that's not often done in medicine."
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Animals
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April 28, 2021
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https://www.sciencedaily.com/releases/2021/04/210428113750.htm
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Project to read genomes of all 70,000 vertebrate species reports first discoveries
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It's one of the most audacious projects in biology today -- reading the entire genome of every bird, mammal, lizard, fish, and all other creatures with backbones.
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And now comes the first major payoff from the Vertebrate Genome Project (VGP): near complete, high-quality genomes of 25 species, Howard Hughes Medical Institute (HHMI) Investigator Erich Jarvis with scores of coauthors report April 28, 2021, in the journal The paper also lays out the technical advances that let scientists achieve a new level of accuracy and completeness and paves the way for decoding the genomes of the roughly 70,000 vertebrate species living today, says HHMI Investigator and study coauthor David Haussler, a computational geneticist at the University of California, Santa Cruz (UCSC). "We will get a spectacular picture of how nature actually filled out all the ecosystems with this unbelievably diverse array of animals."Together with a slew of accompanying papers, the work is beginning to deliver on that promise. The project team has discovered previously unknown chromosomes in the zebra finch genome, for example, and a surprise finding about genetic differences between marmoset and human brains. The new research also offers hope for saving the kākāpō parrot and the endangered vaquita dolphin from extinction."These 25 genomes represent a key milestone," explains Jarvis, VGP chair and a neurogeneticist at The Rockefeller University. "We are learning a lot more than we expected," he says. "The work is a proof of principle for what's to come."The VGP milestone has been years in the making. The project's origins date back to the late-2000s, when Haussler, geneticist Stephen O'Brien, and Oliver Ryder, director of conservation genetics at the San Diego Zoo, figured it was time to think big.Instead of sequencing just a few species, such as humans and model organisms like fruit flies, why not read the complete genomes of ten thousand animals in a bold "Genome 10K" effort? At the time, though, the price tag was hundreds of millions of dollars, and the plan never really got off the ground. "Everyone knew it was a great idea, but nobody wanted to pay for it," recalls HHMI Investigator and HHMI Professor Beth Shapiro, an evolutionary biologist at UCSC and a coauthor of the Plus, scientists' early efforts at spelling out, or "sequencing," all the DNA letters in an animal's genome were riddled with errors. In the original approach used to complete the first rough human genome in 2003, scientists chopped up DNA into short pieces a few hundred letters long and read those letters. Then came the fiendishly difficult job of assembling the fragments in the right order. The methods weren't up to task, resulting in misassemblies, major gaps, and other mistakes. Often it wasn't even possible to map genes to individual chromosomes.The introduction of new sequencing technologies with shorter reads helped make the idea of reading thousands of genomes possible. These rapidly developing technologies slashed costs but also reduced quality in genome assembly structure. Then in 2015, Haussler and colleagues brought in Jarvis, a pioneer in deciphering the intricate neural circuits that let birds trill new tunes after listening to others' songs. Jarvis had already shown a knack for managing big, complex efforts. In 2014, he and more than a hundred colleagues sequenced the genomes of 48 bird species, which turned up new genes involved in vocal learning. "David and others asked me to take on leadership of the Genome 10K project," Jarvis recalls. "They felt I had the personality for it." Or, as Shapiro puts it: "Erich is a very pushy leader, in a nice way. What he wants to happen, he will make happen."Jarvis expanded and rebranded the Genome 10K idea to include all vertebrate genomes. He also helped launch a new sequencing center at Rockefeller that, together with one at the Max Planck Institute in Germany led by former HHMI Janelia Research Campus Group Leader Gene Myers, and another at the Sanger Institute in the UK led by Richard Durbin and Mark Blaxter, is currently producing most of the VGP genome data. He asked Adam Phillippy, a leading genome expert at the National Human Genome Research Institute (NHGRI), to Chair the VGP assembly team. Then, he found about 60 top scientists willing to use their own grant money to pay for the sequencing costs at the centers to tackle the genomes they were most interested in. The team also negotiated with the Māori in New Zealand and officials in Mexico to get kākāpō and vaquita samples in "a beautiful example of international collaboration," says Sadye Paez, program director of the VGP at Rockefeller.The massive team of researchers pulled off a series of technological advances. The new sequencing machines let them read DNA chunks 10,000 or more letters long, instead of just a few hundred. The researchers also devised clever methods for assembling those segments into individual chromosomes. They have been able to tease out which genes were inherited from the mother and the father. This solves a particularly thorny problem known as "false duplication," where scientists mistakenly label maternal and paternal copies of the same gene as two separate genes."I think this work opens a set of really important doors, since the technical aspects of assembly have been the bottleneck for sequencing genomes in the past," says Jenny Tung, a geneticist at Duke University, who was not directly involved with the research. Having high-quality sequencing data "will transform the types of question that people can ask," she says.The team's improved accuracy shows that previous genome sequences are seriously incomplete. In the zebra finch, for example, the team found eight new chromosomes and about 900 genes that had been thought to be missing. Previously unknown chromosomes popped up in the platypus as well, as members of the team reported online in That's just the start of what the The new information also may boost efforts to save rare species. "It is a critically important moral duty to help species that are going extinct," Jarvis says. That's why the team collected samples from a kākāpō parrot named Jane, part of a captive breeding program that has brought the parrot back from the brink of extinction. In a paper published in the new journal Cell Genomics, of the Cell family of journals, Nicolas Dussex at the University of Otago and colleagues described their studies of Jane's genes along with other individuals. The work revealed that the last surviving kākāpō population, isolated on an island off New Zealand for the last 10,000 years, has somehow purged deleterious mutations, despite the species' low genetic diversity. A similar finding was seen for the vaquita, with an estimated 10-20 individuals left on the planet, in a study published in Molecular Ecology Resources, led by Phil Morin at the National Oceanic and Atmospheric Administration Fisheries in La Jolla, California. "That means there is hope for conserving the species," Jarvis concludes.VGP is now focused on sequencing even more species. The project team's next goal is finishing 260 genomes, representing all vertebrate orders, and then snaring enough funding to tackle thousands more, representing all families. That work won't be easy, and it will inevitably bring new technical and logistical challenges, Tung says. Once hundreds or even thousands of animals readily found in zoos or labs have been sequenced, scientists may face ethical hurdles obtaining samples from other species, especially when the animals are rare or endangered.But with the new paper, the path ahead looks clearer than it has in years. The VGP model is even inspiring other large sequencing efforts, including the Earth Biogenome Project, which aims to decode the genomes of all eukaryotic species within 10 years. Perhaps for the first time, it seems possible to realize the dream that Haussler and many others share of reading every letter of every organism's genome. Darwin saw the enormous diversity of life on Earth as "endless forms most beautiful," Haussler observes. "Now, we have an incredible opportunity to see how those forms came about."
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April 28, 2021
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https://www.sciencedaily.com/releases/2021/04/210428094401.htm
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Study of marine noise highlights need to protect pristine Australian waters
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New Curtin research has found urgent action is needed to ensure man-made underwater noise in Australian waters does not escalate to levels which could be harmful to marine animals, such as whales, and negatively impact our pristine oceans.
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Lead author Professor Christine Erbe, Director of Curtin's Centre for Marine Science and Technology, said recent studies from the northern hemisphere showed man-made noise, in particular from ships, often dominates the underwater soundscape over large areas, such as entire seas, and could interfere with marine fauna that rely on sound for communication, navigation and foraging."When humans go to sea, they generate underwater noise, from boat and ship traffic, dredging, port construction, offshore exploration for oil and gas, offshore drilling, seafloor surveying, fishing and naval exercises, which impacts a wide variety of animals including, whales, dolphins, fishes and crustaceans," Professor Erbe said."We set out to measure and model underwater sound in Australia's maritime regions and found that on average, over the course of six months, ship noise dominated only in tightly localised regions or right under the major shipping routes when these are confined to a narrow channel or strip."In most of our waters, naturally generated underwater sound dominated and was mostly due to consistently strong winds blowing along Australia's southern coasts and strong whale and fish choruses."Professor Erbe said while these findings show the vast majority of Australian maritime waters were not as polluted by man-made noise as some northern hemisphere waters, action was required in order for it to remain that way."If you define 'pristine' as rich in biological sounds and their diversity, and devoid of man-made noise, then Australia has several regions, not just pockets, where the marine soundscape is undisturbed," Professor Erbe said."We need to set out and protect these regions by becoming more proactive in managing our marine environment.Usually we only become aware of an environmental problem when it's potentially too late, and find ourselves in a race to mitigate negative impacts. But in Australia, we have the opportunity to act early and protect healthy environments now."The research was funded by the Federal Government's National Environmental Science Program and the paper, 'It often howls more than it chugs: Wind versus ship noise under water in Australia's maritime regions' was published in
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Animals
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April 27, 2021
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https://www.sciencedaily.com/releases/2021/04/210427085749.htm
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Extinct 'horned' crocodile gets new spot in the tree of life
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A study led by scientists at the American Museum of Natural History has resolved a long-standing controversy about an extinct "horned" crocodile that likely lived among humans in Madagascar. Based on ancient DNA, the research shows that the horned crocodile was closely related to "true" crocodiles, including the famous Nile crocodile, but on a separate branch of the crocodile family tree. The study, published today in the journal
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"This crocodile was hiding out on the island of Madagascar during the time when people were building the pyramids and was probably still there when pirates were getting stranded on the island," said lead author Evon Hekkala, an assistant professor at Fordham University and a research associate at the American Museum of Natural History. "They blinked out just before we had the modern genomic tools available to make sense of the relationships of living things. And yet, they were the key to understanding the story of all the crocodiles alive today."The arrival of modern humans in Madagascar between about 9,000 and 2,500 years ago preceded the extinction of many of the island's large animals, including giant tortoises, elephant birds, dwarf hippos, and several lemur species. One lesser-known extinction that occurred during this period was that of an endemic "horned" crocodile, Voay robustus. Early explorers to Madagascar noted that Malagasy peoples consistently referred to two types of crocodiles on the island: a large robust crocodile and a more gracile form with a preference for rivers. This suggests that both types persisted until very recently, but only the gracile form, now recognized as an isolated population of the Nile crocodile (Crocodylus niloticus), is currently is found on the island.Despite nearly 150 years of investigation, the position of the horned crocodile in the tree of life has remained controversial. In the 1870s, it was first described as a new species within the "true crocodile" group, which includes the Nile, Asian, and American crocodiles. Then, in the early part of the 20th century, it was thought that the specimens simply represented very old Nile crocodiles. And finally, in 2007, a study based on physical characteristics of the fossil specimens concluded that the horned crocodile was actually not a true crocodile, but in the group that includes dwarf crocodiles."Teasing apart the relationships of modern crocodiles is really difficult because of the physical similarities," Hekkala said. "Many people don't even realize that there are multiple species of crocodiles, and they see them as this animal that's unchanging through time. But we've been trying to get to the bottom of the great diversity that exists among them."To fully examine the horned crocodile's place in the evolutionary tree, Hekkala and her collaborators at the Museum made a number of attempts to sequence DNA from fossil specimens, including two well-preserved skulls that have been at the Museum since the 1930s."This a project we've tried to do on and off for many years, but the technology just hadn't advanced enough, so it always failed," said study co-author George Amato, emeritus director of the Museum's Institute for Comparative Genomics. "But in time, we had both the computational setup and the paleogenomic protocols that could actually fish out this DNA from the fossil and finally find a home for this species."The results place the horned crocodile right next to the true crocodile branch of the evolutionary tree, making it the closest species to the common ancestor of the crocodiles alive today."This finding was surprising and also very informative to how we think about the origin of the true crocodiles found around the tropics today," Amato said. "The placement of this individual suggests that true crocodiles originated in Africa and from there, some went to Asia and some went to the Caribbean and the New World. We really needed the DNA to get the correct answer to this question."Video:
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Animals
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April 26, 2021
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https://www.sciencedaily.com/releases/2021/04/210426154816.htm
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Genetic discovery in songbird provides new insights
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New research reveals a genetic quirk in a small species of songbird in addition to its ability to carry a tune. It turns out the zebra finch is a surprisingly healthy bird.
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A study published today in the journal The function of LDLR, which is responsible for cellular uptake of LDL-bound cholesterol, or "bad cholesterol," has been thought to be conserved across vertebrates. OHSU scientists found that in the case of songbirds, key domains for the function of the receptor were lacking.Mutations like this are a genetic cause of severe high cholesterol and high risk for cardiovascular disease. Surprisingly, this has not resulted in high cholesterol for songbirds; they carry most of their cholesterol in high-density lipoprotein, HDL, or "good cholesterol.""These songbirds seem to have adapted to the LDLR changes and have developed a healthy cholesterol profile, or ratio of low to high cholesterol," said senior author Claudio Mello, M.D., Ph.D., professor of behavioral neuroscience in the School of Medicine at Oregon Health & Science University. "It suggests that songbirds may have some sort of protection from cardiovascular disease."In turn, the discovery could lead to a model to better understand -- and ultimately improve treatment -- for cardiovascular disease in people.This unsuspected difference genetic mutation also has implications for viral entry, cellular transport systems and, potentially, gene therapies.LDLR is also the main receptor for the G protein of vesicular stomatitis virus (VSV G) and are used to pseudotype, by coating, lentiviral vectors for gene manipulation in animals and gene therapy trials in humans. The lack of key functional domains in LDLR explains the low susceptibility of finches to lentiviruses, a family that includes HIV, pseudotyped with VSV-G. Besides the implications for improving gene manipulation tools in finches, this study illustrates the fascinating co-evolution and interplay between viral entry and basic cellular transport systems.The genetic discovery is part of a broader initiative to generate high quality genome sequences in a large number of animals. It was also part of a three-year initiative funded by the National Science Foundation enabling researchers at OHSU and other institutions to study the genetic makeup of zebra finches, an important model in neurobiology.The research was supported by funding from the Instituto Serrapilheira grant award 1709-17844; National Institutes of Health award R21OD028874; and National Science Foundation award 1645199.
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Animals
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April 23, 2021
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https://www.sciencedaily.com/releases/2021/04/210423130119.htm
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Travel paths of primates show how their minds work
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How primates get from A to B gives vital information about their cognitive evolution, say researchers in a new study looking at the travel paths of animals in the wild. Using data from 164 wild primate populations, the global survey examines the mental abilities that primates, including ourselves, use to know where and when to travel in the most efficient way.
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Co-author Miguel de Guinea, expert in Evolutionary Anthropology at Oxford Brookes University commented: "Imagine looking down on a huge outdoor market from high in the sky, perhaps from a drone hovering quietly above. The people below move in different ways. Some wander haphazardly among the stalls: they are learning what's available but are clearly not busy. Others take bee-line routes across the market to a destination they obviously wanted to reach, then, after buying what they need, head back in much the same way."If you could distinguish individuals, and watch them on many occasions, these patterns are likely to change, sometimes dependent on fruit and vegetables in season. We would also begin to learn about social aspects, as networks of repeated contacts show who is friendly with whom. We can get a good idea of people's knowledge, their needs, their ability to think ahead and how they learn over time -- just from watching their travel paths. The same observations have been made by the research team using data from GPS devices and in-field studies of wild primates, giving us fascinating information about their development."The original data was gathered from small GPS devices, used routinely in primate fieldwork: sometimes these are attached to the animals themselves, but in many studies a researcher follows the animals, usually noting a rich variety of background information on what they are doing and for how long.The international team developed a conceptual framework to highlight ways in which these data can be analysed. Currently, primate cognition is studied by comparing measures such as brain size, or conducting experiments with artificial problems to primates in captivity. The evidence from travel decision-making amongst wild populations will enhance these approaches and give a fuller picture of the cognitive development of these species.Lead-author Karline Janmaat from the University of Amsterdam said: "Our ultimate dream is to set up a consortium to support data sharing and collaboration among primatologists. Hopefully this attracts MSc and PhD students from around the world to share and compare their collected data to these existing datasets."The researchers say that further research is urgent, because so many species are now threatened with extinction in the wild. Since 1970, two-thirds of all vertebrate populations have been lost, and large, day-living animals like primates have been significantly impacted.Miguel de Guinea stressed: "Time is fast running out -- if we don't act now we may never be able to understand the drivers of cognitive evolution. By applying our research methodology and findings we can make use of previously collected valuable data from wild populations and apply that to our understanding of the cognitive evolution of primate species."The research Using natural travel paths to infer and compare primate cognition in the wild is published in
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Animals
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April 23, 2021
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https://www.sciencedaily.com/releases/2021/04/210423130106.htm
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Defense mechanisms in aphids can become a double-edged sword, sharpened by the seasons
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Evolution is unfolding in real time within many natural animal populations and researchers are now observing how this influences biodiversity in the field. In a newly published study in
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"We know that certain organisms have many generations in a season, and we know sometimes it just takes a handful of generations for evolution to unfold; and aphids are one of those types of organisms," explained Jacob A. Russell, PhD, a professor in the College of Arts and Sciences, and senior author on the study.Like many insects, aphids play host to symbiotic bacteria -- or endosymbionts -- in their blood and internal tissues. While their full range of impacts is not yet understood, these bacteria typically provide some defense against environmental pressures, like parasites and parasitoids -- parasites that kill their hosts. Hamiltonella defensa, the endosymbiont focused on in this study, for instance, wards off parasitoids in pea aphids. But these bacteria are also of interest to researchers because they are heritable -- passed on from females to their offspring."In essence, these bacteria are inherited like mitochondrial DNA and because of this, they can serve as part of the pea aphid's adaptive arsenal, acting alongside the many thousands of genes in this sap-feeding insect's genome," said Russell.Andrew Smith, PhD, a former Drexel graduate and current Rodale Institute Chief Scientist, led the research efforts that enabled the biologists to get a closer look at the natural forces shaping Hamiltonella prevalence. It was their hope that, through repeated field collections and routine molecular screening, they could shed light on the evolutionary forces affecting aphids in real time."We were motivated to try to understand why this one endosymbiont is maintained in these populations, why is it never lost and why it doesn't just go to 100% frequency," said Russell. "One idea is there must be some times when it helps the aphid, as well as times when it is slightly harmful."To supplement their aphid collection and endosymbiont screening, the field team studied a range of environmental variables within the same alfalfa fields, including the prevalence of Aphidius ervi, a parasitoid wasp introduced in the United States to control populations of the pea aphid, which was once a threat to crops, including alfalfa. The wasps kill aphids by laying eggs inside them. Intriguingly, Hamiltonella endosymbionts prevents young wasp development, but they also come with a cost, according to the researchers."There's this 'rent' that the aphid has to pay to the endosymbiont just to sustain its populations," said Russell. "In the lab, we initially thought the aphids with the endosymbiont would be worse off than the aphids that did not have the endosymbiont due to this 'rent' concept."This concept, that aphids with Hamiltonella endosymbionts were worse off than those without them in the absence of the wasps, was supported by prior lab experiments. But despite this expectation, the authors found no significant relationship between wasp prevalence and endosymbionts. But they did see aphid populations evolving over time -- with the endosymbiont's prevalence shifting rapidly, on several occasions. Correlating most clearly with these shifts was the temperature of the aphids' surrounding environment.Their results suggest "the cost of 'rent' is higher for aphids harboring these endosymbionts when it's cool," said Russell, who thinks "it's actually pretty useful for the aphids to have these endosymbionts when it's warm."The authors conclude that the endosymbiont's dynamics, and hence real time evolution of the pea aphid, likely result from an evolutionary phenomenon known as "balancing selection," which happens due to changing costs and benefits of harboring the endosymbiont at different temperatures.This would render Hamiltonella as a fair weather friend, useful when it's warm, and harmful when it's not. Though the mechanism of this seasonality remains undetermined, their results suggest that temperature could serve as a major factor in conjuring the occurrence of Hamiltonella endosymbionts in aphids.This discovery was only possible because the team made its observations in the field. "We tend to do our lab experiments in these pretty one-dimensional lab environments and temperature is held constant," said Russell, "so those lab findings might not be fully transferable,."This work provides one of the first examples of a study on seasonal insect adaptation that's enabled not by variation in insect genes, but by variation in their endosymbionts. As such, it is among the first to show that maternally transmitted microbes -- found in most insect species -- respond to the pendulum-like nature of changing environments across the seasons.Given the longer-term trends in global climate, it is possible, too, that endosymbionts may govern the future success of insect species in our rapidly warming world.
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Animals
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April 23, 2021
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https://www.sciencedaily.com/releases/2021/04/210423085724.htm
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Fossils of 'giant cloud rats' discovered in Philippine caves
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Rats, by and large, aren't terribly popular animals. But while you don't want an infestation of common black rats living in your house, their distant cousins in the Philippines are downright cuddly. These "giant cloud rats" live in the treetops of misty mountain forests, and they fill an ecological role occupied by squirrels in the US. And, it turns out, we have new evidence that they've been living in the Philippines for a long time -- scientists have discovered the fossils of three new species of giant cloud rats that lived alongside ancient humans.
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"Our previous studies have demonstrated that the Philippines has the greatest concentration of unique species of mammals of any country, most of which are small animals, less than half a pound, that live in the tropical forest," Larry Heaney, the Neguanee Curator of Mammals at Chicago's Field Museum and an author of a study in the "We have had evidence of extinct large mammals on the Philippine island of Luzon for a long time, but there has been virtually no information about fossils of smaller-sized mammals. The reason is probably that research had focused on open-air sites where the large fossil mammal faunas were known to have been preserved, rather than the careful sieving of cave deposits that preserve a broader size-range of vertebrates including the teeth and bones of rodents," says Janine Ochoa, an Assistant Professor of Archaeology at the University of the Philippines -- Diliman and the study's lead author.At the outset of the study, Ochoa was examining the fossil assemblages from caves in the Callao limestone formation, where a couple of years ago, scientists discovered the remains of an ancient species of humans, Homo luzonensis. "We were looking at the fossil assemblages associated with that hominin, and we found teeth and fragments of bone that ended up belonging to these new species of cloud rats," says Ochoa.The fossil fragments discovered by the excavation team in Callao Cave aren't the only traces of the cloud rats, though -- they were able to add to them some other fossils in the collections of the National Museum of the Philippines. "Some of these fossils were actually excavated decades ago, in the 1970s and 1980s, and they were in the museum, waiting for someone to have time to do a detailed study. When we began to analyze the fossil material, we were expecting fossil records for known living species. To our surprise, we found that we were dealing with not just one but three buot, or giant cloud rat species that were previously unknown," said Marian Reyes, a zooarcheologist at the National Museum of the Philippines, one of the study's authors.The researchers didn't have a ton of material to work with, though -- just fifty or so fragments. "Normally, when we're looking at fossil assemblages, we're dealing with thousands and thousands of fragments before you find something rare and really nice," says Ochoa. "It's crazy that in these fifty fragments, we found three new species that haven't been recorded before."The fragments that the researchers found were mostly teeth, which are covered in a hard enamel substance that makes them hardier than bone. From just a few dozen teeth and bits of bone, though, the researchers were able to put together a picture of what these animals were like in life, thanks to, in Heaney's words, "days and days and days staring through a microscope"By comparing the fossils to the 18 living species of giant cloud rats, the researchers have a decent idea of what these three new fossil species would have looked like."The bigger ones would have looked almost like a woodchuck with a squirrel tail," says Heaney. "Cloud rats eat plants, and they've got great big pot bellies that allow them to ferment the plants that they eat, kind of like cows. They have big fluffy or furry tails. They're really quite cute."The newly recorded fossil species came from Callao Cave, where Homo luzonensis was discovered in 2019, and several adjacent smaller caves in Penablanca, Cagayan Province. Some specimens of all three of the new fossil rodents occurred in the same deep layer in the cave where Homo luzonensis was found, which has been dated at about 67,000 years ago. One of the new fossil rodents is known from only two specimens from that ancient layer, but the other two are represented by specimens from that early date all the way up to about 2000 years ago or later, which means that they were resilient and persistent for at least 60,000 years. "Our records demonstrate that these giant rodents were able to survive the profound climatic changes from the Ice Age to current humid tropics that have impacted the earth over tens of millennia. The question is what might have caused their final extinction?" adds Philip Piper, a coauthor based at the Australian National University.Two of these giant rodents apparently disappeared about two thousand years ago, or soon after. "That seems significant, because that is roughly the same time that pottery and Neolithic stone tools first appear in the archeological record, and when dogs, domestic pigs, and probably monkeys were introduced to the Philippines, probably from Borneo. While we can't say for certain based on our current information, this implies that humans likely played some role in their extinction," says Armand Mijares, Professor in the Archaeological Studies Program at the University of the Philippines -- Diliman, who headed the excavations of Callao Cave."Our discoveries suggest that future studies that look specifically for fossils of small mammals may be very productive, and may tell us a great deal about how environmental changes and human activities have impacted the really exceptionally distinctive biodiversity of the Philippines," according to Ochoa. And such studies may also tell us a lot specifically about the impact of human activities, perhaps specifically including over-hunting, on biodiversity, notes Heaney. "This is something we need to understand if we are going to be effective in preventing extinction in the future."
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Animals
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April 22, 2021
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https://www.sciencedaily.com/releases/2021/04/210422181859.htm
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Hungry fruit flies are extreme ultramarathon fliers
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In 2005, an ultramarathon runner ran continuously 560 kilometers (350 miles) in 80 hours, without sleeping or stopping. This distance was roughly 324,000 times the runner's body length. Yet this extreme feat pales in comparison to the relative distances that fruit flies can travel in a single flight, according to new research from Caltech.
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Caltech scientists have now discovered that fruit flies can fly up to 15 kilometers (about 9 miles) in a single journey -- 6 million times their body length, or the equivalent of over 10,000 kilometers for the average human. In comparison to body length, this is further than many migratory species of birds can fly in a day. To discover this, the team conducted experiments in a dry lakebed in California's Mojave Desert, releasing flies and luring them into traps containing fermenting juice in order to determine their top speeds.The research was conducted in the laboratory of Michael Dickinson, Esther M. and Abe M. Zarem Professor of Bioengineering and Aeronautics and executive officer for biology and biological engineering. A paper describing the study appears in the journal The work was motivated by a longstanding paradox that was identified in the 1940s by Theodosius Dobzhansky and other pioneers of population genetics who studied Drosophila species across the Southwest United States. Dobzhansky and others found that fly populations separated by thousands of kilometers appeared much more genetically similar than could be easily explained by their estimates of how far the tiny flies could actually travel. Indeed, when biologists would release flies outdoors, the insects would often simply buzz around in circles over short distances, like they do in our kitchens.Did flies behave differently when out in the wild, in search of food? In the 1970s and '80s, a group of population geneticists attempted to address this paradox by coating hundreds of thousands of flies in fluorescent powder and releasing them one evening in Death Valley. Remarkably, the group detected a few fluorescent flies in buckets of rotting bananas up to 15 kilometers away the next day."These simple experiments raised so many questions," says Dickinson. "How long did it take them to fly there? Were they just blown by the wind? Was it an accident? I have read that paper many times and found it very inspiring. No one had tried to repeat the experiment in a way that would make it possible to measure whether the flies were carried by the wind, how fast they were flying, and how far they can really go."To measure how flies disperse and interact with the wind, the team designed "release and recapture" experiments. Led by former postdoctoral scholar Kate Leitch, the team made several trips to Coyote Lake, a dry lakebed 140 miles from Caltech in the Mojave Desert, with hundreds of thousands of the common lab fruit fly, Drosophila melanogaster, in tow.The aim was to release the flies, lure them into traps at set locations, and measure how long it took the insects to fly there. To do this, the team set up 10 "odor traps" in a circular ring, each located along a one-kilometer radius around the release site. Each trap contained a tantalizing cocktail of fermenting apple juice and champagne yeast, a combination that produces carbon dioxide and ethanol, which are irresistible to a fruit fly. The traps also each had a camera, and were constructed with one-way valves so that the flies could crawl into the trap toward the cocktail but not back out. In addition, the researchers set up a weather station to measure the wind speed and direction at the release site throughout each experiment; this would indicate how the flies' flight was affected by the wind.So as not to interfere with their flight performance, the team did not coat the flies with identifiers like fluorescent powder. So how did they know they were catching their own fruit flies? Before the release, the team first placed the traps and checked them over time, and found that although D. melanogaster are found at date farms within the Mojave, they are extremely rare at Coyote Lake.The flies released by the team had been originally collected at a fruit stand and then were raised in the lab, but they were not genetically modified in any way. The team performed the experiments after receiving permits from the Bureau of Land Management.At experiment time, the team drove the buckets of flies to the center of the circle of traps. The buckets contained plenty of sugar, so that the insects would be fully energized for their flight; however, they contained no protein, giving the flies a strong drive to search for protein-rich food. The team estimated that the flies would not be able to smell the traps from the center of the ring, forcing them to disperse and search.At a precise time, a team member at the center of the circle opened up the buckets simultaneously and quickly released the flies."The person who stayed at the center of the ring to open the lids off of all the buckets witnessed quite a spectacle," says Leitch. "It was beautiful. There were so many flies -- so many that you were overwhelmed by the whirring drone. A few of them would land on you, often crawling in your mouth, ears, and nose."The team repeated these experiments under various wind conditions.It took about 16 minutes for the first fruit flies to cover one kilometer to reach the traps, corresponding to a speed of approximately 1 meter per second. The team interpreted this speed as a lower limit (perhaps these first flies had buzzed around in circles a bit after release or did not fly in a perfectly straight line). Previous studies from the lab showed that a fully fed fruit fly has the energy to fly continuously for up to three hours; extrapolating, the team concluded that D. melanogaster can fly roughly 12 to 15 kilometers in a single flight, even into a gentle breeze, and will go further if aided by a tailwind. This distance is approximately 6 million times the average body length of a fruit fly (2.5 millimeters, or one tenth of an inch). As an analogy, this would be like the average human covering just over 10,000 kilometers in a single journey -- roughly the distance from the North Pole to the equator."The dispersal capability of these little fruit flies has been vastly underestimated. They can travel as far or farther than most migratory birds in a single flight. These flies are the standard laboratory model organism, but they are almost never studied outside of the laboratory and so we had little idea what their flight capabilities were," Dickinson says.In 2018, the Dickinson laboratory discovered that fruit flies use the sun as a landmark in order to fly in a straight line in search of food; flying aimlessly in circles could be deadly, so there is an evolutionary benefit to being able to navigate efficiently. After completing the release experiments described in this study, the team proposed a model that suggests that each fly chooses a direction at random, uses the sun to fly straight in that direction, and carefully regulates its forward speed while allowing itself to be blown sideways by the wind. This enables it to cover as much distance as possible and increases the probability that it will encounter a plume of odor from a food source. The team compared their model with traditional models of random insect dispersal and found that their model could explain the results of the desert releases more accurately because of the flies' propensity to maintain a constant heading once released.Even though D. melanogaster has been co-evolving with humans, this work shows that the fly brain still contains ancient behavioral modules. Dickinson explains: "For any animal, if you find yourself in the middle of nowhere and there's no food, what do you do? Do you just hop around and hope you find some fruit? Or do you say -- 'Okay, I'm going to pick a direction and go as far as I can in that direction and hope for the best.' These experiments suggest that that's what the flies do."The research has broader implications for the field of movement ecology, which studies how populations move around the world, essentially shifting biomass for other animals to eat. In fact, during their early pre-release experiments to check for local populations of Drosophila, the team several times caught an invasive species of fly, the spotted-wing Drosophila (Drosophila suzukii), which causes significant agricultural damage across the West Coast."We set up these traps in the middle of nowhere, not the Central Valley where there would be fields of food, and still we find these agricultural pests cruising through," says Dickinson. "It's kind of scary to see how far these introduced species can travel using simple navigational strategies."
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April 22, 2021
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https://www.sciencedaily.com/releases/2021/04/210422150405.htm
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Toxic masculinity: Y chromosome contributes to a shorter lifespan in male flies
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Males may have shorter lifespans than females due to repetitive sections of the Y chromosome that create toxic effects as males get older. These new findings appear in a study by Doris Bachtrog of the University of California, Berkeley published April 22 in
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In humans and other species with XY sex chromosomes, females often live longer than males. One possible explanation for this disparity may be repetitive sequences within the genome. While both males and females carry these repeat sequences, scientists have suspected that the large number of repeats on the Y chromosome may create a "toxic y effect" that shortens males' lives. To test this idea, Bachtrog studied male fruit flies from the species Drosophila miranda, which have about twice as much repetitive DNA as females and a shorter lifespan. They showed that when the DNA is in its tightly packed form inside the cells of young male flies, the repeat sections are turned off. But as the flies age, the DNA assumes a looser form that can activate the repeat sections, resulting in toxic side effects.The new study demonstrates that Y chromosomes that are rich in repeats are a genomic liability for males. The findings also support a more general link between repeat DNA and aging, which currently, is poorly understood. Previous studies in fruit flies have shown that when repeat sections become active, they impair memory, shorten the lifespan and cause DNA damage. This damage likely contributes to aging's physiological effects, but more research will be needed to uncover the mechanisms underlying repeat DNA's toxic effects.
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April 22, 2021
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https://www.sciencedaily.com/releases/2021/04/210422093835.htm
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Know your ally: Cooperative male dolphins can tell who's on their team
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When it comes to friendships and rivalries, male dolphins know who the good team players are. New findings, published in
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The Bristol researchers, with colleagues from the University of Zurich and University of Massachusetts, used 30 years of observational data from a dolphin population in Shark Bay, Western Australia, and sound playback experiments to assess how male dolphins responded to the calls of other males from their alliance network.Dr Stephanie King, Senior Lecturer from Bristol's School of Biological Sciences who led the research, said: "Social animals can possess sophisticated ways of classifying relationships with members of the same species. In our own society, we use social knowledge to classify individuals into meaningful groups, like sports teams and political allies. Bottlenose dolphins form the most complex alliances outside humans, and we wanted to know how they classify these relationships."Dr Simon Allen, Research Fellow at Bristol's School of Biological Sciences, who contributed to the study, added: "We flew drones above dolphin groups, recording their behaviour during the sound playbacks, tracking their movements underwater and revealing novel insights into how dolphins respond to the calls of other males in their network of allies."Males responded strongly to all of the allies that had consistently helped them out in the past, even if they weren't currently close friends. On the other hand, they didn't respond strongly to males who hadn't consistently helped them out in the past, even if they were friends. What this shows is that these dolphins form social concepts of 'team membership', categorizing allies according to a shared cooperative history.Dr King said: "Such concepts develop through experience and likely played a role in the cooperative behaviour of early humans. Our results show that cooperation-based concepts are not unique to humans, but also occur in other animal societies with extensive cooperation between non-kin."The study was funded by The Branco Weiss Fellowship -- Society in Science and the National Geographic Society.
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April 21, 2021
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https://www.sciencedaily.com/releases/2021/04/210421160031.htm
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Monkeys are less cuddly with each other when dealing with an infection, study finds
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Brandi Wren was studying social distancing and infections before masking tape marks appeared on the grocery store floor and plastic barriers went up in the post office.
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Wren, a visiting scholar in the Department of Anthropology at Purdue University, spent a year studying wild vervet monkey troops in South Africa, tracking both their social grooming behavior and their parasite load. Her results, some of which were published Wednesday (April 21) in With implications for both animal behavior and human health, Wren's results open new avenues for research and new ways to consider old research. Vervet monkeys share surprising similarities with humans. In addition to sharing more than 90% of human DNA -- something that is true of all primate species -- vervet monkeys have also been known to exhibit conditions more familiar in humans than in other animals, including anxiety and hypertension. Biologists have found that studying vervet monkey physiology, genetics and behavior can shed light on some aspects of human biology."We have so many behavioral similarities; the roots and nuances of social behavior tend to be similar across all of the primates, especially from monkeys to humans," Wren said. "This study shows some of those similarities down to, when we feel sick, we don't want to talk to anybody. 'You can rub my back, whatever, but I really want to be left alone.' We see a lot of similarities in how humans and monkeys interact within their own groups."Wild animals typically carry a nominal load of parasites. Biologists have long assumed that these infections are innocuous -- that they are asymptomatic and don't significantly affect either the animal's health or prospects. Even more interesting is that the parasites Wren was studying -- whipworm, or Trichuris -- are not parasites that are typically spread through social contact. These are gastrointestinal parasites that are usually spread through contaminated soil or substances in the environments. But Wren's research shows that they may be spread through social contact and that they can significantly affect an individual's social behavior."Infected individuals show a little bit of lethargy, but the interesting thing is that they still let other individuals groom them; they just don't groom others," Wren said. "They also don't cuddle with the other monkeys as much. It appears they just don't feel well."Wren and her team followed three troops of vervet monkeys, Chlorocebus pygerythrus, throughout their range in the Loskop Dam Nature Preserve in South Africa. By exhaustively cataloging individual monkeys' interactions and grooming habits and by cross-referencing that with infection information from fecal samples, Wren and her team were able to disentangle that monkeys infected with whipworm spent less time grooming other monkeys. They accepted grooming -- when it was offered -- but did not offer to groom their troop-mates back.Wren notes that this difference in behavior is not so stark that it is noticeable just by observing the monkeys. Only by rigorously observing grooming behavior, exhaustively studying fecal samples and analyzing those results in relation to each other, was Wren able to decode this relationship."There's no way we would have been able to tell which monkeys were infected just from observation," Wren said. "There are no other signs of the infection, other than the social behavior. And the change is often so hard to detect. It takes following one individual for a substantial time and collecting the data to see it. The effect is hidden in this complex web of interactions."Wren posits that her discovery is important for animal researchers to bear in mind. As studies of animal personalities begin to gain popularity, she stressed the importance of incorporating information like parasite load and hormone profiles into those studies. Otherwise, biologists might misattribute behaviors to personality traits when really the culprit is an active infection."There are some individuals you watch and you think, 'Gosh, this guy is such a jerk! He always lets everybody groom him, but he doesn't groom anybody else!'" Wren said. "What we're attributing to personality or attitude could just be because he has a gut full of parasites."Wren draws parallels between the troop's behavior and human behavior during the pandemic. Like the monkeys, humans crave social contact, though more in the form of handshakes, high-fives and hugs. Like the monkeys, humans can spread diseases through social contact and tend to withdraw a bit during an illness. Unlike the monkeys, however, humans understand about contagion, about hygiene and about the importance of reducing contact or increasing cleanliness."All these social behaviors affect health on a practical level," Wren said. "We know COVID-19 is spread through close social contact. A fascinating thing about studying other species, and one reason to observe and understand them, is that we are always learning new things. There is always more to learn. Even when we're looking at previous research, even when we thought we understood the results, we still may not know the whole picture."
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April 21, 2021
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https://www.sciencedaily.com/releases/2021/04/210421092555.htm
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Camera traps find endangered dryas monkeys
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The Endangered dryas monkey (
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Using non-invasive research and no-flash camera traps from 2014 to 2019, scientists from Florida Atlantic University in collaboration with researchers from the FZS-Lomami Project, Democratic Republic of the Congo, now have picture-perfect details on this elusive species. They have confirmed the occurrence of the dryas monkey at seven locations in both Lomami National Park and its buffer zone spanning a total area of 3,453 square kilometers, based on opportunistic reports provided by local village residents and park patrols.Their findings, published in Although camera traps -- a method for capturing wild animals on film when researchers are not present -- are widely used to detect and survey cryptic species, the FAU scientists had to develop specific camera trap methods and placements to reliably detect the dryas monkeys.Daniel Alempijevic, M.S., first author and a doctoral student at FAU, and Kate Detwiler, Ph.D., senior author and an associate professor in the Department of Anthropology in FAU's Dorothy F. Schmidt College of Arts and Letters, developed a species-specific multi-strata (0 to 29 meters) camera-trap technique to detect the species with a placement of three camera traps at each survey point, one each monitoring the ground, understory and canopy.Alempijevic positioned the camera traps on game paths (0.2 to 0.5 meters above ground), shrubs and liana tangles (1.5 to 10 meters), and horizontal limbs (14.9 to 29 meters) forming pathways to adjacent tree crowns. He used a single rope technique to access the canopy, and a double-rope technique to move to the desired camera-trap location when needed. With the solicited information on the dryas monkeys from the residents of villages, he selected specific sites for camera-trap surveillance."We selected Bafundo Forest in the buffer zone for camera-trap surveillance, starting at the location where the first reported dryas monkey was killed by a hunter," said Detwiler. "We established the second survey site 40 kilometers west of Bafundo Village, at Camp Bartho in Lomami National Park after a ranger patrol team saw a dryas monkey there in 2014."Camera traps accumulated 1,742 trap days on the ground, 2,821 trap days in the understory and 2,927 trap days in the canopy. Understory camera traps recorded 32 dryas monkey events, canopy camera traps detected a single event, and dryas monkeys were not detected by camera traps at ground level. The cameras that detected the species most frequently were those in the lower strata of the canopy and understory, at 2 to 10 meters above ground. At least 365 trap days are required to achieve a 95 percent detection probability, although dryas monkeys may be detected sooner in suitable habitats."Our camera-trap placements detected dryas monkeys almost exclusively in the understory across all surveys, regardless of canopy structure, which supports our hypothesis that the species appear to prefer structurally complex understories and forest edges," said Alempijevic. "Because our camera traps on the ground did not detect dryas monkeys, it seems unlikely that they travel on the ground. Only one camera trap in the canopy detected a dryas monkey, suggesting that they rarely travel in the upper canopy."The researchers note that high heterozygosity and low inbreeding measures from genomic analysis of a hunter-killed dryas monkey (collected on Oct. 26, 2014) from Bafundo Forest suggest that it was a representative of a larger contiguous population."We recommend that researchers and conservationists working in the central basin of the Democratic Republic of the Congo mobilize local knowledge to identify other areas where the dryas monkey occurs and confirm any reports using our species-specific camera-trap placement technique," said Detwiler.Study co-authors are John A. Hart, Ph.D., and Terese B. Hart, Ph.D., Frankfurt Zoological Society, FZS-Lomami Project, Democratic Republic of the Congo.L'Institut Congolais pour la Conservation de la Nature granted research permission to work in Lomami National Park. The local chiefs of Bafundo, Likandjo and Bote villages and the Balanga sector chief of Maniema Province granted permission to access the forest.Funding for this research was generously provided by the Margot Marsh Biodiversity Foundation, Mohammed Bin Zayed Species Conservation Fund, FAU, Primate Conservation Incorporated, the Lukuru Foundation, International Primatological Society, Dynamic Youth Community and Indigogo crowd funding.
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April 20, 2021
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https://www.sciencedaily.com/releases/2021/04/210420121451.htm
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Chickens and pigs with integrated genetic scissors
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Researchers at the TUM have demonstrated a way to efficiently study molecular mechanisms of disease resistance or biomedical issues in farm animals. Researchers are now able to introduce specific gene mutations into a desired organ or even correct existing genes without creating new animal models for each target gene. This reduces the number of animals required for research..
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CRISPR/Cas9 is a tool to rewrite DNA information. Genes can be inactivated or specifically modified using this method. The CRISPR/Cas9 system consists of two components.The gRNA (guide RNA) is a short sequence that binds specifically to the DNA segment of the gene that is to be modified. The Cas9 nuclease, the actual "gene scissors," binds to the gRNA and cuts the respective section of the target DNA. This cut activates repair mechanisms that can inactivate gene functions or incorporate specific mutations."The generated animals provide the gene scissors, the Cas9 protein, right along with them. So all we have to do is to introduce the guide RNAs to get animals which have specific genetic characteristics," explains Benjamin Schusser, Professor of Reproductive Biotechnology at the TUM. "The initial generation of these animals took about three years. Cas9 can now be used at all stages of animal development, since every cell in the body permanently possesses the Cas9 protein. We have been successfully able to utilize this technique in chicken embryos as well as in living pigs."The healthy chickens and pigs produced by the researchers thus possess the Cas9 nuclease in all organs studied. This is particularly useful in biomedical and agricultural research.Pigs are used as disease models for humans because their anatomy and physiology are much more similar to humans in comparison to mice (currently a common disease model). Thus, a modified pig may help to better understand the mechanism of carcinogenesis in humans. Potential new treatments for humans can also be tested in animal models."Due to the presence of Cas9 in the cells the processes are significantly accelerated and simplified," says Angelika Schnieke, Professor of Livestock Biotechnology at the TUM. "Cas9-equipped animals make it possible, for example, to specifically inactivate tumor-relevant genes and to simulate cancer development."Cas9 pigs and chickens enable researchers to test which genes might be involved in the formation of traits, such as disease resistance, directly in the animal. "The mechanism of the CRISPR/Cas9 system may also be useful for combating infections using DNA viruses. Initial cell culture experiments showed that this already works for the avian herpes virus," says Prof. Schusser.Prof. Schnieke notes, "Our Cas9-expressing chickens and pigs represent an innovative resource for genome editing in the biomedical and agricultural sciences, but beyond that, these animals are also available to other research groups. Hence, efficient genome editing in living animals has the potential to significantly advance biomedical and agricultural research."
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Animals
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April 19, 2021
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https://www.sciencedaily.com/releases/2021/04/210419195312.htm
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Snake venom complexity is driven by prey diet
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Diversity in diet plays a role in the complexity of venom in pit vipers such as rattlesnakes, copperheads and cottonmouths.
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But new collaborative research by Clemson University scientists found the number of prey species a snake ate did not drive venom complexity. Rather, it was how far apart the prey species were from each other evolutionarily."It's not just diet that drives the variation in venom across snakes. It's the breadth of diet," said Christopher Parkinson, a professor in the College of Science's Department of Biological Sciences. "If a snake eats 20 different species of mammals, its venom will not be very complex. But if it eats a centipede, a frog, a bird and a mammal, it's going to have a highly complex venom because each component of that venom is affecting something different in one of the different animals the snake is feeding upon."The journal The research could lead to better anti-venoms and serve as a dietary database for other snake researchers."Snakebite is a neglected tropical disease. It doesn't kill many people in the U.S., only around eight per year. But it causes lasting injury such as neurological and tissue damage. Even though we have good anti-venoms, they could certainly be better. We have produced a library of the venoms of all the species in the U.S. in a higher level of detail than has been done before, so somebody else who is interested in improving anti-venoms could use this information," said Matthew Holding, a former Clemson postdoctoral researcher who is the lead author of the paper.Holding collaborated with researchers from Clemson, Florida State University, Mexico and Brazil to study the venoms and diets of 46 species of North American pit vipers, including all that live in the United States. They next used information about the diets of those species to understand why some venoms are simple and others are very complex.Venoms contain proteins that collectively function to incapacitate prey. The number of different proteins it contains reflects its complexity."You can think of venom as a snake's toolbox," said Holding, who is now a National Science Foundation Postdoctoral Research Fellow at Florida State. "A wrench, a socket and a screwdriver each have a different use. Likewise, each protein has a different function when the venom is injected into a mouse, lizard or centipede or whatever prey the snake is eating.""Some snakes have much simpler venoms with fewer components. Some have many more. We wanted to understand, from an evolutionary standpoint, why that might be, Holding explained."Researchers collected venom and venom gland samples from rattlesnakes and cottonmouths across North America. They used next-generation sequencing techniques to generate the largest dataset of proteomes and venom-gland transcriptomes for viperid snakes to date.Using natural history specimens, researchers compared venom complexity to snake species' diets."Having a prey database based on natural history specimens was paramount because we could not have done this work without those museum collections. We could not have built a comparative phylogenetic framework to compare snakes' diet and evolutionary history without them," said Parkinson, who has a dual appointment in the College of Agriculture, Forestry and Life Science's Department of Forestry and Environmental Conservation.Holding said venom complexity changes in association with the phylogenetic diversity of snake diets, with the evolution of both simpler and more complex venoms. The study shows the amount of divergence among prey species matters for the evolution of targeted venoms, rather than only differences among prey species or major taxonomic groups, regardless of how they are phylogenetically related.Some previous studies have hinted that diet probably caused variation in venom across snakes using coarse data. This project utilized venom gland genetic data for more than 250 individual snakes, a denser sampling that any other study to date. The researchers also compiled a detailed prey item database. Combining these data facilitated understanding of the cause of venom variation."Because we use next-generation sequencing tools, we could do more than counting up the number of components in the venom. We could get much closer to the genetic sequences that are contributing to this trait in these taxa, which had not been done before," Holding said.The study showed that diet diversity predicts expressed complexity in three of the four largest venom gene families in viper venoms. Serine proteases, metalloproteinases and phospholipases had a positive relationship, meaning the more diverse the snake's diet, the more complex its venom. But diet did not have the same effect on c-type lectins. Diet diversity accounts for between 25 and 40 percent of variation in venom complexity."We generated new questions for other researchers to tackle, such as why c-type lectins follow a different pattern of relationship to diet diversity than other gene families and what explains the remaining three-fourths of variation in venom complexity for which we are unable to account," Holding said.Since snake venom-derived drugs are used to treat heart disease, high blood pressure and blood clots in humans, the better scientists understand venom, the more likely they can use it to create human medicines."We see the downstream potential for medical or therapeutic uses. But what gets us excited is asking, 'Why there are so many types of snakes in the first place, and within those snakes, why are there so many types of venom that have so many effects on either prey or people?' " Holding said.This project was supported by the National Science Foundation and the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo. The content is solely the authors' responsibility and does not necessarily represent the official views of the supporting organizations.
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April 19, 2021
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https://www.sciencedaily.com/releases/2021/04/210419135728.htm
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SARS-CoV-2 variants from minks evade inhibition by antibodies
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It has been known for about a year that minks can become infected with SARS-CoV-2. The virus had been transmitted from humans to farmed mink and mutated in infected animals. Mutations were acquired in the spike protein, which is crucial for the entry of the virus into host cells and represents the central point of attack for antibodies. These SARS-CoV-2 variants from mink were transmitted back to humans, raising concerns that minks could be a continuing source of infection of humans with SARS-CoV-2 variants with altered biological properties.
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Researchers at the German Primate Center (DPZ) -- Leibniz Institute for Primate Research in Göttingen, Germany, have now shown that an antibody used for COVID-19 therapy is unable to effectively inhibit SARS-CoV-2 harboring a spike mutation acquired in minks. In addition, the mutation reduced the inhibition of the virus by antibodies produced in SARS-CoV-2 infected humans. These results show that SARS-CoV-2 can acquire mutations in minks that may reduce control of the virus by the human immune system (More than three million people have died worldwide from the pandemic spread of SARS coronavirus-2 and its associated disease COVID-19, according to the World Health Organization (WHO). Animal-to-human transmission of the virus is believed to be the origin of the pandemic, which began in Wuhan, China, in December 2019. In April 2020, mink in Dutch mink farms developed a respiratory disease due to infection with SARS-CoV-2, which was transmitted from infected farm workers to the animals. The virus mutated in mink and different virus variants emerged, which were transmitted back to farm workers and then also transmitted from human to human. This observation was also made in Denmark and millions of minks were killed to prevent the transmission of new viral variants to humans.The spike protein in the envelope of SARS-CoV-2 is responsible for the entry of the virus into cells in which it replicates. Researchers led by Markus Hoffmann and Stefan Pöhlmann of the German Primate Center have studied mutations detected in the spike protein of SARS-CoV-2 from mink, including mutation Y453F. The researchers wanted to find out whether this mutation affects inhibition of the virus by antibodies that are used for COVID-19 therapy or are produced in COVID-19 patients."Our results show that one of two antibodies from an antibody cocktail used for COVID-19 therapy no longer efficiently inhibits the viral variant with the Y453F mutation. Furthermore, our study demonstrates that the Y453F mutation reduces inhibition of the virus by antibodies produced by COVID-19 patients. This means that people who were infected with SARS-CoV-2 may have reduced protection against mink variants of the virus," says Markus Hoffmann, first author of the study. In sum, SARS-CoV-2 can mutate in minks in a way that reduces immune control by antibodies. Whether this is also possible in other animals to which the virus can be transmitted by infected individuals is currently unclear. "In the meantime, the Y453F mutation has also occurred in humans, but not through infection with a mink variant. When the virus replicates for a long time in people who are immunocompromised, resistant variants can emerge. In this case, the resistance-mediating mutation was identical to the one observed in mink," says Stefan Pöhlmann.
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Animals
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April 19, 2021
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https://www.sciencedaily.com/releases/2021/04/210419135714.htm
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Stone Age black bears didn't just defecate in the woods - they did it in a cave too
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Scientists have sequenced ancient DNA from soil for the first time and the advance will transform what is known about everything from evolution to climate change.
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The findings have been described as the 'moon landings' of genomics because researchers will no longer have to rely on finding and testing fossils to determine genetic ancestry, links and discoveries -- and it is thanks to Stone Age black bears who defecated in a remote cave in Mexico 16,000 years ago.A team of scientists from The Lundbeck Foundation GeoGenetics Centre, University of Copenhagen, led by Professor Eske Willerslev, director of the foundation and a Fellow of St John's College, University of Cambridge, recreated the genomes of animals, plants and bacteria of microscopic fragments of DNA found in Chiquihuite Cave.The results, which have been published today (April 19 2021) in This 'scientific first' has wider significance as it increases scientists' ability to study the evolution of animals, plants and microorganisms, which has been hailed as the dawn of an 'entirely new era' of population genetics. The work was possible as a result of advanced technology and understanding over the past five years.This is because working with highly fragmented DNA from soil samples means scientists no longer have to rely on DNA samples from bone or teeth for enough genetic material to recreate a profile of ancient DNA, which opens up the field to what can be tested and studied.The samples included faeces and droplets of urine from an ancestor of North America's most familiar and common bear -- the American black bear -- which allowed scientists to recreate the entire genetic code of two species of the animal. The first is the Stone Age American black bear, the second is an extinct short-faced bear called Arctodus simus which died out 12,000 years ago.Professor Willerslev said: "When an animal or a human urinates or defecates, cells from the organism are also excreted. And the DNA fragments from these cells are what we can detect in the soil samples. Using extremely powerful sequencing techniques, we reconstructed genomes -- genetic profiles -- based on these fragments for the first time. We have shown that hair, urine and faeces all provide genetic material which, in the right conditions, can survive for much longer than 10,000 years."All over the world, everyone scientifically involved in the study of ancient DNA recognised the need to reconstruct genomes from fragments found in soil or sediment. Being able to do that for the first time means we have opened up a new frontier. Analysis of DNA found in soil could have the potential to expand the narrative about everything from the evolution of species to developments in climate change -- this is the moon landing of genomics because fossils will no longer be needed."Chiquihuite Cave, where the samples were taken from, is a high-altitude site, 2,750 metres above sea level. Nearly 2,000 stone tools and small tool fragments, known as flakes, were discovered.The same group of scientists revealed last year that DNA analysis of the plant and animal remains from the sediment packed around the tools in the cave dates the tools and the human occupation of the site to 25,000-30,000 years ago -- 15,000 years earlier than people were previously thought to have reached the Americas. Human DNA has not yet been found.DNA of mice, black bears, rodents, bats, voles and kangaroo rats was found and the genome of the two species of bear has now been sequenced. The huge predatory short-faced bear, which also lived in North America, stood at nearly two metres just on all fours and could weigh up to 1,000 kilos.Assistant Professor Mikkel Winther Pedersen, first author of the paper, said: "The short-faced bears that lived in northern Mexico were distinctly different from the population of black bears living in north-western Canada. This is an excellent example of the new knowledge that suddenly becomes available when you reconstruct genomes based on DNA fragments extracted from soil."Professor Pedersen described the new sequencing as 'the dawn of an entirely new era' of population genomics.He said: "Studies of ancient environmental DNA have been very limited until now. Fragmented DNA from a soil sample could only tell us whether a specific species lived in a certain locality at a certain time, but it gave us no concrete details about the individual in question."So, we couldn't compare this individual with present-day individuals of the same species. But we can now. We have published for the first time a DNA profile of an American black bear that lived in a mountain cave in northern Mexico in the Stone Age. I'm not exaggerating when I say that the potential to extract this type of information from a soil sample of a mere few grams will revolutionise our field."Fragments in sediment will be able to be tested in many former Stone Age settlements around the world.Professor Willerslev added: "Imagine the stories those traces could tell. It's a little insane -- but also fascinating -- to think that, back in the Stone Age, these bears urinated and defecated in the Chiquihuite Cave and left us the traces we're able to analyse today."
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April 19, 2021
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https://www.sciencedaily.com/releases/2021/04/210419110140.htm
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What does the study of domesticated birds tell us about the evolution of human language?
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Language is one of the most notable abilities humans have. It allows us to express complex meanings and transmit knowledge from generation to generation. An important question in human biology is how this ability ended up being developed, and researchers from the universities of Barcelona, Cologne and Tokyo have treated this issue in a recent article.
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Published in the journal The study is based on evidence from diverse fields such as archaeology, evolutionary genomics, neurobiology, animal behaviour and clinical researcher on neuropsychiatric disorders. With these, it shows that the reduction of reactive aggressiveness, resulting from the evolution and process of self-domestication of our species, could have led to an increase in the complexity of speech. According to the authors, this development would be caused by the lowest impact on brain networks of stress hormones, neurotransmitters that activate in aggressive situations, and which would be crucial when learning to speak. To show this interaction, researchers analysed the genomic, neurobiological and singing-type differences between the domesticated Bengalese finch and its closest wild relative.A central aspect of the approach of the authors regarding the evolution of the language is that the aspects that make it special can be elucidated by comparing them to other animals' communication systems. "For instance, see how kids learn to talk and how birds learn to sing: unlike most animal communication systems, young birds' singing and the language of kids are only properly developed in presence of adult tutors. Without the vocal support from adults, the great range of sounds available for humans and singing birds does not develop properly," note researchers.Moreover, although speaking and bird singing evolved independently, authors suggest both communication systems are associated with similar patterns in the brain connectivity and are negatively affected by stress: "Birds that are regularly under stress during their development sing a more stereotypical song as adults, while children with chronic stress problems are more susceptible to developing repetitive tics, including vocalizations in the case of Tourette syndrome."In this context, Kazuo Okanoya, one of the authors of the article, has been studying the Bengalese finch (Lonchura striata domestica) for years. This domesticated singing bird sings a more varied and complex song than its wild ancestor. The study shows that the same happens with other domesticated species: the Bengalese finch has a weakened response to stress and is less aggressive than its wild relative. In fact, according to the authors, there is more and more "evidence of multiple domesticated species to have altered vocal repertoires compared to their wild counterparts."For the researchers, these differences between domestic and wild animals are "the central pieces in the puzzle of the evolution of human language," since our species shares with other domestic animals particular physical changes related to their closest wild species. Modern humans have a plain face, a round skull and a reduced size of teeth compared to our extinct archaic relatives, Neanderthals. Domestic animals have comparable changes in facial and cranial bone structures, often accompanied by the development of other traits such as skin depigmentation, floppy ears and curly tails. Last, modern humans have marked reductions in the response measures to stress and reactive aggression compared to other living apes. These similarities do not stop with physical since, according to researchers, the genomes of modern humans and multiple domesticated species show changes focused on the same genes.In particular, a disproportionate number of these genes would negatively regulate the activity of the glutamate neurotransmitter system, which drives the brain's response to stressful experiences. Authors note that "glutamate, the brain's main excitatory neurotransmitter, dopamine, in learning birdsong, aggressive behaviour, and the repetitive vocal tics of Tourette syndrome."In the study, authors show how the activity of glutamate tends to promote the release of dopamine in the striated body, an evolutionary old brain structure important for learning which is based on rewards and motor activities. "In adult songbirds, the increase in dopamine release in this striatal area is correlated to the learning of a more restricted song, which replaces experimental vocalizations typical of young birds." "Regarding human beings and other mammals -authors add-, dopamine release in the dorsal striatum promotes restrictive and repetitive motor activities, such as vocalizations, while other more experimental and exploratory behaviours are supported by the dopaminergic activity of the ventral striatum." According to the study, many of the involved genes in the glutamatergic activation that changed in the recent human evolution, codify the signalling of receptors that reduce the excitation of the dorsal striatum. That is, these reduce the dopamine release in this area. Meanwhile, these receptors tend not to reduce, and even promote, the dopamine release in ventral striatal regions.The authors say these alterations in the balance of stress hormones in the striated body were an important advance in the evolution of vocal speech in the lineage of modern humans. "These results suggest the glutamate system and its interactions with dopamine are involved in the process in which humans acquired their varied and flexible ability to speak. Therefore, the natural selection against reactive aggressiveness that took place in our species would have altered the interaction of these neurotransmitters promoting the communicative skills of our species. These findings shed light on new ways for comparative biological research on the human ability of speech" conclude researchers.
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April 19, 2021
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https://www.sciencedaily.com/releases/2021/04/210419095130.htm
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Where's my horse-sized rabbit?
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Next to cat videos, watching small and cuddly rabbits is probably one of the most popular internet pastimes. Plus they appear in literature as well as in traditional folklore spanning numerous cultures, thanks likely to the fact that rabbits reside on every continent except Antarctica.
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Yet despite their ubiquity, lagomorphs -- including rabbits, hares, and pikas -- are rather limited in their size diversity. Compare this to their evolutionary sisters, the rodents, which vary in size from the four-gram pygmy mouse to capybaras weighing as much as 50 kilograms.So why don't we see rabbits rivaling the sizes of horses?To answer this question, a research team led by Kyoto University's Primate Research Institute investigated the fossil record and evolutionary history of lagomorphs. In a study in the journal "The largest living wild lagomorphs weigh only about 5 kg on average, a tenth of the largest living rodent, the capybara," says first author Susumu Tomiya."But some breeds of domestic rabbits and other extinct species can weigh up to 8 kg. We were surprised by this, and so began to investigate what sort of external forces keep wild lagomorphs across the world from evolving larger body sizes."The scientists began by analyzing ecological factors, discovering that the body sizes of ungulates -- hoofed animals -- are the most influential predictor."We next compared how much energy is used by populations of lagomorphs and ungulates relative to their body sizes," continues Tomiya, "finding that lagomorphs weighing more than six kilograms are energetically at a competitive disadvantage to ungulates of the same size."The team lastly went through the lagomorph fossil record in North America, discovering that the best predictor for maximum body size was that of the smallest contemporaneous ungulate."We see this pattern today across numerous eco-regions, suggesting that there is an evolutionary 'ceiling' placed on lagomorphs by their ungulate competitors," explains Tomiya.These findings suggest that competitive biotic processes can play an important role in shaping the evolutionary history of mammalian orders, acting in hand with abiotic processes such as changes in climate."An ongoing debate in evolutionary biology concerns whether biological or environmental processes are more important in shaping biological diversity," states Tomiya, "as characterized by the 'red queen' and 'court jester' hypotheses.""For some time, the court jester model -- ascribing diversity to abiotic forces such as the climate -- has been dominant, due to the difficulty of studying biological interactions in the fossil record."The team's results show that biotic interactions do play an important role in guiding the evolutionary trajectories of some species, within the larger context of abiotic influences.
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April 15, 2021
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https://www.sciencedaily.com/releases/2021/04/210415142623.htm
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How many T. rexes were there? Billions
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How many
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That's a question Charles Marshall pestered his paleontologist colleagues with for years until he finally teamed up with his students to find an answer.What the team found, to be published this week in the journal What few paleontologists had fully grasped, he said, including himself, is that this means that some 2.5 billion lived and died over the approximately 2 1/2 million years the dinosaur walked the earth.Until now, no one has been able to compute population numbers for long-extinct animals, and George Gaylord Simpson, one of the most influential paleontologists of the last century, felt that it couldn't be done.Marshall, director of the University of California Museum of Paleontology, the Philip Sandford Boone Chair in Paleontology and a UC Berkeley professor of integrative biology and of earth and planetary science, was also surprised that such a calculation was possible."The project just started off as a lark, in a way," he said. "When I hold a fossil in my hand, I can't help wondering at the improbability that this very beast was alive millions of years ago, and here I am holding part of its skeleton -- it seems so improbable. The question just kept popping into my head, 'Just how improbable is it? Is it one in a thousand, one in a million, one in a billion?' And then I began to realize that maybe we can actually estimate how many were alive, and thus, that I could answer that question."Marshall is quick to point out that the uncertainties in the estimates are large. While the population of "As Simpson observed, it is very hard to make quantitative estimates with the fossil record," he said. "In our study, we focused in developing robust constraints on the variables we needed to make our calculations, rather than on focusing on making best estimates, per se."He and his team then used Monte Carlo computer simulation to determine how the uncertainties in the data translated into uncertainties in the results.The greatest uncertainty in these numbers, Marshall said, centers around questions about the exact nature of the dinosaur's ecology, including how warm-blooded "Our calculations depend on this relationship for living animals between their body mass and their population density, but the uncertainty in the relationship spans about two orders of magnitude," Marshall said. "Surprisingly, then, the uncertainty in our estimates is dominated by this ecological variability and not from the uncertainty in the paleontological data we used."As part of the calculations, Marshall chose to treat The issue of This possibility is supported by a recent study, led by evolutionary biologist Felicia Smith of the University of New Mexico, which hypothesized that the absence of medium-size predators alongside the massive predatory The UC Berkeley scientists mined the scientific literature and the expertise of colleagues for data they used to estimate that the likely age at sexual maturity of a From these estimates, they also calculated that each generation lasted about 19 years, and that the average population density was about one dinosaur for every 100 square kilometers.Then, estimating that the total geographic range of With such a large number of post-juvenile dinosaurs over the history of the species, not to mention the juveniles that were presumably more numerous, where did all those bones go? What proportion of these individuals have been discovered by paleontologists? To date, fewer than 100 "There are about 32 relatively well-preserved, post-juvenile "If we restrict our analysis of the fossil recovery rate to where Marshall expects his colleagues will quibble with many, if not most, of the numbers, but he believes that his calculational framework for estimating extinct populations will stand and be useful for estimating populations of other fossilized creatures."In some ways, this has been a paleontological exercise in how much we can know, and how we go about knowing it," he said. "It's surprising how much we actually know about these dinosaurs and, from that, how much more we can compute. Our knowledge of The framework, which the researchers have made available as computer code, also lays the foundation for estimating how many species paleontologists might have missed when excavating for fossils, he said."With these numbers, we can start to estimate how many short-lived, geographically specialized species we might be missing in the fossil record," he said. "This may be a way of beginning to quantify what we don't know."
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April 15, 2021
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https://www.sciencedaily.com/releases/2021/04/210415133144.htm
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Forest elephants are now critically endangered -- here's how to count them
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A team of scientists led by the Wildlife Conservation Society (WCS) and working closely with experts from the Agence Nationale des Parcs Nationaux du Gabon (ANPN) compared methodologies to count African forest elephants (
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Contrary to savannah elephants (Said the study's lead author, Alice Laguardia of WCS's Gabon Program: "The more accurately we can count forest elephants, the more we can measure whether conservation efforts are successful. We are hopeful that the results of this study will help governments and conservation partners protect this Critically Endangered species throughout its range."Researchers assessed the performance of the methodologies to three relatively large forest elephant populations in Gabon. They found that the SCR method that used DNA sampling of dung was comparable in accuracy to the line transect method but less expensive on larger scales.Stephanie Bourgeois, coauthor and geneticist at ANPN, said: "Testing of this new DNA approach has been made possible by the recent development of novel genetics techniques by ANPN and the creation of a new genetics lab in Gabon enabling to perform all DNA analyses in-country."SCR Camera trap surveys were more precise on smaller scales but more expensive. The authors recommend that the use of both SCR methods, and their development, continue. They say that future findings and improvements should be compiled across studies to ensure their robust evolution as an option for monitoring the African forest elephant across its range and inform strategies and action for its conservation.Forest elephants have been decimated by ivory poachers in recent years. A WCS-led census released in 2014 documented a 65 percent decline in forest elephant numbers between 2002 and 2013. Through this new study, researchers will gain a better understanding of how many forest elephants remain and where they reside. Efforts have been focused on Gabon as it is thought to harbor more than 50 percent of the remaining forest elephant population, despite accounting for less than 15 percent of the species' range, making Gabon the most important country for forest elephant conservation."As long as ivory is a precious commodity, elephants will be at risk," said Lee White, the Gabonese Minister of Water, Forests, the Seas, the Environment, charged with Climate Change & Land Use Planning. "In Africa there is a clear link between environmental governance, peace and security. Countries that have lost their elephant populations have all too often descended into civil strife. Through the results of this study we hope to obtain a clear picture of the trend of poaching and elephant populations in all of Gabon.""Vulcan recognizes the significant role of accurate population data for conservation management and policy decisions," said Ted Schmitt, director, conservation at Vulcan Inc. "By providing timely census data, we can fill critical knowledge gaps and enable prioritization of conservation resources. We are pleased to be part of this effort with Wildlife Conservation Society and the government of Gabon to help preserve this important species."Funding for this critical work was provided by Vulcan Inc., a Seattle company founded by the late philanthropist Paul G. Allen and his sister Jody Allen, who currently serves as chair.
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April 15, 2021
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https://www.sciencedaily.com/releases/2021/04/210415114108.htm
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Confirmed: Island gigantism and dwarfism result of evolutionary island rule
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It is an old-standing theory in evolutionary ecology: animal species on islands have the tendency to become either giants or dwarfs in comparison to mainland relatives. Since its formulation in the 1960s, however, the 'island rule' has been severely debated by scientists. In a new publication in
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Dwarf hippos and elephants in the Mediterranean islands are examples of large species who exhibited dwarfism. On the other hand, small mainland species may have evolved into giants after colonizing islands, giving rise to such oddities as the St Kilda field mouse (twice the size of its mainland ancestor), the infamous dodo of Mauritius (a giant pigeon), and the Komodo dragon.In 1973, Leigh van Valen was the first that formulated the theory, based on the study by mammologist J. Bristol Foster in 1964, that animal species follow an evolutionary pattern when it comes to their body sizes. Species on islands have the tendency to become either giants or dwarfs in comparison to mainland relatives. "Species are limited to the environment on an island. The level of threat from predatory animals is much lower or non-existent," says Ana Benítez-Lopez, who carried out the research at Radboud University, now researcher at Doñana Biological Station (EBD-CSIC, Spain). "But also limited resources are available." However, until now, many studies showed conflicting results which led to severe debate about this theory: is it really a pattern, or just an evolutionary coincidence?The team of scientists at Radboud University, Doñana Biological Station, National Museum of Natural Sciences and Imperial College London has revisited the island rule, aiming to solve this debate by performing a meta-analysis of over a thousand vertebrate species. They show that island rule effects are widespread in mammals, birds and reptiles, but less evident in amphibians, which mostly tend towards gigantism. The study also indicates that the magnitude of insular dwarfism and gigantism is more pronounced in smaller, more remote islands for mammals and reptiles.They also found an effect of climate and seasonality on the island rule. Small mammal and bird species grew larger and large species stayed the same size to conserve heat in colder, harsher insular environments. Furthermore, when seasons are present, availability of resources become less predictable for reptiles, leading smaller reptile species to become larger. Benítez-López: "Using a wealth of data from museum and live specimens, we were able to rigorously demonstrate for the first time that insular gigantism and dwarfism across vertebrates is a generalized pattern and not just an evolutionary coincidence."
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Animals
| 2,021 |
April 15, 2021
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https://www.sciencedaily.com/releases/2021/04/210415090739.htm
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Snake species from different terrains surrender surface secrets behind slithering success
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Some snake species slither across the ground, while others climb trees, dive through sand or glide across water. Today, scientists report that the surface chemistry of snake scales varies among species that negotiate these different terrains. The findings could have implications for designing durable materials, as well as robots that mimic snake locomotion to cross surfaces that would otherwise be impassable.
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The researchers will present their results today at the spring meeting of the American Chemical Society (ACS).The research began as a collaboration with Woodland Park Zoo in Seattle, explains Tobias Weidner, Ph.D., the project's principal investigator. One of the zoo's biologists told Weidner that not much was known about the chemistry of snake surfaces. "Biologists typically don't have techniques that can identify molecules on the outermost layer of a surface such as a snake scale," he says. "But I'm a chemist -- a surface scientist -- so I felt I could add something to the picture with my lab's methods."In that initial project, the researchers discovered that land snakes are covered with a lipid layer. This oily layer is so thin -- a mere one or two nanometers -- that no one had noticed it before. The team also found that the molecules in this layer are disorganized on the snake's back scales but highly organized and densely packed on belly scales, an arrangement that provides lubrication and protection against wear."Some people are afraid of snakes because they think they're slimy, but biologists tell them snakes aren't slimy; they're dry to the touch," Weidner says. "That's true, but it's also In the new study, the team wanted to find out if this nanoslimy surface chemistry differs in species adapted to various habitats, says Mette H. Rasmussen, a graduate student who is presenting the latest findings at the meeting. Both Weidner and Rasmussen are at Aarhus University in Denmark.Working with recently shed skins, Rasmussen compared the surface chemistry of ground, tree and sand snakes. She used laser spectroscopy and an electron microscopy technique that probes the chemistry of the surface by knocking electrons out of it with X-rays. The project was a collaboration with Joe Baio, Ph.D., at Oregon State University; Stanislav Gorb, Ph.D., at Kiel University and researchers at the U.S. National Institute of Standards and Technology.Rasmussen found that the tree snake has a layer of ordered lipid molecules on its belly, just like the ground snake. But the sand snake, which dives through sand, has an ordered lipid layer on both its front and back. "From a snake's point of view, it makes sense," she says. "You would like to have this friction reduction and wear resistance on both sides if you're surrounded by your environment instead of only moving across it." Next, the researchers want to find out where the lipids come from and to look at variations across other snake species, including those that live in water. They would also like to identify the lipids, though Weidner suspects the chemical makeup of the lipid layer is less important than the organization and density of the lipid molecules it contains.The work could have broad applications. "A snake's slithering locomotion requires constant contact with the surface it's crossing, which poses stringent requirements for friction, wear and mechanical stability," Rasmussen says. Learning how snakes maintain the integrity of their skin when encountering sharp rocks, hot sand and other challenges could help in the design of more durable materials.In addition, the researchers say, multiple groups are developing robots that mimic a snake's slithering or sidewinding locomotion and -- unlike robots with wheels -- can therefore negotiate difficult terrain such as steep, sandy slopes. These groups have recently begun taking into account the microstructure of snake scales, Rasmussen notes, but scales' surface chemistry is also critical to their performance. Bringing these fields together could one day lead to snakelike robots capable of helping in rescue operations or freeing a Mars rover stuck in sand, she says.
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Animals
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April 14, 2021
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https://www.sciencedaily.com/releases/2021/04/210414155009.htm
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Blow flies may be the answer to monitoring the environment non-invasively
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They say you are what you eat; that's the case for every living thing, whether it's humans, animals, insects, or plants, thanks to stable isotopes found within.
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Now a new study explores these stable isotopes in blow flies as a non-invasive way to monitor the environment through changes in animals in the ecosystem. The work, led by IUPUI researchers Christine Picard, William Gilhooly III, and Charity Owings, was published April 14 in "Blow flies are found on all continents, with the exception of Antarctica," said Gilhooly, who said the disruptions of climate change have increased the need for new ways to monitor animals' environments without disturbing them. "Therefore, blow flies are effectively sentinels of animal response to climate change in almost any location in the world."The multidisciplinary research between the biology and earth science departments began more than four years ago to answer a fundamental ecological question: "What are they (blow flies) eating in the wild," said Owings, a postdoctoral researcher at the University of Tennessee-Knoxville who was a Ph.D. student at IUPUI at the time of the study. "We know these types of flies feed on dead animals, but until now, we really had no way of actually determining the types of carcasses they were utilizing without actually finding the carcasses themselves.""Stable isotopes are literally the only way we could do that in a meaningful way," Picard added.Stable isotopes, which include carbon, nitrogen, hydrogen and oxygen, are found in the food we eat and become a part of us."When we eat a hamburger, we are getting the carbon isotopes that came from the corn that the cow was fed. Flies do the exact same thing," Gilhooly said.Picard and Owings set out to collect blow flies in Indianapolis, Yellowstone National Park and the Great Smoky Mountains."Collecting flies is easy: Have rotten meat, can travel," Picard said. "That is it: We would go someplace, open up our container of rotten meat, and the flies cannot resist and come flying in. Collections never took longer than 30 minutes, and it was like we were never there."Once the flies were collected, they were placed in a high-temperature furnace to convert the nitrogen and carbon in the blow fly into nitrogen gas and carbon dioxide gas. Those gases were then analyzed in a stable isotope ratio mass spectrometer, which shows slight differences in mass to reveal the original isotope composition of the sample."Nitrogen and carbon isotopes hold valuable information about diet," Gilhooly said. "Animals that eat meat have high nitrogen isotope values, whereas animals that eat mainly plants have low nitrogen isotope values."Carbon isotopes will tell us the main form of sugar that is in a diet. Food from an American diet has a distinct isotope signature because it has a lot of corn in it, either from the corn fed to domesticated animals or high fructose corn syrup used to make most processed foods and drinks. This signal is different from the carbon isotopes of trees and other plants. These isotope patterns are recorded in the fly as they randomly sample animals in the environment."Identifying the stable isotopes allowed the researchers to determine whether the blow flies were feeding on carnivores or herbivores when they were larvae."With repeated sampling, one can keep an eye on animal health and wellness," Picard said. "If the flies indicate a sudden, massive of dead herbivores -- and knowing what we know right now, that typically the herbivores are readily scavenged and not available for flies -- it could tell us one of two things: Herbivores are dying, yet the scavengers don't want anything to do with them as they may be diseased; or there are more herbivores than the carnivores/scavengers, and perhaps the populations of these animals has decreased."In Indianapolis, the majority of the blow fly larvae feed on carnivores. The researchers speculate this is because of the large number of animals being hit and killed by cars, making carcass scavenging less likely and carcasses more available to the blow flies to lay their eggs.However, they were surprised by their findings in the national park sampling sites, where the larvae fed on carnivores instead of herbivores, despite the herbivores' greater numbers. They speculate the competition is higher to scavenge for the larger herbivore carcasses and not readily accessible for the blow flies.Picard, Gilhooly and Owings also observed the impact of humans on animals. The carbon isotopes from the flies found the presence of corn-based foods in Indianapolis, which was expected, but also in the Great Smoky Mountains. With the Smokies being the most visited park in the country, opportunistic scavengers have greater access to human food."This wealth of information provided by the blow flies will be fundamental to detecting changes within the ecosystem," Picard said."This research has the potential to revolutionize the way biologists investigate important global issues, especially in the era of climate change," Owings said. "Researchers will no longer be restricted to finding animals themselves, which is a daunting task; the flies can easily find the animals and then can be 'called in' by scientists."In addition to providing a real-time early-warning system for tracking ecosystem change in response to climate change, the distribution of blow flies makes isotope analysis useful in almost any location."Compared to other approaches, the relative ease of collecting the flies and measuring their isotopes means that ecosystem monitoring efforts can be rapidly deployed in any environmentally sensitive region," Gilhooly said.
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Animals
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April 14, 2021
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https://www.sciencedaily.com/releases/2021/04/210414131943.htm
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In pig brain development, nature beats nurture
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Before humans can benefit from new drug therapies and nutritional additives, scientists test their safety and efficacy in animals, typically mice and rats. But, as much as they've done for biomedical research, rodents aren't always the best research model for studies on neonatal brain development and nutrition. That's where pigs can play an important role.
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University of Illinois researchers say the domestic pig is ideal for these studies because their brain size, rate of development, and digestive system are excellent analogues for human newborns.They know a lot about pig brains, having built the first -- and recently, the second -- complete, MRI-based atlases of the organ. They've used the first to study the effects of numerous nutritional interventions in pigs. But some critics say they can't be sure those outcomes reflect reality. After all, these research subjects are raised in carefully controlled environments, not mingling with siblings and mom in farm-standard farrowing crates.So just how much does the pig's early rearing environment affect brain development?"We've been countering a lot of criticism about whether the development of the pig brain is the same in our laboratory as it is on any pig farm. And the answer is yes. We now have indisputable evidence to say that the brains of pigs raised in an artificial environment grow and develop in the same way structurally as those of pigs raised by their mother," says Ryan Dilger, associate professor in the Department of Animal Sciences and senior author on a new study in In the study, the research team brought 2-day-old piglets to their facility, known as the Piglet Nutrition and Cognition Laboratory, which is outfitted with large individual enclosures that let pigs see, smell, and hear others in adjacent pens. Dilger says the high ambient temperature and ability for pigs to socialize is important."In our nutritional studies, we want to keep them separated to avoid cross-contamination of the bacteria found in their colon, which is collectively known as the microbiota. But the pigs still get to express social behaviors by seeing, hearing, and smelling each other," he says. "And in many of our studies, we let the pigs out of their enclosures to socialize each day, so they get to have a piggy party each afternoon."Another subset of piglets stayed with their littermates and mothers in farrowing crates on a research farm on the U of I campus. At 4 weeks of age, when pigs have developed enough that they no longer need to solely drink milk, the artificially reared pigs moved back to the farm and were group-housed with their sow-reared counterparts. So, in the end, the pigs only lived in different environments for the first four weeks of life and from that point forward, all pigs were treated the same.All pigs were anesthetized and scanned in a state-of-the-art magnetic resonance imaging (MRI) machine at 1, 2, 3, 4, 8, 12, 18, and 24 weeks of age. The researchers assessed brain macro- and microstructure of the artificially reared and sow-reared pigs using the new pig brain atlases for young and adolescent pigs.Not only did the pigs eat and grow at the same rates in the two rearing environments, their brain development was equivalent overall as well. The researchers found no differences in absolute volumes of the whole brain, gray matter, white matter, cerebrospinal fluid growth, or microstructural changes (neuronal connections between brain regions) over time in the two groups.Joanne Fil, doctoral student in the Neuroscience Program at Illinois and first author of the study, says, "We looked at a surrogate measure of myelin, myelin water fraction, which reflects the fat and protein surrounding neurons and helps them communicate more effectively. Humans and pigs develop a lot of myelin significantly after birth, so if we see more myelination, then we assume the brain is maturing at a different rate. Longitudinally, there were no differences between the myelin water fraction in the two groups."We did see slight differences in the rate of development, with artificially reared pigs having a slightly higher rate of myelin development than the sow-reared pigs, but in the end, pigs raised in either environment reached the same place when it came to brain growth."The researchers also compared the pigs' memory in behavioral tests. The pigs were presented with two stationary toys to play with -- one they had previously been able to investigate and one they had never seen before. If they spent more time checking out the new toy, that was evidence they remembered the older one and therefore had encoded a memory.At a couple of early time points, 4 and 8 weeks, pigs in the sow-reared group had slightly greater object recognition. The authors suggest that might have been due to greater peer interaction in the sow-reared environments. However, the differences were slight and temporary."Behavior is always more variable, more subjective. That's why we like the objective and structural measures of the brain we can evaluate by MRI," Dilger says. "And what we found is that when both sets of pigs are healthy and we've met their nutritional requirements, the rearing environment didn't appear to influence brain development. Their brains effectively grew the same."In addition to supporting the continued use of laboratory rearing environments in pig neuroscience research, the study provides new data on pig brain development over time.For half a dozen years, the first pig brain atlas served as the definitive reference for researchers around the world. But that atlas was based on 4-week-old pigs and couldn't be easily extrapolated to older animals. Not only do the new atlases include one for 12-week-old pigs, the rearing environment study provides absolute volume measures for pigs at many more time points, up to adulthood."This provides a lot of foundational data where somebody could come back and ask how many cubic millimeters is the pig brain at a particular age. We can model that based on what we have here," Fil says. "Our objective was comparing the two rearing environments, but also providing what is expected for a certain age of pig. That helps because we can start to develop nutritional interventions for specific ages and understand what parts of brain development can be influenced by nutrition."Dilger adds, "There's a lot of power in the pig as a model for biomedical research, and we're showing that by bringing together engineering and agriculture, which are central to our mission as a land-grant institution. We use lots of mice in research on our campus, but we're also very good at working with pigs. We're mixing the biomedical world with the agricultural world, to ultimately benefit both pig and human nutrition.The Department of Animal Sciences is in the College of Agricultural, Consumer and Environmental Sciences at the University of Illinois.
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April 14, 2021
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https://www.sciencedaily.com/releases/2021/04/210414113550.htm
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Mystery canine illness identified: Animal coronavirus
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An outbreak of vomiting among dogs has been traced back to a type of animal coronavirus by researchers.
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Vets across the country began reporting cases of acute onset prolific vomiting in 2019/20.The Small Animal Veterinary Surveillance Network (SAVSNet) at the University of Liverpool asked vets for help in collecting data, with 1,258 case questionnaires from vets and owners plus 95 clinical samples from 71 animals.Based on this data, a team from the universities of Liverpool, Lancaster, Manchester and Bristol identified the outbreak as most likely to be a variant of canine enteric coronavirus (CeCoV).Canine coronavirus only affects dogs and is not the same as Sars Cov2 which causes Covid in humans. Researchers found no evidence of any similar illness in people.The work is published in The team are working on a project funded by the Dogs Trust called SAVSNet-Agile which aims to develop a national surveillance system for canine health.Dr Barry Rowlingson from Lancaster University said: "We've developed complex statistical models to look for disease outbreaks. Being able to rapidly detect increased incidence, without triggering a false alarm from a natural random variation, is the key problem here. Early detection is crucial to early treatment and enhanced monitoring."The SAVSNet Agile project aims to feed information back to local veterinary practices so they can be alert to any new outbreaks."Vets began to suspect an infectious cause because vomiting was more frequent than is typical for canine gastroenteritis.SAVSNet researchers found a specific and significant increase in the number of dogs recorded as exhibiting gastroenteric signs between late December 2019 and March 2020.As well as reusing health records, SAVSNet also collected questionnaire data from vets and owners caring for affected animals, as well as healthy controls. This showed male dogs were more at risk than females.Charlotte Appleton, SAVSNet Agile PhD Student, said: "Obtaining such important results at an early stage of my PhD is a wonderful achievement and will hopefully provide a pathway of higher visibility into the health of domestic animals."
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April 14, 2021
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https://www.sciencedaily.com/releases/2021/04/210414113508.htm
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Gigantic flying pterosaurs had spoked vertebrae to support their 'ridiculously long' necks
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Little is known about azhdarchid pterosaurs, gigantic flying reptiles with impressive wingspans of up to 12 meters. Cousins of dinosaurs and the largest animals ever to fly, they first appeared in the fossil record in the Late Triassic about 225 million years ago and disappeared again at the end of the Cretaceous period about 66 million years ago. One of their most notable features for such a large flighted animal was a neck longer than that of a giraffe. Now, researchers report an unexpected discovery in the journal
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"One of our most important findings is the arrangement of cross-struts within the vertebral centrum," says Dave Martill of the University of Portsmouth, UK. "It is unlike anything seen previously in a vertebra of any animal. The neural tube is placed centrally within the vertebra and is connected to the external wall via a number of thin rod-like trabeculae, radially arranged like the spokes of a bicycle wheel and helically arranged along the length of the vertebra. They even cross over like the spokes of a bicycle wheel. Evolution shaped these creatures into awesome, breathtakingly efficient flyers."Scientists previously thought the pterosaur's neck had a simpler tube-within-a-tube structure, he explains. But it raised an important question: how could their thin-walled bones, needed to reduce weight in the flying reptiles, still support their bodies and allow them to capture and eat heavy prey animals?Cariad Williams, the study's first author, hadn't set out to answer that question. She wanted to examine the degree of movement between each vertebra of the pterosaur's neck."These animals have ridiculously long necks," Williams says, adding that, in some species, the fifth vertebra of the neck from the head end is as long as the animal's body. "It makes a giraffe look perfectly normal. We wanted to know a bit about how this incredibly long neck functioned, as it seems to have very little mobility between each vertebra."While the Moroccan pterosaur bones they study are well preserved in three dimensions, the researchers still hadn't expected the scans to offer such a clear view of the vertebra's intricate internal structure."We did not originally CT scan it to learn about the inside; we wanted a very detailed image of the outside surface," Martill says. "We could have got this by ordinary surface scanning, but we had an opportunity to put some specimens in a CT scanner, and it seemed churlish to turn the offer down. We were simply trying to model the degree of movement between all the vertebrae to see how the neck might perform in life."He adds, "What was utterly remarkable was that the internal structure was perfectly preserved -- so too was the microhistology when we made some petrographic sections through the bone. As soon as we saw the intricate pattern of radial trabeculae, we realized there was something special going on. As we looked closer, we could see that they were arranged in a helix traveling up and down the vertebral tube and crossing each other like bicycle wheel spokes."His team realized immediately that they needed to bring in engineers to understand how the biomechanics of this unusual neck would have worked. Those analyses suggest that as few as 50 of the spoke-like trabeculae increased the amount of weight their necks could carry without buckling by 90%. Together with the basic tube-within-a-tube structure, it explains how the relatively light-weight animals could capture and carry heavy prey items without breaking their necks."It appears that this structure of extremely thin cervical vertebrae and added helically arranged cross-struts resolved many concerns about the biomechanics of how these creatures were able to support massive heads -- longer than 1.5 meters -- on necks longer than the modern-day giraffe, all whilst retaining the ability of powered flight," Martill says.While pterosaurs are sometimes thought of as evolutionary dead ends, Martill and colleagues say the new findings reveal them as "fantastically complex and sophisticated." Their bones and skeletons were marvels of biology -- extremely light yet strong and durable.The researchers say there's still much to learn in future work about pterosaurs, including seemingly basic questions about their flight abilities and feeding ecology.
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April 14, 2021
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https://www.sciencedaily.com/releases/2021/04/210414100144.htm
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The chillest ape: How humans evolved a super-high cooling capacity
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Humans have a uniquely high density of sweat glands embedded in their skin -- 10 times the density of chimpanzees and macaques. Now, researchers at Penn Medicine have discovered how this distinctive, hyper-cooling trait evolved in the human genome. In a study published today in the
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"This is one of the clearest examples I've ever seen of pinpointing the genetic basis for one of the most extreme and distinctively human evolutionary traits as a whole," said the study's senior author, Yana Kamberov, PhD, an assistant professor of genetics at Penn Medicine. "This kind of research is important not only because it shows how evolution actually works to produce species diversity but also because it gives us access into human biology that is often not possible to gain in other ways, essentially by learning from tweaking the biological system in a way that is actually beneficial, without breaking it."Scientists broadly assume that humans' high density of sweat glands, also called eccrine glands, reflects an ancient evolutionary adaptation. This adaptation, coupled with the loss of fur in early hominins, which promoted cooling through sweat evaporation, is thought to have made it easier for them to run, hunt, and otherwise survive on the hot and relatively treeless African savannah, a markedly different habitat than the jungles occupied by other ape species.Kamberov found in a 2015 study that the expression level of a gene called Engrailed 1 -- EN1 in humans -- helps determine the density of eccrine glands in mice. EN1 encodes a transcription factor protein that, among many other functions, works during development to induce immature skin cells to form eccrine glands. Because of this property, Kamberov and colleagues hypothesized that perhaps one way in which humans could have built more sweat glands in their skin is to evolve genetic changes that increased the production of EN1 in the skin.The activity of a gene is often affected by nearby regions of DNA called enhancer regions, where factors that activate the gene can bind and help drive the gene's expression. In the study, Kamberov and her team identified an enhancer region called hECE18 that boosts the production of EN1 in skin, to induce the formation of more eccrine glands. The researchers showed that the human version of hECE18 is more active than that of ape or macaque versions, which would in turn drive higher levels of EN1 production.Kamberov and her colleagues also teased apart the individual mutations that distinguish human hECE18, showing why some of them boost EN1 expression -- and showing that rolling back those mutations to the chimp version of hECE18 brings the enhancer activity down to chimp levels.Prior studies of evolved human-specific traits, such as language, generally have tied such traits to complex genetic changes involving multiple genes and regulatory regions. In contrast, the work from Kamberov and her team suggest that the human "high-sweat" trait evolved at least in part through repeated mutations to just one regulatory region, hECE18. This means that this single regulatory element could have repeatedly contributed to a gradual evolution of higher eccrine gland density during human evolution.While the study is mainly a feat of basic biology that shines a light on human evolution, it also should have some long-term medical relevance, Kamberov said."Severe wounds or burns often destroy sweat glands in skin, and so far we don't know how to regenerate them -- but this study brings us closer to discovering how to do that," she said. "The next step in this research would be to uncover how the multiple activity enhancing mutations in hECE18 interact with each other to increase EN1 expression and to use these biologically key mutations as starting points to figure out what DNA-binding factors actually bind at these sites. Basically, this provides us with a direct molecular inroad to discover the upstream factors that by activating EN1 expression get skin cells to start making sweat glands."
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Animals
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April 13, 2021
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https://www.sciencedaily.com/releases/2021/04/210413121015.htm
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Amoeba biology reveals potential treatment target for lung disease
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In a series of experiments that began with amoebas -- single-celled organisms that extend podlike appendages to move around -- Johns Hopkins Medicine scientists say they have identified a genetic pathway that could be activated to help sweep out mucus from the lungs of people with chronic obstructive pulmonary disease a widespread lung ailment.
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"Physician-scientists and fundamental biologists worked together to understand a problem at the root of a major human illness, and the problem, as often happens, relates to the core biology of cells," says Doug Robinson, Ph.D., professor of cell biology, pharmacology and molecular sciences, medicine (pulmonary division), oncology, and chemical and biomedical engineering at the Johns Hopkins University School of Medicine.Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the U.S., affecting more the 15 million adults, according to the U.S. Centers for Disease Control and Prevention. The disease causes the lungs to fill up with mucus and phlegm, and people with COPD experience chronic cough, wheezing and difficulty breathing. Cigarette smoking is the main cause in as many as three-quarters of COPD cases, and there is no cure or effective treatment available despite decades of research.In a report on their new work, published Feb. 25 in the Robinson and his collaborator, Ramana Sidhaye, M.D., also a professor of medicine in the Division of Pulmonology at Johns Hopkins, with their former lab member Corrine Kliment, M.D., Ph.D., counted on the knowledge that as species evolved, genetic pathways were frequently retained across the animal kingdom.Enter the soil-dwelling amoeba Dictyostelium discoideum, which has long been studied to understand cell movement and communication. The scientists pumped lab-grade cigarette smoke through a tube and bubbled it into the liquid nutrients bathing the amoeba. Then, the scientists used engineered amoeba to identify genes that could provide protection against the smoke.Looking at the genes that provided protection, creating "survivor" cells, one family of genes stood out among the rest: adenine nucleotide translocase (ANT). Proteins made by this group of genes are found in the membrane, or surface, of a cell's energy powerhouse structure, known as mitochondria. Typically, mitochondria help make the fuel that cells use to survive. When an ANT gene is highly active, cells get better at making fuel, protecting them from the smoke.Kliment, Robinson and the team suspected they also help amoeba overcome the damaging effects of cigarette smoke.To better understand how ANT genes behave in humans, the scientists studied tissue samples of cells lining the lungs taken from 28 people with COPD who were treated at the University of Pittsburgh and compared the lung cells' genetic activity with cells from 20 people with normal lung function.The scientists found that COPD patients had about 20% less genetic expression of the ANT2 gene than those with normal lung function. They also found that mice exposed to smoke lose ANT2 gene expression.Next, Robinson, Kliment and their research team sought to discover how ANT2 might provide protection from cigarette smoke chemicals and, in the process, discovered something completely unexpected.Cells lining the lungs use fingerlike projections called cilia to sweep mucus and other particles out of the lungs. In mammals, including people, the scientists found that the ANT2 gene produces proteins that localize in and around the cilia that work to release tiny amounts of the cell's fuel into a watery substance next to the cell. The fuel enhances the ability of the cilia to "beat" rhythmically and regularly to sweep away the mucus."In COPD patients, mucus becomes too thick to sweep out of the lungs," says Robinson.The Johns Hopkins Medicine team found that, compared with human lung cells with normal ANT2 function, cilia in human lung cells lacking ANT2 beat 35% less effectively when exposed to smoke. In addition, the watery liquid next to the cell was about half the height of normal cells, suggesting the liquid was denser, which can also contribute to lower beat rates.When the scientists genetically engineered the lung cells to have an overactive ANT2 gene and exposed them to smoke, the cells' cilia beat with the same intensity as normal cells not exposed to smoke. The watery layer next to these cells was about 2.5 times taller than that of cells lacking ANT2."Cells are good at repurposing cellular processes across species, and in our experiments, we found that mammals have repurposed the ANT gene to help deliver cellular cues to build the appropriate hydration layer in airways," says Robinson. "Who would have thought that a mitochondrial protein could also live at the cell surface and be responsible for helping airway cilia beat and move?"Robinson says that further research may yield discoveries to develop gene therapy or drugs to add ANT2 function back into lung-lining cells as a potential treatment for COPD.
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April 13, 2021
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https://www.sciencedaily.com/releases/2021/04/210413110638.htm
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Multiple factors shape timing of birth in mule deer
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A five-year study of mule deer does and newborn fawns in western Wyoming shows that migrating deer have a lot to balance when it comes to birth timing.
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The study led by University of Wyoming scientists challenges the long-held assumption that animals match offspring birth with the peak green-up of forage at the birth site. Instead, only deer that migrated long distances and followed the flush of spring green-up from low elevation winter ranges to higher-elevation summer ranges were able to match birth with peak green-up. Other deer migrated shorter distances and gave birth earlier, but birth was out of sync with green-up.The researchers' work appears in the journal To examine the factors shaping birth timing, researchers integrated highly detailed data on female deer, including movement data from GPS collars, body condition and gestational development from ultrasonography of adult female deer, and intensive fieldwork to locate newborn fawns."In contrast to existing theory, which predicts that conditions at the birth site should shape optimal birth timing, our results provide a clear example of birth timing being shaped by trade-offs arising from events occurring away from the birth site and from other parts of the annual cycle," the researchers wrote.Migration results in animals having to time important events, such as reproduction, within tight time schedules. In general, mule deer in western Wyoming give birth in early June, generally after migration is over but early enough for fawns to grow large enough to survive the onset of winter. The deer that were part of the study included animals that migrated long distances between winter and summer ranges, as well as those that migrated shorter distances.Among the study's findings:"Conceptualizing birth timing through the lens of the full annual cycle helps to illuminate additional trade-offs that migrants face when balancing reproduction with migration, foraging and accumulation of fat reserves," the researchers wrote.They say the link between movement tactics and timing of birth has important conservation and management implications. For example, human-caused disturbances to migration patterns could harm deer reproduction until animals have time to adjust. Additionally, the diversity of movement behaviors among western Wyoming mule deer is important to preserve, as animal populations with greater life-history diversity have been found to be more able to withstand environmental changes.
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Animals
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April 13, 2021
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https://www.sciencedaily.com/releases/2021/04/210413095458.htm
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Megafauna extinction mystery: Size isn't everything
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Ancient clues, in the shape of fossils and archaeological evidence of varying quality scattered across Australia, have formed the basis of several hypotheses about the fate of megafauna that vanished about 42,000 years ago from the ancient continent of Sahul, comprising mainland Australia, Tasmania, New Guinea and neighbouring islands.
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There is a growing consensus that multiple factors were at play, including climate change, the impact of people on the environment, and access to freshwater sources.Now, research led by Professor Corey Bradshaw of Flinders University and the Australian Research Council Centre of Excellence of Australian Biodiversity and Heritage (CABAH) has used sophisticated mathematical modelling to assess how susceptible different species were to extinction -- and what it means for the survival of creatures today.Using various characteristics such as body size, weight, lifespan, survival rate, and fertility, they created population simulation models to predict the likelihood of these species surviving under different types of environmental disturbance.Simulations included everything from increasing droughts to increasing hunting pressure to see which species of 13 extinct megafauna, as well as 8 comparative species still alive today, had the highest chances of surviving.Published in the journal While they did find that slower-growing species with lower fertility, like the rhino-sized wombat relative Diprotodon, were generally more susceptible to extinction than more-fecund species like the marsupial 'tiger' thylacine, the relative susceptibility rank across species did not match the timing of their extinctions recorded in the fossil record."We found no clear relationship between a species' inherent vulnerability to extinction -- such as being slower and heavier and/or slower to reproduce -- and the timing of its extinction in the fossil record," explained Professor Bradshaw."In fact, we found that most of the living species used for comparison -- such as short-beaked echidnas, emus, brush turkeys, and common wombats -- were more susceptible on average than their now-extinct counterparts."The researchers concluded that the true extinction cascade was likely the result of complex, localised scenarios, including impacts of regional climate variation, and different pressures from people across regions.Associate Professor Vera Weisbecker of Flinders University and co-author of the study said: "The relative speed of different species to escape hunters, as well as whether or not a species dug protective burrows, also likely contributed to the mismatch between extinction susceptibility and timing."For example, fast-hopping red kangaroos still alive today might have had an escape advantage over some of the slower-striding short-faced kangaroos that went extinct. Small wombats that dug burrows might also have been more difficult for people to hunt than the bigger, non-burrowing megafauna."Co-author Dr Frédérik Saltré of Flinders University added: "We determined that the kangaroo species were the least-susceptible to extinction based on their biology, followed by the monotremes (echidnas), and the giant 'wombat' species. Interestingly, the large, flightless birds, like emu and the giant mihirung 'thunderbird' Genyornis, had the highest susceptibilities."Our results support the notion that extinction risk can be high across all body sizes depending on a species' particular ecology, meaning that predicting future extinctions from climate change and human impacts aren't always straightforward based on the first principles of biology," concluded Professor Bradshaw.
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April 13, 2021
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https://www.sciencedaily.com/releases/2021/04/210413081357.htm
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Frog species with 6 sex chromosomes offer new clues on evolution of complex XY systems
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Scientists found six sex chromosomes in the
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The discovery was a surprise to the international research team led by Associate Professor Ikuo Miura of Hiroshima University's Amphibian Research Center. In 1980, the first reported instance of multiple sex chromosome systems in amphibians was found in the Taiwanese brown frog The finding suggested that translocation -- a chromosomal abnormality that happens when a chromosome breaks and its fragment fuses to another -- occurred between two potential sex-determining chromosomes. At that time, however, the identification of the chromosomes involved in the translocation was uncertain.So when the researchers set out to precisely identify the chromosomes involved, they were expecting only one translocation and not three. The three male-specific translocations created a system of six sex chromosomes, ♂X1Y1X2Y2X3Y3-♀X1X1X2X2X3X3. Their findings were published in the journal Cells last March 16, 2021.Cases of multiple chromosomes in amphibians are rare and their karyotypes, or collection of chromosomes, are generally highly conserved with little rearrangement among species. A majority are also homomorphic with undifferentiated sex chromosomes, unlike mammals and birds which have heteromorphic XY and ZW sex-determination systems. So far, there are only 10 known cases of multiple sex chromosome systems in amphibians.What's more, the research team uncovered that the potential sex-chromosomes involved in the translocations contained orthologs of the sex-determining genes in mammals, birds, and fishes. Orthologs are genes that evolved from an ancestral gene found in the shared ancestor of those species.The researchers found the This is the first time that sex chromosomes containing orthologs of the sex-determining genes in mammals, birds, and fishes are found together in a vertebrate species.Sex chromosomes evolve from an ordinary autosomal pair after acquiring a sex-determining gene. But the team has yet to figure out which of the three pairs is the original sex chromosome and which is the major sex-determining gene of the three candidates: Miura explained that up to now sex chromosome-autosome fusion has been documented as a chance occurrence."In fact, it was like that in this frog, too. The break and fusion of the chromosomes may have occurred by chance," he said.But the researchers believe that the chromosome members involved in the fusions were selected non-randomly or inevitably chosen as they probably share a common genomic region."To be so, the three may share a common DNA sequence on each of them, which makes them closely localized to each other, and this makes it possible to join the simultaneously occurring breakages and translocations.""This rare case suggests sex-specific, nonrandom translocations and thus provides a new viewpoint for the evolutionary meaning of the multiple sex chromosome system."Miura said identifying the genomic sequence common to the potential sex chromosomes would improve understanding of the mechanisms of its evolution and turnover.
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Animals
| 2,021 |
April 12, 2021
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https://www.sciencedaily.com/releases/2021/04/210412084554.htm
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Shift in diet allowed gray wolves to survive ice-age mass extinction
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Gray wolves are among the largest predators to have survived the extinction at the end of the last ice age around11,700 years ago. Today, they can be found roaming Yukon's boreal forest and tundra, with caribou and moose as their main sources of food.
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A new study led by the Canadian Museum of Nature shows that wolves may have survived by adapting their diet over thousands of years -- from a primary reliance on horses during the Pleistocene, to caribou and moose today. The results are published in the journal The research team, led by museum palaeontologist Dr. Danielle Fraser and student Zoe Landry, analysed evidence preserved in teeth and bones from skulls of both ancient (50,000 to 26,000 years ago) and modern gray wolves. All the specimens were collected in Yukon, a region that once supported the Beringia mammoth-steppe ecosystem, and are curated in the museum's national collections as well as those of the Yukon government."We can study the change in diet by examining wear patterns on the teeth and chemical traces in the wolf bones," says Landry, the lead author who completed the work as a Carleton University student under Fraser's supervision. "These can tell us a lot about how the animal ate, and what the animal was eating throughout its life, up until about a few weeks before it died."Landry and Fraser relied on established models that can determine an animal's eating behaviour by examining microscopic wear patterns on its teeth. Scratch marks indicate the wolf would have been consuming flesh, while the presence of pits would suggest chewing and gnawing on bones, likely as a scavenger.Analysis showed that scratch marks prevailed in both the ancient and modern wolf teeth, meaning that the wolves continued to survive as primary predators, hunting their prey.What then were the gray wolves eating? The modern diet -- caribou and moose -- is well established. The diet of the ancient wolves was assessed by looking at the ratios of carbon and nitrogen isotopes extracted from collagen in the bones. Relative levels of the isotopes can be compared with established indicators for specific species. "The axiom, you are what you eat comes into play here," says Landry.Results showed that horses, which went extinct during the Pleistocene, accounted for about half of the gray wolf diet. About 15% came from caribou and Dall's sheep, with some mammoth mixed in. All this at a time when the ancient wolves would have co-existed with other large predators such as scimitar cats and short-faced bears. The eventual extinction of these predators could have created more opportunity for the wolves to transition to new prey species."This is really a story of ice age survival and adaptation, and the building up of a species towards the modern form in terms of ecological adaptation," notes Dr. Grant Zazula, study co-author, and Government of Yukon paleontologist who is an expert on the ice-age animals that populated Beringia.The findings have implications for conservation today. "The gray wolves showed flexibility in adapting to a changing climate and a shift in habitat from a steppe ecosystem to boreal forest," explains Fraser. "And their survival is closely linked to the survival of prey species that they are able to eat."Given the reliance of modern gray wolves on caribou, the study's authors suggest that the preservation of caribou populations will be an important factor in maintaining a healthy wolf population.
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Animals
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April 12, 2021
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https://www.sciencedaily.com/releases/2021/04/210412084531.htm
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Conservationists may be unintentionally spreading pathogens between threatened animal populations
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Moving endangered species to new locations is often used as part of species conservation strategies, and can help to restore degraded ecosystems. But scientists say there is a high risk that these relocations are accidentally spreading diseases and parasites.
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The new report published today in the journal Mussels play an important role in cleaning the water of many of the world's rivers and lakes, but are one of the most threatened animal groups on Earth. There is growing interest in moving mussels to new locations to boost threatened populations, or so they can be used as 'biological filters' to improve water quality.A gonad-eating parasitic worm, Rhipidocotyle campanula, which can leave mussels completely sterile, was identified as a huge risk for captive breeding programmes where mussels from many isolated populations are brought together."We need to be much more cautious about moving animals to new places for conservation purposes, because the costs may outweigh the benefits," said Dr David Aldridge in the Department of Zoology at the University of Cambridge, senior author of the report.He added: "We've seen that mixing different populations of mussels can allow widespread transmission of gonad-eating worms -- it only takes one infected mussel to spread this parasite, which in extreme cases can lead to collapse of an entire population."Pathogens can easily be transferred between locations when mussels are moved. In extreme cases, the pathogens may cause a population of mussels to completely collapse. In other cases infections may not cause a problem unless they are present when other factors, such as lack of food or high temperatures, put a population under stress leading to a sudden outbreak.The report recommends that species are only relocated when absolutely necessary and quarantine periods, tailored to stop transmission of the most likely pathogens being carried, are used.It identifies four key factors that determine the risk of spreading pathogens when relocating animals: proportion of infected animals in both source and recipient populations; density of the resulting population; host immunity; and the life-cycle of the pathogen. Pathogens that must infect multiple species to complete their life-cycle, like parasitic mites, will only persist if all of the species are present in a given location."Moving animals to a new location is often used to protect or supplement endangered populations. But we must consider the risk this will spread pathogens that we don't understand very well at all, which could put these populations in even greater danger," said Josh Brian, a PhD student in the Department of Zoology at the University of Cambridge and first author of the report.Different populations of the same species may respond differently to infection with the same pathogen because of adaptations in their immune system. For example, a pack of endangered wolves moved to Yellowstone National Park died because the wolves had no immunity to parasites carried by the local canines.The researchers say that stocking rivers with fish for anglers, and sourcing exotic plants for home gardens could also move around parasites or diseases."Being aware of the risks of spreading diseases between populations is a vital first step towards making sure we avoid unintentional harm in future conservation work," said Isobel Ollard, a PhD student in the Department of Zoology at the University of Cambridge, who was also involved in the study.
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Animals
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April 12, 2021
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https://www.sciencedaily.com/releases/2021/04/210412101914.htm
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Speeding up sequence alignment across the tree of life
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A team of researchers from the Max Planck Institutes of Developmental Biology in Tübingen and the Max Planck Computing and Data Facility in Garching develops new search capabilities that will allow to compare the biochemical makeup of different species from across the tree of life. Its combination of accuracy and speed is hitherto unrivalled.
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Humans share many sequences of nucleotides that make up our genes with other species -- with pigs in particular, but also with mice and even bananas. Accordingly, some proteins in our bodies -- strings of amino acids assembled according to the blueprint of the genes -- can also be the same as (or similar to) some proteins in other species. These similarities might sometimes indicate that two species have a common ancestry, or they may simply come about if the evolutionary need for a certain feature or molecular function happens to arise in the two species.But of course, finding out what you share with a pig or a banana can be a monumental task; the search of a database with all the information about you, the pig, and the banana is computationally quite involved. Researchers are expecting that the genomes of more than 1.5 million eukaryotic species -- that includes all animals, plants, and mushrooms -- will be sequenced within the next decade. "Even now, with only hundreds of thousand genomes available (mostly representing small genomes of bacteria and viruses), we are already looking at databases with up to 370 million sequences. Most current search tools would simply be impracticable and take too long to analyze data of the magnitude that we are expecting in the near future," explains Hajk-Georg Drost, Computational Biology group leader in the Department of Molecular Biology of the Max Planck Institute of Developmental Biology in Tübingen."For a long time, the gold standard for this kind of analyses used to be a tool called BLAST," recalls Drost. "If you tried to trace how a protein was maintained by natural selection or how it developed in different phylogenetic lineages, BLAST gave you the best matches at this scale. But it is foreseeable that at some point the databases will grow too large for comprehensive BLAST searches."At the core of the problem is a tradeoff between speed versus sensitivity: just like you will miss some small or well-hidden Easter eggs if you scan a room only briefly, speeding up the search for similarities of protein sequences in a database typically comes with downside of missing some of the less obvious matches."This is why some time ago, we started to devise the DIAMOND algorithm, in the hope that it would allow us to deal with large datasets in a reasonable amount of time," remembers Benjamin Buchfink, collaborator and PhD student in Drost's research group who has been developing DIAMOND since 2013. "It did, but it also came with a downside: it couldn't pick up some of the more distant evolutionary relationships." That means that while the original DIAMOND may have been sensitive enough to detect a given human amino acid sequence in a chimpanzee, it may have been blind to the occurrence of a similar sequence in an evolutionary more remote species.While being useful for studying material that was directly extracted from environmental samples, other research goals require more sensitive tools than the original DIAMOND search algorithm. The team of researchers from Tübingen and Garching was now able to modify and extend DIAMOND to make it as sensitive as BLAST while maintaining its superior speed: with the improved DIAMOND, researchers will be able to do comparative genomics research with the accuracy of BLAST at an 80- to 360-fold computational speedup. "In addition, DIAMOND enables researchers to perform alignments with BLAST-like sensitivity on a supercomputer, a high-performance computing cluster, or the Cloud in a truly massively parallel fashion, making extremely large-scale sequence alignments possible in tractable time," adds Klaus Reuter, collaborator from the Max Planck Computing and Data Facility."Some queries that would have taken other tools two months on a supercomputer can be accomplished in several hours with the new DIAMOND infrastructure. "Considering the exponential growth of the number of available genomes, the speed and accuracy of DIAMOND are exactly what modern genomics will need to learn from the entire collection of all genomes rather than having to focus only on a smaller number of particular species due to a lack of sensitive search capacity," Drost predicts. The team is thus convinced that the full advantages of DIAMOND will become apparent in the years to come.
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April 8, 2021
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https://www.sciencedaily.com/releases/2021/04/210408163436.htm
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New pig brain maps facilitate human neuroscience discoveries
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When scientists need to understand the effects of new infant formula ingredients on brain development, it's rarely possible for them to carry out initial safety studies with human subjects. After all, few parents are willing to hand over their newborns to test unproven ingredients.
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Enter the domestic pig. Its brain and gut development are strikingly similar to human infants -- much more so than traditional lab animals, rats and mice. And, like infants, young pigs can be scanned using clinically available equipment, including non-invasive magnetic resonance imaging, or MRI. That means researchers can test nutritional interventions in pigs, look at their effects on the developing brain via MRI, and make educated predictions about how those same nutrients will affect human infants.For nearly a decade, scientists have relied on an MRI-based map, or atlas, of the pig brain -- developed at the University of Illinois using 4-week-old pigs -- to understand where and how nutrients and other interventions affect the developing brain. Now, Illinois scientists have updated that atlas, increasing its resolution by a factor of four, and they have also added a new atlas for adolescent 12-week-old pigs."That improvement in spatial resolution makes a huge difference when you're looking at development in a small pig brain and trying to see how your intervention is changing structure, size, or even function in the brain," says Brad Sutton, professor in the Department of Bioengineering, technical director of the Biomedical Imaging Center at Illinois' Beckman Institute, and a co-author on the brain atlas study, published in the Ryan Dilger, associate professor in the Department of Animal Sciences and senior author on the atlas study, adds, "It's about our ability to discern one part of the brain from another. The higher the resolution, the more reliably we can say this piece is the hippocampus, for example. Part of the need for an atlas is for every research group working in this area to be referencing the same parts or regions of the brain consistently. We have to have common terms and infrastructure to speak the same language."To build the updated atlas, the researchers anesthetized and scanned 4- and 12-week old pigs at Beckman's Biomedical Imaging Center using a state-of-the-art Siemens Prisma 3 T MRI scanner. Scans from multiple pigs in each age class were averaged into a single atlas for each age, to account for variation among individuals. Subsequently, the researchers identified and digitally isolated 26 regions of interest, such as the cerebellum, medulla, right and left cortex, and others, and provided volumetric standards for each in the pig."We provide the absolute and relative volumes for not only the whole brain, but tissues such as gray matter, white matter, cerebrospinal fluid, as well as all the different regions of interest. That normative data can act as a reference for other individuals who might be interested in seeing how a particular intervention influences brain growth or development in the pig," says Joanne Fil, doctoral student in the Neuroscience Program at Illinois and lead author on the atlas study.The previous pig brain atlas has been used by researchers to advance neuroscience around the world, with some 450 downloads to date. The collective discoveries made possible by the atlas go well beyond pediatric nutrition to include deeper understanding of the microbiota-gut-brain axis, which appears to relate to common clinical situations.Dilger says the new atlas will give researchers an even more precise view of the brain, enabling more advanced discoveries. And with the addition of the atlas for older pigs, they'll be able to extend their findings even farther."At 24 weeks of age, or six months, the pig is sexually mature. We would expect that by this age, the pig would have most, if not all, of its brain development completed," Fil says. "So now we're able to see how our interventions impact development not only at an early age, but also into adulthood in the pig."Fil adds the study also provides a detailed account of the process they used to create the atlas, giving researchers the blueprints to create additional atlases for other animals.But there's a lot to be said for pigs as an important biomedical research animal."You can study brain development in a mouse, but for some studies, the mouse brain is not similar to a human brain in some important aspects. Also, you can't really study intervention effects on the brain directly in humans, because although we can get people in the scanner, we can't always modify their diet and test out different components," Sutton says."So the pig is right in that sweet spot: its brain is the right size to use human MRI scanners and pig brain development closely matches that of humans. And we have tools to be able to study it in great detail, especially on this campus, and do great things with it. The pig is perfect for studying the brain."Dilger adds, "We are using the actual human clinical equipment in the pig. We're effectively, non-invasively, taking a microscope to the pig brain while it's still alive. That's the benefit. We can take a virtual peek inside the pig brain multiple times throughout the life of the pig to see how the brain is structurally developing."The new atlases are freely available for download at
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April 8, 2021
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https://www.sciencedaily.com/releases/2021/04/210408152306.htm
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Novel algorithm reveals birdsong features that may be key for courtship
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Researchers have developed a new algorithm capable of identifying features of male zebra finch songs that may underlie the distinction between a short phrase sung during courtship, and the same phrase sung in a non-courtship context. Sarah Woolley of McGill University in Montreal, Canada, and colleagues present these findings in the open-access journal
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Like many animals, male zebra finches adjust their vocal signals for their audience. They may sing the same sequence of syllables during courtship interactions with females as when singing alone, but with subtle modifications. However, humans cannot detect these differences, and it was not clear that female zebra finches could, either.For the new study, Woolley and colleagues first conducted behavioral experiments demonstrating that female zebra finches are indeed highly adept at discriminating between short segments of males' songs recorded in courtship versus non-courtship settings.Next, they sought to expand on earlier studies that have focused on just a few specific song features that may underlie the distinction between courtship and non-courtship song. Taking a "bottom-up" approach, the researchers extracted over 5,000 song features from recordings and trained an algorithm to use those features to distinguish between courtship and non-courtship song phrases.The trained algorithm uncovered features that may be key for song perception, some of which had not been identified previously. It also made predictions about the distinction capabilities of female zebra finches that aligned well with the results of the behavioral experiments.These findings highlight the potential for bottom-up approaches to reveal acoustic features important for communication and social discrimination."As vocal communicators ourselves, we have a tendency to focus on aspects of communication signals that are salient to us," Woolley says. "Using our bottom-up approach, we identified features that might never have been on our radar."Next, the researchers plan to test whether manipulating the acoustic features they discovered alters what female finches think about those songs. They also hope to evaluate how well their findings might generalize to courtship and non-courtship songs in other species.
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April 8, 2021
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https://www.sciencedaily.com/releases/2021/04/210408131427.htm
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Archaeologists uncover earliest evidence of domesticated dogs in Arabian Peninsula
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A team of archaeologists in north-west the Kingdom of Saudi Arabia has uncovered the earliest evidence of dog domestication by the region's ancient inhabitants.
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The discovery came from one of the projects in the large-scale archaeological surveys and excavations of the region commissioned by the Royal Commission for AlUla (RCU).The researchers found the dog's bones in a burial site that is one of the earliest monumental tombs identified in the Arabian Peninsula, roughly contemporary with such tombs already dated further north in the Levant.Evidence shows the earliest use of the tomb was circa 4300 BCE and received burials for at least 600 years during the Neolithic-Chalcolithic era -- an indication that the inhabitants may have had a shared memory of people, places and the connection between them."What we are finding will revolutionize how we view periods like the Neolithic in the Middle East. To have that kind of memory, that people may have known for hundreds of years where their kin were buried -- that's unheard of in this period in this region," said Melissa Kennedy, assistant director of the Aerial Archaeology in the Kingdom of Saudi Arabia (AAKSAU) -- AlUla project."AlUla is at a point where we're going to begin to realize how important it was to the development of humankind across the Middle East," said the AAKSAU director, Hugh Thomas.This is the earliest evidence of a domesticated dog in the Arabian Peninsula by a margin of circa 1,000 years.The findings are published in the The project team, with Saudi and international members, focused its efforts on two above-ground burial sites dating to the 5th and 4th millennia BCE and located 130 kilometers apart, one in volcanic uplands and the other in arid badlands. The sites were above ground, which is unique for that period of Arabian history, and were positioned for maximum visibility.The research team detected the sites by using satellite imagery and then by aerial photography from a helicopter. Ground fieldwork began in late 2018.It was in the volcanic uplands site that 26 fragments of a single dog's bones were found, alongside with bones from 11 humans -- six adults, an adolescent and four children.The dog's bones showed signs of arthritis, which suggests the animal lived with the humans into its middle or old age.After assembling the bones, the team then had to determine that they were from a dog and not from a similar animal such as a desert wolf.The team's zoo archaeologist, Laura Strolin, was able to show it was indeed a dog by analyzing one bone in particular, from the animal's left front leg. The breadth of this bone was 21.0 mm, which is in the range of other ancient Middle Eastern dogs. In comparison, the wolves of that time and place had a breadth of 24.7 to 26 mm for the same bone.The dog's bones were dated to between circa 4200 and 4000 BCE.Rock art found in the region indicates that the Neolithic inhabitants used dogs when hunting ibex, and other animals.The fieldwork uncovered other noteworthy artefacts, including a leaf-shaped mother-of-pearl pendant at the volcanic uplands site and a carnelian bead found at the arid badlands site.The researchers expect more findings in future as a result of the massive survey from the air and on the ground, and multiple targeted excavations in the AlUla region undertaken by the AAKSAU and other teams, which are operating under the auspices of the Royal Commission for AlUla (RCU). The AAKSAU team is led by researchers from the University of Western Australia in Perth, Australia.The researchers note that AlUla is a largely unexplored area located in a part of the world that has a fertile archaeological heritage of recognized global value."This article from RCU's work at AlUla establishes benchmarks. There is much more to come as we reveal the depth and breadth of the area's archaeological heritage," said Rebecca Foote, Director of Archaeology and Cultural Heritage Research for RCU.
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April 8, 2021
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https://www.sciencedaily.com/releases/2021/04/210408131418.htm
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'Bug brain soup' expands menu for scientists studying animal brains
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Using a surprisingly simple technique, researchers in the University of Arizona Department of Neuroscience have succeeded in approximating how many brain cells make up the brains of several species of bees, ants and wasps. The work revealed that certain species of bees have a higher density of brain cells than even some species of birds, whereas ants turned out to have fewer brain cells than originally expected.
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Published in the scientific journal For more than a century, scientists have attempted to measure and compare the brains and brain components of vertebrates across species in efforts to draw conclusions about how brains support the animals' behavioral and cognitive abilities and ecological requirements. Theories of cognitive capacities of animal brains, including those of fossilized remains of the evolutionary ancestors of humans, are based on such measures.To that end, scientists need to know how many neurons make up a given brain. Until recently, it was extremely tedious and time-consuming to count or estimate the number of neurons in a brain, even with computer and software-based systems.For this reason, there were very few reliable neuron numbers available for any animals, including the human brain. Instead, brain researchers relied on estimates and extrapolations based on measurements of brain size or mass. But that approach can be fraught with uncertainties and biases, according to the authors of this study. For example, while larger animals, as a general rule, tend to have larger brains than smaller animals, the volume and mass of a given brain alone don't say much about its cognitive capabilities."How big or how heavy a brain is does not give you the best measure of an animal's cognitive capabilities," says the study's lead author, R. Keating Godfrey, a postdoctoral researcher in the Department of Molecular and Cellular Biology.One major reason is that the size of a brain is less relevant for its processing capacities compared with the number of neurons, or nerve cells, it contains. This is analogous to the processing power of a computer, which has little to do with the physical size of its central processor. Neurons are highly specialized types of cells found in virtually any species across the animal kingdom.Contrast, for example, the sea hare -- a giant sea slug found off the coast of California that can weigh more than 12 pounds -- with the fruit fly Drosophila. The sea slug's brain alone dwarfs the entire fly by a lot, yet it has just 18,000 neurons, far fewer than the fly's approximately 100,000."Just because the brain of one species may be 10 times larger than that of another does not mean it has 10 times as many neurons," says the paper's senior author, Wulfila Gronenberg, a professor of neuroscience who heads a Department of Neuroscience research group dedicated to unraveling the mysteries of insect brains.Whereas "bird brain" is widely used as a derogatory term for a lack of intelligence, it actually is a misnomer, Gronenberg says."Bird brains have many more neurons than a typical mammal of comparable size," he says. "Birds have to navigate a three-dimensional space by flight, and in order to get all that processing power into a small, lightweight package, their neurons are smaller and more densely packed."Gronenberg's research group is interested in the neuronal underpinnings of insects that live in social communities, like honeybees or many wasps."We wanted to know: Is there something special about the brains of social insects?" Godfrey says.Specifically, she and her colleagues set out to study whether the "social brain" hypothesis, which was developed for vertebrate animals and postulates that the size of a brain or particular brain region is correlated with social group size and group behaviors, also holds true for social insects.With the help of undergraduate students, Godfrey worked on adapting a technique -- developed in 2005 by Brazilian neuroscientist Suzanna Herculano-Houzel that revolutionized the field of vertebrate neuroscience -- to the insect brains. Instead of slicing brains into hundreds or thousands of thin sections and counting neurons in each section, the method requires only that the brain tissue is homogenized. That's science speak for "blended," which results in a brain soup."We release the nuclei from the cells so we can count them," Godfrey says. "Vertebrates have dedicated brain regions and structures that you can sample from, but in insects, we can only really squish the whole thing. So we get a neuron density count for the entire brain."Godfrey and her co-authors compared the brain cell counts with the body sizes of a large range of hymenoptera -- bees, wasps and ants -- and found that the neuron number and brain size relationships are very similar to those found in vertebrates.Certain bees, the team reports, have particularly high numbers of neurons, which should stimulate renewed research into their behavioral capacities, and ants, in general, have fewer neurons than their wasp and bee relatives, probably because they do not fly and thus need less brain power for visual processing and flight control.Some bees, it turned out, have even higher brain cell densities than some of the most compact bird and mammal brains. For example, the metallic green sweat bee, which is commonly seen in the Southwest and belongs to the genus Augochlorella, has a particularly high number of neurons for its brain size: about 2 million per milligram, more than the highest neuron densities found in the smallest vertebrate species -- smoky shrews in mammals and goldcrests in birds.Ants, on the other hand, tended to come in on the lower end of the spectrum. Compared with bees and wasps, ants had small brains and relatively few brain cells. A desert harvesting ant species common in Arizona amounted to just 400,000 cells per milligram of brain mass. Considering that this ant's brain weighs in at less than 1 milligram, this animal makes do with a total of 90,000 or so brain cells, Gronenberg estimates."We think this has to do with the ability to fly, which would make it less about intelligence but more about processing of information," he says. "Ants rely on scent information, whereas bees rely more on visual information."These findings beg the question of how many brain cells nature needs to make a functioning brain. Invertebrate brains tend to have highly specialized neurons, each performing a certain task, according to the authors of the study, which allows them to accomplish tasks with a small brain and a small number of neurons.Gronenberg points to the tiny fairy wasp as a strong contender for the "tiniest brain in the insect world" award. Three strands of human hair, laid side by side, would cover the body length of the tiny creature, whose brain consists of fewer than 10,000 neurons."Yet, this parasitic wasp can do all the things it needs to do to survive," Gronenberg says."It can find a host, it can mate, it can lay eggs, it can walk and it can fly," he says. "While a small insect may just have one or a few neurons to perform a particular function, humans and other vertebrates tend to have many thousands, or even tens of thousands, of these specialized neurons dedicated to one task, which allows us to do things more precisely and in a more sophisticated way."This work was supported by the National Science Foundation (grant number ISO-1354191) and a fellowship from the university's Graduate Interdisciplinary Program.
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April 8, 2021
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https://www.sciencedaily.com/releases/2021/04/210408131415.htm
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Dogs act jealously even when they don't see their rival
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Past surveys have shown that more than 80% of dog owners report observing jealous behaviors from their dogs -- vocalizations, agitated behavior, pulling on a leash -- when they give attention to other dogs. New research published in the journal
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"Research has supported what many dog owners firmly believe -- dogs exhibit jealous behavior when their human companion interacts with a potential rival," said Amalia Bastos with the University of Auckland and lead author on the paper. "We wanted to study this behavior more fully to determine if dogs could, like humans, mentally represent a situation that evoked jealousy."Dogs appear to be one of the few species that might display jealous behaviors in ways similar to a human child showing jealousy when their mother gives affection to another child. In humans, jealousy is closely linked with self-awareness, which is one reason animal-cognition researchers are so interested in studying jealousy and other secondary emotions in animals.To test how and when dogs display jealous behavior, the researchers presented 18 dogs with situations where they could imagine a social interaction between their human companion and either a realistic fake dog or a fleece cylinder. The fake dog served as a potential rival for attention while the cylinder served as a control.In the experiment, the dogs observed the fake-dog rival positioned next to their owner. A barrier was then placed between the dog and the potential rival obscuring them from view. Despite blocking the line of sight, the dogs forcefully attempted to reach their owners when they appeared to stroke the rival fake dog behind the barrier. In a repeat experiment using a fleece cylinder rather than a fake dog, the dogs pulled on the lead with far less force.Through their study, Bastos and her colleagues found that dogs showed three human-like signatures of jealous behavior. Jealous behavior emerged only when their owner interacted with a perceived social rival and not an inanimate object; occurred as a consequence of that interaction and not due to a potential rival's mere presence; and emerged even for an out-of-sight interaction between their owner and a social rival."These results support claims that dogs display jealous behavior. They also provide the first evidence that dogs can mentally represent jealousy-inducing social interactions," said Bastos. "Previous studies confounded jealous behavior with play, interest, or aggression, because they never tested the dogs' reactions to the owner and the social rival being present in the same room but not interacting.""There is still plenty of work to do to establish the extent of the similarities between the minds of humans and other animals, especially in terms of understanding the nature of nonhuman animals' emotional experiences," said Bastos. "It is too early to say whether dogs experience jealousy as we do, but it is now clear that they react to jealousy-inducing situations, even if these occur out-of-sight."
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April 8, 2021
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https://www.sciencedaily.com/releases/2021/04/210408112358.htm
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Gorillas do not bluff when they chest beat: Honest signalling indicates body size
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Gorillas usually stand bipedally and rapidly beat their chests with cupped hands in rapid succession. Chest beating is a unique sound because is it not a vocalization, like frogs croaking, but rather it is a form of gestural communication that can be both heard and seen. The emanating drumming sound can be heard over one kilometre away. The presumed function of gorilla chest beats is to attract females and intimidate rival males.
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Researchers recorded chest beats and used a technique called photogrammetry to non-invasively measured body size of adult male wild mountain gorillas monitored by the Dian Fossey Gorilla Fund in Volcanoes National Park, Rwanda. They found that larger males emitted chest beats with lower peak frequencies than smaller ones. In other words, chest beats conveyed information regarding the body size of the chest beater."The gorilla chest beat is one of those iconic sounds from the animal kingdom, so it is great that we have been able to show that body size is encoded in these spectacular displays," says Edward Wright, the first author of the study from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.Body size is a key attribute in many animals as it often reflects fighting or competitive ability. Previous research by this team showed that larger males were more socially dominant and more successful in terms of reproduction than smaller males."Conducting this study was challenging because the chest beats are relatively short in duration and the we needed to be in the right place at the right time to obtain the sound recordings, as well as staying clear from these large powerful animals," says co-author Eric Ndayishimiye, research assistant with the Dian Fossey Gorilla Fund.Rival males are likely to attend to the body size information transmitted in chest beats as it allows them to assess the competitive ability of the chest beater, this will help them decide whether to initiate, escalate or retreat in aggressive contests with them. Females on the other hand, are likely to use this information in their choice of potential mates.Interestingly, the researchers also found a great deal of variation among males in both the number of beats comprised in a chest beat as well as the duration of the chest beat. "This hints at the possibility that chest beats may have individual signatures, but further study is needed to test this," says Wright.
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April 8, 2021
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https://www.sciencedaily.com/releases/2021/04/210408112349.htm
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Early dispersal of neolithic domesticated sheep into the heart of central Asia
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Along the Tian Shan and Alay mountain ranges of Central Asia, sheep and other domestic livestock form the core economy of contemporary life. Although it was here that the movements of their ancient predecessors helped to shape the great trade networks of the Silk Road, domestic animals were thought to have come relatively late to the region. A new study, published today in the journal
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The domestication of sheep, goat, and cattle first took place in the Fertile Crescent of Mesopotamia and the nearby mountain zones of western Asia roughly 10,000 years ago, in lockstep with the first domestication of plant crops like wheat and barley. This innovation in human subsistence, known as the Neolithic Revolution, spread northwards to Europe and southwards to Africa and India, transforming human societies across three continents. But until recently, it seemed that this dramatic expansion of domestic plants and animals failed to reach eastward to the rich mountain zones of Central Asia, where -- despite their outsized significance in the later millennia of the Bronze Age and beyond -- there was little evidence of a Neolithic dispersal.That changed when a joint team of international scientists, led by Dr. Svetlana Shnaider of Russia's Institute of Archaeology and Ethnography (RAS-Siberia, Novosibirsk) and Dr. Aida Abdykanova of the American University of Central Asia (Kyrgyzstan), decided to revisit rockshelter Obishir V, tucked into a mountain precipice along Kyrgyzstan's southern border with Uzbekistan. The site, which was first discovered and excavated by Soviet archaeologists in the 20th century, had yielded an unusual assemblage of stone tools, some of which seemed to have been used for processing grains. Furthermore, sprinkled throughout the layers of the site's geologic strata were the fragmented remains of what appeared to be sheep and goats.Could this be evidence of an ancient, undocumented Neolithic movement of domestic animals deep into the interior of Central Asia? To find out, Shnaider and Abykanova partnered with lead author Dr. William Taylor, a specialist in the study of animal domestication at the University of Colorado-Boulder's Museum of Natural History and the Max Planck Institute for the Science of Human History, along with a team of international experts from across Europe and the United States. After radiocarbon dating bones and teeth from the site, it became clear that the oldest cultural layer dated at least as far back as ca. 6000 BCE, or more than 8,000 years ago -- three millennia earlier than domestic animals were thought to have reached Central Asia.Burning, cut marks, and other changes to the animal bones showed that they had been butchered, while patterns of microscopic seasonal layering within the animals' tooth cementum indicated that they were slaughtered in the fall, as is common in many herding societies. But because the bones were highly fragmented, the species could not be identified using standard anatomical analysis. Instead, the researchers applied an interdisciplinary approach using both paleogenomics and collagen peptide fingerprinting to identify the animal remains. Comparing their results with the genomes of wild and domestic sheep species from across Eurasia, the researchers made a shocking discovery."With each new line of evidence, it became increasingly clear... these were not wild sheep -- they were domestic animals," says Taylor.For those that have worked for years to understand Central Asia's prehistory, the results are startling."This discovery just illustrates how many mysteries still remain regarding the prehistory of Inner Asia -- the cultural crossroads of the ancient world," says the Max Planck Institute's Dr. Robert Spengler -- a study co-author and author of Future work will be necessary to understand the full impact of the study's findings and their implications for the rest of ancient Eurasia. Shnaider plans to return to Obishir this coming summer to look for clues and to determine whether other domestic animals, like cattle, or domestic plants, such as wheat and barley, also spread to Kyrgyzstan from Mesopotamia in the deep past. With an award from the European Research Council, project partner and co-author Dr. Christina Warinner (Harvard/MPI-SHH) is spearheading an effort to investigate whether these first Central Asian sheep spread elsewhere in the region and whether they were used to produce dairy or wool."This work is just the beginning," says Taylor. "By applying these interdisciplinary techniques from archaeological science, we are starting to unlock the clues to Central Asia's past."
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April 7, 2021
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https://www.sciencedaily.com/releases/2021/04/210407135746.htm
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Ant responses to social isolation resemble those of humans
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Ants react to social isolation in a similar way as do humans and other social mammals. A study by an Israeli-German research team has revealed alterations to the social and hygienic behavior of ants that had been isolated from their group. The research team was particularly surprised by the fact that immune and stress genes were downregulated in the brains of the isolated ants. "This makes the immune system less efficient, a phenomenon that is also apparent in socially isolating humans -- notably at present during the COVID-19 crisis," said Professor Susanne Foitzik, who headed up the study at Johannes Gutenberg University Mainz (JGU). The study on a species of ant native to Germany has recently been published in
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Humans and other social mammals experience isolation from their group as stressful, having a negative impact on their general well-being and physical health. "Isolated people become lonely, depressed, and anxious, develop addictions more easily, and suffer from a weakened immune system and impaired overall health," added Professor Inon Scharf, lead author of the article and cooperation partner of the Mainz research group at Tel Aviv University in Israel. While the effects of isolation have been extensively studied in social mammals such as humans and mice, less is known about how social insects respond in comparable situations -- even though they live in highly evolved social systems. Ants, for instance, live their entire lives as members of the same colony and are dependent on their colony mates. The worker ants relinquish their own reproductive potential and devote themselves to feeding the larvae, cleaning and defending the nest, and searching for food, while the queen does little more than just lay eggs.The research team looked at the consequences of social isolation in the case of ants of the species Temnothorax nylanderi. These ants inhabit cavities in acorns and sticks on the ground in European forests, forming colonies of a few dozen workers. Young workers engaged in brood care were taken singly from 14 colonies and kept in isolation for varying lengths of time, from one hour to a maximum of 28 days. The study was conducted between January and March 2019 and highlighted three particular aspects in which changes were observed. After the end of their isolation, the workers were less interested in their adult colony mates, but the length of time they spent in brood contact increased; they also spent less time grooming themselves. "This reduction in hygienic behavior may make the ants more susceptible to parasites, but it is also a feature typical of social deprivation in other social organisms," explained Professor Susanne Foitzik.While the study revealed significant changes in the behaviors of the isolated insects, its findings with regard to gene activity were even more striking: Many genes related to immune system function and stress response were downregulated. In other words, these genes were less active. "This finding is consistent with studies on other social animals that demonstrated a weakening of the immune system after isolation," said Professor Inon Scharf.The discovery by the team of biologists led by Professor Susanne Foitzik is the first of its kind, combining behavioral and genetic analyses on the effects of isolation in social insects. "Our study shows that ants are as affected by isolation as social mammals are and suggests a general link between social well-being, stress tolerance, and immunocompetence in social animals," concluded Foitzik, summarizing the results of the Israeli-German study. Foitzik is also collaborating with her Israeli partner Professor Inon Scharf and with co-author and group leader Dr. Romain Libbrecht of JGU on a new joint project on the fitness benefits and the molecular basis of spatial learning in ants, funded by the German Research Foundation (DFG).
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April 7, 2021
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https://www.sciencedaily.com/releases/2021/04/210407135726.htm
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Scientists discover two new species of ancient, burrowing mammal ancestors
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Paleontologists have discovered two new species of mammal-like, burrowing animals that lived about 120 million years ago in what is now northeastern China. The new species, described today in the journal
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"There are many hypotheses about why animals dig into the soil and live underground," said lead author Jin Meng, a curator in the American Museum of Natural History's Division of Paleontology. "For protection against predators, to maintain a temperature that's relatively constant -- not too hot in the summer and not too cold in the winter -- or to find food sources like insects and plant roots. These two fossils are a very unusual, deep-time example of animals that are not closely related and yet both evolved the highly specialized characteristics of a digger."The fossil mammaliamorph species -- predecessors to mammals -- were discovered in the Jehol Biota, which represents the Early Cretaceous epoch, about 145 to 100 million years ago. One is a mammal-like reptile called a tritylodontid and is the first of its kind to be identified in this biota. About a foot in length, it was given the name Fossiomanus sinensis (Fossio, "digging" and manus "hand;" sinensis, "from China"). The other is named Jueconodon cheni (Jue, "digging" -- Chinese pinyin -- and conodon "cuspate tooth"; cheni for Y. Chen, who collected the fossil). It is a eutriconodontan, a distant cousin of modern placental mammals and marsupials, which were common in the habitat. It is about 7 inches long.Mammals that are adapted to burrowing have specialized traits for digging. The researchers found some of these hallmark features -- including shorter limbs, strong forelimbs with robust hands, and a short tail -- in both Fossiomanus and Jueconodon. In particular, these characteristics point to a type of digging behavior known as "scratch digging," accomplished mainly by the claws of the forelimbs."This is the first convincing evidence for fossorial life in those two groups," Meng said. "It also is the first case of scratch diggers we know about in the Jehol Biota, which was home to a great diversity of life, from dinosaurs to insects to plants."The animals also share another unusual feature: an elongated vertebral column. Typically, mammals have 26 vertebrae from the neck to the hip. However, Fossiomanus had 38 vertebrae -- a staggering 12 more than the common state -- while Jueconodon had 28. To try to determine how these animals got their elongated trunks, the paleontologists turned to recent studies in developmental biology, finding that the variation could be attributed to gene mutations that determine the number and shape of the vertebrae in the beginning of the animals' embryotic development. Variation in vertebrae number can be found in modern mammals as well, including in elephants, manatees, and hyraxes.Other authors on the study include Fangyuan Mao from the Chinese Academy of Sciences and the American Museum of Natural History, Chi Zhang from the Chinese Academy of Sceinces, and Cunyu Liu from the Beipiao Pterosaur Museum of China.This study was supported in part by the National Natural Science Foundation of China, grant no.s 41688103 and 42072002; the Chinese Academy of Sciences Strategic Priority Research Program, Youth Innovation Promotion Association, and 100 Young Talents Program; and the Kalbfleisch Fellowship of the American Museum of Natural History's Richard Gilder Graduate School.
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Animals
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April 6, 2021
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https://www.sciencedaily.com/releases/2021/04/210406131941.htm
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Understanding fruit fly behavior may be next step toward autonomous vehicles
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With over 70% of respondents to a AAA annual survey on autonomous driving reporting they would fear being in a fully self-driving car, makers like Tesla may be back to the drawing board before rolling out fully autonomous self-driving systems. But new research from Northwestern University shows us we may be better off putting fruit flies behind the wheel instead of robots.
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Drosophila have been subjects of science as long as humans have been running experiments in labs. But given their size, it's easy to wonder what can be learned by observing them. Research published today in the journal "The discovery that flexible decision-making, learning and memory are used by flies during such a simple navigational task is both novel and surprising," said Marco Gallio, the corresponding author on the study. "It may make us rethink what we need to do to program safe and flexible self-driving vehicles."According to Gallio, an associate professor of neurobiology in the Weinberg College of Arts and Sciences, the questions behind this study are similar to those vexing engineers building cars that move on their own. How does a fruit fly (or a car) cope with novelty? How can we build a car that is flexibly able to adapt to new conditions?This discovery reveals brain functions in the household pest that are typically associated with more complex brains like those of mice and humans."Animal behavior, especially that of insects, is often considered largely fixed and hard-wired -- like machines," Gallio said. "Most people have a hard time imagining that animals as different from us as a fruit fly may possess complex brain functions, such as the ability to learn, remember or make decisions."To study how fruit flies tend to escape heat, the Gallio lab built a tiny plastic chamber with four floor tiles whose temperatures could be independently controlled and confined flies inside. They then used high-resolution video recordings to map how a fly reacted when it encountered a boundary between a warm tile and a cool tile. They found flies were remarkably good at treating heat boundaries as invisible barriers to avoid pain or harm.Using real measurements, the team created a 3D model to estimate the exact temperature of each part of the fly's tiny body throughout the experiment. During other trials, they opened a window in the fly's head and recorded brain activity in neurons that process external temperature signals.Miguel Simões, a postdoctoral fellow in the Gallio lab and co-first author of the study, said flies are able to determine with remarkable accuracy if the best path to thermal safety is to the left or right. Mapping the direction of escape, Simões said flies "nearly always" escape left when they approach from the right, "like a tennis ball bouncing off a wall.""When flies encounter heat, they have to make a rapid decision," Simões said. "Is it safe to continue, or should it turn back? This decision is highly dependent on how dangerous the temperature is on the other side."Observing the simple response reminded the scientists of one of the classic concepts in early robotics."In his famous book, the cyberneticist Valentino Braitenberg imagined simple models made of sensors and motors that could come close to reproducing animal behavior," said Josh Levy, an applied math graduate student and a member of the labs of Gallio and applied math professor William Kath. "The vehicles are a combination of simple wires, but the resulting behavior appears complex and even intelligent."Braitenberg argued that much of animal behavior could be explained by the same principles. But does that mean fly behavior is as predictable as that of one of Braitenberg's imagined robots?The Northwestern team built a vehicle using a computer simulation of fly behavior with the same wiring and algorithm as a Braitenberg vehicle to see how closely they could replicate animal behavior. After running model race simulations, the team ran a natural selection process of sorts, choosing the cars that did best and mutating them slightly before recombining them with other high-performing vehicles. Levy ran 500 generations of evolution in the powerful NU computing cluster, building cars they ultimately hoped would do as well as flies at escaping the virtual heat.This simulation demonstrated that "hard-wired" vehicles eventually evolved to perform nearly as well as flies. But while real flies continued to improve performance over time and learn to adopt better strategies to become more efficient, the vehicles remain "dumb" and inflexible. The researchers also discovered that even as flies performed the simple task of escaping the heat, fly behavior remains somewhat unpredictable, leaving space for individual decisions. Finally, the scientists observed that while flies missing an antenna adapt and figure out new strategies to escape heat, vehicles "damaged" in the same way are unable to cope with the new situation and turn in the direction of the missing part, eventually getting trapped in a spin like a dog chasing its tail.Gallio said the idea that simple navigation contains such complexity provides fodder for future work in this area.Work in the Gallio lab is supported by the NIH (Award No. R01NS086859 and R21EY031849), a Pew Scholars Program in the Biomedical Sciences and a McKnight Technological Innovation in Neuroscience Awards.
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Animals
| 2,021 |
April 6, 2021
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https://www.sciencedaily.com/releases/2021/04/210406131937.htm
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Birds can change their traditions for the better, study shows
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Researchers at the University of Konstanz and Max Planck Institute for Animal Behavior in Germany have found that birds are able to change their culture to become more efficient. Populations of great tits were able to switch from one behavior to a better alternative when their group members were slowly replaced with new birds. Published today as open access in the journal
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In animals, "culture" is considered to be any behavior that is learned from others, shared by members of the group, and persistent over generations. Cultural traditions are known to exist in many animal groups, including primates, dolphins and whales, rodents, and birds.Great tits provide a classic example of animal culture. In the 1920s, birds in a town in Great Britain were observed to open the foil tops of milk bottles to steal cream. This behavior spread over 20 years, until birds throughout the country were doing the same.In 2015 scientists experimentally confirmed that great tits were able to maintain cultural traditions. A new way of feeding -- what scientists refer to as an innovation -- could be taught to a single bird, and that solution would be learned by other birds and gradually spread throughout populations.But for great tits, and other animals with cultural traditions, it was still not known if groups can change. Once a tradition has taken root, are animals condemned to repeating the same behaviors or can they pivot to more efficient ones?Now, the new study has demonstrated that more efficient behaviors can outcompete an established inefficient behavior. It pinpoints a fundamental process -- population turnover -- as crucial for the ability of animals to change their traditions. The study, which involved teaching wild-caught birds to solve puzzles and fine-scale tracking of their behavior, provides quantitative support for the evolution of culture."Experimental evidence of cultural change in animals is pretty rare, so we were surprised and excited by the outcome," says first author Michael Chimento, a doctoral student in the Research Group of Cognitive and Cultural Ecology at the Max Planck Institute of Animal Behavior.The research team led by senior author Lucy Aplin, who is a Max Planck Research Group Leader and also a principal investigator at the Custer of Excellence 'Centre for the Advanced Study of Collective Behavior' at the University of Konstanz, studied populations of great tits caught from forests around Konstanz. Because wild great tits form changeable social groups during winter, when conditions are harshest, the scientists thought that immigration could play a part in cultural evolution."These fluid groups could influence how their culture changes, as new group members might see solutions to problems with clearer eyes, because of their lack of experience," says Chimento.The researchers used captive populations of wild-caught great tits to ask how fluid social groups might change a socially learned feeding tradition. They created 18 groups of birds, each with an automated puzzle-box that gave a reward. When a bird solved the puzzle, the type of solution, time of solution, and identity were recorded using RFID, infrared, and computer vision technology. Each group had a tutor that was trained on a relatively inefficient puzzle solution, which then spread through the group. Then, half of the groups were kept static, and in the other half, group members were gradually replaced with new birds from wild over the course of 4 weeks.Despite both types of groups innovating a more efficient solution, fluid groups were much more likely to adopt it as their preferred behavior. The original residents, who were experienced with the puzzle, were generally the ones who innovated the efficient solution, but didn't adopt it as their preferred behavior. The inexperienced immigrants, on the other hand, picked up on this innovation and did adopt it, amplifying the available social information. Birds in fluid groups were able to solve the puzzle-box faster than in static groups, despite having less overall experience."Great tits seem to do well in and among human-made habitats, compared to other species," says Chimento. "Our study shows how their fluid social dynamics might be part of their secret to success and contribute to their flexibility.
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Animals
| 2,021 |
April 6, 2021
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https://www.sciencedaily.com/releases/2021/04/210406120720.htm
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New wasp species discovered in Norway
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Cuckoo wasps -- also called emerald wasps -- are some of the most beautiful insects we have, with colourful exteriors that shine like jewels. However, these beauties have also created a lot of headaches.
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"Normally we distinguish insects from each other by their appearance, but cuckoo wasps are so similar to each other that it makes it difficult," says Frode Ødegaard.Ødegaard is an insect researcher at the NTNU (Norwegian University of Science and Technology) University Museum and belongs to the European research group that has now described thia recent contribution to species diversity. The new species is very rare, and is only a single specimen has been found on the Lista peninsula in Agder county in Norway.For more than 200 years, insect researchers have struggled to sort cuckoo wasps into the right "species boxes," and to determine which characteristics are variations within a species and which are species-specific differences.In the last 10 years, DNA barcoding has brought about a major breakthrough by making it possible to distinguish different species of cuckoo wasps from each other by looking at the differences in their genetic material."But it's not always that easy, either. In this case, we had two cuckoo wasps with microscopic differences in appearance and very small differences in DNA," Ødegaard says."The next step was to look at the language of each of the wasps to find out if they belonged to different species," he says.Insects communicate with each other through pheromones -- in other words, they have a chemical language. Very closely related species often have completely different languages to prevent them from interbreeding.The cuckoo wasp is an insect with above-average linguistic abilities. They are parasites, which means that they behave like cuckoos and lay their eggs in the nests of other bees and wasps. The larvae grow quickly and hatch before the host's eggs. Then they eat the eggs, the larvae and the food supply that the host has arranged in the nest."When you live as a parasite, it's important not to be discovered, and therefore the cuckoo wasp has also learned the language of its host," says Ødegaard.By conducting an ever-so-small language study, the researchers were able to discover that the two almost identical cuckoo wasps did indeed belong to different species. They use different hosts -- and that means that they also speak completely different languages."The evolutionary development associated with sponging off another species happens very fast. That's why you can have two species that are really similar genetically but still belong to different species," says Ødegaard.When a new species is described it has to be given a name, and Frode Ødegaard had the good fortune to receive the honour of naming the newcomer."A naming competition was announced among researchers in Europe who work with cuckoo wasps, and then the proposals that came in were voted on. It turned out my proposal actually got the most votes!" Ødegaard says."As mentioned, the new wasp is very similar to another species called Ødegaard was also responsible for giving the species its slightly simpler Norwegian name of sporegullveps. He makes no secret of the fact that he found it great to be able to name a new species."In a way, you place yourself in the perspective of eternity, because that species will always have that name. There's something very fundamental about it."The only known specimen of this cuckoo wasp has been captured and pinned in an insect collection. So it may seem both morally reprehensible and unnecessary that this one lone individual was stuck onto a needle."Even with today's advanced methods, using live animals for studies like this isn't possible, but collecting individual specimens fortunately has no impact on the population," Ødegaard says."The insects have enormous reproductive potential, and the size and quality of the habitats are what determine the viability of the population, not whether any specimens are eaten by birds or collected by an insect researcher."He adds that the collected insects are absolutely crucial for researchers to be able to map and describe their diversity and thus take care of viable populations for posterity.
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Animals
| 2,021 |
April 6, 2021
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https://www.sciencedaily.com/releases/2021/04/210406120701.htm
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Being top baboon costs males their longevity
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Some guys have it all: the muscle, the power, the high social status, the accelerated aging.
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But wait. Faster aging? Who wants that? For male baboons, it's the price they pay to be at the top.New research appearing April 6 in Using blood samples from 245 wild baboons in the Amboseli ecosystem in Kenya, the team analyzed chemical modifications to DNA known as DNA methylation marks."These marks change with age in a clock-like fashion," Tung said. "However, environmental stressors can make the clock tick faster." This would make an individual appear older than they really are, and, research in humans suggests, can put them at a higher risk of aging-related disease.Since this cohort of baboons is one of the most intensively studied wild mammal populations in the world, the researchers already knew not only each baboon's age, but also the environment in which they grew up, their exposure to early life adversity, and a great deal about their adult environment, especially the aspects that predict how long they live and how many offspring they leave behind."We used DNA methylation to compare the baboons known ages to their 'biological ages,'" said Jordan Anderson, a graduate student in the Tung lab who co-led the work. These methylation markers are found across the genome, so the team first needed to measure a large number of these sites -- about 400,000 of them -- and then, through statistical methods and models, whittle the number of sites down to about 500 that best predicted age.Interestingly, for males, early life adversity didn't affect how fast their biological clocks tick.Adult social status was the strongest factor that affected aging. "Male baboons who compete successfully for high social status appear to age faster," Tung said. "We repeatedly sampled some of these males and were able to show that the clock can speed up or slow down as males move up or down the social ladder."This is contrary to what we see in humans. Typically, high social status in humans predicts better health, not worse. The most wealthy and powerful humans have access to and can afford the best houses, schools, healthcare and more. Those who live in poverty and have lower socioeconomic status are at increased risk and have higher rates of disease, cancer and all-cause mortality.Male baboons, though, have to fight for their social status. Because of this, it's common to see male-male competition on a regular basis, where baboon observers can see a clear winner and a clear loser.To maintain their social status, males at the top regularly have to hold their ground and defend themselves physically. Because of this, male baboons at the top tend to have more muscle mass and better body condition than lower ranking baboons. But as their physicality starts to diminish with age, a new, younger, stronger male may overcome them for the top spot.High ranking males also spend a lot of time mate-guarding females. Around ovulation, they follow females closely and ward off other males. Mate-guarding constrains a male's other activities, and Tung and her team think it is likely to be energetically costly -- perhaps helping to explain their accelerated aging result.So why do these males work so hard to achieve a high stress social status? It's simple: to have offspring."If male baboons are going to have babies, they need to achieve high rank," Tung said. "They will have very little chance to leave offspring if they don't achieve high rank, which creates a powerful evolutionary motivation."This study highlights one way that the social environment can influence aging. "Our research shows that the manner in which social status is attained and maintained is crucial to understanding its consequences," Tung said.
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Animals
| 2,021 |
April 1, 2021
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https://www.sciencedaily.com/releases/2021/04/210401112411.htm
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Low risk of researchers passing coronavirus to North American bats
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The risk is low that scientists could pass coronavirus to North American bats during winter research, according to a new study led by the U.S. Geological Survey. Scientists find the overall risk to be 1 in 1,000 if no protective measures are taken, and the risk falls lower, to 1 in 3,333 or less, with proper use of personal protective equipment or if scientists test negative for COVID-19 before beginning research.
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The research specifically looked at the potential transmission of SARS-CoV-2, which is the type of coronavirus that causes COVID-19, from people to bats. Scientists did not examine potential transmission from bats to people."This is a small number, but the consequences of human-to-bat transmission of coronavirus are potentially large," said USGS scientist Evan Grant, an author of the new rapid risk assessment. "The virus has not been identified in North American bats, but if it is introduced, it could lead to illness and mortality, which may imperil long-term bat conservation. It could also represent a source for new exposure and infection in humans.""These are hard risks for wildlife managers and other decision makers to weigh as they consider whether and how to allow researchers to study bats in their winter colonies," continued Grant.Bats provide natural services that people value; for example, previous USGS studies found that bats save the U.S. agriculture industry more than $3 billion per year by eating pests that damage crops, reducing the need for pesticides. Yet they are often erroneously portrayed as menacing creatures at Halloween and in horror movies. They are also under duress from white-nose syndrome, a disease that has killed millions of bats in North America.The origin of SARS-CoV-2 is not confirmed, but studies indicate the virus likely originated from similar viruses found in bats in the Eastern Hemisphere.The rapid risk assessment conducted by the USGS and U.S. Fish and Wildlife Service focused on the winter season, when some wildlife scientists conduct field work that may require close contact with or direct handling of the animals. This includes research on white-nose syndrome and population studies that support Endangered Species Act decisions."If scientists wear protective equipment, particularly properly fitted masks with high filtration efficiency, or test negative for COVID-19 before conducting the research, they greatly reduce the risk of transmission to North American bats," said USGS scientist Michael Runge, another author on the new assessment."The current assessment represents the best available information and is useful for informing time-sensitive management decisions, but there are still many unknowns about how susceptible North American bats are to SARS-CoV-2 and how future virus variants may affect transmission," said Grant."The potential for SARS-CoV-2 to infect wildlife is a real concern for state and federal wildlife management agencies and reflects the important connections between human health and healthy environments," said Jeremy Coleman, National White-nose Syndrome Coordinator for the USFWS and an author of the paper. "Natural resource managers need information from these kinds of analyses to make science-based decisions that advance conservation efforts while also protecting the health of people, bats, and other wildlife."Three bat species -- free-tailed bats, little brown bats and big brown bats -- were included in the analysis. They were chosen because they have physical and behavioral differences and are typical of the kinds of bats studied in winter. Scientists considered different ways the virus could be transmitted between humans and bats, with airborne transmission as the main pathway.This study estimates transmission risk to at least one bat during a typical winter survey, which includes a team of five scientists spending one hour in a cave colonized by 1,000 bats.This research builds on a USGS-led study published last year that examined the likelihood of researchers transmitting SARS-CoV-2 to bats during summer research. Since that study, a substantial amount of new data and knowledge on the virus has been acquired and applied. Winter and summer research can involve different settings and activities.The USGS research was conducted through the Eastern Ecological Science Center at the Patuxent Research Refuge and National Wildlife Health Center.
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Animals
| 2,021 |
March 31, 2021
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https://www.sciencedaily.com/releases/2021/03/210331143144.htm
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Female monkeys use males as 'hired guns' for defense against predators
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Researchers with the Wildlife Conservation Society's (WCS) Congo Program and the Nouabalé-Ndoki Foundation found that female putty-nosed monkeys (Cercopithecus nictitans) use males as "hired guns" to defend from predators such as leopards.
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Publishing their results in the journal The results promote the idea that females' general alarm requires males to assess the nature of the threat and that it serves to recruit males to ensure group defense. Females only cease the alarm call when males produce calls associated with anti-predator defense. Results suggest that alarm-calling strategies depend on the sex of the signaler. Females recruit males, who identify themselves while approaching, for protection. Males reassure their female of their quality in predation defense, probably to assure future reproduction opportunities.Males advertise their commitment to serve as hired guns by emitting general "pyow" calls while approaching the rest of their group -- a call containing little information about ongoing events, but cues to male identity, similar as to a signature call. Hearing his "pyow" call during male approaches enables females to identify high quality group defenders already from a distance. This might contribute to long-term male reputation in groups, which would equip females to choose males that ensure their offspring's survival most reliably.Said the study's lead author Frederic Gnepa Mehon of WCS's Congo Program and the Nouabalé-Ndoki Foundation: "Our observations on other forest guenons suggest that if males do not prove to be good group protectors, they likely have to leave groups earlier than good defenders. To date, it remains unclear whether female guenons have a saying in mate choice, but our current results strongly suggest this possibility."In the course of this study, a new call type was consistently recorded named "kek." They found that the males used the "kek" call when exposed to a moving leopard model created by researchers for field experiments. Previous studies of putty-nosed monkeys in Nigeria never reported "keks." This new type of call could thus be population-specific or it could be uttered towards moving threats. If "kek" calls are population specific, this could suggest that different "dialects" exist amongst putty-nosed monkeys -- a strong indicator for vocal production learning, which is fiercely debated to exist in the animal kingdom.Said co-author Claudia Stephan Wildlife Conservation Society's (WCS) Congo Program and the Nouabalé-Ndoki Foundation: "Sexual selection might play a far more important role in the evolution of communication systems than previously thought. In a phylogenetic context, what strategies ultimately drove the evolution of communication in females and in males? Might there even be any parallels to female and male monkeys' different communication strategies in human language?"The authors say that current results considerably advanced the understanding of different female and male alarm calling both in terms of sexual dimorphisms in call production and call usage. Interestingly, although males have more complex vocal repertoires than females, the cognitive skills that are necessary to strategically use simple female repertoires seem to be more complex than those necessary to follow male calling strategies. In other words, female putty-nosed monkeys' alarms may contain little information, but they do so by purpose, namely to facilitate the manipulation of male behavior.
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Animals
| 2,021 |
March 31, 2021
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https://www.sciencedaily.com/releases/2021/03/210331143039.htm
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Invasive species costing over 1. 3 trillion over 4 decades
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An invasive exotic species is one deliberately or unwittingly introduced by humans into a new habitat, where it becomes an environmental menace. In addition to the loss of biodiversity and other ecological impacts resulting from its presence, an invasive species can lead to economic losses in certain sectors, including agriculture, tourism, and public health. Though biological invasion is the second leading cause of species extinction, decision makers and the general public are still largely unaware of the issue.
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After five years of study, the international research team directed by scientists from the Écologie, Systématique et Évolution (CNRS / Paris-Saclay University / AgroParisTech) research unit have reached an estimate of the cost to human society of invasive species: at least $1.288 trillion in the period from 1970 to 2017. While this yields an annual average of $26.8 billion, the yearly bill actually tripled each decade. In 2017 alone, it hit $162.7 billion, or 20 times the combined budgets of the WHO and the UN Secretariat that year.Yet the costs of biological invasions remain vastly underestimated and under-reported. They have ballooned over the last decades, and no reversal of the trend is visible on the horizon since the continued expansion of international commerce and transport generally brings with it more invasive species. Furthermore, the researchers note that expenses associated with preventing, monitoring, or combating the spread of these species are trifling in comparison with the cost of the damage they cause. The ravages of biological invasions by exotic species as diverse as the Asian tiger mosquito, red imported fire ant, floating primrose willow, zebra mussel, and black rat each account for losses of tens of billions of dollars.This research has provided the first complete tally of reported costs resulting from biological invasions around the world, all species combined. It is based on the conservative analysis of 850 studies, covering 2,419 cost estimates that the team of scientists standardized to enable comparison and categorization, according to forty-some variables (e.g., species, region, habitat, and economic sector), within the InvaCost database, whose ongoing development affords a real-time snapshot of the costs associated with biological invasions.
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Animals
| 2,021 |
March 31, 2021
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https://www.sciencedaily.com/releases/2021/03/210331143025.htm
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450-million-year-old sea creatures had a leg up on breathing
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A new study has found the first evidence of sophisticated breathing organs in 450-million-year-old sea creatures. Contrary to previous thought, trilobites were leg breathers, with structures resembling gills hanging off their thighs.
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Trilobites were a group of marine animals with half-moon-like heads that resembled horseshoe crabs, and they were wildly successful in terms of evolution. Though they are now extinct, they survived for more than 250 million years -- longer than the dinosaurs.Thanks to new technologies and an extremely rare set of fossils, scientists from UC Riverside can now show that trilobites breathed oxygen and explain how they did so. Published in the journal "Up until now, scientists have compared the upper branch of the trilobite leg to the non-respiratory upper branch in crustaceans, but our paper shows, for the first time, that the upper branch functioned as a gill," said Jin-Bo Hou, a UCR paleontology doctoral student who led the research.Among the oldest animals on earth, this work helps situate trilobites on the evolutionary tree more securely in between older arthropods, a large group of animals with exoskeletons, and crustaceans.The research was possible, in part, because of unusually preserved fossil specimens. There are more than 22,000 trilobite species that have been discovered, but the soft parts of the animals are visible in only about two dozen."These were preserved in pyrite -- fool's gold -- but it's more important than gold to us, because it's key to understanding these ancient structures," said UCR geology professor and paper co-author Nigel Hughes.A CT scanner was able to read the differences in density between the pyrite and the surrounding rock and helped create three-dimensional models of these rarely seen gill structures."It allowed us to see the fossil without having to do a lot of drilling and grinding away at the rock covering the specimen," said paleontologist Melanie Hopkins, a research team member at the American Museum of Natural History."This way we could get a view that would even be hard to see under a microscope -- really small trilobite anatomical structures on the order of 10 to 30 microns wide," she said. For comparison, a human hair is roughly 100 microns thick.Though these specimens were first described in the late 1800s and others have used CT scans to examine them, this is the first study to use the technology to examine this part of the animal.The researchers could see how blood would have filtered through chambers in these delicate structures, picking up oxygen along its way as it moved. They appear much the same as gills in modern marine arthropods like crabs and lobsters.Comparing the specimens in pyrite to another trilobite species gave the team additional detail about how the filaments were arranged relative to one another, and to the legs.Most trilobites scavenged the ocean floor, using spikes on their lower legs to catch and grind prey. Above those parts, on the upper branch of the limbs, were these additional structures that some believed were meant to help with swimming or digging."In the past, there was some debate about the purpose of these structures because the upper leg isn't a great location for breathing apparatus," Hopkins said. "You'd think it would be easy for those filaments to get clogged with sediment where they are. It's an open question why they evolved the structure in that place on their bodies."The Hughes lab uses fossils to answer questions about how life developed in response to changes in Earth's atmosphere. Roughly 540 million years ago, there was an explosive diversification in the variety and complexity of animals living in the oceans."We've known theoretically this change must have been related to a rise in oxygen, since these animals require its presence. But we have had very little ability to measure that," Hughes said. "Which makes findings like these all the more exciting."
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Animals
| 2,021 |
March 31, 2021
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https://www.sciencedaily.com/releases/2021/03/210331114805.htm
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Mice naturally engage in physical distancing
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When someone is sick, it's natural to want to stay as far from them as possible. It turns out this is also true for mice, according to an MIT study that also identified the brain circuit responsible for this distancing behavior.
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In a study that explores how otherwise powerful instincts can be overridden in some situations, researchers from MIT's Picower Institute for Learning and Memory found that when male mice encountered a female mouse showing signs of illness, the males interacted very little with the females and made no attempts to mate with them as they normally would. The researchers also showed that this behavior is controlled by a circuit in the amygdala, which detects distinctive odors from sick animals and triggers a warning signal to stay away."As a community, it's very important for animals to be able to socially distance themselves from sick individuals," says Gloria Choi, an associate professor of brain and cognitive sciences at MIT and a member of the Picower Institute. "Especially in species like mice, where mating is instinctively driven, it's imperative to be able to have a mechanism that can shut it down when the risk is high."Choi's lab has previously studied how illness influences behavior and neurological development in mice, including the development of autism-like behaviors following maternal illness during pregnancy. The new study, which appears today in The paper's lead author is MIT postdoc Jeong-Tae Kwon. Other authors of the paper include Myriam Heiman, the Latham Family Career Development Associate Professor of Neuroscience and a member of the Picower Institute, and Hyeseung Lee, a postdoc in Heiman's lab.For mice and many other animals, certain behaviors such as mating and fighting are innately programmed, meaning that the animals automatically engage in them when certain stimuli are present. However, there is evidence that under certain circumstances, these behaviors can be overridden, Choi says."We wanted to see whether there's a brain mechanism that would be engaged when an animal encounters a sick member of the same species that would modulate these innate, automatic social behaviors," she says.Previous studies have shown that mice can distinguish between healthy mice and mice that have been injected with a bacterial component called LPS, which induces mild inflammation when given at a low dose. These studies suggested that mice use odor, processed by their vomeronasal organ, to identify sick individuals.To explore whether mice would change their innate behavior when exposed to sick animals, the researchers placed male mice in the same cage with either a healthy female or a female that was showing LPS-induced signs of illness. They found that the males engaged much less with the sick females and made no effort to mount them.The researchers then tried to identify the brain circuit underlying this behavior. The vomeronasal organ, which processes pheromones, feeds into a part of the amygdala called the COApm, and the MIT team found that this region is activated by the presence of LPS-injected animals.Further experiments revealed that activity in the COApm is necessary to suppress the males' mating behavior in the presence of sick females. When COApm activity was turned off, males would try to mate with sick females. Additionally, artificially stimulating the COApm suppressed mating behavior in males even when they were around healthy females.The researchers also showed that the COApm communicates with another part of the amygdala called the medial amygdala, and this communication, carried by a hormone called thyrotropin releasing hormone (TRH), is necessary to suppress mating behavior. The link to TRH is intriguing, Choi says, because thyroid dysfunction has been implicated in depression and social withdrawal in humans. She now plans to explore the possibility that internal factors (such as mental state) can alter TRH levels in the COApm circuits to modulate social behavior."This is something we are trying to probe in the future: whether there's a link between thyroid dysfunction and modulation of this amygdala circuit that controls social behavior," she says.This study is part of a larger effort in Choi's lab to study the role of neuro-immune interactions in coordinating "sickness behaviors." One area they are investigating, for example, is whether pathogens might attempt to exert control over the animals' behavior and stimulate them to socialize more, allowing viruses or bacteria to spread further."Pathogens may also have the ability to utilize immune systems, including cytokines and other molecules, to engage the same circuits in the opposite way, to promote more engagement," Choi says. "This is a sort of far-flung, but very interesting and exciting idea. We want to examine host-pathogen interactions at a network level to understand how the same neuro-immune mechanisms can be differently employed by the host versus pathogen to either contain or spread the infection, respectively, within a community. For example, we want to follow sick animals through their interactions within the community while controlling their immune status and manipulating their neural circuits."The research was funded by the National Institute of Mental Health, the JPB Foundation, the Simons Center for the Social Brain Postdoctoral Fellowship program, and the Picower Fellowship program.
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March 31, 2021
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https://www.sciencedaily.com/releases/2021/03/210331103549.htm
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Scientists pinpoint our most distant animal relatives
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Scientists from Trinity College Dublin believe they have pinpointed our most distant animal relative in the tree of life and, in doing so, have resolved an ongoing debate. Their work finds strong evidence that sponges -- not more complex comb jellies -- were our most distant relatives.
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Sponges are structurally simple, lacking complex traits such as a nervous system, muscles, and a though-gut. Logically, you would expect these complex traits to have emerged only once during animal evolution -- after our lineage diverged from that of sponges -- and then be retained in newly evolved creatures thereafter.However, a debate has been raging ever since phylogenomic studies found evidence that our most distant animal relatives were in fact comb jellies. Comb jellies are considerably more complex than sponges, using a nervous system and muscles to detect and capture prey, for example, and a through-gut to help them digest it.As such, if they were our most distant animal relatives, it would seem likely that the complex traits they evolved were later lost in simple animals such as sponges, or that they evolved twice over the course of evolutionary history -- once in comb jellies and again, independently, in humans, sharks, flies and other related animals that have them.Anthony Redmond, Postdoctoral Research Fellow in Trinity's School of Genetics and Microbiology, is first author of the research article just published in leading international journal, "It may seem very unlikely that such complex traits could evolve twice, independently, but evolution doesn't always follow a simple path. For example, birds and bats are distantly related but have independently evolved wings for flight."However, instead of comb jellies, our improved analyses point to sponges as our most distant animal relatives, restoring the traditional, simpler hypothesis of animal evolution. This means both that the animal ancestor was simple and that muscles, and the nervous and digestive systems, although further elaborated upon in many lineages, have a single origin."Comparing genomes to assess how species are related is a lot harder than it sounds. There are multiple different methods for doing so and different methods reach different conclusions -- hence the disagreement as to whether sponges or comb jellies are our most distant relatives.To resolve the debate, the Trinity team developed a new approach to analysing the amino acid sequences that make up an animal's proteins. Their approach reduced the errors associated with the all-important comparisons.Natural selection to maintain the shape and function of proteins means that any given amino acid in a protein will usually only change to other amino acids with similar biochemical properties during evolution, e.g. like-for-like substitutions with respect to features such as positive/negative charge.Failing to account for this can lead to errors when reconstructing phylogenetic relationships, which the Trinity researchers believe led to the recovery of comb jellies as our most distant animal relatives in some previous studies.Aoife McLysaght, Professor of Genetics in Trinity's School of Genetics and Microbiology, and senior author of the research article, said:"Our approach bridges the gap between two disagreeing methodologies, and provides strong evidence that sponges, and not comb jellies, are our most distant animal relatives. This means our last common animal ancestor was morphologically simple and suggests that repeated evolution and/or loss of complex features like a nervous system is less likely than if comb jellies were our most distant animal relatives."This is fascinating in its own regard, but it also represents an important step forward in phylogenomic research. Other researchers had come to different conclusions about our most distant animal relative, and that was the case even when they used the same data -- they had just used different methods."Our new approach should be useful for similar studies in which scientists try to resolve how certain species are related to each other. This information is crucial to our understanding of evolution and can have important implications in other, related fields, such as biodiversity and conservation science."
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Animals
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March 30, 2021
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https://www.sciencedaily.com/releases/2021/03/210330210956.htm
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The 'one who causes fear' - new meat-eating predator discovered
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Research published today in the peer-reviewed
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Around 80 million years ago as tyrannosaurs ruled the Northern Hemisphere, this lookalike was one of 10 currently known species of abelisaurids flourishing in the southern continents.A fearsome killer, It had a strange short skull with rough bones, so in life its head had bulges and prominences like some current reptiles such as the Gila monster or some iguanas. Its hearing was also different to other abelisaurids. The make-up of its skull suggests this was better than most of the other abelisaurids and similar to that of modern-day crocodiles.Its full name comes from the native Mapuche for 'one who causes fear' -- It lived in the same small area and period of time as another species of furileusaurian (stiff-backed lizard) abelisaurid -- Viavenator exxoni -- just a few million years before the end of the age of dinosaurs.Fossil remains of "This is a particularly important discovery because it suggests that the diversity and abundance of abelisaurids were remarkable, not only across Patagonia, but also in more local areas during the dinosaurs' twilight period," says lead author Dr Federico Gianechini, a paleontologist at the National University of San Luis, Argentina.Abelisauridae were a striking family of theropod dinosaurs averaging five to nine meters long that prowled mainly in Patagonia and other areas of the ancient southern subcontinent Gondwana -- recognised today as Africa, India, Antarctica, Australia, and South America. To date, almost 10 species of this fearsome predator have been unearthed across Patagonia. While abelisaurids resembled T-Rex in general appearance with tiny stubby arms, they had unusually short, deep skulls which often bore crests, bumps, and horns, and were unique.Moving upright on their hind limbs with huge claws that they may have used to stab their prey, The fossilised remains of It means that "This finding implies a different hearing adaptation from other abelisaurids, and likely a keener sense of hearing," says Dr Mendez.However it may have lived, the fossil evidence of "These dinosaurs were still trying out new evolutionary pathways and rapidly diversifying right before they died out completely," adds Mendez.Despite their significant finding there is still a lot to discover. "This discovery also suggests that there are likely more abelisaurid out there that we just haven't found yet, so we will be looking for other new species and a better understanding of the relationship among furilesaurs," says Gianechini.
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Animals
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March 30, 2021
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https://www.sciencedaily.com/releases/2021/03/210330171037.htm
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Sounds like home: Murrelets choose breeding locations by eavesdropping on other murrelets
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Oregon State University researchers broadcast marbled murrelet calls in mature forests and found that the threatened seabirds' choice of breeding locations is strongly influenced by whether they hear other murrelets in the area.
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The research by scientists in the OSU College of Forestry and College of Agricultural Sciences is important because the elusive seabird's populations are in decline and recovery may be hindered by there being too few birds around to provide information to each other about where to nest.Findings were published in "The odds that marbled murrelets would consider nesting at sites where we broadcast murrelet calls were many times greater than at sites where we didn't," said lead author Jonathon Valente, a postdoctoral researcher with the College of Forestry's Oregon Marbled Murrelet Project.Marbled murrelets are closely related to puffins and murres but unlike those birds, murrelets raise their young as far as 60 miles inland in mature and old-growth forests."There aren't many species like it," said study co-author Jim Rivers, also a faculty member in the College of Forestry. "In fact, there's no other bird that feeds in the ocean and commutes such long distances to inland nest sites. This behavior is really unusual and it makes this species especially challenging to study."In 2016, Valente, Rivers and three collaborators at Oregon State simulated the presence of murrelets at 14 randomly selected potential breeding sites by broadcasting the bird's calls during breeding season. Between the rounds of simulations, they recorded wild murrelet calls at the sites and compared call rates with rates at 14 control sites where no recorded were broadcast.In the year of the broadcast experiment, simulated murrelet calls increased the odds of recording wild murrelet calls by as much as 15 times. The scientists hypothesized that these were young "prospecting" birds, on the lookout for new nesting sites.To the researchers' surprise, these prospectors appeared to have remembered the locations of experimental areas the following breeding season, nearly a year after broadcasts of murrelet calls had ceased. The odds of a site being occupied during the 2017 breeding season were 10 times greater at the experimental sites than the control sites."That means it would likely be a good idea for conservation managers to consider broadcasting vocalizations to encourage murrelets to nest in unused, high-quality habitat," said co-author Matt Betts of the College of Forestry. "And because murrelets are attracted to other murrelets, protecting areas adjacent to known nesting sites may also be an effective conservation approach."The dove-sized marbled murrelet spends most of its time in coastal waters eating krill, other invertebrates and forage fish such as herring, anchovies, smelt and capelin. Murrelets can only produce one offspring per year, if the nest is successful, and their young require forage fish for proper growth and development.The secretive birds typically lay their single egg high in a tree on a horizontal limb at least 4 inches in diameter. Steller's jays, crows and ravens are the main predators of murrelet nests.Along the West Coast, marbled murrelets are found regularly from Santa Cruz, California, north to the Aleutian Islands. The species is listed as threatened under the U.S. Endangered Species Act in Washington, Oregon and California.Also collaborating on the vocalization study were Kim Nelson and Dan Roby of the OSU College of Agricultural Sciences. The College of Forestry and the USDA National Institute of Food and Agriculture supported this research.
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Animals
| 2,021 |
March 30, 2021
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https://www.sciencedaily.com/releases/2021/03/210330143057.htm
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Herpesvirus triggers cervical cancer affecting nearly 1 in 4 adult sea lions
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After more than three decades of research, scientists have proven that the cancer affecting up to one in four adult California sea lions necrospied at The Marine Mammal Center in Sausalito, CA, is caused by a sexually transmitted herpesvirus. The cancer, known as sea lion urogenital carcinoma, has clear parallels to cervical cancer in humans and provides a helpful model for human cancer study.
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Scientists have long suspected this cancer was associated with a virus, but this is the first study to prove this theory. The study, which was published in A second recently published paper (Sea lions are dying from a mysterious cancer. -- Los Angeles Times) led by the same team showed that pollutants such as PCBs and DDT play a significant role as co-factors in the development of this cancer. This is particularly relevant to Southern California where there is a large DDT dumpsite in the Southern California bight which is also where the majority of the sea lion population gather each year to give birth and raise their pups (How the waters off Catalina became a DDT dumping ground -- Los Angeles Times)."The confirmation that this is a virally induced cancer combined with the knowledge that contaminants play a significant role in the cancer's development means that we can use these sea lions as a naturally occurring disease model to better understand how cancer develops and spreads in all species, including humans," says Dr. Alissa Deming, the lead author of the study who completed this work during her Ph.D. studies at University of Florida in Gainesville, FL., while she was a Research Fellow at The Marine Mammal Center in Sausalito, CA. (Dr. Deming is now Director of Clinical Medicine at the Pacific Marine Mammal Center in Laguna Beach, CA.)The Marine Mammal Center is the world's largest marine mammal hospital and has been on the forefront of researching and understanding cancer in California sea lions and its connection to both ocean and human health. Since cancer in sea lions was first discovered in 1979, researchers have found that between 18-23 percent of adult sea lions admitted to the Center's hospital have died of the fatal disease. In 2010, the Center brought together an array of international researchers to form the Sea Lion Cancer Consortium to further investigate this disease, many of whom helped co-author the paper."This research is critical as these sea lions may hold the key to understanding virally induced cancers as well as how cancer metastasizes, or spreads through the body," says Dr. Pádraig Duignan, Director of Pathology at The Marine Mammal Center and a co-author on the study. "This knowledge is an important link that could help scientists better understand various cancers in people." Most cancers are caused by an accumulation of several factors, making it challenging to study cancer in traditional laboratory models. However, wild sea lions experience multiple layers of stressors including infectious agents, exposure to pollutants, nutrition, and environmental influences, all of which are much more representative of how cancer develops in the "real world."According to Duignan, "the cancer begins in the sea lion's genital tract and aggressively spreads throughout the sea lion's body, resulting in death, often from kidney failure." Because of the advanced state of cancer by the time these patients strand on beaches and are rescued by rehabilitation centers, euthanasia is the only humane option. "This cancer is devastating to see in California sea lions. They come to the hospital in end-stage disease," says Dr. Deming.The paper was the result of an international, cross-discipline effort, combining multiple techniques from a variety of specialists to unlock the mysteries of this disease. The research relied on novel techniques using RNAscope® Technology and Base Scope™, tools that allow researchers to pinpoint high viral gene expression within tumor tissue but not in surrounding healthy tissue."Our study was the first time that this revolutionary technique has been used on a marine mammal species," says Dr. Kathleen Colegrove, Clinical Professor of the Zoological Pathology Program at the University of Illinois Urbana-Champaign, and a key researcher on the study. "This proved that the virus was integral to cancer development and was not just being detected in the reproductive tracts or tissue as a bystander."
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Animals
| 2,021 |
March 29, 2021
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https://www.sciencedaily.com/releases/2021/03/210329153328.htm
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Mummified parrots point to trade in the ancient Atacama desert
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Ancient Egyptians mummified cats, dogs, ibises and other animals, but closer to home in the South American Atacama desert, parrot mummies reveal that between 1100 and 1450 CE, trade from other areas brought parrots and macaws to oasis communities, according to an international and interdisciplinary team.
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"Feathers are valued across the Americas and we see them in high-status burials," said José M. Capriles, assistant professor of anthropology, Penn State. "We don't know how the feathers got there, the routes they took or the network."Parrots and macaws are not native to the Atacama, which is in northern Chile and is the driest desert in the world, but archaeologists have found feathers in burial context and preserved in leather boxes or other protective material, and they have also found mummified birds -- parrots and macaws -- at archaeological sites."The fact that live birds made their way across the more-than-10,000-foot-high Andes is amazing," said Capriles. "They had to be transported across huge steppes, cold weather and difficult terrain to the Atacama. And they had to be kept alive."Capriles, an archaeologist, grew up around parrots and macaws because his father was a wildlife manager and his mother, Eliana Flores Bedregal, was a Bolivian ornithologist at the Museo Nacional de Historia Natural in La Paz until her death in 2017.While a postdoctoral fellow in Chile, Capriles investigated the trade and transport of goods like coca, shell, metals, feathers and animals around Bolivia, Peru and Chile."Calogero Santoro, professor of anthropology at Universidad de Tarapacá, mentioned the birds to my mother when she came to visit and suggested we study them," said Capriles. "Our idea was to say something about these parrots, where they were coming from and what species were represented. My mother is a coauthor on this paper."Most parrot and macaw remains, whether mummified or not, reside in museums. The team visited collections around northern Chile for nearly three years looking at a wide range of what had been found."Once we started working on this, we found so much material about macaws and parrots," said Capriles. "Columbus took parrots back to Europe and the historical importance of macaw feathers for pre-Columbian societies was ubiquitous."Most of the bird remains the researchers found date to between 1000 and 1460 CE, beginning at the end of the Tiwanaku empire and just before the Inca came through the area. According to Capriles, it was a time of warfare, but also a great time for commerce, with frequent llama caravans moving about.The researchers studied 27 complete or partial remains of scarlet macaws and Amazon parrots from five oasis sites in the Atacama. They report their results today (Mar. 29) in the Using zooarchaeological analysis, isotopic dietary reconstruction, radiocarbon dating and ancient DNA testing, the research catalogued scarlet macaws and at least five other parrot species that were transported from over 300 miles away in the eastern Amazon. The team mapped the distinct natural habitation ranges of scarlet macaws, blue and yellow macaws and the various parrots to try to determine how they traveled to the Atacama.The researchers also found that the birds were eating the same diet as the agriculturalists who owned them."What we consider acceptable interactions with animals under our care was very different back then," said Capriles. "Some of these birds did not live a happy life. They were kept to produce feathers and their feathers were plucked out as soon as they grew in."Perhaps more unusual than the import of parrots and macaws and their usefulness in feather production was their treatment after death. Many of the parrots were found mummified with their mouths wide open and their tongues sticking out. Others had their wings spread wide in permanent flight."We have absolutely no idea why they were mummified like this," said Capriles. "They seem to be eviscerated through their cloaca (a common excretory and reproductive opening), which helped to preserve them. Many times, they were wrapped in textiles or bags."Unfortunately, many of the birds were salvage finds -- acquired outside of formal archaeological projects -- so some types of data are missing, but the birds are typically associated with human burials.The majority of the mummies were found at Pica 8, a site near an oasis community that still exists today as a locus of goods transport. Pica 8 had agriculture during the time the birds lived there and is currently the source of prized lemons."We know that the birds were living there," said Capriles. "That they were eating the same foods that people were eating enriched with the nitrogen from maize fertilized with marine bird manure. Llamas are not the best pack animals, because they aren't that strong. The fact that llama caravans brought macaws and parrots across the Andes and across the desert to this oasis is amazing."
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Animals
| 2,021 |
March 29, 2021
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https://www.sciencedaily.com/releases/2021/03/210329153319.htm
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Although not venemous, a mouse's bite holds venomous potential
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We are not venomous, and neither are mice -- but within our genomes lurks that potential, suggest scientists from the Okinawa Institute of Science and Technology Graduate University (OIST) and the Australian National University.
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Reporting this week in The study also provides the first concrete evidence of an underlying molecular link between venom glands in snakes and salivary glands in mammals."Venoms are a cocktail of proteins that animals have weaponized to immobilize and kill prey, as well as for self-defense," said first author, Agneesh Barua, a PhD student at OIST. "What's interesting about venom is that it has arisen in so many different animals: jellyfish, spiders, scorpions, snakes, and even some mammals. Although these animals evolved different ways to deliver venom, an oral system -- where venom is injected through a bite -- is one of the most common and well-studied."But scientists are still zeroing in on the origin of oral venom. This latest research into snakes, a group of animals renowned and feared for their potent bite, now reveals oral venom's ancient foundation.Previously, scientists have focused on the genes that code for the proteins that make up the toxic mixture. "However, many of the toxins currently found in venom were incorporated after the oral venom system was already established. We needed to look at the genes that were present before venom's origin, genes which enabled the rise of venom systems," Barua said.So instead, the team searched for genes that work alongside and interact strongly with the venom genes. The scientists used venom glands collected from the Taiwan habu snake -- a pit viper found in Asia.The researchers identified around 3,000 of these 'cooperating' genes and found that they played important roles in protecting the cells from stress caused by producing lots of proteins. The genes were also key in regulating protein modification and folding.When proteins are made, the long chains of amino acids must fold together in a specific way. Just like a wrong fold when doing origami, one misstep prevents the protein from assuming the required shape needed for it to function properly. Misfolded proteins can also accumulate and damage cells."The role of these genes in the unfolded protein response pathway makes a lot of sense as venoms are complex mixtures of proteins. So to ensure you can manufacture all these proteins, you need a robust system in place to make sure the proteins are folded correctly so they can function effectively," explained Barua.The researchers then looked at the genomes of other creatures across the animal kingdom, including mammals like dogs, chimpanzees and humans, and found that they contained their own versions of these genes.When the team looked at the salivary gland tissues within mammals, they found that the genes had a similar pattern of activity to that seen in snake venom glands. The scientists therefore think that salivary glands in mammals and venom glands in snakes share an ancient functional core that has been maintained since the two lineages split hundreds of millions of years ago."Many scientists have intuitively believed this is true, but this is the first real solid evidence for the theory that venom glands evolved from early salivary glands," said Barua. "And while snakes then went crazy, incorporating many different toxins into their venom and increasing the number of genes involved in producing venom, mammals like shrews produce simpler venom that has a high similarity to saliva."The apparent ease with which the function of salivary glands can be repurposed to be venomous is startling -- and could mean that scientists start looking at other mammals in an unsettling new light."There were experiments in the 1980s that showed that male mice produce compounds in their saliva that are highly toxic when injected into rats," said Barua. "If under certain ecological conditions, mice that produce more toxic proteins in their saliva have better reproductive success, then in a few thousand years, we might encounter venomous mice."Whether mice are or are not on this evolutionary path is a matter that requires further investigation, but it certainly blurs the line between venomous and non-venomous species.And although very unlikely, if the right ecological conditions ever existed, humans too could become venomous. "It definitely gives a whole new meaning to a toxic person," joked Barua.
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Animals
| 2,021 |
March 29, 2021
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https://www.sciencedaily.com/releases/2021/03/210329122858.htm
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Apes show dramatically different early immune responses compared to monkeys
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A new study out of the University of Chicago and the University of Illinois Urbana-Champaign in humans, chimpanzees, rhesus macaques and baboons has found key differences in early gene expression in response to pathogen exposure, highlighting the importance of choosing the right animal model for the right questions. The study was published on March 26 in
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The researchers previously studied differences in primate immunity and immune responses and wanted to conduct a large-scale, whole transcriptomic investigation into the differences in gene expression seen after exposure to viral and bacterial stimulation.Often, macaques and baboons are used as research models for studying immune conditions such as sepsis, a widespread inflammatory condition triggered by a severe infection that can cause profound organ damage if it goes untreated. However, while only very small amounts of certain pathogens are required to induce septic shock in humans, much higher doses are needed to induce similar symptoms in some of our closest relatives, such as rhesus macaques or baboons."There are massive differences between species in the susceptibility to certain infectious diseases," said co-senior author Luis Barreiro, PhD, an associate professor of medicine at UChicago. "For example, humans are very susceptible to septic shock triggered by certain types of bacteria, while some African and Asian monkeys are incredibly resistant. We wanted to know if we could understand what might be the immunological differences underlying such differences in disease susceptibility."To conduct the study, the team coordinated with investigators throughout the U.S. to conduct identical blood draws and transcriptional analysis in groups of chimpanzees and humans, as well as in two African and Asian monkey species -- rhesus macaques and olive baboons.Blood samples were exposed to either hexa-acylated lipopolysaccharide (LPS) or gardiquimod (GARD), which mimic bacterial and viral infections, respectively. After either a four- or 24-hour exposure period, investigators conducted whole genome transcriptome analysis of the leukocytes within the samples and examined the changes in gene expression after the stimulation.The results showed that the apes mounted a much stronger early response and activated a broader array of defense molecules in response to both types of stimulation compared to African and Asian monkeys. This indicates that upon early pathogen exposure, apes mount a strong, nonspecific response that is costly in terms of energy expenditure and possible tissue damage, with the trade-off of being more efficient at killing those pathogens.The difference in response may be due to differences in life history, according to the investigators. Apes, including chimpanzees and humans, tend to live much longer and are larger, increasing their lifetime risk of pathogen exposure and making a rapid, robust pathogen detection and elimination response evolutionarily beneficial, despite the potential costs.The finding that African and Asian monkeys showed a much more specific response when compared to apes was a surprise. "I was expecting to see a huge, amplified response from the ape lineage, and the same response but more blunted in the African and Asian monkeys," said co-senior author Jessica Brinkworth, PhD, an assistant professor of anthropology at the University of Illinois Urbana-Champaign. "Like the response in apes would be the same, just louder. But instead we saw this specificity of the genes and the ways the networks activated -- the patterns were different than we expected."Understanding the differences and similarities in the early immune response is important for both understanding the nature of the human immune system and for determining which model organisms can most accurately recapitulate the human immune response when developing drugs and therapies."If we're going to talk about human health and look for drugs or genes you can target to improve that health, then we need to appreciate why those genes are there in a species and what they are doing," said Brinkworth. "That requires understanding the evolution of the animal model and how it compares to our own. This study suggests, for example, that African and Asian monkeys are likely not strong models for certain types of sepsis because their immune response doesn't reflect what we see when we compare them to humans and chimpanzees."
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Animals
| 2,021 |
March 29, 2021
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https://www.sciencedaily.com/releases/2021/03/210329122749.htm
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Love bats? Think twice about that bat box, experts say
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Ever thought about buying or building a bat box to help bats? Think carefully about the design and where you put it, University of Illinois researchers say.
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Here's why: Bats and their pups can overheat and die in poorly designed or placed bat boxes, and in a warming climate, it could happen more often.Illinois bat ecologists Joy O'Keefe and Reed Crawford recently synthesized the available data on bat boxes, also known as bat houses or artificial roosts, to raise awareness of the issue and motivate change in bat box design, marketing, and consumer education. Their recommendations are published in "Conservation practitioners and homeowners are well-intentioned; they want to help bats. Inevitably, the first thing they do is go online and buy a bat house," says Crawford, a doctoral student in the Program in Ecology, Evolution, and Conservation Biology at Illinois. "But unfortunately, a lot of bat houses on the market are small and painted dark colors, and they get hot really quickly. They're likely to hurt bats if they're installed in the wrong spot."We're trying to highlight that there's a lot of misleading information out there. We want to steer people away from putting up bat boxes as a first course of action, to instead consider the risks and ask if there is anything we can do that's going to be more beneficial for bats."Crawford has read just about every study that's ever been done on bat boxes, and he and O'Keefe have conducted their fair share of studies, as well. They and other members of the bat research community have identified a critical temperature threshold -- 104 degrees Fahrenheit or 40 Celsius -- above which most bat species are significantly heat-stressed.Although very few studies have documented temperatures inside the countless bat boxes currently in use across the world, researchers have recorded temperatures as high as 142 degrees Fahrenheit in artificial roosts. And they've observed bats in natural roosts moving to avoid temperatures above 97 degrees.In many bat boxes, bats can't move around to avoid hot spots. The most common design is a small, flat-panel box with vertical slats creating one to four chambers. The boxes are often painted or stained dark colors, and that can be a big part of the problem."We know darker boxes can be, on average, 41-43 degrees hotter than white boxes and are more likely to overheat. Yet we see companies marketing black boxes as preferable to bats and suitable for most U.S. climates," Crawford says. "But one hot summer day in a really tiny black bat house is probably going to kill anything that's in there. So it's very dangerous."O'Keefe, an assistant professor and wildlife extension specialist in the Department of Natural Resources and Environmental Sciences at Illinois, adds, "Even our colleagues in cooler climates have seen a number of bat deaths in dark-colored boxes. That's why we advocate for not painting boxes in dark colors."But she points out that bat deaths have also occurred in unpainted, light-wood boxes in warm climates. "Clearly, more intervention is needed than just the color of the box."Bats do like to be warm and protected when they're sleeping and raising their young. But when they're seeking out natural roosts in the wild, they choose spots that allow them some flexibility to move when it gets too hot.That's why Crawford and O'Keefe say if you're going to invest in a bat box, large designs are better. For example, tall, four-sided boxes allow bats to move up and down in space and around to the back side when the front is being blasted by sun.Researchers are also investigating novel materials and design elements that are better temperature buffers than the usual plywood, including wood-cement (a molded mixture of wood shavings and cement), insulating water chambers, and chimneys.But regardless of design and color, placement has implications that go beyond overheating."Obviously, you're going to want to avoid hanging a small, dark bat house where it's going to get direct sun all day, especially in warmer, southern climates," Crawford says. "But we're just starting to learn about how artificial roosts might represent ecological traps for bats. They could be preferentially selecting the bat box because of where it is and passing over natural habitats that would keep them safer from predators and parasites, as well as dangerously warm temperatures."O'Keefe adds, "Bat houses can also draw bats to areas that are inappropriate. That's one of the reasons I've moved away from advising people to put out bat boxes as a first step in bat conservation. People need to think about what they're drawing bats to. Do they have to cross any difficult boundaries, like busy roads, to get there?"I encourage homeowners to think about doing something else that could benefit bats instead, like planting native trees or wildflowers to attract insect prey, providing clean water sources, or leaving standing dead trees wherever it is safe to do so, as these are natural roosting habitat for bat box users."
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Animals
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March 29, 2021
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https://www.sciencedaily.com/releases/2021/03/210329122743.htm
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Narwal tusks reveal mercury exposure related to climate change
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In the Arctic, climate change and pollution are the biggest threats to top predators like narwals. Studying the animals' tusks reveals that diet and exposure to pollution have shifted over the past half century in response to sea-ice decline. Human emissions have also led to a sharp rise in the presence of mercury in recent years, according to an international team of researchers.
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"Our research shows that climate change is having substantial impacts on Arctic ecosystems, with consequences for exposure to toxic pollutants like mercury," says co-author Jean-Pierre Desforges, a Postdoctoral Fellow at McGill University under the supervision of Nil Basu and Melissa McKinney.Using natural growth layers in the tusk of male narwhals, the researchers were able to document yearly changes in mercury exposure dating back to the 1960s in a study published in The narwhals' unicorn-like tusk projects from the left side of the upper jaw of the males and can reach up to three metres long. Just like rings in a tree trunk, every year a new growth layer is added to the narwhal's tusk.Because the tusk is connected to the rest of body through blood, each new layer records aspects of the animal's physiology, the researchers explain. This includes information on what and where the animals have eaten each year and exposure to contaminants from human activity."Heavy metals like mercury and other contaminants accumulate at each link in the food chain. The higher you are in the food chain, the more mercury you accumulate in your body throughout your life," says Desforges. Elevated amounts of heavy metals in the body are toxic and can affect cognitive functions, behaviour, and the ability to reproduce.The researchers found that from 1990 until 2000, narwhals accumulated relatively small quantities of mercury as the new prey sat lower in the food chain. Up until around 1990, the narwhals' food consisted particularly of prey linked to the sea ice, such as halibut and Arctic cod. During this period, the ice cover was extensive in areas like Baffin Bay.After 1990, the ice cover declined consistently year after year and the diet of the narwhals changed to open ocean prey like capelin and polar cod. However, from around 2000, the amount of mercury increased significantly in the narwhal tusks without a simultaneous shift in diet.The researchers attribute the rise in mercury emissions to on-going fossil fuel combustion in South-East Asia. The increase could also be due to changing sea ice conditions as the climate warms, causing changes in the environmental mercury cycle in the Arctic.Over the past 30 to 40 years, climate change has reduced sea ice cover in the Arctic. Many species depend on the ice to evade predators and in their search for food or important breeding grounds. This affects the entire Arctic food chain and the living conditions of all species.Changes in temperature and sea ice also lead to invasion by new species from warmer areas. For the narwhal, the ice acts as a protection against enemies like killer whales, they say."The narwhal is one of the Arctic mammals most affected by climate change. They lack the physiological properties that help eliminate environmental contaminants. They can't get rid of mercury by forming hair and feathers like polar bears, seals, or seabirds," explains co-author Professor Rune Dietz from the Department of Bioscience at Aarhus University in Denmark.The findings show that each layer of the narwal tusk offers valuable information on the animals' living conditions and a window into developments in the Arctic."With our discovery, we now know that there's a bank of data in the narwhal tusks found in museums around the world. By analysing them, we can hopefully get insight into the narwhals' food strategy from different periods. This will provide us with a solid basis for evaluating how the species copes with the changing conditions that it encounters today in the Arctic," says Dietz, who is also affiliated with Aarhus University's Arctic Research Centre.
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Animals
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March 29, 2021
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https://www.sciencedaily.com/releases/2021/03/210329094855.htm
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Genetic sleuthing reveals endangered river dolphins in Asia as different species
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New genetic analysis and years of painstaking research has revealed that one of the world's most endangered marine mammals is actually two species rather than one, as scientists had long assumed.
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Scientists spent about two decades crossing Asia and Europe in pursuit of river dolphins skulls and reexamining tissue samples with modern genetic techniques. Their findings revealed that Indus and Ganges river dolphins are separate species, according to a new study published in The two dolphins that live in the muddy waters of the Ganges and Indus rivers have lost their eyesight and rely on sophisticated sonar to hunt for prey. The new research recognized that the dolphins have clear genetic differences, as well as different numbers of teeth, coloration, growth patterns and skull shapes. Together, these differences distinguish them as separate species."The genetic tools we have today help us extract new information from samples collected years ago," said Eric Archer, leader of the Marine Mammal Genetics Program at NOAA Fisheries' Southwest Fisheries Science Center. The analysis of the river dolphin genetics included tissue samples from the Science Center's Marine Mammal and Sea Turtle Research Tissue Collection, the largest of its kind in the world. Archer added: "Without collections such as this and those at other museums around the world, it would be impossible to identify difficult to study species such as these dolphins."An estimated several thousand Ganges river dolphins live in the rivers of Bangladesh, India, and Nepal, but their numbers and range are thought to be declining. Indus river dolphins have increased in number from about 1,200 in 2001 to almost 2,000 in 2017. This increase reflects dedicated conservation efforts by local communities and the provincial and national government authorities that oversee their management.Some scientists suggested as early as the 1970s that the two dolphins were separate species. However, the findings were dismissed until the new analysis proved the original indications were accurate. The revelation is one of many recent genetic studies that have revealed new information about marine mammal populations around the world. Other recent discoveries include a new subspecies of fin whale in the Pacific Ocean and a new and critically endangered whale species in the Gulf of Mexico."Recognizing the species-level differences between Indus and Ganges river dolphins is extremely important, as only a few thousand individual dolphins of each species remain," said Gill Braulik of the Sea Mammal Research Unit at the University of St. Andrews, who led the study. "My hope is that our findings will bring much-needed attention to these remarkable animals, helping to prevent them sliding towards extinction.""Serious challenges still face this incredible species and all other river dolphin populations, but we can save them," said Uzma Kahn, Asia Coordinator of the WWF River Dolphin Initiative. "By doing so we'll save so much more, since hundreds of millions of people and countless other species depend on the health" of similar rivers around the world.
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Animals
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March 26, 2021
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https://www.sciencedaily.com/releases/2021/03/210326104708.htm
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Dogs (not) gone wild: DNA tests show most 'wild dogs' in Australia are pure dingoes
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Almost all wild canines in Australia are genetically more than half dingo, a new study led by UNSW Sydney shows -- suggesting that lethal measures to control 'wild dog' populations are primarily targeting dingoes.
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The study, published today in The team found that 99 per cent of wild canines tested were pure dingoes or dingo-dominant hybrids (that is, a hybrid canine with more than 50 per cent dingo genes).Of the remaining one per cent, roughly half were dog-dominant hybrids and the other half feral dogs."We don't have a feral dog problem in Australia," says Dr Kylie Cairns, a conservation biologist from UNSW Science and lead author of the study. "They just aren't established in the wild."There are rare times when a dog might go bush, but it isn't contributing significantly to the dingo population."The study builds on a 2019 paper by the team that found most wild canines in NSW are pure dingoes or dingo-dominant hybrids. The newer paper looked at DNA samples from past studies across Australia, including more than 600 previously unpublished data samples.Pure dingoes -- dingoes with no detectable dog ancestry -- made up 64 per cent of the wild canines tested, while an additional 20 per cent were at least three-quarters dingo.The findings challenge the view that pure dingoes are virtually extinct in the wild -- and call to question the widespread use of the term 'wild dog'."'Wild dog' isn't a scientific term -- it's a euphemism," says Dr Cairns."Dingoes are a native Australian animal, and many people don't like the idea of using lethal control on native animals."The term 'wild dog' is often used in government legislation when talking about lethal control of dingo populations."The terminology used to refer to a species can influence our underlying attitudes about them, especially when it comes to native and culturally significant animals.This language can contribute to other misunderstandings about dingoes, like being able to judge a dingo's ancestry by the colour of its coat -- which can naturally be sandy, black, white, brindle, tan, patchy, or black and tan."There is an urgent need to stop using the term 'wild dog' and go back to calling them dingoes," says Mr Brad Nesbitt, an Adjunct Research Fellow at the University of New England and a co-author on the study."Only then can we have an open public discussion about finding a balance between dingo control and dingo conservation in the Australian bush."While the study found dingo-dog hybridisation isn't widespread in Australia, it also identified areas across the country with higher traces of dog DNA than the national average.Most hybridisation is taking place in southeast Australia -- and particularly in areas that use long-term lethal control, like aerial baiting. This landscape-wide form of lethal control involves dropping meat baits filled with the pesticide sodium fluoroacetate (commonly known as 1080) into forests via helicopter or airplane."The pattern of hybridisation is really stark now that we have the whole country to look at," says Dr Cairns."Dingo populations are more stable and intact in areas that use less lethal control, like western and northern Australia. In fact, 98 per cent of the animals tested here are pure dingoes."But areas of the country that used long-term lethal control, like NSW, Victoria and southern Queensland, have higher rates of dog ancestry."The researchers suggest that higher human densities (and in turn, higher domestic dog populations) in southeast Australia are likely playing a key part in this hybridisation.But the contributing role of aerial baiting -- which fractures the dingo pack structure and allows dogs to integrate into the breeding packs -- is something that can be addressed."If we're going to aerial bait the dingo population, we should be thinking more carefully about where and when we use this lethal control," she says."Avoiding baiting in national parks, and during dingoes' annual breeding season, will help protect the population from future hybridisation."Professor Mike Letnic, senior author of the study and professor of conservation biology, has been researching dingoes and their interaction with the ecosystem for 25 years.He says they play an important role in maintaining the biodiversity and health of the ecosystem."As apex predators, dingoes play a fundamental role in shaping ecosystems by keeping number of herbivores and smaller predators in check," says Prof. Letnic."Apex predators' effects can trickle all the way through ecosystems and even extend to plants and soils."Prof. Letnic's previous research has shown that suppressing dingo populations can lead to a growth in kangaroo numbers, which has repercussions for the rest of the ecosystem.For example, high kangaroo populations can lead to overgrazing, which in turn damages the soil, changes the face of the landscape and can jeopardise land conservation.A study published last month found the long-term impacts of these changes are so pronounced they are visible from space.But despite the valuable role they play in the ecosystem, dingoes are not being conserved across Australia -- unlike many other native species."Dingoes are a listed threatened species in Victoria, so they're protected in national parks," says Dr Cairns. "They're not protected in NSW and many other states."Dr Cairns, who is also a scientific advisor to the Australian Dingo Foundation, says the timing of this paper is important."There is a large amount of funding currently going towards aerial baiting inside national parks," she says. "This funding is to aid bushfire recovery, but aerial wild dog baiting doesn't target invasive animals or 'wild dogs' -- it targets dingoes."We need to have a discussion about whether killing a native animal -- which has been shown to have benefits for the ecosystem -- is the best way to go about ecosystem recovery."Dingoes are known to negatively impact farming by preying on livestock, especially sheep.The researchers say it's important that these impacts are minimised, but how we manage these issues is deserving of wider consultation -- including discussing non-lethal methods to protect livestock."There needs to be a public consultation about how we balance dingo management and conservation," says Dr Cairns. "The first step in having these clear and meaningful conversations is to start calling dingoes what they are."The animals are dingoes or predominantly dingo, and there are virtually no feral dogs, so it makes no sense to use the term 'wild dog'. It's time to call a spade a spade and a dingo a dingo.
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Animals
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March 25, 2021
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https://www.sciencedaily.com/releases/2021/03/210325150205.htm
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Gene required for jumping identified in rabbits
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Rabbits and other hopping animals require a functional RORB gene to move around by jumping, according to a new study by Miguel Carneiro of the Universidade do Porto and Leif Andersson of Uppsala University published March 25th in
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Rabbits, hares, kangaroos and some rodent species all travel by jumping, but this type of movement is not well understood on a molecular and genetic level. In the new paper, researchers investigated jumping-related genes using an unusual breed of domesticated rabbit called the sauteur d'Alfort. Instead of hopping, it has a strange gait where it lifts its back legs and walks on its front paws. By breeding sauteur d'Alfort rabbits with another breed and comparing the offspring's genomes and jumping abilities, the researchers identified the cause of this developmental defect. They identified a specific mutation in the RAR related orphan receptor B (RORB) gene. Typically, the RORB protein is found in many regions of the rabbit nervous system, but the mutation leads to a sharp decrease in the number of neurons in the spinal cord that produce RORB. This change is responsible for the sauteur d'Alfort's weird walk.The new study demonstrates that a functional RORB gene is necessary for rabbits and likely other hopping animals to perform their characteristic jumping gait. The findings build on previous studies in mice, showing that animals that lack the RORB gene had a duck-like walk. Additionally, this work advances our understanding of the different ways that animals with backbones move."This study provides a rare example of an abnormal gait behavior mapped to a single base change and the first description of a gene required for saltatorial locomotion," the authors conclude. "It further demonstrates the importance of the RORB protein for the normal wiring of the spinal cord, consistent with previous studies in mouse."
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Animals
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March 25, 2021
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https://www.sciencedaily.com/releases/2021/03/210325150202.htm
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What is killing bald eagles in the U.S.?
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Bald eagles, as well as other wildlife, have been succumbing to a mysterious neurodegenerative disease in the southern United States since the 1990s. New research by the Martin Luther University Halle-Wittenberg (MLU) in Germany and the University of Georgia, USA, identifies the cause of these deaths: a toxin produced by cyanobacteria that grow on invasive aquatic plants. The problem is potentially exacerbated by herbicides used to control those plants. The results were published in
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In 1994, bald eagles were dying on a mass scale in the U.S. state of Arkansas. The animals were losing control over their bodies, and holes were developing in their brains. A previously unknown neurodegenerative disease, termed vacuolar myelinopathy (VM), was identified. "The origin of the disease was a complete mystery," says Professor Timo Niedermeyer from the Institute of Pharmacy at MLU.Later on, American researchers found that not only eagles were affected, but also their herbivorous prey. The scientists discovered a connection to an invasive aquatic plant (Hydrilla verticillata) that grows in freshwater lakes in the affected regions. However, there were still some lakes with the aquatic plant where the disease was not manifesting. In 2005 Susan B. Wilde, a professor at the Warnell School of Forestry and Natural Resources at the University of Georgia, identified a previously unknown cyanobacterium on the leaves of Hydrilla verticillata, which appeared to be the cause of the disease. It turned out that vacuolar myelinopathy only occurs in places where the cyanobacterium colonizes the invasive plant. She called the bacterium "eagle killer that grows on Hydrilla": Aetokthonos hydrillicola."I stumbled across a press release issued by the university in Georgia and was fascinated by these findings, because I've worked with cyanobacteria for years," says Niedermeyer. He had samples sent to him, cultivated the bacteria in the laboratory and sent them back to the U.S. for further testing. But the tests came back negative: The bacteria from the lab did not induce the disease. "It's not just the birds that were going crazy, we were too. We wanted to figure this out," says Niedermeyer. Once again, he had colonized leaves sent to him. Steffen Breinlinger, a doctoral student in his research group, then used a new imaging mass spectrometer to investigate the composition on the surface of the plant's leaf, molecule by molecule. He discovered a new substance that only occurs on the leaves where the cyanobacteria grow, but is not produced in the cultivated bacteria.His investigations into the chemical structure of the isolated molecule showed that it contains five bromine atoms. "The structure is really spectacular," says Breinlinger. The properties are unusual for a molecule formed by bacteria. And they provide an explanation for why the toxin did not form under laboratory conditions. Standard culture media in which cyanobacteria grow do not contain bromide. "We then added bromide to our lab cultures, and -- the bacteria started producing the toxin," says Breinlinger. Wilde and her colleagues tested the isolated molecule in birds, and finally, after almost a decade of research in the Wilde and Niedermeyer labs, they had the proof: the molecule does trigger VM. According to the name of the bacterium, the researchers call their discovery aetokthonotoxin, "poison that kills the eagle." "Finally, we did not only catch the murderer, but we also identified the weapon the bacteria use to kill those eagles," says Wilde.A research group participating in the study from the Czech Academy of Sciences also found sections of DNA containing genetic information for the synthesis of the new molecule. Why the cyanobacteria form the toxin on the aquatic plants in the first place, however, has yet to be studied. One of the herbicides used to combat the invasive aquatic plant might play a crucial part in VM occurrence: It contains bromide and thus might stimulate toxin production.The neurological disease has not yet occurred in Europe, and no instance of the toxin-forming cyanobacterium has been reported.
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Animals
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March 25, 2021
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https://www.sciencedaily.com/releases/2021/03/210325115407.htm
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Warriors' down bedding could ease journey to realm of the dead
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This may well be the most interesting story about pillows and bedding you will ever read.
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The burial field in Valsgärde outside Uppsala in central Sweden contains more than 90 graves from the Iron Age."On a light note, we could say that Valsgärde is Scandinavia's answer to Sutton Hoo in England as portrayed in the film The Dig on Netflix," says Birgitta Berglund, professor emeritus of archaeology at the Norwegian University of Science and Technology's NTNU University Museum.Valsgärde is especially known for its spectacular boat graves from the 600s and 700s CE. This timeframe is in the middle of what Norway calls the Merovingian period, the era just before the Viking Age.Two of these spectacular boat graves are at the centre of this story -- or more specifically, the story is really about the down bedding that was found in the graves.When researchers from NTNU investigated which birds contributed their feathers to the bedding, they made a surprising discovery that provides new insight into Iron Age society.The boats carrying the two dead men were about 10 metres long, with room for four to five pairs of oars. Both were outfitted for high-ranking warriors, with richly decorated helmets, shields and weapons. Provisions and tools for hunting and cooking were also included for their last voyage.In one grave, an Eurasian eagle owl ("The buried warriors appear to have been equipped to row to the underworld, but also to be able to get ashore with the help of the horses," says Berglund.Beauty sleep was also taken care of in death.Two warriors lay atop several layers of down bedding. The contents of the bedding probably had a greater function than simply serving as filler.You might have thought of down bedding as a modern concept, which admittedly only became available for common folk in recent times. The down bedding in the graves at Valsgärde is the oldest known from Scandinavia and indicate that the two buried men belonged to the top strata of society.Wealthy Greeks and Romans used down for their bedding a few hundred years earlier, but down probably wasn't used more widely by wealthy people in Europe until the Middle Ages, Berglund says.Berglund has been studying down harvesting in Helgeland coastal communities in southern Nordland county for many years, where people commercialized down production early on by building houses for the eider ducks that were the source of the down. The theory was that down from this location might have been exported south, so Berglund wanted to investigate whether the bedding at Valsgärde contained eider down."It turned out that a lot of kinds of feathers had been used in the bedding at Valsgärde. Only a few feathers from eider ducks were identified, so we have little reason to believe that they were a commodity from Helgeland or other northern areas," says Berglund.However, she was not disappointed by this discovery. The great variety of species gave the researchers unique insight into the bird fauna in the immediate area in prehistoric times, along with people's relationship to it."The feathers provide a source for gaining new perspectives on the relationship between humans and birds in the past. Archaeological excavations rarely find traces of birds other than those that were used for food," the researcher says."We also think the choice of feathers in the bedding may hold a deeper, symbolic meaning. It's exciting."Berglund explains that according to Nordic folklore, the type of feathers contained in the bedding of the dying person was important."For example, people believed that using feathers from domestic chickens, owls and other birds of prey, pigeons, crows and squirrels would prolong the death struggle. In some Scandinavian areas, goose feathers were considered best to enable the soul to be released from the body," she said.These are well-known folk traditions that have been collected from the 18th century onwards. But they may have their roots in prehistoric times.In the Icelandic Erik the Red saga, a pillow stuffed with feathers from domestic hens was placed on the throne at Heriólfsnes in Greenland, where a visiting female shaman was to sit. The saga is considered to have been written down in the 13th century, but addresses events around the year 1000, says Berglund.The examples show that that feathers in the bedding from Valsgärde most likely also had a deeper meaning than just serving as a filler. It's also well known that birds could hold special importance for obtaining information in shamanism -- think of Odin's two ravens Hugin and Munin.Exactly what ritual function the feathers at Valsgärde had is hard to say. But the bedding contained feathers from geese, ducks, grouse, crows, sparrows, waders and -- perhaps most surprisingly -- eagle owls.Biologist Jørgen Rosvold, now employed at the Norwegian Institute for Natural History (NINA), identified the species from the feather material."It was a time consuming and challenging job for several reasons. The material is decomposed, tangled and dirty. This means that a lot of the special features that you can easily observe in fresh material has become indistinct, and you have to spend a lot more time looking for the distinctive features," Rosvold says."I'm still surprised at how well the feathers were preserved, despite the fact that they'd been lying in the ground for over 1000 years."The feathers in the down bedding weren't the only interesting bird find in the graves. One of the graves also contained a headless owl.From recent graves we know that people took measures to prevent the buried from returning from the dead, and it's easy to imagine that this was also done longer ago as well."We believe the beheading had a ritual significance in connection with the burial," says Berglund.Swords found in tombs from Viking times were sometimes intentionally bent before being laid in the tomb. This was probably done to prevent the deceased from using the weapon if he returned."It's conceivable that the owl's head was cut off to prevent it from coming back. Maybe the owl feather in the bedding also had a similar function? In Salme in Estonia, boat graves from the same period have recently been found that are similar to those in Valsgärde. Two birds of prey with a severed head were found there," says Berglund.
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Animals
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March 24, 2021
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https://www.sciencedaily.com/releases/2021/03/210324113502.htm
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How humans develop larger brains than other apes
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A new study is the first to identify how human brains grow much larger, with three times as many neurons, compared with chimpanzee and gorilla brains. The study, led by researchers at the Medical Research Council (MRC) Laboratory of Molecular Biology in Cambridge, UK, identified a key molecular switch that can make ape brain organoids grow more like human organoids, and vice versa.
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The study, published in the journal Similar to actual brains, the human brain organoids grew a lot larger than the organoids from other apes.Dr Madeline Lancaster, from the MRC Laboratory of Molecular Biology, who led the study, said: "This provides some of the first insight into what is different about the developing human brain that sets us apart from our closest living relatives, the other great apes. The most striking difference between us and other apes is just how incredibly big our brains are."During the early stages of brain development, neurons are made by stem cells called neural progenitors. These progenitor cells initially have a cylindrical shape that makes it easy for them to split into identical daughter cells with the same shape.The more times the neural progenitor cells multiply at this stage, the more neurons there will be later.As the cells mature and slow their multiplication, they elongate, forming a shape like a stretched ice-cream cone.Previously, research in mice had shown that their neural progenitor cells mature into a conical shape and slow their multiplication within hours.Now, brain organoids have allowed researchers to uncover how this development happens in humans, gorillas and chimpanzees.They found that in gorillas and chimpanzees this transition takes a long time, occurring over approximately five days.Human progenitors were even more delayed in this transition, taking around seven days. The human progenitor cells maintained their cylinder-like shape for longer than other apes and during this time they split more frequently, producing more cells.This difference in the speed of transition from neural progenitors to neurons means that the human cells have more time to multiply. This could be largely responsible for the approximately three-fold greater number of neurons in human brains compared with gorilla or chimpanzee brains.Dr Lancaster said: "We have found that a delayed change in the shape of cells in the early brain is enough to change the course of development, helping determine the numbers of neurons that are made."It's remarkable that a relatively simple evolutionary change in cell shape could have major consequences in brain evolution. I feel like we've really learnt something fundamental about the questions I've been interested in for as long as I can remember -- what makes us human."To uncover the genetic mechanism driving these differences, the researchers compared gene expression -- which genes are turned on and off -- in the human brain organoids versus the other apes.They identified differences in a gene called 'ZEB2', which was turned on sooner in gorilla brain organoids than in the human organoids.To test the effects of the gene in gorilla progenitor cells, they delayed the effects of ZEB2. This slowed the maturation of the progenitor cells, making the gorilla brain organoids develop more similarly to human -- slower and larger.Conversely, turning on the ZEB2 gene sooner in human progenitor cells promoted premature transition in human organoids, so that they developed more like ape organoids.The researchers note that organoids are a model and, like all models, do not to fully replicate real brains, especially mature brain function. But for fundamental questions about our evolution, these brain tissues in a dish provide an unprecedented view into key stages of brain development that would be impossible to study otherwise.Dr Lancaster was part of the team that created the first brain organoids in 2013.This study was funded by the Medical Research Council, European Research Council and Cancer Research UK.
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Animals
| 2,021 |
March 24, 2021
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https://www.sciencedaily.com/releases/2021/03/210324094723.htm
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Older than expected: Teeth reveal the origin of the tiger shark
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With a total length of up to 5.5m, the tiger shark is one of the largest predatory sharks known today. This shark is a cosmopolitan species occurring in all oceans worldwide. It is characterized by a striped pattern on its back, which is well marked in juveniles but usually fades in adults.
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An international team of researchers led by Julia Türtscher from the University of Vienna examined the fossil record of these apex predators and found out that modern tiger sharks are older than previously thought and that several tiger shark species existed in past compared to the single species living today. The results of this study are published in the journal The fossil history of modern sharks reaches back to the Permian, about 295 million years ago. Complete fossil shark skeletons are very rare -- the skeleton, which consists almost entirely of cartilage, is only preserved under very special circumstances during the fossilization processes. Due to the lifelong continuous tooth replacement, most extinct sharks are therefore only known by their well-mineralized teeth, which, nonetheless, can provide deep insights into their evolutionary history.The teeth of the modern tiger shark are unique: they have a broad, double-serrated cutting edge which even allows them to cut through sea turtle shells with ease. Tiger shark teeth are known in the fossil record since about 56 million years. Based on these fossil teeth, over 22 extinct tiger shark species have been described.An international team of researchers led by Julia Türtscher from the University of Vienna has now examined the fossil history of the tiger shark and its extinct relatives. With the help of geometric morphometrics, the scientists were able to show that only 5 of the 22 known fossil tiger sharks actually represent valid species. Nevertheless, tiger sharks were more diverse in the past and only a single species survived until today.Another intriguing detail in the tiger shark fossil record emerged during this study. Up to now, it was assumed that the modern tiger shark originated ca. 5.3 million years ago. The team, however, was able to identify several 13.8 million year old fossil teeth as belonging to this shark demonstrating that it originated much earlier than previously assumed.
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Animals
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March 24, 2021
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https://www.sciencedaily.com/releases/2021/03/210324094714.htm
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Giant fossil's 'bird-brain'
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The largest flightless bird ever to live weighed in up to 600kg and had a whopping head about half a metre long -- but its brain was squeezed for space.
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Dromornis stirtoni, the largest of the 'mihirungs' (an Aboriginal word for 'giant bird'), stood up to 3m high and had a cranium wider and higher than it was long due to a powerful big beak, leading Australian palaeontologists to look inside its brain space to see how it worked.The new study, just published in the journal "Together with their large, forward-facing eyes and very large bills, the shape of their brains and nerves suggested these birds likely had well-developed stereoscopic vision, or depth perception, and fed on a diet of soft leaves and fruit," says lead author Flinders University researcher Dr Warren Handley."The shape of their brains and nerves have told us a lot about their sensory capabilities, and something about their possible lifestyle which enabled these remarkable birds to live in the forests around river channels and lakes across Australia for an extremely long time."It's exciting when we can apply modern imaging methods to reveal features of dromornithid morphology that were previously completely unknown," Dr Handley says.The new research, based on fossil remains ranging from about 24 million years ago to the last in the line (Dromornis stirtoni), indicates mihirung brains and nerves are most like those of modern day chickens and Australian mallee fowl."The unlikely truth is these birds were related to fowl -- chickens and ducks -- but their closest cousin and much of their biology still remains a mystery," says vertebrate palaeontologist and senior author Associate Professor Trevor Worthy."While the brains of dromornithids were very different to any bird living today, it also appears they shared a similar reliance on good vision for survival with living ratities such as ostrich and emu."The researchers compared the brain structures of four mihirungs -- from the earliest Dromornis murrayi at about 24 million years ago (Ma) to Dromornis planei and Ilbandornis woodburnei from 12 Ma and Dromornis stirtoni, at 7 Ma.Ranging from cassowary in size to what's known as the world's largest bird, Flinders vertebrate palaeontologist Associate Professor Worthy says the largest and last species Dromornis stirtoni was an "extreme evolutionary experiment.""This bird had the largest skull but behind the massive bill was a weird cranium. To accommodate the muscles to wield this massive bill, the cranium had become taller and wider than it was long, and so the brain within was squeezed and flattened to fit."It would appear these giant birds were probably what evolution produced when it gave chickens free reign in Australian environmental conditions and so they became very different to their relatives the megapodes -- or chicken-like landfowls which still exist in the Australasian region," Associate Professor Worthy says.The large, flightless birds Dromornithidae -- also called demon ducks of doom or thunder birds -- existed from the Oligocene to Pleistocene Epochs.During prehistory, the body sizes of eight species of dromornithids became larger and smaller depending climate and available feed.The Flinders researchers used the skulls of fossil birds to extract endocasts of the brains to describe how these related to modern birds such as megapodes and waterfowl. Brain models were also made from CT scans of five other dromornithid skulls from fossil sites in Queensland and the Northern Territory. The oldest 25 Ma Dromornis murrayi specimen was found in the famed Riversleigh World Heritage Area in Queensland.
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Animals
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March 22, 2021
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https://www.sciencedaily.com/releases/2021/03/210322121318.htm
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Researchers create map of potential undiscovered life
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Less than a decade after unveiling the "Map of Life," a global database that marks the distribution of known species across the planet, Yale researchers have launched an even more ambitious and perhaps important project -- creating a map of where life has yet to be discovered.
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For Walter Jetz, a professor of ecology and evolutionary biology at Yale who spearheaded the Map of Life project, the new effort is a moral imperative that can help support biodiversity discovery and preservation around the world."At the current pace of global environmental change, there is no doubt that many species will go extinct before we have ever learned about their existence and had the chance to consider their fate," Jetz said. "I feel such ignorance is inexcusable, and we owe it to future generations to rapidly close these knowledge gaps."The new map of undiscovered species was published March 22 in the journal Lead author Mario Moura, a former Yale postdoctoral associate in Jetz's lab and now professor at Federal University of Paraiba, said the new study shifts the focus from questions like "How many undiscovered species exist?" to more applied ones such as "Where and what?""Known species are the 'working units' in many conservation approaches, thus unknown species are usually left out of conservation planning, management, and decision-making," Moura said. "Finding the missing pieces of the Earth's biodiversity puzzle is therefore crucial to improve biodiversity conservation worldwide."According to conservative scientific estimates, only some 10 to 20 percent of species on earth have been formally described. In an effort to help find some of these missing species, Moura and Jetz compiled exhaustive data that included the location, geographical range, historical discovery dates, and other environmental and biological characteristics of about 32,000 known terrestrial vertebrates. Their analysis allowed them to extrapolate where and what kinds of unknown species of the four main vertebrate groups are most likely to yet be identified.They looked at 11 key factors which allowed the team to better predict locations where undiscovered species might be located. For instance, large animals with wide geographical ranges in populated areas are more likely to have already been discovered. New discoveries of such species are likely to be rare in the future. However, smaller animals with limited ranges who live in more inaccessible regions are more likely to have avoided detection so far."The chances of being discovered and described early are not equal among species," Moura said. For instance, the emu, a large bird in Australia, was discovered in 1790 soon after taxonomic descriptions of species began. However, the small, elusive frog species Brachycephalus guarani wasn't discovered in Brazil until 2012, suggesting more such amphibians remain to be found.Moura and Jetz show that the chances of new species discovery varies widely across the globe. Their analysis suggests Brazil, Indonesia, Madagascar, and Colombia hold the greatest opportunities for identifying new species overall, with a quarter of all potential discoveries. Unidentified species of amphibians and reptiles are most likely to turn up in neotropical regions and Indo-Malayan forests.Moura and Jetz also focused on another key variable in uncovering missing species -- the number of taxonomists who are looking for them."We tend to discover the 'obvious' first and the 'obscure' later," Moura said. "We need more funding for taxonomists to find the remaining undiscovered species."But the global distribution of taxonomists is greatly uneven and a map of undiscovered life can help focus new efforts, Jetz noted. That work will become increasingly important as nations worldwide gather to negotiate a new Global Biodiversity Framework under the Convention of Biological Diversity later this year and make commitments to halting biodiversity loss."A more even distribution of taxonomic resources can accelerate species discoveries and limit the number of 'forever unknown' extinctions," Jetz said.With partners worldwide, Jetz and colleagues plan to expand their map of undiscovered life to plant, marine, and invertebrate species in the coming years. Such information will be help governments and science institutions grapple with where to concentrate efforts on documenting and preserving biodiversity, Jetz said.This work was produced, in part, with the support of the National Geographic Society through a partnership with the E.O. Wilson Biodiversity Foundation.Interactive Map:
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Animals
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March 19, 2021
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https://www.sciencedaily.com/releases/2021/03/210319125507.htm
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How do humpback whales rest?
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An international research collaboration has used an omnidirectional camera attached to humpback whale to reveal how these creatures rest underwater. These findings demonstrate how wide-angle lens cameras can be useful tools for illuminating the ecology of difficult-to-observe animals in detail.
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The research group consisted of Assistant Professor Takashi Iwata of Kobe University's Graduate School of Maritime Sciences, Researcher Martin Biuw of the Norwegian Institute of Marine Research, Assistant Professor Kagari Aoki and Professor Katsufumi Sato of the Atmosphere and Ocean Research Institute, the University of Tokyo, and Professor Patrick Miller of the University of St. Andrews.These research results were published online in It is difficult to observe the ecology of marine animals directly as they spend the majority of their lives underwater. However, studies on the ecology of difficult-to-observe marine animals have been recently conducted using a method called bio-logging. This method involves attaching a camera to an animal and recording environmental information related to their behavior and surroundings. Various kinds of data can be recorded and measured, and this information can be used to understand aspects such as animal behavior and diving physiology. Such data includes depth, swimming speed, acceleration (which can be used to understand the animal's posture and detailed movements), vocalizations, heart rate and GPS (Global Positioning System) location data.Cameras in particular are a powerful tool as they enable researchers to view the individual animal's surroundings, which in turn helps them to understand the animal's behavior. However, the camera's limited field of view has been an issue with animal-borne cameras up until now. For example, research using a camera attached to a humpback whale (Megaptera novaeangliae) revealed that the whale would quickly move away from foraging sites if a competitor was present. However, the competitor was not visible due to the limited scope of the camera, therefore its presence was merely assumed. A camera with a wide-angle lens is therefore necessary to film the animal's entire surroundings.This research focused on the humpback whale, a species of baleen whale that is found in oceans around the globe. Using bio-logging, researchers have learned more about humpback whales' foraging habits, however little is known about their resting behaviors. Foraging events can be identified from the recorded depth, swimming speed and acceleration (movement) of the whale that are characteristic signs that it is chasing prey. However, researchers have not identified the characteristic signs of resting, and it is not understood what the differences are between resting and swimming slowly. Information about an animal's resting behavior is necessary in order to understand their ecology. For example, if we consider animal behaviors in terms of their time budget, the percentage of time for other activities such as foraging decreases if their resting periods increase. Even though information about resting behaviors is essential for understanding animal ecology, hardly anything is known about baleen whales' resting habits.This research group used an omnidirectional camera (with a 360° field-of-view on land and a 270° field-of-view underwater) and a behavioral data logger in order to illuminate the resting behavior of humpback whales.RICOH supplied the basic THETA camera module for this research, which was made pressure-resistant and waterproofed using epoxy glue by Little Leonardo Corp., leading to the development of a new type of animal-borne omnidirectional camera. A suction cup tag was made out of buoyant materials that could be attached to the whale. The tag contained an omnidirectional camera, a behavioral data logger and a radio transmitter.The field study was conducted in January 2016, off the Tromsø coast in Norway. To tag the whale, the researchers approached it in a small vessel (5-6m) and used a 6m pole to attach the tag to the animal. The tag was designed so that it would fall off naturally after several hours and float up to the surface. The tag was then recovered by determining its location via the signal from the transmitter.The research team were able to tag one individual, obtaining around one hour of video data and approximately eleven hours of behavioral data. From the behavioral data, the researchers discovered that the whale was inactive during the first half of the recorded period and demonstrated active behavior in the latter half.Based on past research, it was assumed that this active movement in the latter half was foraging activity. The video data was captured during the first half of the behavioral data recording period when the whale did not move much. In this videoed period, the tagged whale's deepest dive was 11m on average and its average swimming speed (cruising speed) was 0.75m/s-1. It has been reported that humpback whales' regular swimming speed is 1.45m/s-1, however the tagged whale was moving much more slowly during this period. Whales usually move their flukes (tails) when they swim but there were no signs that the individual whale moved its fluke in the behavioral data recorded during the videoed period. In the footage, two other whales that are drifting underwater without moving their flukes are visible. It was determined that the tagged individual was also drifting underwater from its slow swimming speed, lack of fluke movement and the continued presence in the video footage of other individuals that were drifting. Seal species, sperm whales and loggerhead turtles are known to drift underwater while they are resting. Therefore, it is believed that the tagged humpback whale in this study was also resting. Previous research has reported that baleen whale species rest on the surface but this study has revealed that they also rest while drifting underwater. It is thought that whales consider factors such as marine conditions and their own physical condition when choosing from the two different resting environments: on the surface or underwater. In addition, the footage from the omnidirectional camera shows that whales rest underwater in a group rather than on their own.Researchers have been using animal-borne cameras as a tool to investigate the ecology of marine animals. For example, a backwards-facing camera attached to a mother seal recorded images of a pup swimming behind her. However, to ascertain the significance of these images (for example, whether or not the mother was teaching the pup how to hunt) it is necessary to use a camera with a wide field of view so that we can obtain knowledge about the surrounding environment. Still camera images of touching behaviors between whales have also been recorded; however, a wide-lens camera would aid researchers in determining the frequency at which this behavior occurs. These examples show how necessary wide-lens cameras, such as omnidirectional cameras, are for investigating the ecology of marine animals. Such cameras enable researchers to record the environment surrounding the tagged animal, enabling them to determine whether other individuals (such as competitors, collaborators, or predators) are present or not, and understand the frequency and distribution of food sources.This research group inferred that the tagged whale was resting based on the captured footage of nearby individuals at rest, demonstrating the usefulness of omnidirectional cameras. It is hoped that these cameras can be utilized to illuminate the ecology of marine animals that are difficult to observe.Video of whale tagging:
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Animals
| 2,021 |
March 18, 2021
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https://www.sciencedaily.com/releases/2021/03/210318142503.htm
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Dogs infected with Leishmania parasites smell more attractive to female sand flies
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Dogs infected with the Leishmania parasite smell more attractive to female sand flies than males, say researchers.
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The study published in In Brazil, the parasite Leishmania infantum is transmitted by the bite of infected female Lutzomyia longipalpis sand flies.Globally over 350 million people are at risk of leishmaniasis, with up to 300,000 new cases annually. In Brazil alone there are approximately 4,500 deaths each year from the visceral form of the disease and children under 15 years old are more likely to be affected.Leishmania parasites are transmitted from infected dogs to people by sand flies when they bite. Visceral leishmaniasis affects the internal organs and is fatal if not treated.As only female sand flies transmit the parasite, researchers wanted to understand if infection made dogs more attractive to the insect.Professor Gordon Hamilton of Lancaster University said: "In this study we showed that infected dog odour is much more attractive than uninfected dog odour to the female sand flies. Only the females can transmit the pathogen and male sand flies, which do not transmit the parasite, are not affected by the changed odour."This clear-cut difference in attraction of female and male sand flies suggests that the females are preferentially attracted by parasite infected hosts and this could lead to enhanced infection and transmission opportunities for the parasite."The researchers had previously found that dogs infected with Leishmania parasites smelled different compared to uninfected dogs.Professor Hamilton said: "Domestic dogs are the reservoir of infection, therefore understanding how the infection affects the attractiveness of dogs to the insect vector is important in understanding the epidemiology of the disease and offers opportunities for new control and diagnostic methodologies."
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Animals
| 2,021 |
March 18, 2021
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https://www.sciencedaily.com/releases/2021/03/210318142442.htm
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Discovery of a 'winged' shark in the Cretaceous seas
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93 million years ago, bizarre, winged sharks swam in the waters of the Gulf of Mexico. This newly described fossil species, called Aquilolamna milarcae, has allowed its discoverers to erect a new family. Like manta rays, these 'eagle sharks' are characterised by extremely long and thin pectoral fins reminiscent of wings. The specimen studied was 1.65 metres long and had a span of 1.90 metres.
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Aquilolamna milarcae had a caudal fin with a well-developed superior lobe, typical of most pelagic sharks, such as whale sharks and tiger sharks. Thus, its anatomical features thus give it a chimeric appearance that combines both sharks and rays.With its large mouth and supposed very small teeth, it must have fed on plankton, according to the international research team led by Romain Vullo of the CNRS.Scientists have identified only one category of large plankton feeders in Cretaceous seasuntil now: a group of large bony fish (pachycormidae), which is now extinct. Thanks to this discovery, they now know that a second group, the eagle sharks, was also present in the Cretaceous oceans.The complete specimen was found in 2012 in Vallecillo (Mexico), a locality yielding remarkably preserved fossils. This site, already famous for its many fossils of ammonites, bony fish and other marine reptiles, is most useful for documenting the evolution of oceanic animals.As well as shedding light on the structure of Cretaceous marine ecosystems, the discovery of eagle sharks reveals a new, hitherto unsuspected, facet of sharks' evolutionary history.
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Animals
| 2,021 |
March 18, 2021
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https://www.sciencedaily.com/releases/2021/03/210318113640.htm
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Enigmatic circling behavior captured in whales, sharks, penguins, and sea turtles
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Technological advances have made it possible for researchers to track the movements of large ocean-dwelling animals in three dimensions with remarkable precision in both time and space. Researchers reporting in the journal
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"We've found that a wide variety of marine megafauna showed similar circling behavior, in which animals circled consecutively at a relatively constant speed more than twice," says Tomoko Narazaki of the University of Tokyo.Narazaki's team first discovered the mysterious circling behaviors in homing green turtles during a displacement experiment. They had transferred nesting turtles from one place to another to study their navigation abilities."To be honest, I doubted my eyes when I first saw the data because the turtle circles so constantly, just like a machine!" Narazaki says. "When I got back in my lab, I reported this interesting discovery to my colleagues who use the same 3D data loggers to study a wide range of marine megafauna taxa."What came next surprised the researchers even more: they realized that various species of marine animals showed more or less the same circling movements. This finding is surprising in part because swimming in a straight line is the most efficient way to move about. It suggests there must be some good reason that animals circle.Narazaki's team reports that some circling events were recorded at animals' foraging areas, suggesting that it might have some benefit for finding food. For example, they note that a total of 272 circling events were observed in four tiger sharks tagged off Hawaii. However, fur seals were found to circle mainly during the day even though they primarily feed at night. Other circling events also appeared unrelated to foraging. For example, they saw a male tiger shark circling to approach a female for courtship, and the evidence in sea turtles suggests circling might play some role in navigation."What surprised me most was that homing turtles undertake circling behavior at seemingly navigationally important locations, such as just before the final approach to their goal," Narazaki says.It's possible the circling helps the animals to detect the magnetic field to navigate; interestingly, the researchers say, submarines also circle during geomagnetic observations. But it's also possible that the circling serves more than one purpose.The researchers say that studies of such fine-scale movements, including circling, in more marine species might reveal important behaviors that have otherwise been overlooked. In future studies, they'd like to examine animal movements in relation to the animals' internal state and environmental conditions in search of more clues as to why they circle.This work was supported by IPEV, a JSPS Research Fellowship for Young Scientists, a grant from JSPS, and the Bio-Logging Science, the University of Tokyo.
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Animals
| 2,021 |
March 18, 2021
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https://www.sciencedaily.com/releases/2021/03/210318101541.htm
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Christmas Island reptile-killer identified
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Native reptile populations on Christmas Island have been in severe decline with two species, Lister's gecko and the blue-tailed skink, entirely disappearing from the wild. While previously the main driver for this decline is likely predation by invasive species and habitat destruction, a silent killer is now threatening to wipe the species out entirely.
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Those bred in captivity on the Australian Territory in the Indian Ocean have also been mysteriously dying, leaving the two species -- which number only around 1000 each -- in danger of extinction. Veterinary scientists from the University of Sydney, the Australian Registry of Wildlife Health and the Taronga Conservation Society Australia have now discovered the cause of these deaths: a bacterium, Enterococcus lacertideformus (E. lacertideformus).The bacterium was discovered in 2014 after captive reptiles presented with facial deformities and lethargy, and some even died. Samples were collected and analysed using microscopy and genetic testing.The researchers' findings, published in The bacterium grows in the animal's head, then in its internal organs, before eventually causing death. It can be spread by direct contact -- including through reptiles' mouths, or via reptiles biting one another -- often during breeding season fights."This means that healthy captive animals need to be kept apart from infected ones and should also be kept away from areas where infected animals have been," said Jessica Agius, co-lead researcher and PhD candidate in the Sydney School of Veterinary Science.Ms Agius and the research team not only identified the bacterium, they decoded its genetic structure using whole genome sequencing.Specific genes were identified that are likely to be associated with the bacterium's ability to infect its host, invade its tissues and avoid the immune system."We also found that the bacterium can surround itself with a biofilm -- a 'community of bacteria' that can help it survive," Ms Agius said."Understanding how E. lacertideformus produces and maintains the biofilm may provide insights on how to treat other species of biofilm-forming bacteria."The search of the genetic code suggested that the killer bacterium was susceptible to most antibiotics.Professor David Phalen, research co-lead and Ms Agius' PhD supervisor, said: "This suggests that infected animals might be successfully treated. That's what we need to determine now."In another effort to protect the endangered reptiles on Christmas Island, a population of blue-tailed skinks has been established on the Cocos Islands. Ms Agius played a critical role in the translocation, testing reptiles on the Cocos Islands to make sure that they were free of E. lacertideformus."It's critical we act now to ensure these native reptiles survive," Ms Agius said.
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Animals
| 2,021 |
March 18, 2021
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https://www.sciencedaily.com/releases/2021/03/210318091644.htm
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Declining caribou population victim of ecological chain reaction
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A new study comparing decades of environmental monitoring records has confirmed that Canada's caribou are not faring as well as other animals like moose and wolves in the same areas -- and also teased out why.
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The study used 16 years of data to examine changes in vegetation, moose, wolves and caribou. "Caribou are declining across Canada and have been recently lost in the Lower 48 States," says Melanie Dickie, a doctoral student with UBC Okanagan's Irving K. Barber Faculty of Science."Understanding why caribou are declining is the first step to effectively managing the species -- it tells us which parts of the issue we can target with management actions and how that might help caribou."Dickie, along with fellow UBCO researchers Dr. Clayton Lamb and Dr. Adam Ford, describe the decline in caribou populations as an ecological puzzle. Typically, there are multiple factors, all changing at once, making it hard to identify how the pieces fit together. Factors such as predation from wolves and other large carnivores, increasing moose and deer populations, and habitat alteration through resource extraction and wildfires all play a part. The study aimed to sort out the roles each of these play in caribou population declines.Once land is cleared by either wildfire or harvesting, the mature forest transforms into more productive early seral forage. With the tree canopy removed, there is a significant increase in sunlight, allowing understory plants to thrive. These plants provide food that benefits moose, deer and their predators. These predators then have a spillover effect on the rarer caribou, creating apparent competition between moose and caribou."Changes in primary productivity have the potential to substantially alter food webs, with positive outcomes for some species and negative outcomes for others," Dickie explains. "Understanding the environmental context and species interactions that give rise to these different outcomes is a major challenge to both theoretical and applied ecology."To establish the link between habitat alteration and primary productivity, the researchers first examined satellite imagery to show a link between logging and new vegetation growth. They then used data on moose, caribou and wolf numbers to compare the leading hypotheses on how changes in vegetation influence these populations. The analysis was conducted across a 598,000-square kilometre area located in the boreal shield and boreal plains of western Canada.Ultimately, the researchers determined that lower caribou populations were a victim of an ecological chain reaction. Caribou have a lower population growth rate relative to moose, making them more susceptible to landscape changes."We found that increased deciduous vegetation on the landscape, which moose like to eat, increased moose populations, which increased wolves, and in turn, means declining caribou," Dickie says. "We also found that human land use, like forestry, significantly increased vegetation productivity, suggesting that these kinds of land uses are leading to caribou declines via changes to predators and prey."Caribou conservation will be a defining point for Canada in the 21st century, adds Dr. Lamb, a Liber Ero Fellow at UBCO. Caribou highlight an unresolved tension between land stewardship, wildlife conservation and resource extraction. Further, as caribou populations continue to decline, Indigenous Peoples are forced to grapple with mounting threats to food security, cultural traditions, and infringed treaty rights."We can't attribute caribou declines to just one factor or another," he says. "But understanding the relative importance of these factors, and how they interact, can help us understand how we can manage caribou populations in the face of continued climate change and land use."The study, published recently in the
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Animals
| 2,021 |
March 17, 2021
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https://www.sciencedaily.com/releases/2021/03/210317155201.htm
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Giraffes: The trouble with being tall
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The giraffe is a truly puzzling animal. With its exceptional anatomy and suite of evolutionary adaptations, the giraffe is an outstanding case of animal evolution and physiology. Now, an international team of researchers from the University of Copenhagen and Northwestern Polytechnical University in China have produced a high-quality genome from the giraffe and investigated which genes are likely to be responsible for its unique biological features.
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The extraordinary stature of the giraffe has led to a long list of physiological co-adaptations. The blood pressure of the giraffe, for instance, is twice as high as in humans and most other mammals to allow a steady blood supply to the lofty head. How does the giraffe avoid the usual side effects of high blood pressure, such as severe damage to the cardiovascular system or strokes?The team discovered a particular gene -- known as FGFRL1 -- that has undergone many changes in the giraffe compared to all other animals. Using sophisticated gene editing techniques they introduced giraffe-specific FGFRL1 mutations into lab mice. Interestingly, the giraffe-type mice differed from normal mice in two important aspects: they suffered less cardiovascular and organ damage when treated with a blood pressure increasing drug, and they grew more compact and denser bones."Both of these changes are directly related to the unique physiological features of the giraffe -- coping with high blood pressure and maintaining compact and strong bones, despite growing them faster than any other mammal, to form the elongated neck and legs.," says Rasmus Heller from the Department of Biology, University of Copenhagen, one of the lead authors on the study.While jumping out of bed for (some) humans might be an effortless and elegant affair, this is definitely not the case for the giraffe. Merely standing up is an a lengthy and awkward procedure, let alone getting up and running away from a ferocious predator. Therefore, giraffes have evolved into spending much less time sleeping than most other mammals.Rasmus Heller elaborates: "We found that key genes regulating the circadian rhythm and sleep were under strong selection in giraffes, possibly allowing the giraffe a more interrupted sleep-wake cycle than other mammals."In line with research in other animals an evolutionary trade-off also seem to be determining their sensory perception, Rasmus continues:"Giraffes are in general very alert and exploit their height advantage to scan the horizon using their excellent eyesight. Conversely, they have lost many genes related to olfaction, which is probably related to a radically diluted presence of scents at 5m compared to ground level."These findings provide insights into basic modes of evolution. The dual effects of the strongly selected FGFRL1 gene are compatible with the phenomenon that one gene can affect several different aspects of the phenotype, so called evolutionary pleiotropy. Pleiotropy is particularly relevant for explaining unusually large phenotypic changes, because such changes often require that a suite of traits are changed within a short evolutionary time. Therefore, pleiotropy could provide one solution to the riddle of how evolution could achieve the many co-dependent changes needed to form an animal as extreme as a giraffe. Furthermore, the findings even identifies FGFRL1 as a possible target of research in human cardiovascular disease."These results showcase that animals are interesting models, not only to understand the basic principles of evolution, but also to help us understand which genes influence some of the phenotypes we are really interested in -- such as those related to disease. However, it's worth pointing out that genetic variants do not necessarily have the same phenotypic effect in different species, and that phenotypes are affected by many other things than variation in coding regions.," says Qiang Qiu from Northwestern Polytechnical University, another lead author on the study.The results have just been published in the
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Animals
| 2,021 |
March 16, 2021
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https://www.sciencedaily.com/releases/2021/03/210316214642.htm
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Trouble for honeyeaters that sing the wrong song
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The critically endangered regent honeyeater is losing its "song culture" due to the bird's rapidly declining population, according to new research from The Australian National University (ANU).
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Just like humans learning to speak, many birds learn to sing by associating with older birds of the same species. They risk losing this skill if adults become too rare. And if they don't learn to sing a sexy enough song, their chances of mating are reduced."If endangered birds are unable to learn how to sing correctly, it seriously impacts their ability to communicate," lead author Dr Ross Crates said."It could also be exacerbating the honeyeater's population decline, because we know a sexy song increases the odds of reproduction in songbirds. Females will avoid males that sing unusual songs."The study found that in places where there were still reasonable numbers of regent honeyeaters, males sang rich and complex songs. Where the birds were rare, males sang simplified or "totally incorrect" songs."For example, 18 male regent honeyeaters -- or around 12 per cent of the total population -- were only able to copy the songs of other bird species," study co-author Dr Dejan Stojanovic said."This lack of ability to communicate with their own species is unprecedented in a wild animal. We can assume that regent honeyeaters are now so rare that some young males never find an older male teacher."The study also showed regent honeyeaters born in captivity have totally different songs to wild birds.The research team believe this could prove crucial when it comes to conservation."The unusual songs of captive-bred birds could reduce their attractiveness to wild birds when they are eventually released," Dr Crates said."So we've devised a new strategy to teach young captive regent honeyeaters to sing the same song as the wild birds by playing them audio recordings."Loss of song culture is a major warning sign the regent honeyeater is on the brink of extinction and we still have a lot to learn about how to help them."
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Animals
| 2,021 |
March 16, 2021
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https://www.sciencedaily.com/releases/2021/03/210316132059.htm
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New study predicts changing Lyme disease habitat across the West Coast
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The findings of a recent analysis conducted by the Translational Genomics Research Institute (TGen), an affiliate of City of Hope, suggest that ecosystems suitable for harboring ticks that carry debilitating Lyme disease could be more widespread than previously thought in California, Oregon and Washington.
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Bolstering the research were the efforts of an army of "citizen scientists" who collected and submitted 18,881 ticks over nearly three years through the Free Tick Testing Program created by the Bay Area Lyme Foundation, which funded the research, producing a wealth of data for scientists to analyze.This new study builds on initial research led by the late Nate Nieto, Ph.D., at Northern Arizona University, and Daniel Salkeld, Ph.D., of Colorado State University.This immense sample collection represented a multi-fold increase in the number of ticks that could be gathered by professional biologists conducting field surveys in far less time and at a fraction of the cost. This kind of citizen participation -- which in the future could include smart-phone apps and photography -- could become "a powerful tool" for tracking other animal- and insect-borne infectious diseases important for monitoring human and environmental health, according to study results published in the scientific journal This study expands on previous work in California and is the first study to produce high resolution distributions of both actual and potential tick habitat in Oregon and Washington."This study is a great example of how citizen scientists can help -- whether tracking climate change, fires, habitat changes or species distribution shifts -- at a much finer scale than ever before," said Tanner Porter, Ph.D., a TGen Research Associate and lead author of the study.Specifically, Dr. Porter said the findings of this study could help raise awareness among physicians across the West, and throughout the nation, that tick-borne diseases are possible throughout a wider expanse than ever thought before.Lyme disease is caused by a bacteria, If not treated promptly, Lyme disease can progress to a debilitating stage, becoming difficult and sometimes impossible to cure. This may include inflammation of the heart and brain.Lyme disease is the most common tickborne illness in the U.S., annually causing an estimated 500,000 infections, according to the CDC. However, even the most commonly-used diagnostic test for Lyme disease misses up to 70% of early stage cases. There is no treatment that works for all patients."We hope this study data encourages residents of California, Oregon and Washington to take precautions against ticks in the outdoors, and helps to ensure that local healthcare professionals will consider diagnoses of Lyme when patients present with symptoms," said Linda Giampa, Executive Director of the Bay Area Lyme Foundation.Citizen scientists were encouraged to mail in ticks collected off individuals' bodies, pets and clothing. They noted the time and place where the ticks were discovered, and described activities involved, the surrounding environment, and in many cases specific GPS coordinates.Field studies could take decades to produce the same amount of data, said Dr. Porter, adding, "this citizen science technique could allow for real-time distribution monitoring of ticks and other relevant species, an important consideration with emerging pathogens, changing land-use patterns, and climate change."This study builds on TGen's "One Health Collaborative," an initiative that uses a holistic approach to monitor the health of humans, animals and the environment, according to David Engelthaler, Ph.D., head of TGen's infectious disease studies.The study -- "Predicting the current and future distribution of the western black-legged tick,
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Animals
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March 16, 2021
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https://www.sciencedaily.com/releases/2021/03/210316112246.htm
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Deforestation taking a heavy toll on international bird haven
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An analysis has found deforestation is severely affecting forest bird species in Colombia, home to the greatest number of bird species in the world.
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University of Queensland-led research, steered by Dr Pablo Negret, analysed the impact of deforestation on 550 bird species, including 69 only found in the South American nation."Our study has shown an astonishing reduction in bird species habitat," Dr Negret said."One third of the forest bird species in Colombia have lost at least a third of their historical habitat, and that's just using the most recent data we have available -- from 2015."Moreover, 18 per cent or 99 species have lost more than half of their historical habitat to date."By 2040, we expect this will increase to 38 per cent or 209 species."Sadly, many of those species are endemic to the country and are not currently classified as threatened by the International Union for Conservation of Nature, suggesting that there are many unlisted species that face an imminent extinction threat from ongoing habitat loss."Dr Negret said the results were concerning but not surprising."Deforestation is one of the main drivers of habitat loss for many species in the tropics," he said."We know that deforestation affects thousands of species in these ecosystems, but our attention is usually focused on a tiny fraction -- threatened and charismatic species."This study provides more data on species previously thought abundant that are actually dwindling -- hopefully we can shine a light on them, so they can be recognised as under threat and don't fall through the cracks."The researchers used historical and present satellite forest cover data, while collating spatial information on other variables associated with deforestation patterns.UQ's Professor Martine Maron said the research would help predict future habitat loss for already-threatened species."This methodology, and the technologies behind it, allow us to identify places where future habitat loss is predicted."This means that we can reveal the locations where threatened species are most likely to lose precious habitat, and prioritise their protection."And, in a country with growing threats to rich bird diversity, it pays to be ahead of the game."The authors hope the Colombian government and NGOs working in this space will use the research to guide conservation of Colombia's bird species.
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Animals
| 2,021 |
March 16, 2021
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https://www.sciencedaily.com/releases/2021/03/210316093429.htm
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How varying climate conditions impact vulnerable species
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New findings on the diet of Arctic foxes, determined by the condition of their teeth, show how varying climate conditions in the Arctic affect the animals that live there.
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In a study published in Studying the effect of varying climate conditions within this region helps scientists understand the impact of climate change on vulnerable animals and could explain future responses and adaptation, given the warming trend and thawing in Arctic areas. The researchers' study is the first to combine dental proxies for short-term, or seasonal, and long-term, or lifetime, diet to better understand how resource depletion affects species differently in different locations within the Arctic.In this study, the researchers compared the condition of the teeth over space -- northern versus southern peninsula -- and time and found that foxes from the northern peninsula likely had to periodically rely on larger prey rather than their preferred prey of rodents such as lemmings and voles.Microwear analysis of teeth indicated the foxes in both locations dined on the preferred smaller prey during rodent "rich" years. However, during rodent "bust" years in the southern peninsula, the foxes had to adapt to conditions and fall back on larger prey, such as ptarmigans and hares. In the north, where these species were less available, foxes evidently scavenged more reindeer carcasses.Bone consumption by animals causes tooth breakage, heavy wear and microscopic pitting. Breakage and gross wear reflect animal diet over the course of a lifetime, whereas microscopic pitting reflects a pattern of seasonal changes over time. Ungar is a leading expert in dental microwear analysis, including what it says about animals' diet as it relates to evolution."These data together suggest that dental evidence can provide important insights into variation in the feeding ecology of Arctic foxes and potentially into the impacts of changes in food abundance across space and time," Ungar said.The Arctic fox is listed as a climate change flagship species by the International Union for Conservation of Nature.The researchers, including colleagues from the United States, Russia, Norway and France, examined 78 Arctic fox specimens, all caught by indigenous trappers on Yamal for the purpose of harvesting fur. Preliminary analysis focused on three trapping periods -- December 1981 to March 1982, November 1983 to March 1984 and October 2007 to March 2008. The foxes were selected from the northern and southern Yamal regions during the rodent-poor periods of 1981-1982 and 2007-2008 and rodent-rich period of 1983-1984."Time or space alone is not enough to get the full story of fox ecological response to environmental variation," Ungar said. "Combining these proxies for understanding life in the past is essential to inform us on the ecology of living animals in a rapidly changing and fragile ecosystem."The researchers' study is part of a large, multi-year project focused on the Yamal Peninsula, which serves as a small-scale and manageable research model for the Arctic as a whole. Habitats of the Yamal region, roughly 1,400 miles northeast of Moscow, range from forest in the south to tundra in the north. The Yamal has a rich diversity of native and invasive plant and animal species, a large indigenous population with strong traditional culture, and economically critical natural resources. As part of this project, Ungar and his colleagues are studying how climate change -- specifically warming and extreme weather -- has affected the temperature, precipitation and landforms in the region, and how people, animals and plants have adapted to these changes.Ungar's co-authors are Alexandria Peterson, graduate student in the U of A's Environmental Dynamics program; Blaire Van Valkenburgh at the University of California, Los Angeles; Dorothee Ehrich from the Arctic University of Norway; Olivier Gilg from the Groupe de Recherche en Écologie Arctique in France; and Aleksandr Sokolov, Natalia Sokolova, Ivan Fufachev, Alexandra Terekhina, Alexander Volkovitskiy and Viktor Shtro from the Arctic Research Station, Institute of Plant and Animal Ecology of the Ural Branch of the Russian Academy of Sciences.This project was made possible through funding from the National Science Foundation's Navigating the New Arctic initiative, one of NSF's 10 Big Ideas.Ungar is director of the Environmental Dynamics program at the University of Arkansas.
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Animals
| 2,021 |
March 15, 2021
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https://www.sciencedaily.com/releases/2021/03/210315180614.htm
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Blight may increase public health risk from mosquito-borne diseases
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Louisiana State University researchers recently published findings that blight leads to an increased abundance of disease-carrying mosquitoes. The researchers investigated the presence of several mosquito species in two adjacent but socio-economically contrasting neighborhoods in Baton Rouge: the historic Garden District, a high-income neighborhood, and the Old South neighborhood, a low-income area. They found significantly higher adult and larvae abundance of the Asian tiger mosquito (a carrier of Zika and dengue) and higher mosquito habitat availability -- particularly discarded tires -- in the Old South neighborhood. This indicates that environmental conditions in the low-income neighborhood were most ideal for this mosquito to breed and proliferate.
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"These two neighborhoods are very similar in terms of vegetation cover, human population and density of households. One of the main differences is blight. One neighborhood has a lot of blight in the form of abandoned residences, empty lots and mismanaged waste, and the other neighborhood does not. It was the perfect set of conditions for addressing this question," said Rebeca de Jesús Crespo, lead author and an assistant professor in LSU's College of the Coast & Environment.In recent years, the Old South neighborhood has been the focus of revitalization plans by multiple stakeholder groups. The researchers recommended that these blight reduction efforts continue for the benefit of public health."This is an area at high risk of these mosquito-borne diseases," said Madison Harrison, co-author of the publication. "All that it takes for these diseases to spread is for the right vector to be infected with the pathogen and to bite humans at the right point of incubation of said pathogen."So far, Zika and dengue are not currently present in the state. However, Louisiana's climate is ideal for these diseases to spread once introduced.According to de Jesús Crespo, Harrison was an invaluable addition to the team. Currently, she is a public health master's student at LSU Health New Orleans."In the College of the Coast & Environment, for almost every project that we do, we are integrated and interdisciplinary. We take a broad approach to doing research that is important for solving problems in real time. For this project, it was important to me to include Madison from LSU Health Sciences as well as community stakeholders who could provide their expertise and unique perspectives," de Jesús Crespo said.The researchers examined the prevalence of two container-breeding species of mosquitoes that are known to spread disease, the Asian tiger mosquito and the southern house mosquito (a carrier of West Nile virus). They inspected potential larvae habitats (such as discarded tires, discarded Styrofoam cups and snack bags, plant pots and water baths) in publicly accessible locations and calculated the percentage of those that contained larvae. Additionally, they placed adult mosquito traps around the perimeter of some private homes with the permission from the homeowner, in an abandoned house and in an empty lot with trash accumulation in the higher income neighborhood.They found that the adult population of the southern house mosquito was fairly diffuse, but the lower income neighborhood had significantly higher numbers of Asian tiger mosquito (adults and larvae) and higher numbers of total mosquito larvae. This shows that the presence of discarded container habitats due to neglect provides more breeding grounds for disease-carrying mosquitoes, disproportionately affecting low-income groups."I think everybody can agree that urban blight is a problem we need to solve here in Baton Rouge. Mosquito risk is one of those factors that could impact human health and that adds another level of importance with that," de Jesús Crespo said.
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Animals
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March 15, 2021
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https://www.sciencedaily.com/releases/2021/03/210302130653.htm
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Lateral-to-sagittal shift in mammal spine evolution challenged in new study
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When it comes to the evolution of the mammal spine -- think of animals whose backbone allows them to gallop, hop, swim, run, or walk upright -- a key part of the tale is quite simple.
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Because nonmammalian synapsids, the extinct forerunners to mammals, had similar traits to living reptiles (like having their limbs splayed out to the side instead of tucked into their body like today's mammals), the strongheld belief was that they must have also moved in similar ways. Primarily, their backbones must have moved side-to-side, bending like those of modern lizards, instead of the up-and-down bending motion mammal spines are known for. It's believed over time, and in response to selective pressures, the mammal spine evolved from that lizard like side-to-side bending to the mammal-like up-and-down bending seen today. The transition is known as the lateral-to-sagittal paradigm.It's an easy to grasp story that's been taught in college textbooks on anatomy and evolution for decades. But, according to a new Harvard-led study, that long held belief is wrong."The problem with the original story was that, as opposed to being based on fossil evidence, it was primarily based just on a correlation with something else that was seen in living animals," said former Harvard postdoctoral researcher Katrina Jones. "It relied upon this assumption that these forerunners of mammals must function the same as lizards because this one aspect of their anatomy was similar to lizards.... We're saying just because the limb posture looked similar doesn't mean they moved the same."The work, led by Jones, challenges the lateral-to-sagittal hypothesis by looking at the vertebrae of modern reptiles, mammals, and the extinct nonmammalian synapsids to determine how their vertebrae changed over time and its effect on how these creatures likely moved.The analysis demonstrates the three lineages differ from one another other when it comes to the morphology, function, and characteristics of their spines, and suggests that mammal backbones didn't evolve from a reptile-like ancestor. There had to have been a completely different type of backbone function not observed in today's living vertebrates."The ancestral stock that mammals evolved from didn't look or function like a living reptile," said Stephanie Pierce, Thomas D. Cabot Associate Professor of Organismic and Evolutionary Biology and curator of vertebrate paleontology in the Museum of Comparative Zoology and the study's senior author. "They started off with their own unique set of characteristics and functions and then evolved towards mammals."The study published in It included collaborators Kenneth Angielczyk at the Field Museum of Natural History and Blake Dickson, Ph.D. '20 who worked in the Pierce lab as a graduate student but is now a postdoctoral researcher at Duke University.Dickson's earlier work with the lab, reconstructing the evolution of terrestrial movement in early tetrapods by analyzing 3D scans of fossils, provided the method the researchers modified for the new study.The team wanted to see how the origin story of the mammalian backbone, which comes in all shapes and sizes, held up under intense scrutiny.They took CT scans of the spine of reptiles, mammals, and fossil nonmammalian synapsids to get 3D reconstructions of key portions of their backbones to see their shape. They then used statistical comparisons of those shapes and measured of how they bent to determine how they functioned and what movement they allowed.They saw that the nonmammalian synapsids clearly had their own vertebral shapes and that they were distinct from both mammals and reptiles. This showed that key parts of the spine belonging to the ancestors of mammals had their own unique characteristics that are not seen in any living group.When comparing function of the different spines, the researchers saw the nonmammalian synapsid spine acted very differently from both mammals and reptiles. Its dominant trait, was being very stiff with more limited capacity for lateral bending, unlike the lateral bending in the back of reptile spines. That suggested the long-held notion that these creatures moved like today's reptiles, particularly lizards, is wrong.Looking at the spines of the living mammals they sampled, they saw that they were a sort of a jack-of-all-trades, displaying abilities in each of the functional traits they measured. This means that mammal backs can do much more than just sagittal bending, and that during their evolutionary history other functions were added to the stiff backs of their forerunners, such as spinal twisting for grooming fur. The results make the simple lateral-to-sagittal paradigm a much more complicated story.The researchers cited advances in today's CT scanning technology, computational data, and statistical programs with making the study possible. They are currently working on further confirming their findings and creating full 3D spinal reconstructions for the species they looked at.The group believes the work shows the power of the fossil record for testing long-held evolutionary ideas."If we only look at modern animals, such as living mammals and reptiles, we can come up with evolutionary hypotheses but they may not be correct," Pierce said. "Unless we go back into the fossil record and really dig into those extinct animals, we can't trace what those anatomical changes were, when they happen, or what selective pressures drove their evolution."
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Animals
| 2,021 |
March 12, 2021
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https://www.sciencedaily.com/releases/2021/03/210312095814.htm
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Accurate aging of wild animals thanks to first epigenetic clock for bats
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A new study led by University of Maryland and UCLA researchers found that DNA from tissue samples can be used to accurately predict the age of bats in the wild. The study also showed age-related changes to the DNA of long-lived species are different from those in short-lived species, especially in regions of the genome near genes associated with cancer and immunity. This work provides new insight into causes of age-related declines.
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This is the first research paper to show that animals in the wild can be accurately aged using an epigenetic clock, which predicts age based on specific changes to DNA. This work provides a new tool for biologists studying animals in the wild. In addition, the results provide insight into possible mechanisms behind the exceptional longevity of many bat species. The study appears in the March 12, 2021, issue of the journal "We hoped that these epigenetic changes would be predictive of age," said Gerald Wilkinson, a professor of biology at UMD and co-lead author of the paper. "But now we have the data to show that instead of having to follow animals over their lifetime to be sure of their age, you can just go out and take a tiny sample of an individual in the wild and be able to know its age, which allows us to ask all kinds of questions we couldn't before."The researchers looked at DNA from 712 bats of known age, representing 26 species, to find changes in DNA methylation at sites in the genome known to be associated with aging. DNA methylation is a process that switches genes off. It occurs throughout development and is an important regulator for cells. Overall, methylation tends to decrease throughout the genome with age. Using machine learning to find patterns in the data, the researchers found that they could estimate a bat's age to within a year based on changes in methylation at 160 sites in the genome. The data also revealed that very long-lived bat species exhibit less change in methylation overall as they age than shorter-lived bats.Wilkinson and his team then analyzed the genomes of four bat species -- three long-lived and one short-lived -- to identify the specific genes present in those regions of the genome where age-related differences in methylation correlated with longevity. They found specific sites on the genome where methylation was more likely to increase rather than decrease with age in the short-lived bats, but not in long-lived bats, and that those sites were located near 57 genes that mutate frequently in cancerous tumors and 195 genes involved in immunity."What's really interesting is that the sites where we found methylation increasing with age in the short-lived bats are near genes that have been shown to be involved in tumorigenesis -- cancer -- and immune response," Wilkinson said. "This suggests there may be something to look at in these regions regarding mechanisms responsible for longevity."Wilkinson said analyzing methylation may provide insight into many age-related differences between species and lead to a better understanding of the causes for age-related declines across many species."Bats live a long time, and yet their hearing doesn't decay with age, the way ours does," he said. "You could use this method to see whether there are differences in methylation that are associated with hearing. There are all kinds of questions like this we can ask now."
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Animals
| 2,021 |
March 11, 2021
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https://www.sciencedaily.com/releases/2021/03/210311185936.htm
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Birds learn to avoid flashy, hard-to-catch butterflies and their lookalikes
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The showy colors of some butterflies could advertise their speed and nimbleness, much like a coat of bright yellow paint on a sports car. A new study shows birds can learn to recognize these visual cues, avoiding not only butterflies they've failed to nab in the past but similar-looking species as well.
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The research provides some of the strongest evidence to date for the idea of evasive mimicry, a strategy in which animals protect themselves from predators by matching the colors or patterns of agile relatives. First proposed more than 60 years ago, the hypothesis has been a challenge to test.But in an experimental setting, researchers found that wild birds learned and remembered the wing patterns of artificial butterflies that evaded their attacks, as well as those that had a foul flavor, equally spurning both in follow-up tests and often ignoring lookalikes with similar color patterns. Unexpectedly, the birds learned to avoid evasive butterflies faster than distasteful ones.The results suggest that being hard to catch may deter predators at least as effectively as chemical defenses."There's a common idea that being distasteful is one of the best kinds of defense to have, but at least in this experiment, that didn't prove to be the case," said study co-author Keith Willmott, curator and director of the Florida Museum of Natural History's McGuire Center for Lepidoptera and Biodiversity.Most research on warning coloration has focused on species with chemical defenses and those that mimic them. Monarch butterflies, for example, sport bright wing patterns of black lines on a field of orange, indicating they contain bad-tasting toxins. A predator that eats one will likely avoid both monarchs and the similar-looking viceroy butterfly in the future.But a growing number of studies suggest a flashy exterior can mean something entirely different: that an animal is quick. Predators learn to associate these kinds of patterns with a futile chase that leaves them hungry, and species that evolve imitations of these "racing stripes" can capitalize on a defensive strategy while reinforcing the visual message."When many species share the same color pattern, they're better able to educate predators to avoid them," Willmott said. "The more species that share it, the better."During his Ph.D. studies, Willmott worked on the classification of a group of fast-flying tropical butterflies known as Adelpha. At first, he found them nearly impossible to identify. It seemed the genus either contained only a few species with slight variations in wing pattern or dozens of species that looked virtually the same. The latter turned out to be the case, with more than 90 species making up the group. Like some researchers before him, Willmott began to wonder whether evasive mimicry could explain why so many species of Adelpha looked alike."It was always mysterious to me," he said. "Species whose upper wings looked incredibly similar were distantly related, and we started to see cases where even subspecies of multiple species suddenly developed very unique color patterns. Really, the only way you can explain that is through mimicry."While other researchers suggested some Adelpha must have hidden chemical defenses, the explanation didn't quite satisfy Willmott. Toxic butterflies are usually slow fliers with long wings and a propensity for playing dead when caught. Adelpha butterflies, however, don't display these traits, having instead a short, stout thorax and smaller, triangular wings -- characteristics that enable fast, erratic flight and sharp turns.But he wasn't sure how to test this hypothesis until a conversation with fellow researchers at a 2018 conference in India: Johanna Mappes was an expert at developing predator-prey experiments with wild birds; Pável Matos-Maraví was interested in the evasive behavior of skipper butterflies; and Marianne Elias and her Ph.D. student Erika Páez were eager to study what drove the evolution of wing color patterns in the genus Adelpha, including the possible effects of predators.Simulating how evasive mimicry might play out in the wild appealed to the group. The ability of prey to escape predators' attacks has been "virtually unstudied," said Elias, a research group leader at the Institute of Systematics, Evolution, Biodiversity at the National Museum of Natural History in France.Previous work had shown birds can identify the visual cues of evasive prey. Together, the team designed an experiment to test whether potential examples of evasive mimicry in Adelpha could be the result of natural selection.At a special facility in Finland, the researchers collaborated with Janne Valkonen of the University of Jyväskylä to capture wild blue tits, birds that would never have encountered tropical Adelpha butterflies, and train them to catch a paper butterfly with an almond treat attached to its underside. Then, the birds were presented with a plain brown paper butterfly as a control and a paper butterfly with one of three common Adelpha wing patterns: a vertical white band on black forewings, a vertical orange band on black forewings or a combination of orange-striped forewings with white-striped hindwings.The paper Adelpha butterfly either concealed an almond soaked in a bitter substance -- a proxy for chemical defense -- or evaded the bird's attack by gliding away on a rail. The birds learned to connect a particular wing pattern with the negative experience of distastefulness or escape, eventually avoiding this butterfly and striking the control instead. In a final test, they were given four butterflies at the same time: the plain brown butterfly and all three Adelpha butterflies, including one with the pattern they had seen before.They strongly avoided the butterfly they had learned to associate with the bitter almond or fast flight and often avoided butterflies that shared a similar color or pattern.Birds were 1.6 times more likely to attack the distasteful butterfly than evasive ones, perhaps because they had varying levels of tolerance for the bad-tasting almond, said Páez, who co-led the study with Valkonen. After all, even a bitter morsel of food is better than nothing."Bad-tasting prey could provide a nutritive meal whereas missing prey completely cannot," she said.While birds tend to avoid colorful prey by default, the study provides evidence of learned behavior, Willmott said."This potentially explains many cases of apparent mimicry that lacked evidence of chemical defense."Matos-Maraví of the Biology Centre, Czech Academy of Sciences, and Mappes of the University of Jyväskylä and the University of Helsinki also co-authored the study.
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Animals
| 2,021 |
March 11, 2021
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https://www.sciencedaily.com/releases/2021/03/210311152727.htm
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Weakened protections led to more disappearances of endangered Mexican wolves
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Mexican wolves in the American Southwest disappeared more quickly during periods of relaxed legal protections, almost certainly succumbing to poaching, according to new research published Wednesday.
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Scientists from the University of Wisconsin-Madison found that Mexican wolves were 121% more likely to disappear -- despite high levels of monitoring through radio collars -- when legal rulings permitted easier lethal and non-lethal removal of the protected wolves between 1998 and 2016. The disappearances were not due to legal removal, the researchers say, but instead were likely caused by poachers hiding evidence of their activities.The findings suggest that consistently strong protections for endangered predators lead to reduced poaching, contrary to theories that legalizing lethal removal might reduce the motivation to poach. Instead, the scientists say, strong protections could signal both the value of endangered predators and the government's intent to enforce protections. However, exactly how government policies ultimately influence poaching activity remains unclear."Top predators are very important to healthy ecosystems," says Adrian Treves, a UW-Madison professor of environmental studies who oversaw the new research. "They are imperiled globally by human activities. And among human-caused mortality, poaching is the leading cause."Treves, graduate student Naomi Louchouarn and postdoctoral researcher Francisco Santiago-Ávila published their findings March 10 in the Royal Society Open Science journal. They collaborated with David Parsons, a former U.S. Fish and Wildlife Service agent and a member the Project Coyote science advisory board, to perform the analysis.The new report comes on the heels of the federal government's delisting of the grey wolf in November 2020 under the Endangered Species Act, which reduced protections for the carnivores.The Mexican wolf population, a subspecies of the grey wolf, is an ideal candidate for studying the effect of government policies. Thanks to intensive reintroduction efforts, more than half of the wolves are monitored through tracking collars, which provide high-quality data on the fate of individual wolves. Policies changed multiple times over roughly two decades, creating a natural experiment that researchers can use to observe how more relaxed or stringent protections affected wolf populations.The Treves lab asked how two distinct changes in federal protections for Mexican wolves affected the mortality of the predators in the ensuing years. From 2005 to 2009, and again from 2015 until the end of the study period in 2016, federal regulators relaxed protections for the wolves. These new policies allowed agencies to more readily remove by lethal means wolves that were deemed threats to people or livestock. Public hunting was never legalized.The researchers found that the only cause of lost wolves that changed significantly during times of reduced protections was a category known as lost-to-follow-up, or LTF. The LTF category includes all wolves that can no longer be accounted for. LTFs can be caused by radio collar battery failures, or by wolves migrating beyond the monitored area.Yet, the U.S. Fish and Wildlife Service found few, if any, migrants out of the recovery area and LTF events occurred significantly earlier than the expected battery life of radio collars. Those results mean that these two common causes of LTF status likely can't account for the large increase in wolves lost-to-follow-up during years of relaxed protections. The Treves group also found no evidence of changes in diseases or climate that correlated with policy changes and would increase disappearances.Instead, they believe that the increased risk of disappearance comes from poachers who act to hide their activities by destroying radio collars and hiding carcasses. Without that evidence, however, federal agencies can't confirm a cause of death, forcing them to declare the wolves lost-to-follow-up.Agency removal of wolves and confirmed poaching activities did not vary significantly based on policy period."The fact that these changes line up with these periods really tells you a lot. The wolves don't understand that policy changed, but people do," says Louchouarn. "Yet the disappearances did increase, so somebody was changing their behavior. These methods really helped us to make that connection to likely poaching."To reduce sources of bias, the researchers developed their methods and submitted them to peer review before completing their analysis. This pre-review encourages more transparent publishing of scientific findings, regardless of the final results."Our findings suggest that there is no evidence for the tolerance killing hypothesis, where allowing the killing of more individuals is going to increase the tolerance for the species and therefore reduce killings," says Santiago-Ávila, who originally developed the data analysis methods to study Wisconsin's wolf population. "There is a very minimal reduction in the poaching that gets reported. But that's only because the poaching gets translated to lost individuals, which we believe represents underreported poaching."The researchers say government agencies should reassess their assumptions that lethal removal can ultimately lead to better outcomes for the wolves. Federal policies are developed based on scientific research, so reports like this one and a previous study of Wisconsin's wolf population could help federal agencies reevaluate for the future."Protection is the thing that's reducing poaching," says Treves.
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Animals
| 2,021 |
March 11, 2021
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https://www.sciencedaily.com/releases/2021/03/210311152724.htm
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Paleontology: Microscope helps with dinosaur puzzle
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Fossil sites sometimes resemble a living room table on which half a dozen different jigsaw puzzles have been dumped: It is often difficult to say which bone belongs to which animal. Together with colleagues from Switzerland, researchers from the University of Bonn have now presented a method that allows a more certain answer to this question. Their results are published in the journal
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Fossilized dinosaur bones are relatively rare. But if any are found, it is often in large quantities. "Many sites contain the remains of dozens of animals," explains Prof. Dr. Martin Sander from the Institute of Geosciences at the University of Bonn.If the finder is lucky, the bones are still arranged exactly as in the living dinosaur. Some are even still connected to each other at their joints. All too often, however, they were pulled apart and dispersed by scavengers and flowing water before being embedded in the soil. "Assigning this pile of hundreds of fossilized bones to the respective individuals from which they originally came is then usually very difficult," stresses Sander, who is also a member of the transdisciplinary research area "Building Blocks of Matter and Fundamental Interactions."This is because, for one thing, "long bones" from the arms and legs, like the thigh bone, look remarkably similar even in different species. This means that even experts are often unable to say whether a fossil thigh bone is from Diplodocus or Brachiosaurus. And even if this could be ascertained, perhaps the excavation produced several Diplodocus specimens to which it could belong.Sander and his doctoral student Kayleigh Wiersma-Weyand have now been able to demonstrate how this can be achieved. They used dinosaur bones from the U.S. state of Wyoming as a test object. These had been excavated and partially combined into skeletons by a team from the Aathal dinosaur museum in Switzerland shortly before the turn of the millennium.The Swiss researchers made their finds available to the paleontologists in Bonn for the study. Wiersma-Weyand and Sander drilled into the 150-million-year-old bones and examined the extracted core under the microscope. "This allows us to find out how old the animal in question was when it died," Wiersma-Weyand explains. For one thing, young bones are better vascularized than old ones; this means that after fossilization they have more cavities in which the blood vessels used to be. Second, bone growth proceeds in spurts. "We therefore often see characteristic annual rings, similar to what we see in trees," the researcher says.Estimating the age often makes it possible to rule out that a bone belongs to a particular skeleton. "If the left thigh bone is ten years older than the right one, we have a problem," Sander says laconically. There were no such discrepancies in the finds examined for the study. "However, we came across bones that had previously been attributed to two different animals, but probably belong to one and the same skeleton."The study addresses a problem that has begun to come into scientific focus in recent years: With many mounted dinosaur skeletons located in museums and collections around the world, it is still not clear whether their bones come from one or more individuals. This combination is often done deliberately during mounting, since dinosaur skeletons are rarely preserved in their entirety. Supplementing missing bones with finds from other specimens is therefore common practice and, in principle, not a big deal as long as it is recorded. More critical, however, is when researchers combine finds unknowingly and these then come from different species or animals of different ages.This becomes particularly relevant when the skeletons are so-called type specimens. This is because these are considered the "standard" for the corresponding species, similar to the prototype meter. But what if, for example, the original Diplodocus contains the lower legs of a younger (and thus smaller) Diplodocus specimen? "Then some of the conclusions we draw about its locomotion and lifestyle may be wrong," Sander points out. "Our research therefore also helps combat the much-cited replication crisis in science."Together with Kayleigh Wiersma-Weyand and Master student Nico Roccazzella, he will soon be using this method to take a closer look at a famous exhibit: the "Arapahoe" skeleton, the longest skeleton of a dinosaur in Europe, which is currently on display at the Museum Koenig in Bonn.
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Animals
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March 11, 2021
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https://www.sciencedaily.com/releases/2021/03/210311123449.htm
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Tracing and controlling High Pathogenicity Avian Influenza
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Scientists have discovered a route of introduction for High Pathogenicity Avian Influenza Virus (HPAIV) H5N8 into Japan and, in parallel, have investigated the potential of two human anti-influenza drugs for the control of HPAI in birds.
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Since October 30, 2020, there have been over 30 recorded outbreaks of High Pathogenicity Avian Influenza (HPAI) in domestic poultry and wild fowl in Japan. This outbreak was caused by the influenza A virus H5N8, a known High Pathogenicity Avian Influenza Virus (HPAIV). In such a scenario, identification of the source of the virus and its transmission route is important to control its spread.A team of scientists led by Professor Yoshihiro Sakoda of Hokkaido University have recently found the probable route of introduction of the current HPAIV into Japan -- by migratory birds from Europe. Separately, they showed that anti-influenza drugs used for humans can potentially be used to treat HPAI in poultry and wild fowl, providing an alternative to culling infected birds. Their findings were published within a week of each other in the journal HPAI is a devastating disease in poultry, leading to large losses both economically and materially. Once present in domesticated poultry, the primary means of controlling HPAI is by culling all infected populations. There is no approved drug for the treatment of HPAI. In addition, it can infect captive wild birds, such as those in zoos and sanctuaries, which has major implications for the protection and conservation of endangered species.In addition, HPAI is closely related to influenza in humans; certain strains of HPAIV have jumped to humans in the past, most recently in mid February 2021, in Russia. For prevention and control, it is vital to track the spread of this disease.The scientists collected migratory duck feces samples from the lakeside of Lake Komuke, eastern Hokkaido in October 2020. After a number of tests, they confirmed the presence of H5N8 virus in one of the samples. Further, their genetic analysis showed that the H5N8 virus was closely related to the variants that caused outbreaks in Europe from late 2019 to early 2020 and the variants found in Korea and southern Japan from October to November 2020, rather than from the H5N8 viruses in East Asia from 2018-2019. This suggested that the H5N8 virus transmitted with migratory birds from Europe to Eastern Asia within 10 months. In addition, the team found that it is a different H5N8 variant that is causing current outbreaks in Europe, raising the alarm that the northern biosphere is becoming a reservoir of HPAIV.The scientists also investigated two antivirals, baloxavir marboxil (BXM) and peramivir (PR), used for the treatment of influenza in humans for their potential to treat HPAI in poultry. In their experiments, both drugs improved the survival rate of infected chickens and reduced viral amounts in their organs and feces, with BXM showing higher efficacy. Further work on BXM suggested that an early single-administration of BXM at doses of 2.5 mg/kg or higher would be most effective for the treatment of HPAI in real-life settings."Based on our findings, the government authorities warned poultries in Japan in November last year, which helped local businesses take measures to prevent potential outbreaks. As in the past years, we will continue to monitor HPAIV in migratory birds visiting Hokkaido as well as researching possible treatments of the disease," said Sakoda.The next steps would be to confirm if the strain of H5N8 detected by the scientists is responsible for the ongoing HPAI outbreak in Japan, and to verify if BXM is capable of treating HPAI in rare wild birds and poultry farms.
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Animals
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March 10, 2021
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https://www.sciencedaily.com/releases/2021/03/210310204212.htm
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Dog's body size and shape could indicate a greater bone tumor risk
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Osteosarcoma is a painful and aggressive bone tumour in dogs that is known to be more common in certain breeds than others. New research has now confirmed that larger breeds, such as Rottweiler, Great Dane and Rhodesian Ridgeback, have a greater risk of osteosarcoma than smaller breeds, as well as showing that breeds with shorter skulls and legs have lower osteosarcoma risk. The findings could inform future breed health reforms as well as studies into the way tumours develop from normal bone.
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The study led by the University of Bristol Veterinary School in collaboration with Cardiff University and Royal Veterinary College (RVC) London, and using data from VetCompass™ and Veterinary Pathology Group (VPG) histology, looked at the epidemiology surrounding which dog breeds get osteosarcoma, and what this means for canine welfare. This study also shows the huge benefits from studying dogs as a model to study this cancer. The findings are published in The study included 1,756 laboratory-confirmed osteosarcoma cases in dogs compared with 905,211 dogs under veterinary care in the VetCompass™ database during 2016.The research team found twenty-seven breeds, mainly larger breeds, had an increased risk of osteosarcoma compared to crossbreeds. Thirty breeds, mainly smaller breeds, including Jack Russell, Border Terrier, Bichon Frise, French Bulldog, Cavalier King Charles Spaniel, had reduced risk of osteosarcoma compared to crossbreeds.The study also compared various measures of body mass and leg length, and confirmed previous findings that heavier dogs with longer legs and longer skull shapes are at greatest risk of bone tumours. The results could inform breed health reforms, especially in predisposed breeds such as the Rottweiler, Great Dane and Rhodesian Ridgeback, Mastiff and German Pointer. Whereas previous studies have identified high-risk breeds for bone tumours, this paper is novel by being able to identify breeds at lowest risk because of the huge size of the study population. The breeds identified here could be researched and compared to recognise novel genetic differences which cause bone tumours.The findings that bone tumours are more common in certain breeds and conformations indicates that a dog's genetics play a role in bone tumour development. This link between the biology of conformation and the biology of bone tumours in dogs provides valuable opportunities for further study into what causes bone tumours to develop, and how they could be treated in the future.Osteosarcoma can affect any dog breed. However, owners of high-risk breeds should be especially alert for signs of the disease. These include lameness and painful, bony swelling and dog owners should contact their vet if concerned.Dr Grace Edmunds, Clinical Veterinary Research Fellow and lead author at Bristol Veterinary School, said: "As a vet, I am always focussed on improving animal welfare by looking outwards to find new treatments for their diseases. As osteosarcoma also affects adolescents, it is hugely exciting that by understanding the biology of bone tumours, and working with my collaborators in human cancer research, we may make a difference to both canine and human cancer patients."Dr Dan O'Neill, Senior Lecturer in Companion Animals Epidemiology at the RVC, added: "There are increasing concerns about the wisdom of breeding dogs with extreme body shapes such as flat-faced breeds like French Bulldogs or breeds with long backs such as Dachshunds."This study highlights the health risks from another extreme body shape -- large body size. The breeds at highest risk of osteosarcoma were large-sized breeds such as Rottweiler, Great Dane and Mastiff. To reduce the risks of picking a dog that may develop bone cancer, owners may need to consider choosing puppies from smaller-sized parents of these giant breeds or opting for different smaller breeds instead."Professor Rachel Errington at Cardiff University explained: "As a human cancer researcher at the School of Medicine this study shows that we can propose similar questions in human and canine disease with the aim of determining new therapies and diagnostics for both and this provides an exciting opportunity of joining forces across a diverse group of expertise."The research team is currently developing a project that will sequence certain genes in at-risk and protected breeds for osteosarcoma, with the aim of identifying those genetic pathways that cause bone tumours to develop from normal bone. Identifying such pathways will allow new drugs, or older, repurposed drugs, to be used to see if the outcomes when treating bone tumours in dogs can be improved.Drs Grace Edmunds and Helen Winter, members of the study team, will be engaging with owners of dogs with cancer and younger patients who have had cancer as part of a One Health approach, and they would welcome contact from patients or dog owners who would like to participate in this research.
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Animals
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March 9, 2021
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https://www.sciencedaily.com/releases/2021/03/210309153845.htm
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Milk prebiotics are the cat's meow
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If you haven't been the parent or caregiver of an infant in recent years, you'd be forgiven for missing the human milk oligosaccharide trend in infant formulas. These complex carbohydrate supplements mimic human breast milk and act like prebiotics, boosting beneficial microbes in babies' guts.
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Milk oligosaccharides aren't just for humans, though; all mammals make them. And new University of Illinois research suggests milk oligosaccharides may be beneficial for cats and dogs when added to pet diets.But before testing the compounds, scientists had to find them."When we first looked into this, there had only been one study on milk oligosaccharides in dogs, and none in domestic cats. The closest were really small studies on a single lion and a single clouded leopard," says Kelly Swanson, the Kraft Heinz Company Endowed Professor in Human Nutrition in the Department of Animal Sciences and the Division of Nutritional Sciences at Illinois."Our study was the first robust characterization of dog and cat milk oligosaccharides," he adds. "Our data not only provide a better understanding of how milk meets the nutritional needs of newborn kittens and puppies, but also how it helps promote gut immunity and establish a healthy gut microbial community early in life." That research appears in the journal The foundational study identified three predominant oligosaccharide structures in canine milk: 3'sialyllactose, 6'-sialyllactose, and 2'fucosyllactose, the same compound showing up in many infant formulas today. Together, these three structures made up more than 90% of the total oligosaccharides in canine milk.Feline milk was much more complex and balanced, with approximately 15 structures making up 90% of total oligosaccharides. Of these, difucosyllactose-N-hexaose b, 3'-sialyllactose, and lacto-N-neohexaose represented more than 10% each."Even though domestic dogs and cats both evolved as carnivores, they are metabolically distinct in many ways. Although pet cats still exist as true carnivores, pet dogs are omnivorous in nature," Swanson says. "These new milk oligosaccharide data highlight another interesting difference between the species, justifying further research to reveal their role in the nutritional and health status of newborn puppies and kittens."Even before Swanson and his colleagues identified the oligosaccharides in cat and dog milk, the pet food industry was beginning to recognize the potential benefits of these compounds as supplements in pet foods. In 2019, Swiss biotech company Gnubiotics Sciences announced an animal milk oligosaccharide-like product known as GNU100, but it hadn't been tested in animals. Swanson's team took that on.In two separate studies, both published in the First, in vitro laboratory tests with cellular colonies showed no toxic effects or tendencies to cause cell mutation. There was no reason to expect toxicity, but the result satisfies one of the basic FDA requirements for inclusion of any new ingredient in pet foods.Next, the researchers mixed GNU100 at 1% with a fat source and coated commercial dry diets for cats or dogs. As a control, fat-coated diets without GNU100 were also offered. When animals got to choose between the control and 1% bowls, they went crazy for the GNU100."In the cats, it was a huge preference. They ate nearly 18 times more food with GNU100 than the control food. We had just been hoping they wouldn't reject it. You know, cats can be pretty finicky," Swanson says. "When we got the data back it was like, wow, they really love that stuff! And the dogs did, too."Swanson explains GNU100 is composed of a complex mixture of oligosaccharides and peptides, small protein-containing compounds that may make the food more appetizing to cats and dogs.Finally, the researchers included GNU100 in experimental diets at 0%, 0.5%, 1%, and 1.5% and fed them to healthy adult dogs and cats for six months. During that time, they measured stool quality, blood metabolites, and nutrient digestibility, and evaluated changes in gut metabolites and the gut microbial community.Overall, cats and dogs did well with GNU100, with no adverse health effects. And the researchers saw shifts in the gut microbiome toward more beneficial species and their metabolite profiles.Aside from the palatability test, changes associated with GNU100 were as expected, showing intriguing trends in gut microbiota and gut metabolites that Gnubiotics plans to explore in future studies. Swanson thinks they would have seen bigger benefits in a more targeted study focusing on newborn cats and dogs, geriatrics, or pets with compromised immune systems."Theoretically, these products should stabilize and feed good bacteria in the gut as well as limit the growth of potentially undesirable bacteria. So if an animal is undergoing treatment for something with antibiotics or is in a high stress situation, having that product in the diet might keep the gut from destabilizing," Swanson says. "Another target group for these products might be young animals as a way to maintain beneficial bacteria in the gut as they wean off their mothers. We'd need to do more testing to see if the product holds up in those target groups, but at least we know now that it is safe and well tolerated."
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Animals
| 2,021 |
March 9, 2021
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https://www.sciencedaily.com/releases/2021/03/210309114354.htm
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Younger Tyrannosaurus Rex bites were less ferocious than their adult counterparts
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By closely examining the jaw mechanics of juvenile and adult tyrannosaurids, some of the fiercest dinosaurs to inhabit earth, scientists led by the University of Bristol have uncovered differences in how they bit into their prey.
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They found that younger tyrannosaurs were incapable of delivering the bone-crunching bite that is often synonymous with the The team also found that tension from the insertion of the lower pterygoid muscle is linked to decreasing stresses near the front of the typical tyrannosaur jaw, where the animals may have applied their highest impact bite forces using their large, conical teeth.This would be advantageous with the highly robust teeth on the anterior end of the tyrannosaur jaw, where, usually, they may have applied their highest impact bite forces. Crocodilians experience the reverse situation -- they possess robust teeth near the posterior end of their mandible where they apply their highest bite forces.Adult tyrannosaurids have been extensively studied due to the availability of relatively complete specimens that have been CT scanned.The availability of this material has allowed for studies of their feeding mechanics. The adult The team were interested in inferring more about the feeding mechanics and implications for juvenile tyrannosaurs.Their main hypotheses were that larger tyrannosaurid mandibles experienced absolutely lower peak stress, because they became more robust (deeper and wider relative to length) as they grew, and that at equalized mandible lengths, younger tyrannosaurids experienced greater stress and strain relative to the adults, suggesting relatively lower bite forces consistent with proportionally slender jaws.At actual size the juveniles experienced lower absolute stresses when compared to the adult, contradicting our first hypothesis. This means that in real life, adult tyrannosaurs would experience high absolute stresses during feeding but shrug it off due to its immense size. However, when mandible lengths are equalized, the juvenile specimens experienced greater stresses, due to the relatively lower bite forces typical in slender jaws.Lead author Andre Rowe, a Geology PhD Student at the University of Bristol's School of Earth Sciences, said: "Tyrannosaurids were active predators and their prey likely varied based on their developmental stage."Based on biomechanical data, we presume that they pursued smaller prey and fulfilled an environmental role similar to the 'raptor' dinosaurs such as the dromaeosaurs. Adult tyrannosaurs were likely subduing large dinosaurs such as the duckbilled hadrosaurs and Triceratops, which would be quickly killed by their bone-crunching bite."This study illustrates the importance of 3D modeling and computational studies in vertebrate paleontology -- the methodology we used in our study can be applied to many different groups of extinct animals so that we can better understand how they adapted to their respective environments."There are two major components of this research that Andre and the team would like to see future researchers delve into continued CT and surface scanning of dinosaur cranial material and more application of 3D models in dinosaur biomechanics research.Andre added: "There remains a plethora of unearthed dinosaur material that has not been utilized in studies of feeding and function -- ideally, all of our existing specimens will one day be scanned and made widely available online to researchers everywhere."The current lack of 3D model availability is noticeable in dinosaur research; relatively few studies involving 3D models of carnivorous dinosaurs have been published thus far. There is still much work to be done concerning skull function in all extinct animals -- not only dinosaurs."
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Animals
| 2,021 |
March 9, 2021
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https://www.sciencedaily.com/releases/2021/03/210309114315.htm
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Bird parents that receive help live longer
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Long life is common among bird parents that get help with childcare. This finding comes from researchers at the universities of Lund and Oxford who reviewed data from more than 9,000 studies.
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Being a parent can be tough. In general, animals that care for many offspring die young, at least in species where parents are not helped by others. However, in some species things are different and parents recruit 'helpers' to assist with childcare. In such group-living species, parents often produce lots of young and also live an exceptionally long time. This new research now shows that this happens because helpers reduce the burden of care on parents."A common pattern in group-living species is that parents do not care very much for their own young. Instead, the helpers are responsible for feeding and protecting the young and performing the other tasks that are usually associated with being a parent," says Philip Downing at Lund University.The fact that the parents avoid this work-load means that they can reproduce again and again and still live a long time.Some group-living species take this to the extreme with parents always relying on helpers for offspring care. For example, breeding individuals in ants, termites and naked mole rats live for many decades, producing thousands of offspring without ever caring for a single offspring. While these species are fascinating, it is impossible to tell if the secret to breeders living for such a long time is outsourcing parental care as all breeders have helpers.Instead Philip Downing, his Lund colleague Charlie Cornwallis, and Ashleigh Griffin from Oxford University, focused their review on 23 bird species where some parents get help raising their young, while other parents take care of their young on their own. Such species occur throughout the world and include long-tailed tits in Sweden, sociable weavers in Southern Africa and the Seychelles warbler that occurs on a few islands in the Indian Ocean."It is within these 23 species that we see clear differences in longevity. Parents who get help with caring for young live, on average, one to two years longer than parents who don't. This may not sound like a lot, but in human terms it equates to about six and a half glorious years," says Charlie Cornwallis.However, the researchers add a twist: Not all helpers take their job seriously. If the helpers are lazy, parents are forced into putting more effort into raising their young, something that shortens their lives.So what is the secret behind living a long time and having many offspring at the same time? Philip Downing has the answer:"As a parent, make sure you have hard-working helpers."
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Animals
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