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January 11, 2021
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https://www.sciencedaily.com/releases/2021/01/210111190102.htm
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Researchers find nonnative species in Oahu play greater role in seed dispersal
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University of Wyoming researchers headed a study that shows nonnative birds in Oahu, Hawaii, have taken over the role of seed dispersal networks on the island, with most of the seeds coming from nonnative plants.
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"Hawaii is one of the most altered ecosystems in the world, and we are lucky enough to examine how these nonnative-dominated communities alter important processes, such as seed dispersal," says Corey Tarwater, an assistant professor in the UW Department of Zoology and Physiology. "What we have found is that not only do nonnative species dominate species interactions, but that these nonnative species play a greater role in shaping the structure and stability of seed dispersal networks than native species. This means that loss of a nonnative species from the community will alter species interactions to a greater extent than loss of a native species."Tarwater was the anchor author of a paper, titled "Ecological Correlates of Species' Roles in Highly Invaded Seed Dispersal Networks," which was published Jan. 11 (today) in the Jeferson Vizentin-Bugoni, a postdoctoral researcher at UW and the U.S. Army Research Laboratory at the time of the research, is the paper's lead author. He performed most analyses and conceptualized and outlined the first version of the manuscript.Becky Wilcox, of Napa, Calif., a recent UW Ph.D. graduate and now a postdoctoral researcher, and Sam Case, of Eden Prairie, Minn., a UW Ph.D. student in the Program in Ecology as well as in zoology and physiology, worked with Tarwater. The two aided in field data collection, processing all of the footage from the game cameras, and assisted in writing the paper. Patrick Kelley, a UW assistant research scientist in zoology and physiology, and in the Honors College, helped with developing project ideas, data processing and management, and writing the paper.Other researchers who contributed to the paper are from the University of Hawaii, University of Illinois, Northern Arizona University and the U.S. Army Corps of Engineers in Champaign, Ill."This is one of the first studies showing that nonnative species can take over the most important roles in seed dispersal networks. This means that Oahu's ecosystems have been so affected by species extinctions and invasions that most of the seeds dispersed on the island belong to nonnative plants, and most of them are dispersed by nonnative birds," Vizentin-Bugoni says. "This forms what has been called 'ecological meltdown,' which is a process occurring when nonnative mutualistic partners benefit each other and put the system into a vortex of continuous modification."Seed dispersal by animals and birds is one of the most crucial ecosystem functions. It is linked to plant population dynamics, community structure, biodiversity maintenance and regeneration of degraded ecosystems, according to the paper.Before Hawaii became the extinction and species invasion capital of the world, its ecological communities were much more diverse. Experts estimate that, in the last 700 years, 77 species and subspecies of birds in the Hawaiian Archipelago have gone extinct, accounting for 15 percent of bird extinctions worldwide."The Hawaiian Islands have experienced major changes in flora and fauna and, while the structure of seed dispersal networks before human arrival to the islands is unknown, we know from some of our previous work, recently published in Functional Ecology, that the traits of historic seed dispersers differ from the traits of introduced ones," Case says. "For instance, some of the extinct dispersers were larger and could likely consume a greater range in seed sizes compared to the current assemblage of seed dispersers."Because of the large number of invasive plants and the absence of large dispersers, the invasive dispersers are incompletely filling the role of extinct native dispersers, and many native plants are not being dispersed, Tarwater says. On the island of Oahu, 11.1 percent of bird species and 46.4 percent of plant species in the networks are native to the island. Ninety-three percent of all seed dispersal events are between introduced species, and no native species interact with each other, the paper says."Nonnative birds are a 'double-edged sword' for the ecosystem because, while they are the only dispersers of native plants at the present, most of the seeds dispersed on Oahu belong to nonnative plants," Vizentin-Bugoni says. "Many native plant species have large seeds resulting from coevolution with large birds. Such birds are now extinct, and the seeds cannot be swallowed and, thus, be dispersed by the small-billed passerines now common on Oahu."Researchers compiled a dataset of 3,438 fecal samples from 24 bird species, and gathered 4,897 days of camera trappings on 58 fruiting species of plants. It was determined that 18 bird species were recorded dispersing plant species.In contrast to predictions, the traits that influence the role of species in these novel networks are similar to those in native-dominated communities, Tarwater says."In particular, niche-based traits, such as degree of frugivory (animals that feed on fruit, nuts and seeds) and lipid content, rather than neutral-based traits, such as abundance, were more important in these nonnative-dominated networks," Tarwater says. "We can then use the niche-based traits of dispersers and plants to predict the roles species may play in networks, which is critical for deciding what species to target for management."Tarwater adds that the roles of different species in Oahu's seed dispersal networks can be predicted by the species' ecological traits. For example, the research group found that bird species that consume a greater amount of fruit in their diets are more likely to disperse seeds from a greater number of plant species. Likewise, the team found that plants that fruit for extended periods of time have smaller seeds and have fruits rich in lipids, will get dispersed more frequently."Land managers can use these ecological traits to identify species that can be removed or added to a system to improve seed dispersal," Tarwater explains. "For example, removal of highly important nonnative plants or the addition of native plants with traits that increase their probability of dispersal, could aid in restoration efforts."Kelley and Tarwater obtained funding for the project. The research was funded by a U.S. Department of Defense award, UW, University of Hawaii, University of New Hampshire and Northern Arizona University."This upcoming year, we will be experimentally removing one nonnative plant species that is incredibly important for network structure and examining how the seed dispersal network changes in response," Tarwater says. "The results of this experiment can inform land managers as to whether removal of a highly invasive plant will improve seed dispersal for the remaining native plants, or whether it does not."
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Animals
| 2,021 |
January 11, 2021
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https://www.sciencedaily.com/releases/2021/01/210111112153.htm
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This tree snake climbs with a lasso-like motion
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Researchers reporting in
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"Our most important finding is a new mode of snake locomotion," says co-senior author Julie Savidge of Colorado State University (CSU). "Only four major types have been recognized for nearly 100 years, and we have discovered a fifth mode."The discovery of a fifth mode of locomotion -- in additional to the known rectilinear, lateral undulation, sidewinding, and concertina modes -- was a matter of serendipity. Savidge was working on a project aimed at protecting the nests of Micronesia starlings, one of only two native forest species still remaining on Guam.People accidentally introduced the nocturnal snakes to Guam in the late 1940s or early 1950s. Shortly thereafter, bird populations started to decline. It's now recognized that the invasive snakes have decimated forest bird populations on the island. They are also responsible for extensive damage and many power outages across the island each year."Most of the native forest birds are gone on Guam," says Savidge. "There's a relatively small population of Micronesian starlings and another cave-nesting bird that have survived in small numbers.""Understanding what brown tree snakes can and cannot climb has direct implications for designing barriers to reduce the dispersal and some of the deleterious effects of this highly invasive species," says co-senior author Bruce Jayne of the University of Cincinnati."For example," adds Thomas Seibert, also at CSU, "given that brown tree snakes can use lasso locomotion to defeat poles or cylinders of a certain size, we can design baffles to better protect bird houses used for restoring some of Guam's birds."In the new study, the researchers were attempting to use a three-foot long metal baffle to keep the brown tree snakes from climbing up to bird boxes. The same baffles have been used to keep other snakes and raccoons away from nest boxes in the yards of birdwatchers. But, they soon found, their ability to deter brown tree snakes was rather short lived."We didn't expect that the brown tree snake would be able to find a way around the baffle," Seibert says. "Initially, the baffle did work, for the most part. Martin Kastner, a CSU biologist, and I had watched about four hours of video and then all of a sudden, we saw this snake form what looked like a lasso around the cylinder and wiggle its body up. We watched that part of the video about 15 times. It was a shocker. Nothing I'd ever seen compares to it."Jayne explains that snakes typically climb steep, smooth branches or pipes using concertina locomotion, bending sideways to grip in at least two places. But lasso locomotion is different. Using the loop of the "lasso," the snakes form a single gripping region.By recording and carefully analyzing high-resolution video of this new climbing method, the researchers found that the snakes have these little bends within the loop of the lasso. Those bends allow them to advance upwards slowly, by shifting the location of each bend.That's not to say this way of climbing isn't a struggle for the snakes. In the process of their lasso locomotion, the researchers observed the snakes moving quite slowly. They also slip often, stop to rest, and breathe heavily."Even though they can climb using this mode, it is pushing them to the limits," Jayne says.Savidge and Seibert say they hope to continue with the development of a baffle that brown tree snakes can't get around, which could then be used on Guam for bird restoration. Jayne plans to further test what brown tree snakes can and cannot traverse. He also wants to test the limits of the locomotor abilities of other snake species and learn more about the anatomy and physiology involved.
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Animals
| 2,021 |
January 8, 2021
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https://www.sciencedaily.com/releases/2021/01/210108123440.htm
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Jellyfish create a 'virtual wall' to enhance performance
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New research led by the University of South Florida has uncovered one of the reasons jellyfish have come to be known as the "world's most efficient swimmer." Brad Gemmell, associate professor of integrative biology, found jellyfish produce two vortex rings, which are donut-shaped bodies of fluid underneath their translucent bodies, that spin in opposite directions. They appear as jellyfish squeeze and reopen throughout each swim cycle, providing a "ground effect" force as if they were to be pushing off the seafloor.
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The "ground effect" is most widely understood on airport runways. During take-off, air squeezes between the airplane and ground, which builds pressure and a force that boosts performance. Gemmell's experiments have shown that jellyfish can use their two vortex rings in place of the ground. The vortex rings resist each other, creating a "virtual wall" that provides a similar boost in performance compared to animals that swim near the bottom. Never before has it been proven that an animal can create this phenomenon away from a solid boundary."The fact that these simple animals have figured out how to achieve a 'ground effect' type boost in open water, away from any solid surfaces, has the potential to open up a range of new possibilities for engineered vehicles to take advantage of this phenomenon," Gemmell said.In the study published in Unlike locomotion by propellers, jellyfish do not produce cavitation bubbles and are silent, allowing them to move quietly through the water. The high efficiency of swimming also helps them store energy for growth and reproduction. Several research groups use jellyfish as a model for developing underwater vehicles that can be equipped with sensors that monitor the ocean without disruption. These new findings may enhance development of these technologies and further understanding of the ocean.
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Animals
| 2,021 |
January 8, 2021
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https://www.sciencedaily.com/releases/2021/01/210108111059.htm
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Tasmanian tiger pups found to be extraordinary similar to wolf pups
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Micro-CT scanning and digital reconstructions have been used to compare the skulls of the Tasmanian tiger (thylacine) and wolf across their early development and into adulthood, establishing that not only did the thylacine resemble the wolf as adults, but also as newborns and juveniles.
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"Remarkably, the Tasmanian tiger pups were more similar to wolf pups than to other closely related marsupials," Professor Andrew Pask from the University of Melbourne said.The collaborative study with Flinders University and Museums Victoria complement earlier findings that thylacine and wolf have evolved similar instructions in their genome, which influence cranial stem cells during development.While scientists have worked out that different animals evolve to look the same because they occupy similar places in the ecosystem, they have yet to explain how animals evolve to become convergent, particularly the forces driving their early development. The study provides significant new insights into how animals develop to look a certain way and then when in development these things happen.Through collaborations with Australian museums and the Museum of the North in Alaska, USA, the team loaned thylacine and wolf skulls of different ages, stages and sizes, from newborns through to fully grown adults. They then applied micro-CT scanning to the skulls to generate digital models which could be compared to determine when during development similarities arose between the thylacine and wolf.After reconstructing the early pouch development of the thylacine, lead author Dr Axel Newton focused on the question of when during development the Tasmanian tiger establish its dog-like skull shape."We know that the thylacine and wolf look similar as adults, but we don't know when they started to exhibit their remarkable similarities during development," he said.Micro-CT scanning is a technique similar to a medical CAT scan, allowing researchers to generate high-resolution, digital reconstructions of complex shapes such as skulls and bones. From here they were able to establish that not only did the Tasmanian tiger resemble the wolf as adults but were very similar as newborns and juveniles.Dr Vera Weisbecker, from Flinders University, said all marsupials -- including the thylacine -- are born with unusually well-developed jaws relative to the rest of the head."Scientists think that this reduces the potential of marsupials to evolve some extreme skull shapes. However, it clearly did not prevent the evolution of the thylacine's unusual wolf-like skull!"The University of Melbourne's Dr Christy Hipsley, who specialises in CT, said the research shows how 3D imaging can reveal hidden diversity in nature."By comparing entire growth series from newborns to adults, we were able to visualise tiny differences in development that pinpoint when and where in the skull adaptations to carnivory arise on a cellular level. That is only made possible through museum loans of preserved specimens, in this case from as far away as Alaska."
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Animals
| 2,021 |
January 8, 2021
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https://www.sciencedaily.com/releases/2021/01/210108111055.htm
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Which came first, sleep or the brain?
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Stay awake too long, and thinking straight can become extremely difficult. Thankfully, a few winks of sleep is often enough to get our brains functioning up to speed again. But just when and why did animals start to require sleep? And is having a brain even a prerequisite?
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In a study that could help to understand the evolutional origin of sleep in animals, an international team of researchers has shown that tiny, water-dwelling hydras not only show signs of a sleep-like state despite lacking central nervous systems but also respond to molecules associated with sleep in more evolved animals."We now have strong evidence that animals must have acquired the need to sleep before acquiring a brain," says Taichi Q. Itoh, assistant professor at Kyushu University's Faculty of Arts and Science and leader of the research reported in While sleeping behavior was also recently found in jellyfish, a relative of hydras and fellow member of the phylum Cnidaria, the new study from researchers at Kyushu University in Japan and Ulsan National Institute of Science and Technology in Korea found that several chemicals eliciting drowsiness and sleep even in humans had similar effects on the species "Based on our findings and previous reports regarding jellyfish, we can say that sleep evolution is independent of brain evolution," states Itoh."Many questions still remain regarding how sleep emerged in animals, but hydras provide an easy-to-handle creature for further investigating the detailed mechanisms producing sleep in brainless animals to help possibly one day answer these questions."Only a couple of centimeters long, hydras have a diffuse network of nerves but lack the centralization associated with a brain.While sleep is often monitored based on the measurement of brain waves, this is not an option for tiny, brainless animals.As an alternative, the researchers used a video system to track movement to determine when hydras were in a sleep-like state characterized by reduced movement -- which could be disrupted with a flash of light.Instead of repeating every 24 hours like a circadian rhythm, the researchers found that the hydras exhibit a four-hour cycle of active and sleep-like states.More importantly, the researchers uncovered many similarities related to sleep regulation on a molecular and genetic level regardless of the possession of a brain.Exposing the hydras to melatonin, a commonly used sleep aid, moderately increased the sleep amount and frequency, while the inhibitory neurotransmitter GABA, another chemical linked to sleep activity in many animals, greatly increased sleep activity.On the other hand, dopamine, which causes arousal in many animals, actually promoted sleep in the hydras."While some sleep mechanisms appear to have been conserved, others may have switched function during evolution of the brain," suggests Itoh.Furthermore, the researchers could use vibrations and temperature changes to disturb the hydras' sleep and induce signs of sleep deprivation, causing the hydras to sleep longer during the following day and even suppressing cell proliferation.Investigating more closely, the researchers found that sleep deprivation led to changes in the expression of 212 genes, including one related to PRKG, a protein involved in sleep regulation in the wide range of animals, including mice, fruit flies, and nematodes.Disrupting other fruit fly genes appearing to share a common evolutional origin with the sleep-related ones in hydras altered sleep duration in fruit flies, and further investigation of such genes may help to identify currently unknown sleep-related genes in animals with brains."Taken all together, these experiments provide strong evidence that animals acquired sleep-related mechanisms before the evolutional development of the central nervous system and that many of these mechanisms were conserved as brains evolved," says Itoh.
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Animals
| 2,021 |
January 8, 2021
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https://www.sciencedaily.com/releases/2021/01/210108084112.htm
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Bats with white-nose syndrome prefer suboptimal habitats despite the consequences
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Since 2006, a fungal disease called white-nose syndrome has caused sharp declines in bat populations across the eastern United States. The fungus that causes the disease, Pseudogymnoascus destructans, thrives in subterranean habitats where bats hibernate over the winter months.
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Bats roosting in the warmest sites have been hit particularly hard, since more fungus grows on their skin, and they are more likely to die from white-nose syndrome, according to a new study by researchers at Virginia Tech.But instead of avoiding these warm and deadly sites, bats continue to use them year after year. The reason? Bats are mistakenly preferring sites where fungal growth is high and therefore their survival is low. This is one of the first clear examples of an infectious disease creating an "ecological trap" for wildlife.Kate Langwig and Joseph Hoyt, both assistant professors from the Department of Biological Sciences in the College of Science, have been studying little brown bat (Myotis lucifugus) populations in Michigan and Wisconsin since 2012, before the fungus first reached those states. This long-term study was the perfect opportunity to see if bats alter their preferences across hibernacula, or hibernation sites, in response to the invasion of white-nose syndrome."We see that there is a shift across the regional bat population over time," said Skylar Hopkins, a previous postdoctoral scholar at Virginia Tech and now assistant professor at North Carolina State University."When we look at the population post-invasion, we see that more than 50 percent of the bats are still choosing to roost in warmer sites, even though colder sites are available. But on average, bat roosting temperatures have declined, because the colder-roosting bats have had higher survival rates."Their findings were posted in To understand how temperatures are playing a role in bat population declines, the researchers used a mark-recapture method, which involves banding bats and then trying to find them later.The team visited bat hibernacula for sampling twice per year: once in early hibernation, after all of the bats had arrived and settled down for the winter, and once again in late hibernation, before the bats emerged from their hibernation habitat.If bats were missing in late hibernation that had been present earlier in the winter, those bats had left the hibernacula early and likely died in the cold, insect-free Midwest winter.The research team also used a swab to measure the fungal loads that were on each individual bat and used a laser thermometer to measure the roosting temperature of the rocks next to each bat.Now that they know that bats are preferring high mortality sites, Hopkins hopes that their data can be used to think about which sites researchers and conservationists need to prioritize for conservation and how to conserve them."Because we know that bats are doing better in the cold sites, the cold sites may be good ones for us to conserve," said Hopkins. "We can also think more about the warm sites that are acting as ecological traps and whether we should be trying to manage those sites in a different way. Maybe there are interventions that should be done at those sites to prevent most of the population from going there each year and having these big mortality events."One's first instinct upon hearing about these interventions would be to close off these deadly hibernacula entirely. But according to Langwig, it's just not that simple."The thing that is hard is that there are multiple bat species in these habitats. And I worry that there would be cascading impacts on some of the other bat species if we attempted to alter the sites. It depends a lot on the physiology of the bat," said Langwig, who is an affiliated faculty member of the Fralin Life Sciences Institute and the Global Change Center. "But there may be some creative solutions. There are researchers in Michigan and Pennsylvania who have been working to cool down the warmer sites by modifying the entrances or using solar power to pump air into the sites."Of course, temperature is just one aspect of the microclimate that bats experience while they are hibernating. Hopkins and Langwig expect that humidity could also play a role in the spread of white-nose syndrome. But, measuring humidity is easier said than done. Since underground hibernacula have a high relative humidity, it can be difficult to make accurate measurements."We've designed new humidity loggers to collect better humidity data than has been possible before. These loggers are already deployed in caves and mines across the eastern United States, so we hope to soon understand how humidity has played a role in bat population declines, if at all," said Hopkins.
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Animals
| 2,021 |
January 7, 2021
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https://www.sciencedaily.com/releases/2021/01/210107164744.htm
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Mysterious family life of notorious saber-toothed tiger
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New research indicates adolescent offspring of the menacing sabre-toothed predator, Smilodon fatalis, were more momma's cubs than independent warriors.
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A new study by scientists at the Royal Ontario Museum (ROM) and University of Toronto, published January 7, 2021 in "This study started out as a simple description of previously unpublished fossils," says Ashley Reynolds, a graduate student based at the Royal Ontario Museum who led the study while completing her PhD research in Ecology & Evolutionary Biology at the University of Toronto. "But when we noticed the two lower jaws we were working on shared a type of tooth only found in about five percent of the Encouraged by this new discovery, the researchers dug deeper and found that they were likely looking at three related individuals: one adult and two "teenaged" cats. What's more, they were able to determine that the younger cats were at least two years old at the time of their death, an age at which some living big cats, such as tigers, are already independent.To support this conclusion, the team studied the preservation and formation of the Ecuadorian site (an area of study called taphonomy), based on historic collecting records and the suite of clues on the fossil bones themselves.Historically, "The social lives of these iconic predators have been mysterious, in part because their concentration in tar seeps leaves so much room for interpretation" says Dr. Kevin Seymour, Assistant Curator of Vertebrate Paleontology at the ROM and a co-author of this study, "This historic assemblage of sabre-cat fossils from Ecuador was formed in a different way, allowing us to determine the two juveniles likely lived, and died, together -- and were therefore probably siblings"The fossils were collected from Coralito, Ecuador in 1961 by A. Gordon Edmund, who was curator of Vertebrate Palaeontology at the ROM from 1954-1990, and Roy R. Lemon, who was curator of Invertebrate Palaeontology from 1957-1969. Together, Edmund and Lemon collected tonnes of tar-soaked sediment which was later prepared at the ROM."These world-famous collections made 60 years ago have been studied for years, but a measure of their importance is that they continue to produce new insights into the lives of these extinct animals" says Dr. David Evans, Temerty Chair of Vertebrate Palaeontology at the Royal Ontario Museum and Reynolds's thesis supervisor.
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Animals
| 2,021 |
January 7, 2021
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https://www.sciencedaily.com/releases/2021/01/210107112134.htm
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Unusual sex chromosomes of platypus, emu and pekin duck
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Sex chromosomes are presumed to originate from a pair of identical ancestral chromosomes by acquiring a male- or a female-determining gene on one chromosome. To prevent the sex-determining gene from appearing in the opposite sex, recombination is suppressed on sex chromosomes. This leads to the degeneration of Y chromosome (or the W chromosome in case of birds) and the morphological difference of sex chromosomes between sexes. For example, the human Y chromosome bears only less than 50 genes, while the human X chromosome still maintains over 1500 genes from the autosomal ancestor. This process occurred independently in birds, in monotremes (the Australian platypus and echidnas), and in the other mammals (therians, e.g., kangaroo, mouse and human etc.).
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With its venom, duck-bill, egg, and milk, platypus features an extraordinary combination of reptiles, birds and mammals. Previous work showed that platypus, although undoubtedly a mammalian species, have sex chromosomes that do not share the same origin with those of human. It turns out that male platypus has five pairs of XY chromosomes (named as X1Y1, X2Y2, etc.), and none of them are homologous to the XY of human or mouse. These ten sex chromosomes pair with each other in a head-to-tail manner and form a chain during meiosis when sperm cells develop. The genetic makeup and the evolution process of such a complex and unique sex chromosome system remained unclear, because the previously published platypus genome is was from a female, and only a quarter of the sequences is was mapped onto chromosomes.An international team of researchers adopted a new sequencing technique (called PacBio, or third-generation sequencing) that can "read" the genome information for over 300-fold longer in length than the last-generation technique, and the new chromatin conformation capture technique that can connect and map the genomic sequences into the chromosome level."With further laborious cytogenetic experiments, we improved the genome quality and mapped over 98% of the sequences into 21 autosomes, and 5X and 5Y chromosomes of platypus" says Guojie Zhang from BGI-Shenzhen and University of Copenhagen. "The new genomes are a hugely valuable public resource for research in mammalian biology and evolution, with applications in wildlife conservation and even human health," says Frank Grützner at University of Adelaide in Australia."What surprised us is that, from the new sex chromosome sequences, we found the last Y chromosome, Y5 does not share many sequences with its pairing X5 chromosome, but with the first X chromosome of the chain, X1," says Qi Zhou. "This suggested that the 10 platypus sex chromosomes used to be in a ring shape. Maybe the acquisition of a male-determining gene and suppression of recombination broke the ancestral chromosome ring into a chain." This part of the sex chromosome work provides an entirely new perspective on the evolution of this extraordinary sex chromosome system, along with other new discoveries of platypus genes related to milk production, loss of teeth and so on, were published in With similar new techniques used for the platypus genome, the Zhou group simultaneously decoded the sex chromosome sequences of emu and Pekin duck, which represent the different phase of sex chromosome evolution. Most mammalian and bird species' sex chromosomes have evolved into their terminal stage of evolution like that of human or chicken. A key difference between mammals and birds is that instead of the XY sex system, birds have so-called ZW sex chromosomes. That is, male birds have a pair of ZZ chromosomes, female birds have a Z and a W sex chromosomes.The Y or W chromosomes usually have lost most functional genes, and become a "gene desert" full of repetitive sequences. Emu is an exception: its sex chromosomes are largely like a pair of autosomes, with over two-thirds of the sequences and active genes still shared between the Z and W chromosomes. "This may be related to the slower evolution rate of the emu compared to other birds'', says Jing Liu, a Ph.D. student in the Zhou group. "By comparing the genomes of emu and 11 other bird species, we found that large-bodied birds like emu and ostrich tend to have much less chromosome rearrangements than other birds."Another possible reason is that these flightless large birds may undergo much weaker sexual selection, a potential driver for sex chromosome evolution, compared to other birds, given that male and female emus are largely monomorphic. This provides a great system to understand how sex chromosomes evolve in their early phase -- and in the case of Pekin duck, in the middle phase. Another project from the Zhou group generated the high-quality genome sequence of Pekin duck, a very popular poultry species. Emu, duck and chicken together mark the different time phase of sex chromosome evolution.In this work, the researchers found that the W chromosomes of emu and duck have retained many more functional genes on their W chromosomes compared to the chicken. Such a large variation in the tempo of sex chromosome evolution is not observed in mammals, and reflects the different evolutionary modes of the XY and ZW sex systems. These novel sex chromosome sequences of emu and duck will also provide important resources for poultry studies.
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Animals
| 2,021 |
January 7, 2021
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https://www.sciencedaily.com/releases/2021/01/210107094601.htm
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Where antibiotic resistance comes from
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By comparing thousands of bacterial genomes, scientists in Gothenburg, Sweden have traced back the evolutionary history of antibiotic resistance genes. In almost all cases where an origin could be determined, the gene started to spread from bacteria that, themselves, can cause disease.
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While human DNA is only passed down from parent to child, bacteria also have the habit of sharing some of their genes across species. This often applies to genes that make the bacteria resistant to antibiotics.The use and overuse of antibiotics provide an advantage to those bacteria that have acquired resistance genes, thus further promoting the spread of resistance and making it more difficult to treat infections. This development threatens large parts of modern healthcare.The rapid advances in DNA sequencing during the last decade has made it possible to study bacterial evolution much more effectively than ever before. This is an important background to the new study, published in the scientific journal Communications Biology.The team from Gothenburg explored the scientific literature for claims of recent origins for antibiotic resistance genes, added information from public DNA-sequence-databases, and scrutinized the evidence at hand. While antibiotic-producing bacteria often are speculated to be the source for antibiotic resistance genes (as self-defence), this was not what the scientists found. None of the origin species found are known antibiotic producers. Strikingly, all verified origin species, except one, are known to cause disease, at least from time to time.Professor Joakim Larsson, senior author of the study and director of the Centre for Antibiotic Resistance Research at University of Gothenburg, CARe, comments on the finding:"Given that the overwhelming majority of bacteria are harmless to us, it was quite surprising that these genes almost exclusively came from bacteria causing disease. On the other hand, it makes some sense since such bacteria often trigger antibiotic use when we become infected, and other pathogens are often nearby, ready to engage in gene-transfer. These findings underscores the microbial-rich gut flora humans and domestic animals given antibiotics as arenas for resistance evolution" he says.Knowing where resistance genes come from can inform measures to delay the emergence of additional resistance genes in the clinics. Importantly, the authors conclude that the origin is still unknown for more than 95% of all known resistance genes."Most likely, most of them come from un-sequenced bacterial species. We know the majority of the species that frequently tend to reside in the gut or on the skin of ourselves and of domestic animals. Therefore, this points to an important role of a much less explored gene reservoir -- the environmental microbiota. The role of the environment as a likely source for antibiotic resistance also stress the need reduce risks for resistance development in the environment, for example by limiting discharges of antibiotics though wastewaters," says Larsson.
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Animals
| 2,021 |
January 7, 2021
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https://www.sciencedaily.com/releases/2021/01/210107083751.htm
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Why crocodiles have changed so little since the age of the dinosaurs
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New research by scientists at the University of Bristol explains how a 'stop-start' pattern of evolution, governed by environmental change, could explain why crocodiles have changed so little since the age of the dinosaurs.
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Crocodiles today look very similar to ones from the Jurassic period some 200 million years ago. There are also very few species alive today -- just 25. Other animals such as lizards and birds have achieved a diversity of many thousands of species in the same amount of time or less.Prehistory also saw types of crocodile we don't see today, including giants as big as dinosaurs, plant-eaters, fast runners and serpentine forms that lived in the sea.In the new research, published today in the journal The rate of their evolution is generally slow, but occasionally they evolve more quickly because the environment has changed. In particular, this new research suggests that their evolution speeds up when the climate is warmer, and that their body size increases.Lead author Dr Max Stockdale from the University of Bristol's School of Geographical Sciences, said: "Our analysis used a machine learning algorithm to estimate rates of evolution. Evolutionary rate is the amount of change that has taken place over a given amount of time, which we can work out by comparing measurements from fossils and taking into account how old they are."For our study we measured body size, which is important because it interacts with how fast animals grow, how much food they need, how big their populations are and how likely they are to become extinct."The findings show that the limited diversity of crocodiles and their apparent lack of evolution is a result of a slow evolutionary rate. It seems the crocodiles arrived at a body plan that was very efficient and versatile enough that they didn't need to change it in order to survive.This versatility could be one explanation why crocodiles survived the meteor impact at the end of the Cretaceous period, in which the dinosaurs perished. Crocodiles generally thrive better in warm conditions because they cannot control their body temperature and require warmth from the environment.The climate during the age of dinosaurs was warmer than it is today, and that may explain why there were many more varieties of crocodile than we see now. Being able to draw energy from the sun means they do not need to eat as much as a warm-blooded animal like a bird or a mammal.Dr Stockdale added: "It is fascinating to see how intricate a relationship exists between the earth and the living things we share it with. The crocodiles landed upon a lifestyle that was versatile enough to adapt to the enormous environmental changes that have taken place since the dinosaurs were around."The next step for the team's research is to find out why some types of prehistoric crocodile died out, while others didn't.
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Animals
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January 6, 2021
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https://www.sciencedaily.com/releases/2021/01/210106133034.htm
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Mapping the platypus genome: How Earth's oddest mammal got to be so bizarre
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Often considered the world's oddest mammal, Australia's beaver-like, duck-billed platypus exhibits an array of bizarre characteristics: it lays eggs instead of giving birth to live babies, sweats milk, has venomous spurs and is even equipped with 10 sex chromosomes. Now, an international team of researchers led by University of Copenhagen has conducted a unique mapping of the platypus genome and found answers regarding the origins of a few of its stranger features.
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It lays eggs, but nurses, it is toothless, has a venomous spur, has webbed feet, fur that glows and has 10 sex chromosomes. Ever since Europeans discovered the platypus in Australia during the late 1700's, the quirky, duck-billed, semiaquatic creature has baffled scientific researchers.Modern day researchers are still trying to understand how the platypus -- often considered to be the world's oddest mammal -- got to be so unique. Their understandings have now advanced, to a great degree. For the first time, an international team of researchers, led by University of Copenhagen biologists, has mapped a complete platypus genome. The study is published in the scientific journal, "The complete genome has provided us with the answers to how a few of the platypus' bizarre features emerged. At the same time, decoding the genome for platypus is important for improving our understanding of how other mammals evolved -- including us humans. It holds the key as to why we and other eutheria mammals evolved to become animals that give birth to live young instead of egg-laying animals," explains Professor Guojie Zhang of the Department of Biology.The platypus belongs to an ancient group of mammals -- monotremes -- which existed millions of years prior to the emergence of any modern-day mammal."Indeed, the platypus belongs to the Mammalia class. But genetically, it is a mixture of mammals, birds and reptiles. It has preserved many of its ancestors' original features -- which probably contribute to its success in adapting to the environment they live in," says Professor Zhang.One of the platypus' most unusual characteristics is that, while it lays eggs, it also has mammary glands used to feed its babies, not through nipples, but by milk -- which is sweat from its body.During our own evolution, we humans lost all three so-called vitellogenin genes, each of which is important for the production of egg yolks. Chickens on the other hand, continue to have all three. The study demonstrates that platypuses still carry one of these three vitellogenin genes, despite having lost the other two roughly 130 million years ago. The platypus continues to lay eggs by virtue of this one remaining gene. This is probably because it is not as dependent on creating yolk proteins as birds and reptiles are, as platypuses produce milk for their young.In all other mammals, vitellogenin genes have been replaced with casein genes, which are responsible for our ability to produce casein protein, a major component in mammalian milk. The new research demonstrates that the platypus carries casein genes as well, and that the composition of their milk is thereby quite similar to that of cows, humans and other mammals."It informs us that milk production in all extant mammal species has been developed through the same set of genes derived from a common ancestor which lived more than 170 million years ago -- alongside the early dinosaurs in the Jurassic period," says Guojie Zhang.Another trait that makes the platypus so unique is that, unlike the vast majority of mammals, it is toothless. Although this monotremes' nearest ancestors were toothed, the modern platypus is equipped with two horn plates that are used to mash food. The study reveals that the platypus lost its teeth roughly 120 million years ago, when four of the eight genes responsible for tooth development disappeared.Yet another platypus oddity investigated by the researchers was how their sex is determined. Both humans and every other mammal on Earth have two sex chromosomes that determine sex -- the X and Y chromosome system in which XX is female and XY is male. The monotremes, however, including our duck-billed friends from Down Under, have 10 sex chromosomes, with five Y and five X chromosomes.Thanks to the near-complete chromosomal level genomes, researchers can now suggest that these 10 sex chromosomes in the ancestors of the monotremes were organized in a ring form which was later broken away into many small pieces of X and Y chromosomes. At the same time, the genome mapping reveals that the majority of monotreme sex chromosomes have more in common with chickens than with humans. But what it shows, is an evolutionary link between mammals and birds.
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Animals
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January 5, 2021
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https://www.sciencedaily.com/releases/2021/01/210105084652.htm
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Eurasian eagle owl diet reveals new records of threatened big-bellied glandular bush-crickets
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Bird diets provide a real treasure for research into the distribution and conservation of their prey, such as overlooked and rare bush-cricket species, point out scientists after studying the diet of the Eurasian Eagle Owl (Bubo bubo) in southeastern Bulgaria.
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In their paper, published in the open-access, peer-reviewed journal While the Balkan Peninsula has already been recognised as the area with the highest diversity of orthopterans (grasshoppers, crickets and bush-crickets) in Europe and one of the generally most biologically diverse areas in the whole Palearctic realm, it is also home to a worrying number of threatened species. Additionally, a thorough and updated country assessment of the conservation status of the orthopterans found in Bulgaria is currently lacking. This is why the Bulgarian team undertook a study on the biodiversity of these insects by analysing food remains from pellets of Eurasian Eagle Owls, collected from 53 breeding sites in southeastern Bulgaria.As a result, the scientists reported three species of bush crickets that have become a significant part of the diet of the studied predatory birds. Curiously enough, all three species are rare or threatened in Bulgaria. The case of the Big-Bellied Glandular Bush-Cricket is of special concern, as it is a species threatened by extinction. Meanwhile, the local decline in mammals and birds that weigh between 0.2 and 1.9 kg, which are in fact the preferred prey for the Eurasian Eagle Owl, has led the highly opportunistic predator to increasingly seek large insects for food. The researchers even suspect that there might be more overlooked species attracting the owls.Taking into account the hereby reported interconnected inferences of conservation concern, as well as the vulnerability of the Big-Bellied Glandular Bush-Cricket, a species with a crucial role in the food chain, the scientists call for the newly provided data to prompt the designation of a new Natura 2000 site. Additionally, due to the species' requirements for habitats of low disturbance and high vegetation diversity, and its large size and easy location via singing males, they point out that it makes a suitable indicator for habitat quality and species community health.
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Animals
| 2,021 |
January 5, 2021
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https://www.sciencedaily.com/releases/2020/12/201223125701.htm
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Remarkable new species of snake found hidden in a biodiversity collection
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To be fair, the newly described Waray Dwarf Burrowing Snake (
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In its native habitat, Samar and Leyte islands in the Philippines, the snake spends most of its time burrowing underground, usually surfacing only after heavy rains in much the same way earthworms tend to wash up on suburban sidewalks after a downpour.So, it may not be shocking that when examples of the Waray Dwarf Burrowing Snake were collected in 2006 and 2007, they were misidentified in the field -- nobody had seen them before. The specimens spent years preserved in the collections of the University of Kansas Biodiversity Institute and Natural History Museum, overlooked by researchers who were unaware they possessed an entirely new genus of snake, even after further examples were found in 2014.But that changed once Jeff Weinell, a KU graduate research assistant at the Biodiversity Institute, took a closer look at the specimens' genetics using molecular analysis, then sent them to collaborators at the University of Florida for CT scanning. Now, he's the lead author on a paper describing the snake as both a new genus, and a new species, in the peer-reviewed journal "I was initially interested in studying the group of snakes that I thought it belonged to -- or that other people thought it belonged to," Weinell said. "This is when I first started my Ph.D. at KU. I was interested in collecting data on a lot of different snakes and finding out what I actually wanted to research. I knew this other group of small, burrowing snakes called Pseudorabdion -- there are quite a few species in the Philippines -- and I was interested in understanding the relationships among those snakes. So, I made a list of all the specimens we had in the museum of that group, and I started sequencing DNA for the tissues that were available."As soon as Weinell got the molecular data back, he realized the sample from the subterranean snake didn't fall within Pseudorabdion. But pinpointing where the snake should be classified wasn't a simple task: The Philippine archipelago is an exceptionally biodiverse region that includes at least 112 species of land snakes from 41 genera and 12 families."It was supposed to be closely related, but it was actually related to this entirely different family of snakes," he said. "That led me to look at it in more detail, and I realized that there were actually some features that were quite different from what it was initially identified as."Working with Rafe Brown, professor of ecology & evolutionary biology and curator-in-charge of the KU Biodiversity Institute and Natural History Museum, Weinell took a closer look at the snake's morphology, paying special attention to the scales on the body, which can be used to differentiate species.He then sent one of the specimens to the University of Florida for CT scanning to get a more precise look at the internal anatomy of the mysterious Philippine snake. The CT images turned out to be surprising."The snake has among the fewest number of vertebrae of any snake species in the world, which is likely the result of miniaturization and an adaptation for spending most of its life underground," Weinell said.Finally, the KU graduate research assistant and his colleagues were able to determine the Waray Dwarf Burrowing Snake mirus was a new "miniaturized genus" and species of snake. Now, for the first time, Weinell has had the chance to bestow the snake with its scientific name, "It's actually named for Alan Leviton, who is a researcher at the California Academy of Sciences, and he had spent decades basically studying snakes in the Philippines in the '60s, '70s, '80s and then all the way up to now," Weinell said. "So, that's sort of an honorific genus name for him. Then, 'mirus' is Latin for unexpected. That's referencing the unexpected nature of this discovery -- getting the DNA sequences back and then wondering what was going on."In addition to Brown, Weinell's co-authors on the new paper are Daniel Paluh of the University of Florida and Cameron Siler of the University of Oklahoma. Brown said the description of "In this case, the trained 'expert field biologists' misidentified specimens -- and we did so repeatedly, over years -- failing to recognize the significance of our finds, which were preserved and assumed to be somewhat unremarkable, nondescript juveniles of common snakes," Brown said. "This happens a lot in the real world of biodiversity discovery. It was only much later, when the next generation of scientists came along and had the time and access to accumulated numbers of specimens, and when the right people, like Jeff, who asked the right questions and who had the right tools and expertise, like Dan, came along and took a fresh look, that we were able to identify this snake correctly. It's a good thing we have biodiversity repositories and take our specimen-care oaths seriously."According to Marites Bonachita-Sanguila, a biologist at the Biodiversity Informatics and Research Center at Father Saturnino Urios University, located in the southern Philippines, the snake discovery "tells us that there is still so much more to learn about reptile biodiversity of the southern Philippines by focusing intently on species-preferred microhabitats.""The pioneering Philippine herpetological work of Walter Brown and Angel Alcala from the 1960s to the 1990s taught biologists the important lesson of focusing on species' very specific microhabitat preferences," Bonachita-Sanguila said. "Even so, biologists have really missed many important species occurrences, such as this, because .... well, simply because we did not know basic clues about where to find them. In the case of this discovery, the information that biologists lacked was that we should dig for them when we survey forests. So simple. How did we miss that? All this time, we were literally walking on top of them as we surveyed the forests of Samar and Leyte. Next time, bring a shovel."She added that habitat loss as a result of human-mediated land use (such as conversion of forested habitats for agriculture to produce food for people) is a prevailing issue in Philippine society today."This new information, and what we will learn more in future studies of this remarkable little creature, would inform planning for conservation action, in the strong need for initiatives to conserve Philippine endemic species -- even ones we seldom get to see," Bonachita-Sanguila said. "We need effective land-use management strategies, not only for the conservation of celebrated Philippine species like eagles and tarsiers, but for lesser-known, inconspicuous species and their very specific habitats -- in this case, forest-floor soil, because it's the only home they have."
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Animals
| 2,021 |
January 4, 2021
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https://www.sciencedaily.com/releases/2021/01/210104131946.htm
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Pandas' popularity not protecting neighbors
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Forgive Asiatic black bear if they're not impressed with their popular giant panda neighbors.
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For decades, conservationists have preached that panda popularity, and the resulting support for their habitat, automatically benefits other animals in the mountainous ranges. That logic extends across the world, as animals regarded as cute, noble or otherwise appealing drum up support to protect where they live.Yet in "The popularity of giant pandas, as of the popularity of other beloved threatened animals across the world, has generated tremendous advances in protecting forests and other fragile habitats," said Jianguo "Jack" Liu, Michigan State University's Rachel Carson Chair in Sustainability and a paper author. "But this is an important reminder that it can't assume that what's good for a panda is automatically good for other species. Different species have specific needs and preferences."The authors of "The hidden risk of using umbrella species as conservation surrogates: A spatio-temporal approach" used camera trap data collected throughout mountain ranges to get a clear understanding of what and how animals were using protected habitats.What they discovered is that while the pandas are doing very well (the species in 2016 was declared "threatened" rather than "endangered" -- a conservation point of pride). But three of the eight species focused upon in this study -- the Asiatic black bear, the forest musk deer and the Chinese serow (a goat-like animal) seem to have suffered significant habitat loss and/or degradation under panda-centric habitat management. Pandas are picky about where they live -- needing lots of bamboo, a gentle slope and no contact with humans. And the managed habitats have largely delivered for them. Just not so much for others.Fang Wang, the paper's first author, noted that earlier efforts at tracking how a broader range of animals fared were handicapped by turning a blind eye to different habitat preferences, and not spotting potentially different habitat trends of other animals. The authors suggested that the forests and shrublands in lower elevations next to the habitats that best serve pandas could be better for bear and deer."China has made a tremendous achievement in establishing giant panda nature reserves, and now we're learning that one size does not fit all," said Wang, who with Liu and other authors is part of MSU's Center for Systems Integration and Sustainability. "China as well as other countries that face similar conservation challenges have the opportunity to move forward from rescuing single species to protecting animal communities and ecosystems."
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Animals
| 2,021 |
December 29, 2020
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https://www.sciencedaily.com/releases/2020/12/201229104508.htm
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A single gene 'invented' haemoglobin several times
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Thanks to the marine worm Platynereis dumerilii, an animal whose genes have evolved very slowly, scientists from CNRS, Université de Paris and Sorbonne Université, in association with others at the University of Saint Petersburg and the University of Rio de Janeiro, have shown that while haemoglobin appeared independently in several species, it actually descends from a single gene transmitted to all by their last common ancestor. These findings were published on 29 December 2020 in
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Having red blood is not peculiar to humans or mammals. This colour comes from haemoglobin, a complex protein specialized in transporting the oxygen found in the circulatory system of vertebrates, but also in annelids (a worm family whose most famous members are earthworms), molluscs (especially pond snails) and crustaceans (such as daphnia or 'water fleas'). It was thought that for haemoglobin to have appeared in such diverse species, it must have been 'invented' several times during evolution. But recent research has shown that all of these haemoglobins born 'independently' actually derive from a single ancestral gene.Researchers from the Institut Jacques Monod (CNRS/Université de Paris), the Laboratoire Matière et Systèmes Complexes (CNRS/Université de Paris), the Station Biologique de Roscoff (CNRS/Sorbonne Université), the Universities of Saint Petersburg (Russia) and Rio de Janeiro (Brazil), conducted this research on Platynereis dumerilii, a small marine worm with red blood.It is considered to be an animal that evolved slowly, because its genetic characteristics are close to those of the marine ancestor of most animals, Urbilateria(1). Studying these worms by comparing them with other species with red blood has helped in tracing back to the origins of haemoglobins.The research focused on the broad family to which haemoglobins belong: globins, proteins present in almost all living beings that 'store' gases like oxygen and nitric oxide. But globins usually act inside the cells because they do not circulate in the blood like haemoglobin.This work shows that in all species with red blood, it is the same gene that makes a globin called 'cytoglobin' that independently evolved to become a haemoglobin-encoding gene. This new circulating molecule made oxygen transport more efficient in their ancestors, who became larger and more active.Scientists now want to change scale and continue this work by studying when and how the different specialized cells of bilaterian vascular systems emerged.(1)Urbilateria is the last common ancestor of bilaterians, i.e. animals with bilateral (left-right) symmetry and complex organs, apart from species with simpler organization such as sponges and jellyfish.
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Animals
| 2,020 |
December 23, 2020
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https://www.sciencedaily.com/releases/2020/12/201223125706.htm
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Survival of the thickest: Big brains make mammal populations less dense
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Mammals with big brains tend to be less abundant in local areas than those with smaller brains, new research has shown.
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The University of Reading led an international team of scientists in considering the effect of brain size for the first time in studying why populations densities of land mammals like mice, monkeys, kangaroos and foxes vary so widely in local areas, even among similar creatures.Using statistical models to test different scenarios for hundreds of species, they found an overall trend of mammals with larger brains occurring at lower densities. Where different species had similar diets and body masses, brain size was found to be the deciding factor.Dr Manuela González-Suárez, associate professor in ecological modelling at the University of Reading, who led the study, said: "Although they are associated with being smarter, we found that bigger brains may actually hold mammals back from becoming the most abundant organisms in an area. This may be because bigger brains require more food and other resources, and therefore more space, to sustain them."Understanding which animals are more abundant in different areas is important for conservation. Low densities make species more likely to become extinct, while higher local abundance can increase exposure to some threats like roads."Brain size is not the only thing that influences mammal abundance. Different environments have different levels of stability and competing species, so these will also have an impact. Further research is required to see how the effect of brain size varies in these different environments."There are also some exceptions to the rule. For example, humans appear to have used their advanced intelligence to overcome resource limitations, through agriculture and food production. We can import foods from halfway round the world to allow us to theoretically live almost anywhere in large numbers. Some other brainy species may also be able to partially overcome these limitations."Although body size and diet are known to influence population densities, scientists had previously disagreed over whether bigger brains increased population densities in local areas by allowing creatures to exploit new resources, or decreased them due to requiring additional resources.In the new study, published in the Analysis revealed larger mammals with bigger brains and specialised diets were likely to be less locally abundant. The trend was particularly strong for primates and meat-eating mammals, but less clear in rodents and marsupials.Examples from the study included the Barbary macaque -- the species of monkey found in Gibraltar -- which has an average body weight of 11kg and a brain weighing 95g, and whose average population density is 36 individuals per square kilometre. This density is nearly three times greater than the siamang -- a species of gibbon -- which has the same average body weight and diet but a larger brain weighing 123g, and an average population density of 14 individuals per square kilometre.
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Animals
| 2,020 |
December 22, 2020
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https://www.sciencedaily.com/releases/2020/12/201222192957.htm
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Birds: Competition for mates leads to a deeper voice than expected based on size
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An analysis of the songs of most of the world's passerine birds reveals that the frequency at which birds sing mostly depends on body size, but is also influenced by sexual selection. The new study from researchers of the Max Planck Institute for Ornithology and colleagues suggests that habitat characteristics do not affect song frequency, thereby refuting a long-standing theory.
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Many animals use acoustic signals for communication. These signals have evolved to maximize the effectiveness of the transmission and reception of the sounds, because this helps finding a mate or avoiding predation. One of the fundamental characteristics of acoustic signals is the frequency of the sound. In forested habitats, acoustic signals become attenuated because of sound absorption and scattering from foliage, which is particularly problematic for high-frequency sounds. Hence, a theory from the 1970s predicts that animals living in habitats with dense vegetation emit lower-frequency sounds compared to those living in open areas.A team of researchers led by Bart Kempenaers from the Max Planck Institute for Ornithology in Seewiesen and Tomáš Albrecht from the Charles University in Praha and the Czech Academy of Sciences analysed the variation in song frequency of more than 5,000 passerine bird species, encompassing 85% of all passerines and half of all avian taxa. PhD student Peter Mikula collected song recordings primarily from xeno-canto, a citizen science repository of bird vocalizations, and from the Macaulay Library of the Cornell Lab of Ornithology.Contrary to the theory, the study reveals that the peak frequency of passerine song does not depend on habitat type. If anything, the data suggest that species living in densely vegetated habitats sing at lower frequencies, which is the opposite of what was predicted. As expected from basic physical principles, the researchers found a strong relationship between song frequency and body size and an effect of shared ancestry. "Both limit the range of sound frequencies an animal can produce," says first author Peter Mikula. Heavier species sing at lower frequencies simply due to the larger vibratory structures of the vocal apparatus.The study further reveals that species in which males are larger than females produce songs with lower frequencies than expected from their size. "This supports the hypothesis that the frequency of acoustic signals is affected by competition for access to mates," says Bart Kempenaers. Song frequency may act as an indicator of an individual's size and therefore of its dominance or fighting abilities. Thus, song frequency could influence reproductive success through competition with other males or even because it influences male attractiveness to females."Our results suggest that the global variation in passerine song frequency is mostly driven by natural and sexual selection causing evolutionary shifts in body size rather than by habitat-related selection on sound propagation," summarizes Tomáš Albrecht.
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Animals
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December 22, 2020
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https://www.sciencedaily.com/releases/2020/12/201222132030.htm
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A new species of mammal may have been found in Africa's montane forests
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A research team from the University of Helsinki has discovered a tree hyrax in the Taita Hills, Kenya, which may belong to a species previously unknown to science.
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The discovery, which was part of a study of the vocalisations of nocturnal animals in the Taita Hills, was published in mid-December in the scientific journal Very little is known about the diversity and ecology of tree hyraxes because these animals, which look like large guinea pigs but are distant relatives of elephants, are mainly active at night in the tree canopies in Africa's tropical forests. These animals are known to be able to scream with the strength of more than one hundred decibels, but the 'strangled thwack' calls that have been recorded in Taita's forests have not been described anywhere else.The tree hyrax song may continue for more than twelve minutes, and it consists of different syllables that are combined and repeated in various ways."The singing animals are probably males attempting to attract females that are willing to mate," postulates Hanna Rosti, who spent three months in Taita's forests, following the nocturnal mammals and recording their vocalisations.The results suggest that the two populations of dwarf galago in the Taita Hills may belong to different species. The calls of the animals of the smaller population are very similar to those of the Kenya coast dwarf galago, a species that has previously been thought to live only in coastal, low elevation forests. The peculiar calls of the second population cannot yet be linked with certainty to any known species."The taxonomy of many nocturnal mammals remains poorly known, and many populations have not been studied at all yet," says researcher Henry Pihlström, who reviewed the complex taxonomy of tree hyraxes and galagos for the published study.
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Animals
| 2,020 |
December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201221173124.htm
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Hormone metabolites found in feces give researchers new insight into whale stress
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Fecal samples are an effective, non-invasive tool for monitoring gray whale reproduction, stress and other physiological responses, a new study from Oregon State University shows.
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Researchers from OSU's Geospatial Ecology of Marine Megafauna Laboratory collected 158 fecal samples from Eastern North Pacific gray whales off the coast of Oregon between 2016 and 2018 and used the samples to assess endocrine levels and establish hormone baselines for stress and reproduction in the animals.The study is believed to be the first to use fecal samples as an endocrine assessment tool in Eastern North Pacific gray whales. Fecal samples can provide a wide range of important information about whale health in a noninvasive way, said Leigh Torres, an associate professor in OSU's Marine Mammal Institute and director of the GEMM Lab."Understanding whale physiology is really important to evaluate how human, activities impact whales," Torres said. "But it is really, really hard to study whale physiology. You can't observe most physiological responses. And you can't just ask a whale: Are you stressed out? So we have to get creative."The findings were published this month in the journal Most gray whales migrate from breeding grounds in Mexico to feeding grounds in the Bering and Chukchi seas between Alaska and Russia, where they spend the summer. Torres and her team study a distinct population of gray whales known as the Pacific Coast Feeding Group, which spend the summer months feeding in coastal waters of Oregon, as well as northern California, Washington and southern Canada.Torres and her research team have been observing and conducting annual "health check-ups" on this population since 2016. When they spot a defecating whale from a boat or via a drone, they follow in the animal's wake and use nets to capture samples. The drones are also used to capture images of the whales, allowing researchers to monitor the animals' body condition and behavior.Researchers used the collected fecal samples to analyze four hormone metabolites: two reproductive hormones; a stress hormone; and thyroid, which can indicate nutrition-related stress.With this data, the researchers were able to see how hormones fluctuated with a whale's age and sex and establish baseline hormone levels for different cycles of a whale's life, including during pregnancy."This was a first step to understanding how hormones vary through a whale's life cycle and in times of stress," Lemos said. "It helps us establish baselines and ranges of hormone levels."The researchers also were able to document a stressful event in a specific whale. They collected a fecal sample from a whale within 24 hours of a documented injury from a propeller or vessel strike. The fecal sample collected after the injury showed a spike in stress hormone levels, almost three times higher than this whale's stress levels on previous days without the injury.The researchers also captured a fecal sample from a mature male who was engaged in competitive reproductive behavior with another male whale. That whale's testosterone level was very high and may reflect the typical hormone levels of adult breeding males. The researchers' ability to connect fecal samples to specific individual whales adds important context to the data to help understand what drives hormone variation, Torres said.Researchers have continued to collect fecal samples over the last two summers and will continue to analyze hormones as part of their broader work on whale health.The researchers' ultimate goal is to understand how variations in human-generated ocean noise impacts whale health, Torres said. Analysis of fecal samples is emerging as an important new tool for understanding how different stressors impact whale physiology. They also hope to use the endocrine information to better understand the role of nutrition and changes in diet on overall whale health."Our ability to link hormone variation to an individual's condition is really a significant advance for the study of whale physiology," Torres said. "All of our future work on impacts of disturbance events will build on this foundation. It's super exciting to be able to use these tools to think about whale life in a holistic way."
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Animals
| 2,020 |
December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201221160503.htm
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Ancient wolf pup mummy in Yukon permafrost from 57,000 years ago
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While water blasting at a wall of frozen mud in Yukon, Canada, a gold miner made an extraordinary discovery: a perfectly preserved wolf pup that had been locked in permafrost for 57,000 years. The remarkable condition of the pup, named Zhùr by the local Tr'ondëk Hwëch'in people, gave researchers a wealth of insights about her age, lifestyle, and relationship to modern wolves. The findings appear December 21 in the journal
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"She's the most complete wolf mummy that's ever been found. She's basically 100% intact -- all that's missing are her eyes," says first author Julie Meachen, an associate professor of anatomy at Des Moines University. "And the fact that she's so complete allowed us to do so many lines of inquiry on her to basically reconstruct her life."One of the most important questions about Zhùr that the researchers sought to answer was how she ended up preserved in permafrost to begin with. It takes a unique combination of circumstances to produce a permafrost mummy."It's rare to find these mummies in the Yukon. The animal has to die in a permafrost location, where the ground is frozen all the time, and they have to get buried very quickly, like any other fossilization process," says Meachen. "If it lays out on the frozen tundra too long it'll decompose or get eaten."Another important factor is how the wolf died. Animals that die slowly or are hunted by predators are less likely to be found in pristine condition. "We think she was in her den and died instantaneously by den collapse," says Meachen. "Our data showed that she didn't starve and was about 7 weeks old when she died, so we feel a bit better knowing the poor little girl didn't suffer for too long."In addition to learning how Zhùr died, the team were also able to analyze her diet. As it turns out, her diet was heavily influenced by how close she lived to water. "Normally when you think of wolves in the Ice Age, you think of them eating bison or musk oxen or other large animals on land. One thing that surprised us was that she was eating aquatic resources, particularly salmon."Analyzing Zhùr's genome also confirmed that she is descended from ancient wolves from Russia, Siberia, and Alaska, who are the ancestors of modern wolves as well. Although analyzing Zhùr gave the researchers many answers about wolves of the past, there remain some outstanding questions about Zhùr and her family."We've been asked why she was the only wolf found in the den, and what happened to her mom or siblings," says Meachen. "It could be that she was an only pup. Or the other wolves weren't in the den during the collapse. Unfortunately, we'll never know."The specimen holds special significance for the local Tr'ondëk Hwëch'in people, who have agreed to place Zhùr on display at the Yukon Beringia Interpretive Centre in Whitehorse. She is cleaned and conserved so she will stay intact for years to come, allowing her to travel to other Yukon locations as well. And the research team predicts there may be more and more permafrost mummies found in the coming years."One small upside of climate change is that we're going to find more of these mummies as permafrost melts," says Meachen. "That's a good way for science to reconstruct that time better, but it also shows us how much our planet is actually warming. We really need to be careful."
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December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201221134144.htm
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Under Antarctica's ice, Weddell seals produce ultrasonic vocalizations
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Weddell seals are chirping, whistling and trilling under Antarctica's ice at sound frequencies that are inaudible to humans, according to a research team led by University of Oregon biologists.
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Two years of recordings at a live-streaming underwater observatory in McMurdo Sound have captured nine types of tonal ultrasonic seal vocalizations that reach to 50 kilohertz. Humans hear in the sonic range of 20 to 20,000 hertz, or 20 kilohertz.The discovery is detailed in a paper published online Dec. 18 ahead of print the Weddell seals (The study's lead author Paul Cziko, a visiting research professor in the UO's Institute of Ecology and Evolution, began recording the seals' sonic-ranged vocalizations in 2017 after completing the installation of the McMurdo Oceanographic Observatory. Workers at McMurdo Station, he said, often fell asleep listening to broadcasts of the seals' sonic sounds coming from below."The Weddell seals' calls create an almost unbelievable, otherworldly soundscape under the ice," Cziko said. "It really sounds like you're in the middle of a space battle in 'Star Wars,' laser beams and all."Over the next two years, the observatory's broadband digital hydrophone -- more sensitive than equipment used in earlier recordings -- picked up the higher-frequency vocalizations during passive monitoring of the seals."We kept coming across these ultrasonic call types in the data," said co-author Lisa Munger, a marine biologist who studies marine mammal acoustics and a career instructor in the UO's Clark Honors College. "Finally, it dawned on us that the seals were actually using them quite regularly."The nine new call types were composed of single or multiple vocal elements having ultrasonic fundamental frequencies. Eleven elements, including chirps, whistles and trills, were above 20 kHz. Two exceeded 30 kHz and six were always above 21 kHz. One whistle reached 44.2 kHz and descending chirps in another call type began at about 49.8 kHz. Harmonics, or the overtones, of some vocalizations exceeded 200 kHz."It was really surprising that other researchers previously had, in effect, missed a part of the conversation," said Cziko, who earned a doctorate in evolutionary biology from the UO in 2014.What the ultrasonic vocalizations mean in the Weddell seals' repertoire is unknown. The seals are among 33 species of fin-footed mammals grouped as pinnipeds. Until now, pinnipeds, which also include sea lions and walruses, were believed to vocalize only at sonic levels.It could be, Cziko said, that the seals produce the sounds simply to "stand out over all the lower-frequency noise, like changing to a different channel for communicating."Or, the researchers noted, the ultrasonic vocalizations may be used for echolocation, a biological sonar that dolphins, toothed whales and bats use to navigate in limited visibility to avoid obstacles and locate friends or prey."The possibility of seals using some kind of echolocation has really been discounted over the years," Cziko said. "We actually had a lot of somewhat heated discussions in our group about whether or how the seals use these ultrasonic sounds for echolocation-like behaviors."It is not known how Weddell seals navigate and find prey during the months of near absolute darkness in the Antarctic winter. The study provides no evidence for echolocation."We'd like to know who is producing the ultrasonic calls -- males, females, juveniles, or all of the above," Munger said. "And how are the seals using these sounds when they're out in deeper water, looking for fish? We need to record in more places to be able to correlate sounds with behaviors."Nick Santos of the Center for Information Technology Research in the Interest of Society at the University of California, Merced, and John Terhune, professor emeritus at the University of New Brunswick in Saint John, Canada, were co-authors. Santos engineered the data-collection pipelines for the observatory.The National Science Foundation primarily supported the research through a grant to Cziko and Arthur L. DeVries, professor emeritus at the University of Illinois at Urbana-Champaign who has conducted research since 1961 in Antarctica. DeVries discovered the biological antifreeze that allows fish to survive in seawater at temperatures at and just below freezing.
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December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201221101144.htm
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Crikey! Massive prehistoric croc emerges from South East Queensland
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A prehistoric croc measuring more than five metres long -- dubbed the 'swamp king' -- ruled south eastern Queensland waterways only a few million years ago.
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University of Queensland researchers identified the new species of prehistoric croc -- which they named UQ PhD candidate Jorgo Ristevski, from UQ's School of Biological Sciences, said they named the species after Geoff Vincent who discovered the giant fossilised skull near the town of Chinchilla."In Latin, 'Paludirex' means 'swamp king', and 'vincenti' honours the late Mr Vincent," he said."For several years the fossilised skull was on display in the Queensland Museum, before it was donated to the Chinchilla Museum in 2011."The 'swamp king' was one intimidating croc."Its fossilised skull measures around 65 centimetres, so we estimate "The largest crocodylian today is the Indo-Pacific crocodile, "But Paludirex had a broader, more heavy-set skull so it would've resembled an Indo-Pacific crocodile on steroids."Paludirex was one of the top predators in Australia a few million years ago, capable of preying on giant prehistoric marsupials."The waterways of the Darling Downs would once have been a very dangerous place because of it," Mr Ristevski said.Mr Ristevski's supervisor, Dr Steve Salisbury, said various species of prehistoric crocodylians had existed in Australia."Crocs have been an important component of Australia's fauna for millions of years," Dr Salisbury said."But the two species we have today -- "Whether "The alternative is that it went extinct as the climate dried, and the river systems it once inhabited contracted -- we're currently investigating both scenarios."
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December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201217112955.htm
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Satellite tracking supports whale survival
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Extensive satellite tracking has revealed important new knowledge about the little known pygmy blue whale population of Southern Australia.
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Marine biologists have extensively tracked the movements of foraging and migrating blue whales (Balaenoptera musculus brevicauda) along the Australian continental shelf on a journey towards breeding grounds in Indonesia as part of conservation efforts for the endangered species.A team of researchers led by Flinders University Associate Professor Luciana Möller tracked the movements of 13 of the blue whale subspecies to determine important environmental habitats along foraging grounds and migratory routes in Southern and Western Australia, which incorporate major shipping and fishing routes, and areas targeted for oil and gas exploration -- all activities known to negatively impact whale behaviour.The research team travelled 4236 kilometres deploying tagging equipment and recording photos of individual pygmy blue whales before tracking them up to 382 days as they travelled as much as 15,120 km during the study.Published in Senior author and whale expert at Flinders University, Associate Professor Luciana Möller, says the study for the first time sheds light on the movements and occupancy patterns of the pygmy blue whales along Southern Australia's foraging grounds and migration routes to develop an understanding about potential impacts on their behaviour."Our tracking results provide new information and highlight the importance of understanding the movements and behaviour of pygmy blue whales in their migratory routes from Southern Australian foraging grounds to a Western Australian migratory corridor, and towards breeding grounds in Indonesia," says marine biologist Associate Professor Möller, who leads the Cetacean Ecology, Behaviour and Evolution Lab (CEBEL) and Molecular Ecology Lab at Flinders University."When combined with previous movement data, this information could be used to predict future whale presence and behaviour based on the forecasted effects of climate change, including in coastal and upwelling systems."More importantly, the ecological data can help mitigate the potential impacts of human activities such as oil and gas exploration on the little known pygmy blue whale population."Associate Professor Möller says tagging information for the first time reveals the importance of foraging grounds in the Great Southern Australian Coastal Upwelling System, by identifying the importance of the Bonney Upwelling region and other smaller upwelling centres in Southern Australia."This new information, along with acoustic, sighting, genetic and past catch data, will substantially expand knowledge about the spatial distribution of this recovering blue whale population and its potential exposure to impacts from human activities throughout its travels."The data can contribute positively to various conservation management decisions for policymakers to consider in Australian, West Timor and Indonesian environmental legislation and forward planning, and for the development of international government collaborations to protect this little known subspecies of blue whales."
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December 18, 2020
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https://www.sciencedaily.com/releases/2020/12/201218112526.htm
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Living environment affects the microbiota and health of both dogs and their owners
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In urban environments, allergic diseases are more common among dogs and their owners compared to those living in rural areas. Simultaneous allergic traits appear to be associated with the microbes found in the environment, but microbes relevant to health differ between dogs and humans.
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In a joint research project known as DogEnvi, researchers from the University of Helsinki, the Finnish Environment Institute and the Finnish Institute for Health and Welfare have previously observed that dogs are more likely to have allergies when their owners suffer from allergic symptoms. In a new study, the researchers investigated whether such simultaneous presence of allergic traits is associated with gut or skin microbes shared by dogs and their owners. A total of 168 dog-owner pairs living in rural and urban environments participated in the study."Research shows that dogs and owners living in rural areas have a lower risk of developing an allergic disease compared to urban areas. We assumed that in rural areas both dogs and owners are exposed to health-promoting microbes. We found that the microbial exposure of both was different in rural and urban environments. For instance, the skin microbiota varied more between individuals in rural areas compared to their urban counterparts. A diverse and varying microbial exposure may be precisely what provides the associated health benefit," says Senior Researcher Jenni Lehtimäki, PhD, from the Finnish Environment Institute.Dogs and their owners seemed to share microbes on their skin, but not in their gut. The study demonstrated that the living environment had a markedly more significant effect on the skin microbiota than on that of the gut in dogs and humans. Dogs living in urban areas had on their skin more microbes typically found on human skin, which may be caused by the accumulation of microbes typical to humans indoors and in urban areas, a phenomenon that has been previously observed.In a study conducted earlier, the researchers noticed that both the living environment and living habits affected the canine skin microbiota."The same was now observed in humans. For both dogs and humans, the risk of developing allergic diseases was at its lowest when the skin microbiota was shaped by a rural environment and a lifestyle that promotes microbial abundance. Such a lifestyle was associated with a number of different animals in the family, as well as larger family size," says Professor Hannes Lohi from the University of Helsinki.While the living environment appeared to alter the species of the skin microbiota as well as the risk of allergic diseases in both dogs and their owners, no single shared microbe in the environment had a link to allergies in both dogs and humans."We detected microbes associated with allergies in urban dogs, as well as microbes connected to health in rural dogs and humans, but these microbes were different in dogs and humans. It appears that the microbes in the living environment are important for the health of both dogs and humans, but due to the physiological differences of the species, the microbes that are relevant can vary," Lehtimäki sums up.
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December 18, 2020
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https://www.sciencedaily.com/releases/2020/12/201218112521.htm
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Researchers monitor bees by 'dressing' them in high visibility retro-reflective vests
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A team of researchers from the University of Sheffield and The Bumblebee Conservation Trust have been trialling new, low-cost ways to monitor bee species in the UK, by dressing bees in high visibility retroreflective vests. This novel research will be presented at the British Ecological Society's virtual Festival of Ecology.
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Researchers attached retroreflective tags to seven species of wild bee and to a commercially bred UK bumblebee subspecies. Then, the foraging behaviour and 3D flight path of various bees was monitored using the web interface of a custom-built, real time tracking system.Tracking bees in the wild is a critical part of understanding their ecology, allowing scientists to deduce their foraging and navigational behaviour, as well as their nest preferences.Currently, it is very difficult and expensive to monitor bee populations. Commonly used methods such as harmonic radars are biased toward larger species, such as bumblebees, which are large enough to withstand the weight of the radar's tag. As such, there are several unknowns regarding the behaviour of the UK's smaller bee species.Michael Smith, lead author and computer scientist at the University of Sheffield, said, "Finding the bee itself is difficult, and finding wild bee nests in the first place is massively difficult and time-consuming, especially for rarer or less-known species. This tool hopefully will make finding them far easier, making these studies a practical approach."The system proved successful in monitoring seven wild species (over 100 individuals), across two field sites in the UK, including a wildflower patch at the University of Sheffield. This involved smaller-bodied species such as honeybees and the solitary leafcutter bees.The tracking system was able to detect bees from up to 40 metres away and tags were still detected a week after deployment. The actual retroreflective tag is made of the same fabric as cycling high visibility vests.Retroreflective materials such as high vis jackets are useful because when light hits them, it bounces back to the source. So, the researchers used a camera with a flash to take a photo of the bee, and the bee in its retroreflective vest appears as a tiny bright dot.Michael Smith, said, of the pilot test, "We surprisingly found one of our buff-tailed bumblebees several metres up in a pine tree nearby, about 33 metres from the tracking system. It's not somewhere we would usually have looked, eliminating some human biases and motivating the system's use for re-observation studies."In addition to their durability, the researchers found no significant difference in the length of foraging time or number of flowers visited between tagged and non-tagged individuals. These results suggest that methods such as this could be used to safely monitor bees across their lifespan.The bees were captured with a net and transferred into a queen marking pot, commonly used by beekeepers, and then immobilised using cold air, allowing the tags to be safely and non-invasively deployed.The tracking system is built out of off-the-shelf low-cost components and consists of a camera with a global electronic shutter, a flash and a Raspberry Pi computer. The electronic shutter allows for a very short exposure, which lets the light from the flash illuminate the scene, rather than the sun.A machine learning model was trained to automatically identify a tag within an image frame and to learn the difference between real tags and various false positives. The whole system can then, in real time, detect the appearance of a bee in the field of the camera or discard false positives, such as a piece of pollen.By using a system capable of real time detection, researchers can manually search for the bee and corroborate if the tracking system has correctly detected a real bee and find which individual has been detected.?Richard Comont, Science Manager of The Bumblebee Conservation Trust, said "Being able to track bees from easy-to-find foraging sites back to the hard-to-find nest gives us the chance to find more nests, and nests much earlier in the life cycle. That means that it's much easier to establish nest site requirements, which can be taken into account when doing conservation work."There are also some pending improvements which will upgrade this method. The range of the photo lens is limited to line of sight and a distance of 40m using the default wide-angle lens and flash. In the current prototype, tagged bees appear as identical white dots.Michael Smith said "Given the wider changes in landscape management at policy level, being able to provide answers to foraging and nesting needs of key insect pollinators is increasingly important."However, this work is a significant advancement, Richard Comont said "We currently know very little about the home life of bees away from captive colonies in labs -- a huge omission for this declining group."Future research from the group will involve using the tracking system to find new nests and training the model to distinguish between coloured filters on the retroreflective tags, allowing individual tagged bees to be identified remotely. The low cost of tracking systems such as this can allow for the scale-up of automated pollinator monitoring to address data gaps.Michael Smith's poster will be available on-demand until the 18th of January 2021 at the Festival of Ecology. This work is unpublished and has not been through the peer-review process yet. This online conference will bring together 1,200 ecologists from more than 50 countries to discuss the most recent breakthroughs in ecology.
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217145223.htm
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Researchers use artificial intelligence to ID mosquitoes
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Rapid and accurate identification of mosquitoes that transmit human pathogens such as malaria is an essential part of mosquito-borne disease surveillance. Now, researchers reporting in
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Human malaria is an ongoing public health crisis affecting multiple continents, with the highest numbers of cases and people at risk occurring in sub-Saharan Africa. However the identification of mosquitoes that transmit malaria can be difficult -- some species are nearly indistinguishable even to trained taxonomists.In the new work, Jannelle Couret of University of Rhode Island, USA, and colleagues applied a Convoluted Neural Network (CNN) to a library of 1,709 two-dimensional images of adult mosquitos. The mosquitoes were collected from 16 colonies in five geographic regions and included one species not readily identifiable to trained medical entomologists. They also included mosquitoes that had been stored in two different ways -- by flash freezing or as dried samples.Using the library of identified species, the researchers trained the CNN to distinguish Anopheles from other mosquito genera, to identify species and sex within Anopheles, and to identify two strains within a single species. They found a 99.96% prediction accuracy for class and a 98.48% accuracy for sex."These results demonstrate that image classification with deep learning can be a useful method for malaria mosquito identification, even among species with cryptic morphological variation," the researchers say. "The development of an independent and accurate method of species identification can potentially improve mosquito surveillance practices."
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Animals
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217135237.htm
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More West Nile virus-infected mosquitoes in lower-income areas of Baltimore
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In a new study published in the
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"In order to effectively address environmental injustices, we have to understand where they occur and why," says Sarah Rothman, doctoral student in Environmental Science & Technology at UMD and lead author of this paper. "Urban mosquito sampling often takes place in city parks or other areas where traps are easily accessible to personnel, but we need to ensure we are sampling for mosquitoes in neighborhoods that are diverse in socioeconomic status. Representative surveillance is the first step. Only after identifying where disease risk is actually greatest can we direct public health resources to communities that need them most."This study acts as a first step in addressing environmental justice, providing another important connection between lower-income neighborhoods and risky mosquito populations, according to Paul Leisnham, associate professor in Environmental Science & Technology at UMD. "A higher infection rate was shown in two species of mosquito, the invasive tiger mosquito and the northern house mosquito. In previous studies, we have shown that mosquito abundances and female body sizes, two other ecological parameters that promote virus transmission, are also larger in lower-income neighborhoods. Now we have introduced another piece of the puzzle pointing to higher risks in lower-income areas."Leisnham spends time interacting with locals in urban Baltimore through his research and Extension efforts, highlighting an important point for mosquito population growth that isn't exactly intuitive: "Less trash, fewer mosquitoes." Mosquitoes can surprisingly breed in an amount of water as small as what gathers in a bottle cap left outside in a shady area for four or five days. If the water gathers in a shaded container and isn't infiltrating into the ground through managed stormwater practices, it can easily become a mosquito breeding ground that can produce hundreds of biting adults.Cary Institute disease ecologist Shannon LaDeau, collaborator on the study, explains, "More people are living in cities. At the same time, many other species are also adapting to city living. Invasive species like the tiger mosquito increasingly thrive in temperate urban areas, living among us and fundamentally altering the risk of local disease emergence. People living in neighborhoods with abandoned infrastructure are more at risk, because tiger mosquitoes flourish in less managed landscapes."While the connection between vacant lots, more trash, and more mosquitoes is established, more research is needed to further connect these environmental injustices to higher infection rates in humans. "West Nile virus incidence in the human population is often underestimated," says Rothman. "Most cases are asymptomatic, and mild symptomatic cases are easily confused with other illnesses that present similarly, like the flu. We are likely especially missing cases in underserved populations with reduced access to quality medical care. Since it's hard to track the prevalence of West Nile virus in people, we suggest additional sampling of the virus in mosquitoes. Additional research could also help us figure out why we're seeing patterns of higher mosquito infection rates in lower-income neighborhoods and how these patterns are affected by environmental factors such as weather.""It's important, especially in populations from lower-income areas since they are often immunocompromised with other infections, including HIV and likely COVID-19," adds Leisnham. "The CDC [Centers for Disease Control and Prevention] has reported that the U.S. is not prepared for mosquito and tick-borne risks based on local health agencies' surveys."Rothman stresses the need for this work to improve environmental justice in lower-income areas of cities like Baltimore. "Our research supports the notion that residents in these neighborhoods are disproportionately at risk for mosquito-borne illness," says Rothman. "We need additional research to understand and address the underlying factors, and ultimately protect urban residents."
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December 18, 2020
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https://www.sciencedaily.com/releases/2020/12/201218165112.htm
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King of the Cave: New centipede on top of the food chain in the sulphurous-soaked Movile
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Deemed to never see the light of the day, a new species of endemic, troglobiont centipede was discovered by an international team of scientists in the Romanian cave Movile: a unique underground ecosystem, where the oxygen in the air might be half of the amount of what we're used to, yet the sulphurous abounds; and where the animal life only exists because of chemosynthetic bacteria feeding on carbon dioxide and methane.
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This hellish ecosystem -- where breathing alone could be lethal for most of us -- seems to have finally crowned its king. At a size of between 46 and 52 mm in length, the centipede Cryptops speleorex is the largest of the cave's inhabitants known to date. The new species is described in the open-access, peer-reviewed journal Already isolated from the outside world several millions years ago during the Neogene, the Movile cave has been drawing the attention of scientists ever since its unexpected discovery in 1986 by Romanian workers, searching for locations suitable for building a power plant in the southeastern parts of the country.Surprisingly enough, despite its harsh living conditions, the Movile ecosystem was soon found to harbor a diverse and unique fauna, characterised by exceptional species endemism and specific trophic links. So far, the cave has been known to give home to the troglobiont water scorpion, liocranid and nesticid spiders, cave leeches and certainly many more yet to be discovered.In fact, it was long thought that this unique underground ecosystem was also inhabited by surface-dwelling species widespread in Europe. Convinced that this scenario is highly unlikely, scientists Dr Varpu Vahtera (University of Turku, Finland), Prof Pavel Stoev (National Museum of Natural History, Bulgaria) and Dr Nesrine Akkari (Museum of Natural History Vienna, Austria) decided to examine a curious centipede, collected by speleologists Serban Sarbu and Alexandra Maria Hillebrand, during their recent expedition to Movile."Our results confirmed our doubts and revealed that the Movile centipede is morphologically and genetically different, suggesting that it has been evolving from its closest surface-dwelling relative over the course of millions of years into an entirely new taxon that is better adapted to life in the never-ending darkness," explain the researchers."The centipede we described is a venomous predator, by far the largest of the previously described animals from this cave. Thinking of its top rank in this subterranean system, we decided to name the species Cryptops speleorex, which can be translated to the "King of the cave," they add.
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Animals
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217095536.htm
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Training methods based on punishment compromise dog welfare, study finds
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Dogs trained using aversive stimuli, which involve punishments for incorrect behavior, show evidence of higher stress levels compared to dogs trained with reward-based methods, according to a study publishing December 16 in the open-access journal
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The researchers observed the behavior of 92 companion dogs from 7 dog training schools in Portugal that use either aversive methods (which use mainly aversive stimuli), reward methods (which focus on rewarding desired behaviours), and mixed methods (which combine the use of both rewards and aversive stimuli). They filmed training sessions and tested saliva samples for the stress-related hormone cortisol. Dogs trained using aversive and mixed methods displayed more stress-related behaviors, such as crouching and yelping, and showed greater increases in cortisol levels after training than dogs trained with rewards.The authors also conducted a cognitive bias test in an unfamiliar location outside of the dog's usual training environment with 79 of the dogs, to measure their underlying emotional state. They found that dogs from schools using aversive methods responded more pessimistically to ambiguous situations compared with dogs receiving mixed- or reward-based training.Previous survey-based studies and anecdotal evidence has suggested that punishment-based training techniques may reduce animal welfare, but the authors state that this study is the first systematic investigation of how different training methods influence welfare both during training and in other contexts. They say that these results suggest that aversive training techniques may compromise animal welfare, especially when used at high frequency.The authors add: "This is the first large scale study of companion dogs in a real training setting, using the types of training methods typically applied in dog training schools and data collected by the research team. The results suggest that the use of aversive training methods, especially in high proportions, should be avoided because of their negative impact on dog welfare."
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December 16, 2020
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https://www.sciencedaily.com/releases/2020/12/201216134657.htm
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Whole genomes map pathways of chimpanzee and bonobo divergence
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Chimpanzees and bonobos are sister species that diverged around 1.8 million years ago as the Congo River formed a geographic boundary and they evolved in separate environments. Now, a whole-genome comparison of bonobos and chimpanzees reveals the gene pathways associated with the striking differences between the two species' diets, sociality and sexual behaviors.
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The journal "Our paper is the first whole-genome positive selection scan between chimpanzees and bonobos," says John Lindo, Emory assistant professor of anthropology and senior author of the study. "We contrasted the genomes of both species to understand how natural selection has shaped differences between the two closely related primates."Lindo is a geneticist specialized in ancient DNA and natural selection. "Chimpanzees and bonobos are fascinating because they are very, very closely linked genetically but they have huge behavioral differences," he says.The two species also share around 99 percent of human DNA, making them our closest living relatives in the animal kingdom. "Understanding the physiological mechanisms underlying the differences in chimpanzee and bonobo behaviors -- particularly the much stronger propensity of bonobos toward conflict resolution instead of fighting -- may also give us information about the genes underlying our own behaviors," Lindo says.Sarah Kovalaskas, an Emory graduate student of anthropology, is first author of the paper. Before joining Emory she spent nine months in the field, studying the social development of juvenile bonobos in the Democratic Republic of Congo (DRC). Wild bonobos, an endangered species, are only found in forests south of the Congo River in the DRC."Bonobos are well-known for being playful, even as adults," Kovalaskas says. "It was fun to observe the juveniles twirling around in the trees, chasing one another and trying to pull each other down. When the mothers tried to wean them, they would sometimes throw tantrums and scream and run around. You can't help but recognize the similarity in behaviors to humans."Populations of chimpanzees, also an endangered species, are found in a forested belt north of the Congo River and scattered in a few other areas of west and central Africa.Bonobos and chimpanzees closely resemble one another physically and they were not recognized as separate species until the 1930s. Their behavioral differences are much more distinct. While bonobos organize into female-led societies, chimpanzees are patriarchal. When bonobos encounter other bonobo groups they generally interact peacefully. Bonobos are also known for using sexual behaviors to defuse tension -- including same-sex behaviors among females. Chimpanzees, however, tend to act more aggressively when encountering other chimpanzee groups and may even have violent exchanges that include fatalities.A leading hypothesis suggests that different feeding ecologies were key to the behavioral divergence between the two species. This theory posits that the abundant ground vegetation in the bonobo territory provided easy access to year-round food without competition from other individuals. Larger groups could feed together instead of foraging in isolation, allowing females to develop strong bonds to counter male domination, and to mate with less aggressive males, leading a kind of "self-domestication."The whole genome comparison showed selection in bonobos for genes related to the production of pancreatic amylase -- an enzyme that breaks down starch. Previous research has shown that human populations that began consuming more grains with the rise of agriculture show an increase in copies of a closely related gene that codes for amylase."Our results add to the evidence that diet and the available resources had a definite impact on bonobo evolution," Kovalaskas says. "We can see it in the genome."Compared to chimpanzees, bonobos also showed differences in genetic pathways well-known to be related to social behaviors of animals -- as well as humans. Bonobos had strong selection for genes in the oxytocin receptor pathway, which plays a role in promoting social bonds; serotonin, involved in modulating aggression; and gonadotropin, known to affect sexual behavior."The strong female bonds among bonobos, in part, may be mediated by their same-sex sexual behaviors," says co-author James Rilling, professor and chair of Emory's Department of Anthropology. "Our data suggest that something interesting is going on in the bonobo pathways for oxytocin, serotonin and gonadotropin and that future research into the physiological mechanisms underlying behavioral differences between bonobos and chimpanzees may want to target those specific systems."
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December 15, 2020
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https://www.sciencedaily.com/releases/2020/12/201215164923.htm
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Researchers turn DNA detectives to aid rhino poaching prosecutions with forensic evidence
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The project is part of the Rhino DNA Indexing System (RhODIS- India) conservation program. This database has been created to build a DNA catalogue of the existing Indian greater one-horned rhinoceros, Rhinoceros unicornis, to tackle rhino poaching and assist conservation efforts for this vulnerable species.
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Inspired by a similar program in South Africa, PhD student and senior research fellow Tista Ghosh, along with Dr Samrat Mondol (WII) and Amit Sharma (WWF India), collected dung from 749 rhinoceros to gather vital genetic information. By analysing dung for traces of population specific genetic signals, a genetic baseline was created for rhinoceros across India and 406 unique individuals were identified.Microsatellite markers are present in nuclear DNA, similar to a fingerprint, where each individual has its own unique genetic signature. The use of 14 markers helps to identify individuals from dung data based on unique individual rhino's signature.By comparing seized rhino horn samples to these specific genetic signals, the researchers could trace the rhino back to its breeding population, thus identifying trade routes and pinpointing poaching hotspots, which are notoriously difficult for traditional law enforcement to track."Having an allele frequency map aids in pinpointing the location of the orphan seized rhino sample to its breeding population based on genetic signatures," commented Tista Ghosh.The forensics team at WII were also able to match a suspected poached carcass from a protected area to a seized horn found elsewhere along the trade route in India. Occasionally, they had as little to work with as blood-stained soil, pebbles or a bullet to perform DNA profiling.These results display the powerful abilities which this microsatellite panel has for tackling wildlife crime and providing valuable insights to the forest department. Furthermore, individual DNA matching assists in court prosecutions by providing concrete scientific evidence regarding the poaching of wild rhino, native to India.On the significance of this method, Tista said: "Many times the seized rhino body parts are found after a long time of poaching incidence as a result of which it becomes difficult to pinpoint the location of the crime. Thus, it is important to locate such networks and have law enforcement resulting in breaking the chain of trading."India's current population of greater one-horned rhinoceros' is relatively small, at approximately 3,500 rhino individuals. Using statistical probabilities, the team calculated that 14 microsatellite markers were sufficient to be able to do individual matching across the whole range of the population.In addition, the researchers are keen to collaborate with Nepal field teams to extend this work to the second strong hold of greater one-horned rhinoceros.However, in the field of wildlife forensics, there are severe limitations due to the poor quality of samples, and circumstances when data could not be generated using microsatellite only. In those scenarios Tista said, of these exciting developments, "We are planning to do a mitochondrial DNA screening to look for park/state specific genetic markers and combine that data with our existing database to avoid such situations."Further the RhODIS-India marker panel is still in the process of developing an 'allelic ladder' (reference point) for comparisons with other laboratories. When this becomes available, this will foster greater collaboration between the global wildlife forensics community. In order to increase the size of the database, plans are already in place to carry out wider sampling across the Indian rhino's range.Tista Ghosh's talk will be available on-demand from the 14th -- 18th of December 2020 at the Festival of Ecology. The selection procedure of a 14-microsatellite panel and its application in curbing rhino poaching in India is currently under review in a peer reviewed scientific journal. This online conference will bring together 1,400 ecologists from than 50 countries to discuss the most recent breakthroughs in ecology.This research is managed by the Wildlife Institute of India is led by the MOEFC&C (environment ministry) in India in collaboration with WWF India and the Wildlife Institute of India.
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Animals
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December 15, 2020
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https://www.sciencedaily.com/releases/2020/12/201215095925.htm
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Creating a ground plan for stonefly evolution
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If a creature with eight legs, a large abdomen, and lots of eyes comes crawling your way, even if you have never seen one like it before, you know instinctively that it is a spider. Likewise, an animal with wings, feathers, and a beak is unlikely to be mistaken for anything other than a bird. The common features of a group of animals that make them immediately recognizable are often called a ground plan or body plan, and have traditionally been used to categorize animals.
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More recently, researchers have found that comparative embryology, the study of how different animals develop at the embryonic stage, can also shed light on the ground plan of a group of animals and help identify their evolutionary history.In a study published in the December 2020 issue of "Although there are more than 3,500 described species of stonefly (order Plecoptera) distributed across all continents except Antarctica, there are only two main groups (called sub-orders): Antarctoperlaria, found mainly in the Southern Hemisphere, and Arctoperlaria, which includes the Northern Hemisphere species," explains senior author Professor Ryuichiro Machida. "While previous studies have uncovered the main features of the embryonic ground plan of Arctoperlaria, there is little information on the embryonic development of Antarctoperlaria."To establish the embryonic ground plan of the Antarctoperlaria, and potentially the wider order Plecoptera, the researchers examined the eggs from five different stonefly species representing three of the four main families of Antarctoperlaria. Both the entire eggs and ultrathin egg sections for transmission electron microscopy were examined.By determining the shared and divergent characteristics of the five species, the researchers were able to infer the ground plans not only of the four main antarctoperlarian families, but also of the larger order Plecoptera."Eggs from two of the four main families had hard outer membranes, called chorions, which, although functionally similar, were structurally very different," says Professor Machida. "Given that only one group of arctoperlarian eggs have a similar hard chorion, we can infer that a thin chorion is a ground plan character of Plecoptera and that a hard chorion is an evolved trait."Similarly, attachment structures, which anchor the eggs to the riverbed, have been regarded as being an ancestral feature. However, careful inspection revealed that they were actually acquired in parallel in each lineage, proving that determining the embryonic ground plan of a species can answer important questions about its evolutionary history.
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Animals
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December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214192349.htm
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New dinosaur showed descendants how to dress to impress
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Scientists have found the most elaborately dressed-to-impress dinosaur ever described and say it sheds new light on how birds such as peacocks inherited their ability to show off.
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The new species, Ubirajara jubatus, was chicken-sized with a mane of long fur down its back and stiff ribbons projecting out and back from its shoulders, features never before seen in the fossil record.It is thought its flamboyant features were used to dazzle mates or intimidate foe.An international team of scientists co-led by Professor David Martill and researcher Robert Smyth, both at the University of Portsmouth, and Professor Dino Frey at the State Museum of Natural History, Karlsruhe, Germany discovered the new species while examining fossils in Karlsruhe´s collection.The study is published in the scientific journal Professor Martill said: "What is especially unusual about the beast is the presence of two very long, probably stiff ribbons on either side of its shoulders that were probably used for display, for mate attraction, inter-male rivalry or to frighten off foe."We cannot prove that the specimen is a male, but given the disparity between male and female birds, it appears likely the specimen was a male, and young, too, which is surprising given most complex display abilities are reserved for mature adult males."Given its flamboyance, we can imagine that the dinosaur may have indulged in elaborate dancing to show off its display structures."The ribbons are not scales or fur, nor are they feathers in the modern sense. They appear to be structures unique to this animal.Mr Smyth said: "These are such extravagant features for such a small animal and not at all what we would predict if we only had the skeleton preserved. Why adorn yourself in a way that makes you more obvious to both your prey and to potential predators?"The truth is that for many animals, evolutionary success is about more than just surviving, you also have to look good if you want to pass your genes on to the next generation."Modern birds are famed for their elaborate plumage and displays that are used to attract mates -- the peacock's tail and male birds-of-paradise are textbook examples of this. Ubirajara shows us that this tendency to show off is not a uniquely avian characteristic, but something that birds inherited from their dinosaur ancestors."Ubirajara jubatus lived about 110 million years ago, during the Aptian stage of the Cretaceous period, and is closely related to the European Jurassic dinosaur Compsognathus.A section of the long, thick mane running down the animal´s back is preserved nearly intact. The arms were also covered in fur-like filaments down to the hands.The mane is thought to have been controlled by muscles allowing it to be raised, in a similar way a dog raises its hackles or a porcupine raises its spines when threatened.Ubirajara could lower its mane close to the skin when not in a display mode allowing the creature to move fast without getting tangled in vegetation.Professor Martill said: "Any creature with movable hair or feathers as a body coverage has a great advantage in streamlining the body contour for faster hunts or escapes but also to capture or release heat."The mane isn't the only extraordinary feature.The researchers describe as 'enigmatic' the creature's long, flat, stiff shoulder ribbons of keratin, each with a small sharp ridge running along the middle. These ribbons were positioned to not impede freedom of movement in its arms and legs, so wouldn't have limited the animal's ability to hunt, preen and send signals.Mr Smyth argues the elaborate plumage of Ubirajara might have improved its chances of survival.He said: "We know lots of dinosaurs had bony crests, spines and frills that were probably used for display but we don't see these very often in living birds. In birds, crests are made of feathers."This little dinosaur provides some insight into why this might be the case."Bone requires a lot of energy for a body to grow and maintain, it's also heavy and can cause serious injury if broken."Keratin -- the material that makes up hair, feathers and scales -- is a much better display alternative for a small animal like this one. Keratin is less costly for a body to produce, it's also lightweight, flexible and can be regularly replaced if damaged."Ubirajara is the most primitive known dinosaur to possess integumentary display structures. It represents a revolution in dinosaur communication, the effects of which we can still see today in living birds."Professor Frey excavated the specimen from the two slabs of stone in which it lay and, using x-ray, found previously hidden skeletal elements and soft tissue, allowing the researchers to build a clear picture of its features.Ubirajara jubatus is the first non-avian dinosaur to be described from Brazil's Crato Formation, a shallow inland sea laid down about 110 million years ago. It is also the first non-avian dinosaur found on the ancient supercontinent of Gondwana with preserved skin.Another of the researchers on the team, Hector Rivera Sylva, from Museo del Desierto, Mexico, said as well as the discovery being a watershed in this field, it was also important for the Americas.He said: "The Ubirajara jubatus is not only important because of the integumentary structures present for the first time in a non-avian dinosaur, completely changing the way of seeing the behaviour of certain dinosaurs. Rather, the scientific value transcends, forming a watershed, since it is the first evidence for this group in Latin America, as well as one of the few reported for the subcontinent of Gondwana, expanding the knowledge about non-avian feathered dinosaurs for America, whose evidence is very scarce."
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Animals
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December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214192327.htm
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A human gene placed in fruit flies reveals details about a human developmental disorder
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Meier-Gorlin syndrome, or MGS, is a rare genetic developmental disorder that causes dwarfism, small ears, a small brain, missing patella and other skeletal abnormalities. In severe cases, MGS results in miscarriages and stillbirths.
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Igor Chesnokov, Ph.D., and his University of Alabama at Birmingham colleagues study this recessive, autosomal disorder in an unusual way -- by placing mutant human genes into fruit flies. Specifically, they look at one of the genes involved in MGS called Orc6.In a study published in Those two mutations are interesting to contrast, because position 23 is near the front, or the N-terminal domain, of the long chain of connected amino acids that folds to form the Orc6 protein. Position 225 is near the end, or the C-terminal domain, of the Orc6 protein strand.Orc6 is part of the Origin Recognition Complex, or ORC. This complex of proteins is vital to initiate DNA replication in a cell, whether yeast, fruit fly, human or any other eukaryotic organism. Without DNA division, a cell cannot divide and an organism cannot grow. Poor division will stunt growth, as is seen in MGS.In previous research on the Y225S mutation, published in the American Journal of Medical Genetics, the UAB researchers found that the C-terminal domain of Orc6 is important for protein-protein interactions to help build the ORC complex. In the current study, Chesnokov and colleagues have now found that the K23E mutation in the N-terminal domain of Orc6 disrupts the protein's ability to bind to DNA. This specific binding is a vital step in ORC function.Thus, although the two mutations have different underlying molecular mechanisms, they both cause deficient pre-replicative complex formation and reduced DNA replication, and they produce a similar phenotype in MGS patients.One key in this research was creating chimeric Orc6 genes that are part human gene and part fruit fly gene. Here is why that was necessary. Putting a human Orc6 gene into fruit flies fails to prevent the lethal effect of an Orc6 deletion in fruit flies; in other words, the intact human Orc6 cannot replace the function of the fruit fly Orc6, due to the difference in Orc6 interactions with the core ORC in the two organisms.However, when the UAB researchers made a hybrid Orc6 that was human in the N-terminal domain and fruit fly in the C-terminal domain, the hybrid was able to completely rescue the fruit flies, and they grew into adults that were undistinguishable from fruit flies with wild-type Orc6. This hybrid Orc6 then could be used to test the K23E mutation in fruit flies and study its molecular mechanism."This hybrid approach," Chesnokov said, "allows the study of human protein functions in an animal system, and it revealed the importance of evolutionary conserved and variable domains of the Orc6 protein. We believe that this hybrid approach not only opens a broad avenue to study new Orc6 mutations for medical and general science purposes, but also might be useful in other humanized models."In summary, says Chesnokov, a professor in the UAB Department of Biochemistry and Molecular Genetics, this humanized fly model has the unique advantage of being able to differentially test fly, human, and chimeric Orc6 proteins to reveal conserved and divergent features of the protein and its function in the cells of metazoan organisms.
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Animals
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214150340.htm
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Animals are back at Gorongosa National Park after civil war, but the savanna community doesn't look quite look like how it used to
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When civil war broke out in Mozambique more than 40 years ago, it largely spelled doom for animals in Gorongosa National Park, a 1,500-square-mile reserve on the floor of the southern end of the Great African Rift Valley, in the heart of the country. As the decades-long fighting spilled over into the reserve, many of the creatures became casualties of the conflict.
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Throughout the war and even for some time after, food insecurity drove people to kill the animals to feed themselves. The hunting and poaching were hardest on the large mammals."More than 90% of the large mammals in the park were wiped out," said UC Santa Barbara ecologist Kaitlyn Gaynor, a postdoctoral researcher at UCSB's National Center for Ecological Analysis and Synthesis (NCEAS). After the war, a massive recovery effort was launched to repair and restore the park in the hopes that the animals would make a comeback.With the park now three decades post-war, it appears the animal populations have recovered. While some have been reintroduced, most have simply rebounded from remnant post-war populations thanks to ongoing conservation efforts.But for all the growing abundance in animals in the park, questions about the ecological consequences of the war remained for Gaynor and her team, which included coauthor Josh Daskin (U.S. Fish and Wildlife Service), Lindsey Rich (California Department of Fish and Wildlife and senior author Justin Brashares (UC Berkeley)."How similar is this new system to pre-war conditions, or to African savannas that haven't seen this major shock?" These were the questions the researchers sought to address, using an array of 60 camera traps to document the comings and goings of the animals of Gorongosa.Their results are published in the journal "There are few places in the world that have had such a dramatic reset, where animals have been pretty much wiped out and then have come back," Gaynor said. "It looks a lot like it did before the war, if you look at just the numbers of total animals, or the number of species present throughout the landscape."The researchers identified 38 species during the three months of their survey, which puts Gorongosa's biodiversity on par with other African savannas, such as the Moremi Game Reserve in Botswana's Okavango Delta and Serengeti National Park in Tanzania.But that's where the similarity ends."When you take a closer look at the distribution of species, it's a bit out of whack," Gaynor said. The large herbivores that were dominant before the war -- iconic African animals like zebra, wildebeest and hippopotamus -- were rare. Large carnivores were rarer still, with only lions remaining after the war. The savanna now belonged to baboons, warthogs, bushbuck and especially waterbuck, which dominated the survey."Waterbuck have been reproducing exponentially," Gaynor said, adding that it remained to be seen whether the unchecked population might crash and stabilize, or if their dominance signaled a "new normal" for the park.Additionally, in the first systematic study to focus on smaller predators in the park, the researchers also found a high diversity in mesopredators -- housecat sized animals such as civets, mongoose and genets -- which were widespread throughout the park."There may have been a 'mesopredator release,' where in the absence of apex predators, the smaller predators' populations can grow because they're not facing competition, or they're not being preyed upon by the larger carnivores," Gaynor explained.All of this is happening against a backdrop of a environmental change: Tree cover increased while the herbivores (especially elephants) were absent, but with their return and increased feeding pressure the landscape might shift again, potentially influencing which species may flourish. According to the researchers, a variety of tree cover is important for promoting the diversity of the animals.Time will tell whether the distribution of species in this park will return to pre-war levels, or if they will level off at some other stable state. Since the study was conducted, African wild dogs and leopards were reintroduced in an effort to rebalance the ecosystem. The slow return of large carnivores is bound to shape the dynamics of Gorongosa's animal community, and the researchers are hoping to document those and other developments in future studies."Our study represents the first data point in what will hopefully be a long-term, ongoing camera trap monitoring effort," Gaynor said. "Gorongosa has been a really remarkable conservation success story, but I think it's also pretty interesting how the system has recovered asymmetrically. There remain questions about the causes and consequences of that asymmetry, and how the wildlife community is going to change in the future, given ongoing transformations to the landscape."
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Animals
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214090143.htm
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Unexpected insights into early dinosaur's brain, eating habits and agility
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A pioneering reconstruction of the brain belonging to one of the earliest dinosaurs to roam the Earth has shed new light on its possible diet and ability to move fast.
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Research, led by the University of Bristol, used advanced imaging and 3-D modelling techniques to digitally rebuild the brain of Thecodontosaurus, better known as the Bristol dinosaur due to its origins in the UK city. The palaeontologists found Thecodontosaurus may have eaten meat, unlike its giant long-necked later relatives including Diplodocus and Brontosaurus, which only fed on plants.Antonio Ballell, lead author of the study published today in Thecodontosaurus lived in the late Triassic age some 205 million years ago and was the size of a large dog. Although its fossils were discovered in the 1800s, many of which are carefully preserved at the University of Bristol, scientists have only very recently been able to deploy imaging software to extract new information without destroying them. 3-D models were generated from CT scans by digitally extracting the bone from the rock, identifying anatomical details about its brain and inner ear previously unseen in the fossil."Even though the actual brain is long gone, the software allows us to recreate brain and inner ear shape via the dimensions of the cavities left behind. The braincase of Thecodontosaurus is beautifully preserved so we compared it to other dinosaurs, identifying common features and some that are specific to Thecodontosaurus," Antonio said. "Its brain cast even showed the detail of the floccular lobes, located at the back of the brain, which are important for balance. Their large size indicate it was bipedal. This structure is also associated with the control of balance and eye and neck movements, suggesting Thecodontosaurus was relatively agile and could keep a stable gaze while moving fast."Although Thecodontosaurus is known for being relatively small and agile, its diet has been debated.Antonio, a PhD student at the University of Bristol's School of Earth Sciences, said: "Our analysis showed parts of the brain associated with keeping the head stable and eyes and gaze steady during movement were well-developed. This could also mean Thecodontosaurus could occasionally catch prey, although its tooth morphology suggests plants were the main component of its diet. It's possible it adopted omnivorous habits."The researchers were also able to reconstruct the inner ears, allowing them estimate how well it could hear compared to other dinosaurs. Its hearing frequency was relatively high, pointing towards some sort of social complexity -- an ability to recognise varied squeaks and honks from different animals.Professor Mike Benton, study co-author, said: "It's great to see how new technologies are allowing us to find out even more about how this little dinosaur lived more than 200 million years ago."We began working on Thecodontosaurus in 1990, and it is the emblem of the Bristol Dinosaur Project, an educational outreach scheme where students go to speak about science in local schools. We're very fortunate to have so many well-preserved fossils of such an important dinosaur here in Bristol. This has helped us understand many aspects of the biology of Thecodontosaurus, but there are still many questions about this species yet to be explored."
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Animals
| 2,020 |
December 10, 2020
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https://www.sciencedaily.com/releases/2020/12/201210112147.htm
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Ferrets, cats and civets most susceptible to coronavirus infection after humans
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Humans, followed by ferrets and to a lesser extent cats, civets and dogs are the most susceptible animals to SARS-CoV-2 infection, according to an analysis of ten different species carried out by researchers at the Centre for Genomic Regulation (CRG), based in Barcelona.
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The findings, published in "Knowing which animals are susceptible to SARS-CoV-2 helps us prevent building up animal reservoirs from which the coronavirus can re-emerge at a later date," says Luis Serrano, ICREA Research Professor, Director of the CRG and senior author of the study. "Our findings offer a clue for why minks -- which are closely related to the ferret -- are being infected by the disease, which is probably made worse by their packed living conditions and close contact with human workers.""Though we also find a potential susceptibility to infection by cats, they don't co-exist with humans in the same conditions as other animals, which may explain why so far there are no known cases of people being infected by their pets," adds Dr. Serrano.Ten species were studied in this paper. Five species -- humans, cats, ferrets, civets, and dogs -- have had documented cases of infection by SARS-CoV-2. There are no reports of infection in the other five species -- mice, rats, pigs, chickens and ducks.The researchers used computer modelling to test how the coronavirus uses its spike proteins, which protrude from the surface of the virus, to infiltrate the cells of different animals. The main point of entry on a cell's surface is the ACE2 receptor, which binds with the spike protein through a lock-and-key mechanism. There are many different variants of ACE2 within human populations and across different species.Variants of the ACE2 receptor in humans followed by ferrets, cats, dogs and civets have the highest binding affinities to the viral spike protein, while mice, rats, chicken and ducks have poor binding energy.However, binding affinity is not enough on its own to gauge a cell's susceptibility to infection. The researchers also tested the different species' 'codon adaptation index' -- which is how efficient the coronavirus is at commandeering a cell's machinery once it has entered. The more efficient the process, the better the coronavirus can create the proteins it needs to replicate.Humans, chickens and ducks have the highest codon adaptation index, while the other species are worse adapted.Considering both binding affinity and the codon adaptation index, the researchers conclude that humans, followed by ferrets, cats, civets and dogs are the most susceptible animals to infection by coronavirus.They also found that different human variants of ACE2 showed differences in stability and binding to the spike protein, a sensitivity that may underlie why some people suffer from severe COVID-19 symptoms."We have identified mutations on the S-protein that dramatically reduces the capacity of SARS-CoV-2 to enter into the cell, protecting the host from catching Covid-19," says Javier Delgado, researcher at the CRG and first author of the study. "We are now engineering mini-proteins from the human ACE2 protein to 'distract' the attention of the virus from entering cells and block an infection. Should new mutations of the viral spike protein arise, we could engineer new variants to block them."Understanding SARS-CoV-2 infectivity across different species can better inform public health measures, helping reduce human contact with other susceptible animals and avoiding the potential prolongment of the COVID-19 pandemic.
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Animals
| 2,020 |
December 10, 2020
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https://www.sciencedaily.com/releases/2020/12/201210112122.htm
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A gene from ancient bacteria helps ticks spread Lyme disease
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One of the reasons ticks spread Lyme disease so well goes back to a unique evolutionary event. Researchers reporting in the journal
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"Bacteria exchange DNA with each other all the time, but what's remarkable is that 40 million years ago a gene in bacteria jumped across kingdoms all the way into ticks," says senior author Seemay Chou, a professor of biochemistry at University of California San Francisco. "The ticks effectively stole a page out of the bacteria's playbook, repurposing their arsenal to use against them."The relationship between ticks and the Lyme bacterium is an example of symbiosis, where two species live in harmony with one another, and often, one organism benefits from the other without harming it. But Chou's team found that ticks have a more adversarial relationship with with bacteria found on human skin, and ticks use Dae2 -- the enzyme stolen from ancient bacteria -- as a defense agent to keep them safe.Because the ticks are so well protected against human skin bacteria, they can spread Lyme disease far and wide. However, without Dae2, the whole system falls apart."When we blocked the enzyme, we found that ticks were actually dying from these bacteria." says Chou. "The word 'pathogen' is used in our language to describe a bacteria as 'bad' as opposed to 'good,' but in reality, 'pathogen' is referring to a very specific context rather than in intrinsic identity"The Dae2 defense strategy against human skin microbes was a surprise for the researchers, who had spent several years unsuccessfully testing the toxic enzyme against Borrelia burgdorferi. While they found that the Lyme pathogen could stimulate ticks to produce Dae2, the enzyme didn't kill it."Dae2 seemed to have a mild effect on Borrelia, but nothing like we'd expect. Then a few of my colleagues bet me on a hunch that it would work better against skin bacteria. I lost that bet," Chou says. "It was astounding how fast it worked."The net result is a well-honed biochemical system that benefits ticks and B. burgdorferi alike. The findings support a growing idea among biologists that the key to controlling tick-borne diseases may be controlling the ticks themselves, not just treating the diseases. This is what the research team is exploring next."There are all these old studies that show that tick saliva directly enables disease transmission, so now we're really interested in digging into some of the mechanics underlying that," says Chou. "We've also started to look more closely at the bite site itself. That's basically ground zero for all these different interactions."So while ticks are currently winning the evolutionary war against bacteria and humans, there remains a whole battleground yet to be explored."The beautiful thing about vector biology is that it's like a huge puzzle that we're slowly piecing together to understand how it fits into one big picture," Chou says. "Solving this puzzle is an important step toward the longer-term goal of preventing the spread of debilitating diseases like Lyme."This work was supported by the National Institutes of Health, Research Councils UK, the Chan Zuckerberg Biohub, and the Howard Hughes Medical Institute
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Animals
| 2,020 |
December 10, 2020
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https://www.sciencedaily.com/releases/2020/12/201210112046.htm
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Robots could replace real therapy dogs
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Robotic animals could be the 'pawfect' replacement for our real-life furry friends, a new study published today by the University of Portsmouth has found.
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Animals, especially dogs, can have therapeutic benefits for children and young people. A new paper, published in Dr Leanne Proops from the Department of Psychology, who supervised the study said: "We know that real dogs can provide calming and enjoyable interactions for children -- increasing their feelings of wellbeing, improving motivation and reducing stress."This preliminary study has found that biomimetic robots -- robots that mimic animal behaviours -- may be a suitable replacement in certain situations and there are some benefits to using them over a real dog."Dogs are the most commonly used animals for therapy because of their training potential and generally social nature. However, there are concerns about using them in a setting with children because of the risk of triggering allergies or transmitting disease, and some people do not like dogs, so may not be comfortable in the presence of a real therapy dog.Olivia Barber, who owns a therapy dog herself, and is first author of the paper, said: "Although lots of people in schools and hospitals benefit greatly from receiving visits from a therapy dog, we have to be mindful of the welfare of the therapy dog. Visits can be stressful and incredibly tiring for therapy dogs, meaning that we should be exploring whether using a robotic animal is feasible."There are lots of positives to using a robotic animal over a therapy dog. They can be thoroughly cleaned and can work for longer periods of time. They can also be incredibly lifelike, mirroring the movements and behaviour of a real animal, such as wagging their tails to show excitement, expressing "emotions" through sounds and colour, turning their ears towards sounds and even going to sleep.The researchers used real dogs and a biomimetic robot in a mainstream secondary school in West Sussex to interact with 34 children aged 11-12.The two real-life therapy dogs were a three-year-old Jack Russell crossed with a Poodle and a 12-year-old Labrador-retriever from the charity Pets as Therapy. The robot was a MiRo-E biomimetic robot developed by Consequential Robotics.The children were asked to complete a questionnaire about their beliefs and attitudes towards dogs and robots, before they took part in two separate free-play sessions, one with a real-life dog and one with a robot.The researchers found the children spent a similar amount of time stroking both the real-life dog and the robot, but they spent more time interacting with the robot.Despite the children reporting they significantly preferred the session with the living dog, overall enjoyment was high and they actually expressed more positive emotions following interaction with the robot. The more the children attributed mental states and sentience to the dog and robot, the more they enjoyed the sessions.Dr Proops said: "This is a small-scale study, but the results show that interactive robotic animals could be used as a good comparison to live dogs in research, and a useful alternative to traditional animal therapy."
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Animals
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209170706.htm
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Honey bees fend off giant hornets with animal feces
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What's the best way to ward off giant hornets if you're a honeybee? Animal dung, according to a first-ever University of Guelph study.
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U of G researchers have discovered honeybees in Vietnam collect and apply spots of animal dung around hive entrances to deter deadly nest raids by an Asian hornet (This finding is also the first to document the use of tools by honeybees.An invasive species in North America that came originally from Asia, giant hornets are almost as long as a golf tee and pack about seven times as much venom in a single sting as an ordinary honeybee.Murder hornets (V. mandarinia) were discovered in 2019 in British Columbia and Washington. The arrival of the venomous insect to North America has raised concerns about human safety as well as threats to local honeybees and ecosystems.U of G Prof. Gard Otis, who has studied honeybees in Vietnam for decades, said the hornets could ultimately carry out similar honeybee hive raids in North America."Giant hornets are the biggest wasps that threaten honeybees. They are one of their most significant predators," said the environmental sciences professor.Otis conducted the study with lead author Heather Mattila, who completed her PhD at the University of Guelph in 2006 and is now a biology professor at Wellesley College in Massachusetts. Other co-authors were former U of G grad students Hanh Pham and Olivia Knight, as well as Ngoc Pham and Lien Nguyen in Vietnam.Published recently in the journal These two species are the only hornets that recruit nestmates in organized attacks that can lead to nest breaches, said Otis. The hornets raid the nests, killing the bees and carrying away larvae and pupae to feed their own developing brood.The researchers found that honeybees have developed a pre-emptive defence by collecting animal dung and applying it to hive entrances."This study demonstrates a fairly remarkable trait these bees have to defend themselves against a really awful predator," said Mattila.She said unlike their Asian counterparts, honeybees in Canada lack similar defences. That means North American beekeepers would have to rely on destroying the hornets' nests, or hope that climate or other factors will limit the hornets' spread.Referring to Apis mellifera, the honeybee species commonly found in Canada, Mattila said, "They haven't had the opportunity to evolve defences. It's like going into a war cold."Otis began the project after asking beekeepers in Vietnam about dark spots at hive entrances of Asian honeybees. As part of a successful beekeeping development project funded by the Canadian government, he ran fall workshops from 2007 to 2011 in rural villages with high levels of poverty.During one visit, an experienced beekeeper explained that the substance was buffalo dung. All the beekeepers that Otis worked with linked these hive spots with hornets. "Dung collection is a behaviour never previously reported for honeybees, and no one had studied the phenomenon," he said.In 2013, the U of G team received US$25,000 from the National Geographic Society for the study.The researchers gathered dung from water buffalo, chickens, pigs and cows, and placed it in mounds near an apiary. By the end of the day, some 150 bees had visited the piles, particularly collecting more odoriferous manure of pigs and chickens.The team marked individual bees to identify them at their hives. Minutes later, they recorded videos of the marked bees applying the material at nest entrances.The hornets spent less than half as much time at nest entrances with moderate to heavy dung spotting as they did at hives with few spots, and they spent only one-tenth as much time chewing at the hive entrances to get at the bees' brood. They were also less likely to launch mass attacks on the more heavily spotted hives.The researchers are unsure just what deters the hornets, although they suspect the insects are repelled by the smell of the dung. Dung may also mask odours emitted by the bees.To further understand the hornets' behaviours, the researchers extracted the chemical pheromone applied by hornets when marking their target hive. When the pheromone was applied to the bees' entrance, it prompted honeybees to apply dung to the hive.Many scientists disagree over whether certain animals -- let alone insects -- use tools.To qualify as tool users, animals must meet several criteria, including using an object from the environment -- in this case, dung. The bees clearly use the material to alter the hive with purpose, said Otis. And they shape and mould it with their mouth parts, which he said meets the test of holding or manipulating a tool.Beekeepers in Vietnam normally control hornets by standing guard and swatting away individuals, preventing them from escalating their attacks."If you allow them, a group of hornets assembles, attacks the colony and takes over. The beekeepers control them every day by moving among their hives and whacking hornets."Otis said he was terrified at first about working near the giant hornets. The hazmat suits typically worn for protection by researchers in Japan were impracticable in Vietnamese heat, he added. Within a few days, the team learned the hornets were not defensive when they were in the apiary and away from their own nest."I got stung by one and it was the most excruciating sting in my life."
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December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209115149.htm
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Spiders in space: Without gravity, light becomes key to orientation
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Humans have taken spiders into space more than once to study the importance of gravity to their web-building. What originally began as a somewhat unsuccessful PR experiment for high school students has yielded the surprising insight that light plays a larger role in arachnid orientation than previously thought.
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The spider experiment by the US space agency NASA is a lesson in the frustrating failures and happy accidents that sometimes lead to unexpected research findings. The question was relatively simple: on Earth, spiders build asymmetrical webs with the center displaced towards the upper edge. When resting, spiders sit with their head downwards because they can move towards freshly caught prey faster in the direction of gravity.But what do arachnids do in zero gravity? In 2008, NASA wanted to inspire middle schools in the US with this experiment. But even though the question was simple, the planning and execution of the experiment in space was extremely challenging. This led to a number of mishaps.Two specimens from different spider species flew to the International Space Station (ISS) as "arachnauts," one (Metepeira labyrinthea) as the lead and the other (The reserve spider managed to break out of its storage chamber and into the main chamber. The chamber couldn't be opened for safety reasons, so the extra spider could not be recaptured. The two spiders spun somewhat muddled webs, getting in each other's way.And if that were not enough, the flies included as food reproduced more quickly than expected. Over time, their larvae crawled out of the breeding container on the floor of the case into the experimental chamber, and after two weeks covered large parts of the front window. After a month, the spiders could no longer be seen behind all the fly larvae.This failure long nagged at Paula Cushing of the Denver Museum of Nature & Science, who participated in the planning of the spider experiment. When the opportunity for a similar experiment on board the ISS cropped up again in 2011, the researcher got Dr. Samuel Zschokke of the University of Basel involved to prepare and analyze the new attempt. This time, the experiment started with four spiders of the same species (The plan was originally to use four females. But another mishap occurred: the spiders had to be chosen for the experiment as juveniles and it is extremely difficult to determine the sex of juvenile animals. In the course of the experiment, two of the spiders turned out to be males, which differ markedly in body structure and size from females of this species when fully grown. But finally there was a stroke of luck -- one of the males was on board the space station, the other on Earth.The arachnids spun their webs, dismantled them, and spun new ones. Three cameras in each case took pictures every five minutes. Zschokke, Cushing and Stefanie Countryman of the University of Colorado's BioServe Space Technologies that oversaw the design and launch of the space flight certified habitats containing the spiders and fruit fly larvae and camera system to the International Space Station analyzed the symmetry of 100 spider webs and the orientation of the spider in the web using about 14,500 images.It turned out that the webs built in zero gravity were indeed more symmetrical than those spun on Earth. Their center was closer to the middle and the spiders did not always keep their heads downwards. However, the researchers noticed that it made a difference whether the spiders built their webs in lamplight or in the dark. Webs built on the ISS in lamplight were similarly asymmetrical as the terrestrial webs."We wouldn't have guessed that light would play a role in orienting the spiders in space," says Zschokke, who analyzed the spider experiment and published the results with his colleagues in the journal Analysis of the pictures also showed that the spiders rested in arbitrary orientations in their webs when the lights were turned off, but oriented themselves away -- i.e. downwards -- when the lights were on. It seems spiders use light as an additional orientation aid when gravity is absent. Since spiders also build their webs in the dark and can catch prey without light, it had previously been assumed that light plays no role in their orientation."That spiders have a back-up system for orientation like this seems surprising, since they have never been exposed to an environment without gravity in the course of their evolution," says Zschokke. On the other hand, he says, a spider's sense of position could become confused while it is building its web. The organ responsible for this sense registers the relative position of the front part of the body to the back. During construction of the web, the two body parts are in constant motion, so an additional orientation aid based on the direction of the light is particularly useful.Video:
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December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209094231.htm
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The use of wild mammals in traditional medicine
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In an analysis of published research, investigators identified 565 mammalian species that have been used to source products used in traditional medicine around the world, especially in Asia, Africa, and Latin America. The analysis, which is published in
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The findings suggesting that overexploitation for medicinal use could be an overlooked source of threat for mammalian species."Our study revealed that an impressive mammalian species richness -- 9% of the 6,399 known species -- is used in traditional medical systems worldwide. We also highlight that closely related species are used to treat similar diseases," said lead author Rômulo Romeu Nóbrega Alves, PhD, of the Universidade Estadual da Paraíba, in Brazil. "The widespread utilization of mammals in traditional medicine (including threatened species) is evidence of the importance of understanding such uses in the context of mammal conservation. Sanitary aspects of the use of wild mammals by humans, and their implications for public health, are also key aspects to consider."
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December 7, 2020
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https://www.sciencedaily.com/releases/2020/12/201207195126.htm
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Scientists discover how COVID-19 virus causes multiple organ failure in mice
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UCLA researchers are the first to create a version of COVID-19 in mice that shows how the disease damages organs other than the lungs. Using their model, the scientists discovered that the SARS-CoV-2 virus can shut down energy production in cells of the heart, kidneys, spleen and other organs.
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"This mouse model is a really powerful tool for studying SARS-CoV-2 in a living system," said Dr. Arjun Deb, a co-senior author of a paper about the study and a member of the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA. "Understanding how this virus can hijack our cells might eventually lead to new ways to prevent or treat the organ failure that can accompany COVID-19 in humans."Deb said the same model could also help researchers learn more about other similar viruses that might emerge in the future, and it could be useful for testing eventual treatments.The paper, published in the journal Researchers often study mice to understand the fundamentals of human disease, but translating human health conditions to animal models can be tricky. SARS-CoV-2, for instance, relies on the ACE2 protein to infect humans. But the virus doesn't recognize the mouse version of ACE2, so healthy mice exposed to the SARS-CoV-2 virus don't get sick.In previous experiments by other research teams around the world, mice have been genetically engineered to have the human version of ACE2 in their lungs and then been infected -- through their noses -- with the SARS-CoV-2 virus. Although that enables the virus to infect the mice and cause pneumonia, animals in those experiments don't get as broad a range of other symptoms as humans do."Among COVID-19 patients, those who have organs involved other than the lungs are most at risk of a bad outcome," said Deb, who is also a cardiologist and professor of molecular cell and developmental biology. "So we felt it was really important to understand how the virus affects those other organs."Research in humans has suggested that SARS-CoV-2 can circulate through the bloodstream to reach multiple organs. So in the UCLA experiment, the researchers first engineered mice to have the human version of ACE2 in the heart and other vital organs. Then, they infected half of the animals by injecting SARS-CoV-2 into their bloodstreams. Over the following days, the researchers tracked the animals' overall health and analyzed how levels of certain genes and proteins in their bodies changed.Within seven days, all of the mice with COVID-19 had stopped eating and were completely inactive, and had lost, on average, about 20% of their body weight. Animals that had been engineered to carry the human ACE2 protein but had not been infected with the virus, on the other hand, did not lose a significant amount of weight.Moreover, the COVID-19 infected animals had altered levels of immune cells, swelling of the heart tissue and wasting away of the spleen -- all symptoms that have been observed in people who are critically ill with COVID-19.Deb's team also looked at which genes were turned on and off in the mice infected with SARS-CoV-2, and they discovered other signs of disease. Common molecular processes that help cells generate energy -- through mechanisms known as the tricarboxylic acid cycle, or TCA cycle, and electron transport chain -- were shut off in the heart, kidney, spleen and lungs."If a virus snuffs out the energy-generating pathways in multiple organs of the body, that's going to really wreak havoc," Deb said.Finally, the study also revealed that some changes were long-lasting throughout the organs in mice with COVID-19. In addition to temporarily altering which genes were turned on and off in some cells, the virus made epigenetic changes -- chemical alterations to the structure of DNA that cause more lasting effects. Deb said that could explain why, in some people with COVID-19, symptoms persist for weeks or months after their bodies are rid of the virus.Although the findings don't have immediate implications for treating COVID-19, Deb said the mouse model will be useful for ongoing studies on how the virus infects vital organs other than the lungs, and for trials of new drugs to treat the disease.The research was supported by the National Institutes of Health, the California Institute for Regenerative Medicine and two UCLA David Geffen School of Medicine-Broad Stem Cell Research Center COVID-19 research awards.
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December 7, 2020
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https://www.sciencedaily.com/releases/2020/12/201207161528.htm
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I see you: Honey bees use contagious and honest visual signal to deter attacking hornets
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An Asian hornet sets its sights on a busy honey bee hive. If all goes according to plan, the hornet's attack will result in a haul of bee larvae, precious nourishment to pilfer and feed to its own hornet young.
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But over time, predator-prey evolution has equipped some honey bees with a potent defense mechanism against such an attack. A signal from colony guard bees lets hornets know that their attack plans have been exposed, and also sends an alarm across the bee colony communicating that urgent reinforcements are needed due to the impending danger. This "I see you" (ISY) visual signal involves guard bees shaking their abdomens laterally and increases as the threat intensifies.Hornets are ferocious bee predators that have invaded multiple countries around the world. Yet even the giant "murder" hornets that have generated much concern of late have come to recognize the ISY signal as a warning to back off. They are well aware that ISY can lead to a counter attack in which a mass of bees surrounds the hornet, forming a "heat ball" with a deadly mix of heat, carbon dioxide and stinging for the hornet inside.University of California San Diego biologists studying Asian honey bees (Apis cerana) and hornets (Vespa velutina) have produced new research that deconstructs this ISY signal and shows for the first time that it is visually driven and contagious across the bee colony. The findings are described Dec. 7, 2020 in the "The beauty of the ISY signal is that hornets are only deterred if enough defending bees quickly gather to synchronously produce the signal, thereby showing the hornet that further attack is futile," said study senior author James Nieh, a professor in the Section of Ecology, Behavior and Evolution in UC San Diego's Division of Biological Sciences.But how to gather this defense? Nieh says the ISY signal is contagious and attracts other defenders who immediately copy the signal and rush towards the signaler, even if they cannot directly see or sense the predator."Hornets give off smell and sound but we found that the visual of a hornet alone can elicit the signal, which was not known," said Nieh. Previous speculation held that guard bees might produce a pheromone to alert others in the colony of the impending danger. "Using just a contagious visual signal is better because guards who are too far away to smell or hear the hornet can immediately head towards the threat. In some ways, it's like a fast chain reaction," said Nieh.Nieh says the concept links to the issue of "fake news" since animal communication often contains errors, and a false ISY alarm could rapidly spread within the colony.One solution to the problem of false information spread is that the bees are very selective about what they consider a true threat. Using an iPad to display videos, researchers Shihao Dong, Ken Tan and Nieh found that the visual appearance and motion of the hornet alone could trigger ISY signals. Visual displays of a harmless butterfly, on the other hand, elicited no response. The second and most important safeguard against false reporting is that bees are even more choosy about what they consider to be a real ISY signal."We played back videos of bees performing ISY signals at different speeds, but only the correct bee image at the right speed caused other bees to respond. This helps keep the signal spread honest," said Nieh.It is still true that a bee could occasionally "cry wolf" but Nieh thinks that evolution has limited these errors because nestmates must work together to fight these powerful predators and colonies prone to errors would suffer. Nieh and his colleagues are now testing the details of the visual cues behind ISY. They are developing animations that display related visuals that can be tested, such as whether a harmless butterfly can be depicted as threatening, or whether offshoots such as a hornet displayed without wings could be enough to trigger ISY.Nieh believes that the findings provide a cautionary tale about fake news for all of us."Individuals in a honey bee colony are completely interdependent. They can't go out and make it on their own. Cooperation is paramount, especially when faced with a large, heavily armored predator like hornets," said Nieh. "A couple of hornets can kill thousands of bees in a single day. Yet through teamwork that correctly produces synchronized, massed ISY signals, they can get the hornet to back off without harming a single bee. Maybe that's a lesson for us all."
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December 7, 2020
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https://www.sciencedaily.com/releases/2020/12/201207150450.htm
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Remote Hawaiian island harbors last land snails of their kind
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The island of Nihoa, a slice of jagged rock that juts out of the Pacific Ocean, is the sole refuge for a rediscovered species of native Hawaiian land snail previously presumed to be extinct.
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First recorded in 1923, Endodonta christenseni lacked a scientific name and description until now. It is likely the last remaining species in the Endodonta genus. The other 11 species were collected and described more than 100 years ago and today are known only from museum specimens. A team of researchers from the Bishop Museum and the Florida Museum of Natural History found the snail during a survey of more than 1,000 sites across the Hawaiian Islands.Now the scientists warn that, without protections, the species could vanish within a decade, erasing a lineage that existed for millions of years and the stories it could tell. Giving E. christenseni a name is an essential first step to conserving its remaining population, the researchers said."This sort of work forms the foundation for all conservation efforts," said lead author Kenneth Hayes, director of the Bishop Museum's Pacific Center for Molecular Biodiversity, in a statement. "The gap in knowledge about biodiversity, which is especially severe for understudied and highly threatened groups like snails and insects, prevents effective research needed to inform conservation actions."Land snails in the Pacific islands have suffered more recorded extinctions in the last 400 years than any other group of animals, with declining numbers linked to habitat destruction, invasive predators and climate change. While Hawaii has lost more than half of its land snail species -- once more than 750 species strong -- researchers have recorded nearly 300 species widely assumed to have vanished long ago, including E. christenseni."The results from these extensive survey efforts give us hope that there are still many species left that can be saved," said Norine Yeung, malacology curator at the Bishop Museum and a co-principal investigator of the study. "But we need to act quickly and decisively if we are to beat the extinction clock that ticks louder with each passing day."Museum records -- ranging from the first collection of E. christenseni in 1923 to specimens dating to 1990 -- enabled the team to perform targeted searches on Nihoa to see if the snail still existed, said John Slapcinsky, manager of the Florida Museum's invertebrate zoology collection."Having those museum specimens allowed us to target specific areas and find these things again. Everything depends on prior knowledge," he said.Slapcinsky attributed the long gap between 1923 and the species description published this year to the scarcity of taxonomists who study land snails.E. christenseni is about the size of a pea and has tigerlike stripes. A ground dweller, it relies on the tussocks of variable lovegrass, another native Hawaiian species, for moisture and sustenance. Slapcinsky said it likely lives and reproduces in the "wonderful little habitat" in the plant's moist center, feeding on fungal films that develop on dead blades of grass.But the snail's decline is also linked to its highly specialized lifestyle. Many lowland grass habitats in Hawaii have been replaced by exotic vegetation, and invasive species such as ants and rats are more prevalent in low-lying areas than at high altitudes. Although Nihoa is uninhabited, with visitation highly restricted by the U.S. Fish and Wildlife Service, the researchers said it remains vulnerable to human disturbances -- threats only amplified by the island's small size, where habitat disturbances can have long-term consequences.Slapcinsky said the species has yet to recolonize two-thirds of the island ravaged by an out-of-control campfire in 1885. A network of factors -- including exceptionally limited mobility, habitat specificity and slow reproduction -- has likely prevented E. christenseni from re-expanding its range, he said.The team hopes to incorporate the new species into the Hawaii Department of Land and Natural Resources' Snail Extinction Prevention Program, through which captive breeding can help researchers measure species resilience in the wild. Although DNA samples from E. christenseni and related species will help the researchers trace its evolutionary relationships, a living population will enable them to answer key ecological questions about reproduction, diet and lifecycle, all of which can help inform species recovery plans, Slapcinsky said.He added that rediscovering land snail populations is shedding light on how they can be conserved, signaling that not all is lost for the group."The picture is going from one that was really miserable and hopeless to one that's a little less miserable, but hopeful," he said. "In the recent past, things looked so bad that we were thinking pretty much everything's gone. There wasn't a lot of effort into conservation of many of the land snails, so by doing these surveys and finding some of these species that are still there, we have the ability now to save whole lineages."The name E. christenseni honors Bishop Museum scientist Carl Christensen, an expert on Pacific island land snails and an advocate for their conservation.The study was published in David Sischo of the Snail Extinction Prevention Program and the Bishop Museum's Jaynee Kim also co-authored the study.
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December 3, 2020
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https://www.sciencedaily.com/releases/2020/12/201203144009.htm
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3D protein modeling suggests why COVID-19 infects some animals, but not others
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Some animals are more susceptible to Covid-19 infection than others, and new research suggests this may be due to distinctive structural features of a protein found on the surface of animal cells. João Rodrigues of Stanford University, California, and colleagues present these findings in the open-access journal
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Previous research suggests that the current pandemic began when the virus that causes Covid-19, SARS-CoV-2, jumped from bats or pangolins to humans. Certain other animals, such as cattle and cats, appear to be susceptible to Covid-19, while others, such as pigs and chickens, are not. One zoo even reported infections in tigers. However, it was unclear why some animals are immune and others are not.To address this question, Rodrigues and colleagues looked for clues in the first step of infection, when SARS-CoV-2's "spike" protein binds to an "ACE2" receptor protein on the surface of an animal cell. They used computers to simulate the proteins' 3D structures and investigate how the spike protein interacts with different animals' ACE2 receptors -- similar to checking which locks fit a certain key.The researchers found that certain animals' ACE2 "locks" fit the viral "key" better, and that these animals, including humans, are susceptible to infection. Despite being approximations, the simulations pinpointed certain structural features unique to the ACE2 receptors of these susceptible species. The analysis suggest that other species are immune because their ACE2 receptors lack these features, leading to weaker interactions with spike proteins.These findings could aid development of antiviral strategies that use artificial "locks" to trap the virus and prevent it from interacting with human receptors. They could also help improve models to monitor animal hosts from which a virus could potentially jump to humans, ultimately preventing future outbreaks."Thanks to open-access data, preprints, and freely available academic software, we went from wondering if tigers could catch Covid-19 to having 3D models of protein structures offering a possible explanation as to why that is the case in just a few weeks," Rodrigues says.His team plans to continue refining the computational tools used in this study.
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Animals
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December 3, 2020
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https://www.sciencedaily.com/releases/2020/12/201203133915.htm
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Flightless bird species at risk of extinction
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Bird species that have lost the ability to fly through evolution have become extinct more often than birds that have retained their ability to fly, according to new research from the University of Gothenburg.
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Today, we know that human influence on the environment has caused large numbers of plants and animals to die out. Human impact has fundamentally changed ecosystems and, globally, has driven hundreds of animal species to extinction.One of the consequences of this is that biological pattens have become distorted. This, in turn, means that researchers have a harder time interpreting current data on species diversity, i.e. variations of species within an ecosystem or area."Studying human-caused species extinction can influence our understanding of evolution and help us to better understand the loss of species not caused by chance," says Søren Faurby, senior author behind the new study and a researcher at the University of Gothenburg.Together with his research colleagues, he has studied a larger evolutionary transition: the development of flightlessness among birds. For the first time, a study of this transition includes data from all known flightless species driven to extinction by humans."We have found that, in many cases, the extinctions have had anthropogenic origins, which are effects that can be traced back to human activities.Birds that have lost their ability to fly are a more common phenomenon than research has assumed up until now, according to the study. These species have then been impacted by human activities."Many bird species can develop flightlessness in environments without large predators, such as on islands, but they also become easier prey for both humans and animals, such as rats and cats," says Ferran Sayol, the lead author behind this study and previously a post-doctoral researcher at the University of Gothenburg.The researchers have compiled a list of 581 bird species from 85 different families that have gone extinct during the past 126,000 years."Based on morphological descriptions, we have determined that 166 of these species lacked the ability to fly. This is equivalent to 29 per cent of the extinct bird species. Currently, there are only 60 living flightless bird species. If we add the 166 species that have gone extinct, this totals 226 both existing and extinct flightless bird species."The study shows that by adding these extinct birds to the global picture of bird diversity, it becomes clear that flightlessness developed at least four times as often as if the researchers only looked at living species."We show that the development of flightlessness in birds is a widespread phenomenon. If humans had not caused some of these extinctions, we would still share the planet with more than 150 independently developed flightless groups of birds. Unfortunately, only 60[Accent1] of these remain," says Ferran Sayol.
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December 3, 2020
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https://www.sciencedaily.com/releases/2020/12/201203133908.htm
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Oral drug blocks SARS-CoV-2 transmission, researchers find
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Treatment of SARS-CoV-2 infection with a new antiviral drug, MK-4482/EIDD-2801 or Molnupiravir, completely suppresses virus transmission within 24 hours, researchers in the Institute for Biomedical Sciences at Georgia State University have discovered.
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The group led by Dr. Richard Plemper, Distinguished University Professor at Georgia State, originally discovered that the drug is potent against influenza viruses."This is the first demonstration of an orally available drug to rapidly block SARS-CoV-2 transmission," said Plemper. "MK-4482/EIDD-2801 could be game-changing."Interrupting widespread community transmission of SARS-CoV-2 until mass vaccination is available is paramount to managing COVID-19 and mitigating the catastrophic consequences of the pandemic.Because the drug can be taken by mouth, treatment can be started early for a potentially three-fold benefit: inhibit patients' progress to severe disease, shorten the infectious phase to ease the emotional and socioeconomic toll of prolonged patient isolation and rapidly silence local outbreaks."We noted early on that MK-4482/EIDD-2801 has broad-spectrum activity against respiratory RNA viruses and that treating infected animals by mouth with the drug lowers the amount of shed viral particles by several orders of magnitude, dramatically reducing transmission," said Plemper. "These properties made MK-4482/EIDD/2801 a powerful candidate for pharmacologic control of COVID-19."In the study published in "We believe ferrets are a relevant transmission model because they readily spread SARS-CoV-2, but mostly do not develop severe disease, which closely resembles SARS-CoV-2 spread in young adults," said Dr. Robert Cox, a postdoctoral fellow in the Plemper group and a co-lead author of the study.The researchers infected ferrets with SARS-CoV-2 and initiated treatment with MK-4482/EIDD-2801 when the animals started to shed virus from the nose."When we co-housed those infected and then treated source animals with untreated contact ferrets in the same cage, none of the contacts became infected," said Josef Wolf, a doctoral student in the Plemper lab and co-lead author of the study. By comparison, all contacts of source ferrets that had received placebo became infected.If these ferret-based data translate to humans, COVID-19 patients treated with the drug could become non-infectious within 24 hours after the beginning of treatment.MK-4482/EIDD-2801 is in advanced phase II/III clinical trials against SARS-CoV-2 infection.Co-authors of the study include R.M. Cox, J.D. Wolf and R.K. Plemper at Georgia State.The study was funded by public health service grants from the National Institutes of Health/National Institute of Allergy and Infectious Diseases to Georgia State.
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December 3, 2020
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https://www.sciencedaily.com/releases/2020/12/201203133904.htm
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What makes certain groups more vulnerable to COVID-19?
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What makes the elderly and people with underlying conditions more vulnerable to COVID-19? According to a new study led by McGill University researchers, clues can be found in the proteins involved in initiating infection, as the virus binds to host cells of different animals. Greater cellular oxidation with aging and sickness may explain why seniors and people with chronic illness get infected more often and more severely.
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Over 60 million people have been infected and around 1.5 million have died from COVID-19. The virus is disrupting economies and food supply chains all over the world. Understanding why some animals get infected and others do not could be the key to unlocking new treatments and therapies. In a study published in Computational and Structural Biotechnology Journal, researchers analyzed available protein sequences of the virus and host cell receptors across different spices to find out why."We know that the virus can infect humans, cats, dogs and ferrets but not bovine and swine. Also, COVID-19 hits the elderly and people with underlying conditions more severely than the young and healthy ones. Until now reasons for this were unclear," says McGill Professor Jaswinder Singh.The research was conducted by a multidisciplinary team of scientists led by Professor Singh. The team includes Professor Rajinder Dhindsa (McGill University), Professor Baljit Singh (University of Calgary) and Professor Vikram Misra (University of Saskatchewan).Once inside a host cell, the virus hijacks the cell's metabolic machinery to replicate and spread. The virus's protein spikes attach to a protein receptor on the surface of the host cell called ACE2, fusing the membranes around the cell and the virus together. This process allows the virus to enter the cell and co-opt its protein-making machinery to make new copies of itself. The copies then go on to infect other healthy cells.In analyzing the proteins and their amino acid building blocks, the researchers found that animals susceptible to the virus have a few things in common. Such animals like humans, cats, and dogs have two cysteine amino acids that form a special disulfide bond held together by an oxidizing cellular environment. This disulfide bond creates an anchor for the virus. "Our analysis suggests that greater cellular oxidation in the elderly or those with underlying health conditions could predispose them to more vigorous infection, replication and disease," says co-author Rajinder Dhindsa, an emeritus professor of biology at McGill University.In the case of animals resistant to the virus, like pigs and cows, one of these two cysteine amino acids is missing, and the disulfide bond cannot be formed. As a result, the virus cannot anchor on to the cell.According to the researchers, preventing the anchor from forming could be the key to unlocking new treatments for COVID-19. One strategy, they suggest, could be to disrupt the oxidizing environment that keeps the disulfide bonds intact. "Antioxidants could decrease the severity of COVID-19 by interfering with entry of the virus into host cells and its survival afterwards in establishing further infection," says Professor Singh.In terms of next steps, the researchers say CRISPR technology could be used to edit protein sequences and test out their theory. The researchers are also looking into other proteins near the ACE2 receptor that may facilitate entry of the virus to see if they behave the same way.
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Animals
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December 3, 2020
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https://www.sciencedaily.com/releases/2020/12/201203133900.htm
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Development of new stem cell type may lead to advances in regenerative medicine
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A team led by UT Southwestern has derived a new "intermediate" embryonic stem cell type from multiple species that can contribute to chimeras and create precursors to sperm and eggs in a culture dish.
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The findings, published online this week in Cells in early embryos have a range of distinct pluripotency programs, all of which endow the cells to create various tissue types in the body, explains study leader Jun Wu, Ph.D., assistant professor of molecular biology. A wealth of previous research has focused on developing and characterizing "naïve" embryonic stem cells (those about four days post-fertilization in mice) and "primed" epiblast stem cells (about seven days post-fertilization in mice, shortly after the embryo implants into the uterus).However, says Wu, there's been little progress in deriving and characterizing pluripotent stem cells (PSCs) that exist between these two stages -- largely because researchers have not been able to develop a paradigm for maintaining cells in this intermediate state. Cells in this state have been thought to possess unique properties: the ability to contribute to intraspecies chimeras (organisms that contain a mix of cells from different individuals of the same species) or interspecies chimeras (organisms that contain a mix of cells from different species) and the ability to differentiate into primordial germ cells in culture, the precursors to sperm and eggs.For this study, the researchers successfully created intermediate PSCs, which they named "XPSCs" from mice, horses, and humans.Wu says that these results could eventually lead to an array of advances in both basic and applied research. For example, looking at gene activity in XPSCs from different species and interspecies chimeras could help researchers understand which signatures have been conserved through evolution. Examining the communication between cells in chimeras may help scientists identify strategies that could be used to accelerate the development of tissues and organs from stem cells used for transplantation. And using chimera-derived primordial germ cells to create sperm and eggs could aid in preserving endangered animal species and advancing infertility treatments."These XPSCs have enormous potential. Our study helps open the door to each of these possibilities," says Wu, who is a Virginia Murchison Linthicum Scholar in Medical Research.Wu notes that developing XPSCs presented a special challenge because the conditions that keep naïve PSCs in a stable state are exactly the opposite from those that stabilize primed PSCs. While culture conditions for naïve PSCs must activate a WNT cell-signaling pathway and suppress the FGF and TGF-ß pathways, the conditions to maintain primed PSCs must suppress WNT and activate FGF and TGF-ß.Aiming for the preferred environment for XPSC derivation, Wu and his colleagues placed cells from early mouse embryos into cultures containing chemicals and growth factors that activate all three pathways. These lab-grown cells were extremely stable in culture and able to multiply without developing any further for approximately two years.Additional experiments showed that these cells met the expectations researchers have long strived to meet of contributing to chimeras and directly differentiating into primordial germ cells. Wu and his colleagues made intraspecies chimeras of mice using cells derived from mice with different coat colors by injecting the cells into early mouse embryos. They also tracked the contributions of the XPSCs by tagging the cells with a fluorescent protein and then identifying them throughout the resulting offspring's body.Wu's team made interspecies chimeras by injecting horse XPSCs into early mouse embryos and allowing the embryos to develop in mice for several days. Surprisingly, although horses have a comparatively long gestational period -- nearly a year -- the researchers found that these foreign cells had contributed to mouse organ development, indicating that signals from the mouse cells determine organ developmental timelines.Like XPSCs from other species, the human cells showed that they were capable of differentiating into a variety of tissues if culture conditions allowed them to progress in development, as well as directly form primordial germ cells in a dish.
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Animals
| 2,020 |
December 3, 2020
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https://www.sciencedaily.com/releases/2020/12/201203113234.htm
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Pilot whale study reveals copycat calls to outsmart predators
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New Curtin University research has found southern Australian long-finned pilot whales are able to mimic the calls of its natural predator and food rival -- the killer whale, as a possible ploy to outsmart it.
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The study is the first published research analysing the calls of long-finned pilot whales in the Southern Hemisphere, which were recorded in the Great Australian Bight, off WA and SA, between 2013 and 2017.The research, published in Scientific Reports, also found evidence of 'duetting', which is common in birds and primates but very rarely reported in aquatic mammals, and which suggests the whale's sophisticated acoustic communication system is more complex than previously thought.Lead author Rachael Courts from Curtin's Centre for Marine Science and Technology said the study of long-finned pilot whales off southern Australia showed what appeared to be mimicry of a call of the Australian killer whale."This mimicry may be a clever strategy employed by the whales in order to disguise themselves from predators including killer whales. It may also allow them to scavenge food remnants from killer whales, undetected," Ms Courts said."Duetting refers to coordinated and patterned singing by two animals and is related to social bonding and coordination of behaviour."Some long-finned pilot whale calls were found to be remarkably similar to those of the same species in the Northern Hemisphere, which is surprising as non-equatorial aquatic mammals such as these are not expected to cross the equator for large-scale migrations, meaning the last contact the two hemispheres' populations could have had would have been more than 10,000 years ago."Our findings therefore raise the question of how far these two populations' home ranges really extend and now that we have some of their call repertoire documented, we can monitor home ranges with remote underwater sound recorders such as those used by many countries, including Australia."Professor Christine Erbe, Director of Curtin's Centre for Marine Science and Technology, said the research was not only the first to be published on the calls of long-finned pilot whales off southern Australia but also the first in the entire Southern Hemisphere. Previous studies have only focussed on waters off the US, Canada and Europe."Our research discovered three unique vocalisations recorded from southern Australian long-finned pilot whales, which have not been reported for the species," Professor Erbe said."These were very complex multi-component calls much like killer whale calls, but given this is the first southern hemisphere study, we don't know how common the calls might be in other Southern Hemisphere pilot whales. This aspect could be the focus of future research."
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Animals
| 2,020 |
December 3, 2020
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https://www.sciencedaily.com/releases/2020/12/201203173446.htm
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What's killing killer whales?
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Pathology reports on more than 50 killer whales stranded over nearly a decade in the northeast Pacific and Hawaii show that orcas face a variety of mortal threats -- many stemming from human interactions.
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A study analyzing the reports was published today in the journal The study was conducted by a team of marine mammal and orca specialists led by the British Columbia Ministry of Agriculture and coordinated through the SeaDoc Society, a Washington-based program of the University of California, Davis' School of Veterinary Medicine. The lead author, Dr Stephen Raverty, and coauthor, Dr John Ford, are adjunct professions at the University of British Columbia Institute of Oceans and Fisheries and Department of Zoology, respectively.The whales include those from healthy populations as well as endangered species, such as the southern resident whales regularly sighted off the coasts of British Columbia, Washington and Oregon.Of 52 whales stranded between 2004 and 2013, causes of death were determined for 42 percent. For example, one calf died from sepsis following a halibut hook injury. Another starved from a congenital facial deformity. Two whales died from the blunt force trauma of vessel strikes. Additional causes of death include infectious disease and nutritional deficiencies.Despite there being no singular common cause of death, the study found a common theme: Human-caused deaths occurred in every age class -- from juveniles to subadults and adults."In British Columbia, we lost nine southern resident killer whales: 2 adults, 2 subadults and 1 calf died from trauma; one was a confirmed propeller strike, with one adult and two subadults from suspected ship strikes," said lead author Stephen Raverty, a veterinarian pathologist with the BC Ministry of Agriculture and adjunct professor at UBC's Institute for the Oceans and Fisheries. "One of these iconic species passed away from an infection secondary to satellite tagging. Another death was due to natural causes and the other two undetermined. Half of the southern killer whale deaths identified in this study were caused by human interactions.""Nobody likes to think we're directly harming animals," said co-author and SeaDoc Society Director Joe Gaydos, a wildlife veterinarian with the Karen C. Drayer Wildlife Health Center in the UC Davis School of Veterinary Medicine. "But it's important to realize that we're not just indirectly hurting them from things like lack of salmon, vessel disturbance or legacy toxins. It's also vessel strikes and fish hooks. That humans are directly killing killer whales across all age classes is significant; it says we can do a better job."In 2004, Raverty and Graydos co-developed a standardized killer whale necropsy protocol. Revised in 2014 with help from Judy St. Leger, a pathologist working for SeaWorld, this guide helped improve examinations of deceased whales."The results from systematic necropsies of dead killer whales in this review is unique and will establish critical baseline information to assess future mitigation efforts," Raverty said. "This work contributes to a better understanding of the impacts that ongoing human activities and environmental events have on killer whales."The authors acknowledge the report is an incomplete picture of orca health and mortality. Necropsies can only be performed on whales found in an adequate state to receive them, and even then, the cause of death cannot always be determined. But the report offers one of the most comprehensive looks yet at the multitude of human and environmental threats affecting killer whales and can help inform strategies to better protect them.
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Animals
| 2,020 |
December 2, 2020
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https://www.sciencedaily.com/releases/2020/12/201202192742.htm
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Amphibian die-offs worsened malaria outbreaks in Central America
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The global collapse of frogs and other amphibians due to the amphibian chytrid fungus exacerbated malaria outbreaks in Costa Rica and Panama during the 1990s and 2000s, according to new research.
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The findings provide the first evidence that amphibian population declines have directly affected human health and show how preserving biodiversity can benefit humans as well as local ecosystems."This is like a small building block showing that there could be unwanted human health consequences of amphibian collapses, and so we should really be trying to account for these impacts," said Joakim Weill, an environmental economist at the University of California Davis who will present the results Tuesday, 8 December at AGU's Fall Meeting 2020. "We really view this as an important first step leveraging this type of interdisciplinary work, trying to tease out causal relationship between environmental change and human health."The global spread of Batrachochytrium dendrobatidis, an extremely virulent fungal pathogen known as amphibian chytrid fungus, has been responsible for massive worldwide die-offs of amphibians since the 1980s. A 2019 study found the fungal disease has played a role in the decline of over 500 amphibian species over the past five decades and presumably caused extinctions of 90 species. The authors of that study referred to the die-offs as "the greatest recorded loss of biodiversity attributable to a disease."Chytrid fungal disease traveled across Costa Rica and Panama from the early 1980s through the 2000s. Both countries experienced large increases in malaria cases following this rolling collapse of amphibian populations.In the new study, researchers investigated whether these malaria outbreaks were connected to the amphibian declines because amphibians eat mosquitoes that transmit the disease. They compared the timing and spatial extent of amphibian die-offs with malaria cases in Costa Rica and Panama at the county level from 1976 to 2016.The researchers found a significant increase in malaria cases in these countries that started immediately after the amphibian die-offs began and peaked 5 to 6 years after. In 1980, there were fewer than 1,000 cases of malaria in the two countries, but cases began to rise in 1990 and peaked at about 7,000 in Costa Rica in the mid-1990s and 5,000 in Panama in the mid-2000s.Malaria cases went back down after this peak, and the researchers suspect this is due to local public health interventions like spraying of insecticides.The results show some of the first evidence that species extinctions and biodiversity loss can directly affect human health, according to the researchers.Other environmental factors like deforestation also played a role in exacerbating the outbreaks, but no other factor had as much of an impact on malaria cases as the amphibian declines, according to the study."We are able to find what really seems to be this striking causal relationship between amphibian declines and malaria," Weill said. "It's pretty incredible that we are finding anything in the first place, because these are events that occurred 40 years ago and the right people were in the right place to make observations about amphibian populations and human disease that we can use today to arrive at new insights."
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Animals
| 2,020 |
December 2, 2020
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https://www.sciencedaily.com/releases/2020/12/201202192704.htm
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Incredible vision in ancient marine creatures drove an evolutionary arms race
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Ancient deep sea creatures called radiodonts had incredible vision that likely drove an evolutionary arms race according to new research published today.
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The international study, led by Professor John Paterson from the University of New England's Palaeoscience Research Centre, in collaboration with the University of Adelaide, the South Australian Museum and The Natural History Museum (UK), found that radiodonts developed sophisticated eyes over 500 million years ago, with some adapted to the dim light of deep water."Our study provides critical new information about the evolution of the earliest marine animal ecosystems," Professor Paterson said. "In particular, it supports the idea that vision played a crucial role during the Cambrian Explosion, a pivotal phase in history when most major animal groups first appeared during a rapid burst of evolution over half a billion years ago."Radiodonts, meaning "radiating teeth," are a group of arthropods that dominated the oceans around 500 million years ago. The many species share a similar body layout comprising of a head with a pair of large, segmented appendages for capturing prey, a circular mouth with serrated teeth, and a squid-like body. It now seems likely that some lived at depths down to 1000 metres and had developed large, complex eyes to compensate for the lack of light in this extreme environment."When complex visual systems arose, animals could better sense their surroundings," Professor Paterson explained. "That may have fuelled an evolutionary arms race between predators and prey. Once established, vision became a driving force in evolution and helped shape the biodiversity and ecological interactions we see today."Some of the first radiodont fossils discovered over a century ago were isolated body parts, and initial attempts at reconstructions resulted in "Frankenstein's monsters."But over the past few decades many new discoveries -- including whole radiodont bodies -- have given a clearer picture of their anatomy, diversity and possible lifestyles.Co-author, Associate Professor Diego García-Bellido from the University of Adelaide and South Australian Museum, said the rich treasure trove of fossils at Emu Bay Shale on South Australia's Kangaroo Island in particular has helped to build a clearer picture of Earth's earliest animals."The Emu Bay Shale is the only place in the world that preserves eyes with lenses of Cambrian radiodonts. The more than thirty specimens of eyes we now have, has shed new light on the ecology, behaviour and evolution of these, the largest animals alive half-a-billion years ago," A/Prof. García-Bellido said.In 2011, the team published two papers in the journal Nature on fossil compound eyes from the 513-million-year-old Emu Bay Shale on Kangaroo Island.The first paper on this subject documented isolated eye specimens of up to one centimetre in diameter, but the team were unable to assign them to a known arthropod species. The second paper reported the stalked eyes of Anomalocaris, a top predator up to one metre in length, in great detail."Our new study identifies the owner of the eyes from our first 2011 paper: 'Anomalocaris' briggsi -- representing a new genus that is yet to be formally named," Prof. Paterson said."We discovered much larger specimens of these eyes of up to four centimetres in diameter that possess a distinctive 'acute zone', which is a region of enlarged lenses in the centre of the eye's surface that enhances light capture and resolution."The large lenses of 'Anomalocaris' briggsi suggest that it could see in very dim light at depth, similar to amphipod crustaceans, a type of prawn-like creature that exists today. The frilly spines on its appendages filtered plankton that it detected by looking upwards.Dr Greg Edgecombe, a researcher at The Natural History Museum, London and co-author of the study, added that the South Australian radiodonts show the different feeding strategies previously indicated by the appendages -- either for capturing or filtering prey -- are paralleled by differences in the eyes."The predator has the eyes attached to the head on stalks but the filter feeder has them at the surface of the head. The more we learn about these animals the more diverse their body plan and ecology is turning out to be," Dr Edgecombe said."The new samples also show how the eyes changed as the animal grew. The lenses formed at the margin of the eyes, growing bigger and increasing in numbers in large specimens -- just as in many living arthropods. The way compound eyes grow has been consistent for more than 500 million years."
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Animals
| 2,020 |
December 1, 2020
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https://www.sciencedaily.com/releases/2020/12/201201144046.htm
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False widow spiders bite can transmit harmful antibiotic-resistant bacteria
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A team of zoologists and microbiologists from NUI Galway have published a new study showing that common house spiders carry bacteria susceptible to infect people, with the Noble False Widow spiders also carrying harmful strains resistant to common antibiotic treatments.
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This new research, published in the international journal Australian Black Widows or Funnel Web spiders are well known for their potentially deadly venom, but rare "skin-eating" conditions following seemingly harmless European and North American spider bites were thought to be the result of secondary infections caused by the victim scratching and probing the bite site with contaminated fingers. This new study shows that not only do spiders carry harmful bacteria, but those germs can be transmitted when a spider uses its fangs to bite.Furthermore, many spiders have been shown to have venom with antibacterial activity and it is often debated as to whether the venom would neutralise bacteria at the bite site, but this also demonstrates, at least for the Noble False Widow, that the venom does not inhibit bacteria.Dr Aoife Boyd, Director of the Pathogenic Mechanisms Group at NUI Galway's School of Natural Sciences, and senior author of the study, said: "The diversity of microbes never ceases to amaze me. The power to survive and thrive in every environment is shown here by the presence of antimicrobial resistance bacteria even in spider venom. Antimicrobial resistance (AMR) is an urgent and growing problem worldwide. A One Health approach interconnecting human, animal and environmental health is the only way to tackle the problem."Dr John Dunbar, Zoologist at the Ryan Institute's Venom System Lab in NUI Galway, said: "About 10 species of spiders common in North-western Europe have fangs strong enough to pierce human skin and deliver venom, but only one of them, the recent invasive noble false widow spider, is considered of medical importance. Most of the time, a spider bite results in some redness and pain."In some cases, however, victims seem to develop long lasting infections for which strong antibiotic treatment -- and sometimes a hospital stay -- are necessary. It is this increasing range expansion and massive rise in dense populations of false widow spiders around urbanised areas across Ireland and Britain that has seen a rise in bites with some severe envenomation symptoms but also infections, which in some cases proved even difficult to treat with antibiotics."Neyaz Kahn, co-lead author of the study and PhD student at the Pathogenic Mechanisms Group in NUI Galway's School of Natural Sciences, said: "Our study demonstrates that spiders are not just venomous but are also carriers of dangerous bacteria capable of producing severe infections. The biggest threat is that some of these bacteria are multi-drug resistant, making them particularly difficult to treat with regular medicine. This is something that health care professionals should consider from now on."
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Animals
| 2,020 |
December 1, 2020
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https://www.sciencedaily.com/releases/2020/12/201201091831.htm
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Pets, touch and COVID-19: Why our furry friends are lifesavers
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Lockdowns, job losses and social isolation have been the hallmarks of 2020 as COVID-19 tightens its grip on the world, not only infecting millions and leaving a mounting death toll, but also denying humans the most basic sense -- touch.
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In the absence of human-to-human contact, in millions of households worldwide, animals have stepped into the breach for many people, providing much-needed comfort via cuddles, pats and a constant physical presence.A new study published by University of South Australia researchers points to the lifesaving role that pets have played in 2020 and why governments need to sit up and take notice.Lead author Dr Janette Young says physical touch is a sense that has been taken for granted -- even overlooked -- until COVID-19 visited our door earlier this year."In a year when human contact has been so limited and people have been deprived of touch, the health impacts on our quality of life have been enormous," Dr Young says."To fill the void of loneliness and provide a buffer against stress, there has been a global upsurge in people adopting dogs and cats from animal shelters during lockdowns. Breeders have also been inundated, with demands for puppies quadrupling some waiting lists."Spending on pets was already hitting record levels, topping $13 billion in Australia and in the region of US$260 billion globally in 2020, but this is bound to be surpassed.It is estimated that more than half the global population share their lives with one or more pets. The health benefits have been widely reported, but little data exists regarding the specific benefits that pets bring to humans in terms of touch."Pets seem to be particularly important when people are socially isolated or excluded, providing comfort, companionship and a sense of self-worth," Dr Young says."Touch is an understudied sense, but existing evidence indicates it is crucial for growth, development and health, as well as reducing the levels of the stress hormone cortisol in the body. It is also thought that touch may be particularly important for older people as other senses decline."In interviews with 32 people, more than 90 per cent said touching their pets both comforted and relaxed them -- and the pets seemed to need it as well.Examples of dogs and cats touching their owners when the latter were distressed, sad, or traumatised were cited.Many people referenced pets' innate ability to just "know" when their human counterparts weren't feeling well and to want to get physically close to them."The feedback we received was that pets themselves seem to get just as much pleasure from the tactile interaction as humans," Dr Young says.Not just dogs and cats either. Interviewees mentioned birds, sheep, horses and even reptiles who reciprocate touch."Animals, like people, are living, breathing others, with individual interests, styles and preferences. While culturally, animals are not seen as 'human', they are still seen as individuals with likes and dislikes."In the era of COVID-19, social distancing, sudden lockdowns and societal upheaval, our pets may be the only living beings that many people are able to touch and draw comfort from."Humans have an innate need to connect with others but in the absence of human touch, pets are helping to fill this void. They need to be considered from a policy angle, therefore, to help mitigate some of the mental and physical stressors that people are experiencing during this time."Dr Young says hospitals, hospices and aged care facilities should be encouraging pet connections with residents."Residential aged care is yet to recognise the value of human-animal relationships. Had more pets being living with their owners in aged care when COVID-19 restrictions were applied, it could have helped people immeasurably," she says.
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Animals
| 2,020 |
December 1, 2020
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https://www.sciencedaily.com/releases/2020/12/201201084804.htm
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Flashy lizards are more attractive to mates and to predators
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In the lizard world, flashy colors attract the interest of females looking for mates. But they can make colorful males desirable to other eyes, too -- as lunch.
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Assistant Research Professor of Biological Sciences Lindsey Swierk is the first author of an article in the journal To attract females' notice, male anoles have dewlaps: colorful extendable flaps of skin under their chins. In most species of anole, dewlaps evolved to be as noticeable as possible within the environment, given an environment's predominant colors and lighting conditions."Even so, we see a lot of variation within a species in just how bright dewlaps are," Swierk said.While some water anoles have dramatic red-orange flaps, others have more muted colors, more of a dull brownish-red. Researchers wanted to determine the effect these color variations had on their risk of predation.While it's widely assumed that flashier males will attract more attention from predators, few studies actually test this assumption. Logistics may be a factor: Researchers have to separate the effects of sexual colors from other aspects of a creature's body and behavior, a difficult task when using real animals. As a result, many studies show correlation but not causation.To prove that flashier males face greater risks of being attacked, the researchers created clay models with colored dewlaps -- some bright, some more muted. Many visual predators use a stereotyped "search image" to identify prey, so the models only had to approximate anoles' general size, color and shape. The dewlap color, however, required special attention."Because different animals have different visual sensitivities than we do as humans, getting the colors right was an important consideration in our model design," Swierk explained. "We ran some pilot trials before this experiment to make sure our models were convincing as 'lizards' -- and they certainly seemed to be, as many birds and other lizards took bites out of them!"Researchers were able to identity predators from bite marks in the clay models. They included many species of bird, including the strikingly beautiful motmot with its serrated beak. Basilisks and whiptail lizards were also among the likely attackers. The results proved that flashier lizards really do end up as lunch more often.If bright colors have deadly consequences, why do female anoles prefer them? One answer is that brighter males have either high-quality genetic material or resources that allow them to handle the risk of getting eaten, Swierk explained."Because every individual's evolutionary 'mission' in life is to pass on as many copies of its genes as it can, conspicuous traits like these can evolve if they give an individual a high level of reproductive success -- even if the flashy trait ends up killing them in the end," Swierk said.
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Animals
| 2,020 |
November 30, 2020
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https://www.sciencedaily.com/releases/2020/11/201130131446.htm
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Black bear gut biome surprisingly simple
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In recent decades, researchers have found that most mammals' guts are surprisingly complex environments -- home to a variety of microbial ecosystems that can profoundly affect an animal's well-being. Scientists have now learned that the bear appears to be an exception, with its gut playing host to a microbial population that varies little across the intestinal tract.
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"It's the first mammal species where we've looked at two separate locations in the gut and found microbial communities that are essentially indistinguishable from each other," says Sierra Gillman, first author of a paper on the work and a Ph.D. student at the University of Washington. Gillman did the work while a grad student at Northern Michigan University (NMU)."Bears have really simple guts -- pretty much a garden hose -- so they can't regulate their gut microbes to the extent that animals with longer, more complex guts can," says Erin McKenney, co-author of the paper and an assistant professor of applied ecology at North Carolina State University. "Without that control, the bears' diet and environment may play a greater role in shaping the gut microbiome. It raises some interesting evolutionary questions about the relationship between the shape of an animal's gut, its gut microbiome, and the relationship between the microbiome and the animal's health and behavior."The researchers set out to learn more about the gut microbiome of American black bears (Ursus americanus) with little idea of what to expect. Not much research has been done on microbial ecosystems in the species, and what work has been done has focused on animals in captivity. Since animals in captivity and animals in the wild often have very different gut microbiomes, the researchers were curious as to what they'd find. One major challenge was obtaining samples in the first place.To that end, the researchers worked with guides who lead scheduled trips with hunters in the Upper Peninsula of Michigan. Gillman developed a detailed set of protocols and conducted training sessions with the guides on how to collect samples from bears that were harvested when the guides went on their regularly scheduled trips with hunters. Specifically, Gillman taught the guides how to retrieve samples from both the jejunum, which is the middle section of the small intestine, and the colon, which is also called the large intestine.Ultimately, the researchers obtained 31 useable jejunum samples and 30 useable colon samples. They then analyzed the samples to identify which microbial species were present.The researchers expected to see more, and different, species of microbes in the colon. The colon is often where digestion slows down, enabling gut microbes to break down fiber in the diet -- which normally fosters microbial diversity. But not, apparently, in the black bears of Michigan.Why are bear gut microbiomes different from the microbiomes of other omnivores scientists have looked at? In a word, it's probably the cecum.Omnivores with more complex guts have a small pouch -- called the cecum -- between the small and large intestine. The cecum helps slow down the rate at which food passes through the gut, like an oxbow in a river, and likely serves as a reservoir for microbial populations in the gut, allowing animals to replenish the diversity of their microbiomes, even as their diets and health change."Bears don't have a cecum," Gillman says. "That makes their gut microbiomes more vulnerable to systemic change due to diet, health or other factors."This finding has an immediate practical application for wildlife researchers."In many animal species, a fecal sample can tell you what the microbial diversity of the colon was like -- but it doesn't tell you much about what's happening in other parts of the gut," says Diana Lafferty, co-author of the paper and an assistant professor of wildlife ecology at NMU. "Our work suggests that a fecal sample offers insight into the microbial community across the entire gut for black bears -- and possibly for other carnivores and omnivores that have simple gut morphologies."In other words, they can learn more from wild animal poop than they previously thought.The researchers are currently in the process of comparing the samples collected in Michigan to samples from black bears harvested by hunters in North Carolina, in order to determine if the findings are consistent across geographic regions."We are also looking at carnivore species that also lack a cecum to see if they have a similar lack of microbial diversity across the gut," Gillman says."And we are working on a project that will help us better identify and understand the connections between the gut microbiome and bear health," says Lafferty."One of the things we're curious about is weight gain," McKenney says. "We know that specific shifts in the microbiome can lead to weight gain and obesity in other species, which is usually viewed as a negative. But for species that hibernate, like bears, that could actually be advantageous."The work was done with support from the National Science Foundation, under grant number 1000263298; and from Sigma Xi, the scientific research honor society, under grant number G2018100198233997.
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Animals
| 2,020 |
November 30, 2020
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https://www.sciencedaily.com/releases/2020/11/201130131423.htm
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Experimental vaccine for deadly tickborne virus effective in cynomolgus macaques
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An experimental vaccine developed in Europe to prevent infection by Crimean-Congo hemorrhagic fever virus (CCHFV) has protected cynomolgus macaques in a new collaborative study from National Institutes of Health scientists. The animals received the DNA-based candidate vaccine through intramuscular injection immediately followed by electroporation -- a process in development for human vaccines that helps cells absorb DNA. The study, published in
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Crimean-Congo hemorrhagic fever, first described in 1944, is spread primarily by the bite of Scientists from NIH's National Institute of Allergy and Infectious Diseases (NIAID) in Hamilton, Montana, tested the candidate vaccine on six cynomolgus macaques, each of which received three inoculations, followed by electroporation, at three-week intervals. No animals experienced significant adverse reactions upon vaccination. Through regular blood tests, the researchers confirmed that the candidate vaccine generated protective antibodies against the virus. They then infected the vaccinated animals with CCHFV and monitored them for clinical signs for six days, after which they looked for virus in their organs. Six control animals infected with CCHFV but not given the experimental vaccine showed signs of disease throughout the study. The vaccinated animals did not. Their blood tests remained largely unchanged with no indication of progressive virus infection and no virus shedding. Virus was nearly undetectable in their liver, kidneys, lungs and adrenal glands, all targets of CCHFV.Collaborators at the Karolinska Institute in Sweden developed the candidate vaccine with colleagues from the Public Health Agency of Sweden, the National Veterinary Institute of Sweden, the Justus Liebig University in Germany and NIAID's Rocky Mountain Laboratories in Montana. The candidate vaccine uses two proteins from CCHFV to generate protection.The researchers next plan to study if the vaccine candidate is effective with fewer than three doses and whether it offers long-term protection. They also plan to continue evaluating the use of electroporation to make vaccination more effective.
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Animals
| 2,020 |
November 30, 2020
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https://www.sciencedaily.com/releases/2020/11/201130113534.htm
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Researchers find how stress and the circadian clock affect sleep
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A Nagoya University-led research team in Japan has found a new neural pathway that links the circadian clock, stress, and wakefulness in mammals. The team identified a neuron, called the corticotropin-releasing factor (CRF) neuron, that becomes excessively active when the mammal is under stress, which could trigger insomnia and other sleep disorders. Their findings were recently published in the journal
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Living organisms exhibit a 24-hour oscillation called the circadian rhythm. In mammals, the central circadian clock, located in the brain's suprachiasmatic nucleus (SCN) neurons, regulates the sleep-wake cycle. However, in the event of life-threatening situations, the circadian rhythm signal is shut off to keep the animal awake so that it can escape from danger even when it would normally be time to sleep. Although the temporary shutoff of the sleep-wake cycle is necessary for survival, excessive or prolonged stress caused by such dangers can trigger insomnia and other sleep disorders."It is well-known that the circadian clock and stress have an effect on sleep, but it was unclear which neural pathway is crucial for the circadian regulation of sleep and wakefulness," says Dr. Daisuke Ono of the Research Institute of Environmental Medicine at Nagoya University. To determine the pathway, a Nagoya University research team led by Prof. Akihiro Yamanaka and Dr. Ono, in collaboration with Takashi Sugiyama at Olympus Corporation in Japan, conducted a study using mice.The researchers focused on CRF neurons -- which are known to play a role in stress response -- that are located in the paraventricular nucleus of the hypothalamus. They investigated how sleep and wakefulness in mice would be affected when the CRF neurons were activated. The results showed that the activated CRF neurons kept the animals awake and made them move around vigorously, indicating that their wakefulness was promoted. The researchers also observed that CRF neurons remained active when the mice were awake, and that when the neurons' activity was suppressed, the animals' wakefulness and locomotor activities were reduced.Further investigations also showed that inhibitory neurons in the SCN, called GABAergic neurons, play a significant role in regulating the activity of CRF neurons, and that the activation of CRF neurons stimulates orexin neurons in the lateral hypothalamus, which results in the promotion of wakefulness.The team thus concluded that GABAergic neurons in the SCN control the activity of CRF neurons, which ultimately regulates the sleep-wake cycle. "We identified this neural pathway in mice, which are nocturnal animals. Further studies are required to elucidate how the nocturnal and diurnal difference is regulated in the brain," says Dr. Ono."In today's society, sleep disorders are a serious problem. We hope our finding will contribute to the development of new therapies for insomnia and other sleep disorders caused by stress or a disturbed circadian rhythm."
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November 26, 2020
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https://www.sciencedaily.com/releases/2020/11/201126085929.htm
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Understanding traditional Chinese medicine can help protect species
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Demystifying traditional Chinese medicine for conservationists could be the key to better protecting endangered species like pangolins, tigers and rhino, according to University of Queensland-led researchers.
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UQ PhD candidate Hubert Cheung said efforts to shift entrenched values and beliefs about Chinese medicine are not achieving conservation gains in the short term.He said a better understanding of traditional practices was critical for conservationists to form more effective strategies."The use of endangered species in traditional Chinese medicine threatens species' survival and is a challenge for conservationists," Mr Cheung said."Pushing messages of inefficacy, providing various forms of scientific evidence or promoting biomedical alternatives doesn't seem to be drastically influencing decisions and behaviours."And, although many practices and treatments continue to be criticised for lacking scientific support, the World Health Organization approved the inclusion of traditional Chinese medicine in its global compendium of medical practices last year."The challenge now is for conservationists to work proactively with practitioners and others in the industry to find sustainable solutions."However, most conservation scientists and organisations are unfamiliar with traditional Chinese medicine, which makes it difficult to devise effective and culturally-nuanced interventions."The researchers have examined the core theories and practices of traditional Chinese medicine, in a bid to make it more accessible.They hope their study -- and the nuances within -- will influence policy and campaigning."Today, traditional Chinese medicine is formally integrated into China's healthcare system, and has been central to China's response to the ongoing pandemic," Mr Cheung said."In fact, the Chinese government's COVID-19 clinical guidance has included recommendations for the use of a product containing bear bile, which has raised concerns among conservation groups."UQ's Professor Hugh Possingham said traditional Chinese medicine was now not only entrenched in the social and cultural fabric of Chinese society, but also gaining users elsewhere."A better understanding of traditional Chinese medicine will empower conservationists to engage more constructively with stakeholders in this space," Professor Possingham said."We're hoping that this work can help all parties develop more effective and lasting solutions for species threatened by medicinal use."
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November 25, 2020
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https://www.sciencedaily.com/releases/2020/11/201125164455.htm
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Effect of odor on helpfulness in rats
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Despite their reputation, rats are surprisingly sociable and actually regularly help each other out with tasks. Researchers at the Universities of Göttingen, Bern and St Andrews have now shown that a rat just has to smell the scent of another rat that is engaged in helpful behaviour to increase his or her own helpfulness. This is the first study to show that just the smell of a cooperating individual rat is enough to trigger an altruistic and helpful response in another. The research was published in the
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It is well known that rats will help each other out. What the researchers wanted to know was whether the rat's odour during this behaviour had any effect on another rat's helpfulness. They therefore carried out a series of tests to study the importance of the scent of a rat while making cooperative decisions. The rats being studied could choose to help another rat by pulling a platform containing a reward towards the other rat's cage. This provided food for the other rat but did not have any immediate benefit for them personally. The researchers then provided the test rats either with the smell of a rat that was being helpful to another rat in a different room or with the smell of a rat that was not engaged in helpful behaviour. The researchers were surprised to find that just the scent of a rat engaged in helpful behavior was enough to illicit helpful behaviour in the other.Dr Nina Gerber from the Wildlife Sciences at the University of Göttingen, who led the research, says: "Test rats increased their own helping behaviour when they were presented with the smell of a helpful rat. Remarkably, this holds true even though they did not experience this helpful behaviour themselves." She goes on to say, "Furthermore, such a 'smell of cooperation' depends on the actual activity of helping and is not connected to an individual rat. There isn't a "special smell" for certain nice rats: the same individual can release the scent of being helpful or not, depending solely on their behaviour."The researchers concluded that physical cues -- such as smell -- might be even more important for rats to encourage cooperation than actual experiences. Gerber adds, "Even though people do not seem to rely on communication through scent in the way rats do, some studies indicate that scent is key for finding partners, or that smelling certain chemicals can increase trust in others. Whether there is such a 'smell of cooperation' in humans, however, would be an interesting question for future studies."
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November 25, 2020
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https://www.sciencedaily.com/releases/2020/11/201123100952.htm
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Not just lizards: Alligators can regrow their tails too, new study reveals
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An interdisciplinary team of scientists using advanced imaging technology have answered the question of whether alligators share any of the same regenerative capabilities as much smaller reptiles. Many kinds of small reptiles, such as lizards, are known to regrow their tails. However, with a potential body length of 14 feet, little was known about whether alligators could possibly regrow their massive tails.
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A team of researchers from Arizona State University and the Louisiana Department of Wildlife and Fisheries have uncovered that young alligators have the ability to regrow their tails up to three-quarters of a foot -- about 18% of their total body length. They speculate that regrowing their tails gives the alligators a functional advantage in their murky aquatic habitats.The team combined advanced imaging techniques with demonstrated methods of studying anatomy and tissue organization to examine the structure of these regrown tails. They found that these new tails were complex structures, with a central skeleton composed of cartilage surrounded by connective tissue that was interlaced with blood vessels and nerves. Their findings are published in the journal "What makes the alligator interesting, apart from its size, is that the regrown tail exhibits signs of both regeneration and wound healing within the same structure," said Cindy Xu, a recent PhD graduate from ASU's School of Life Sciences molecular and cellular biology program and lead author of the paper."Regrowth of cartilage, blood vessels, nerves and scales were consistent with previous studies of lizard tail regeneration from our lab and others," she said. "However, we were surprised to discover scar-like connective tissue in place of skeletal muscle in the regrown alligator tail. Future comparative studies will be important to understand why regenerative capacity is variable among different reptile and animal groups.""The spectrum of regenerative ability across species is fascinating, clearly there is a high cost to producing new muscle," said Jeanne Wilson-Rawls, co-senior author and associate professor with ASU's School of Life Sciences.Alligators, lizards and humans all belong to a group of animals with backbones called amniotes. In addition to previous studies about the ability of lizards to regrow their tails, the discovery of such large and complex new tails in alligators provides considerable new information about regenerative process in the larger animal classification of amniotes.This also leads to new questions about the history of these capabilities, and the possibilities for the future."The ancestors of alligators and dinosaurs and birds split off around 250 million years ago," said co-senior author Kenro Kusumi, professor and director of ASU's School of Life Sciences and associate dean in The College of Liberal Arts and Sciences."Our finding that alligators have retained the cellular machinery to regrow complex tails while birds have lost that ability raises the question of when during evolution this ability was lost. Are there fossils out there of dinosaurs, whose lineage led to modern birds, with regrown tails? We haven't found any evidence of that so far in the published literature."The researchers hope their findings will help lead to discoveries of new therapeutic approaches to repairing injuries and treating diseases such as arthritis."If we understand how different animals are able to repair and regenerate tissues, this knowledge can then be leveraged to develop medical therapies," said Rebecca Fisher, co-author and professor with the University of Arizona College of Medicine-Phoenix and ASU's School of Life Sciences.The research team included Kusumi, Xu, Wilson-Rawls and Alan Rawls from ASU's School of Life Sciences; Ruth Elsey from the Louisiana Department of Wildlife and Fisheries; and Fisher from the University of Arizona College of Medicine-Phoenix. This research was funded by support from The College of Liberal Arts and Sciences at ASU. ASU's School of Life Sciences is an academic unit of The College of Liberal Arts and Sciences.
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November 25, 2020
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https://www.sciencedaily.com/releases/2020/11/201125100311.htm
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A new species of rare phylum Loricifera discovered in the deep-sea surrounding Japan
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The Loricifera is a microscopic, sediment-dwelling marine invertebrate, with a head covered in over 200 spines and an abdomen with a protective shell -- known as a lorica. Since it was first discovered in 1983, just under 40 species have been written about. Now, that number is one more thanks to a group of scientists who reported on a new genus and species of Loricifera.
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Their findings were published in the Journal "Loricifera is a rare animal that is still under-researched, but our recent finding improves our understanding of the species' diversity," said lead author Shinta Fujimoto.Loricifera typically inhabit the space between sand and mud particles in the ocean. Fossils exist from the Cambrian period, suggesting a long existence on Earth. They have complicated life cycles and a few species are reported to live in anoxic environments. Their exact position on the animal tree of life is unknown.Researchers from Tohoku University, Kyushu University, Mie University, Hiroshima University and the University of Copenhagen reported on a new species of Loricifera inhabiting Japan's area from the continental slope to the deeper sea -- roughly 177 m to 1059 m below the sea. This marks the second time a new Loricifera species has been found near Japan; the last one was discovered in 1988 in the Izu-Ogasawara Trench.Fujimoto and his team hope to uncover as much as they can about this rare species. "Each new species provides us with answers, but also more questions. We will keep on looking for these extraordinary animals to understand the species' diversity, ecology, life history and evolution."
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November 25, 2020
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https://www.sciencedaily.com/releases/2020/11/201125091446.htm
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How dolphins avoid 'the bends'
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Dolphins actively slow down their hearts before diving, and can even adjust their heart rate depending on how long they plan to dive for, a new study suggests. Published in
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The authors worked with three male bottlenose dolphins (Tursiops truncatus), specially trained to hold their breath for different lengths of time upon instruction. "We trained the dolphins for a long breath-hold, a short one, and one where they could do whatever they want," explains Dr Andreas Fahlman of Fundación Oceanogràfic, Valencia, Spain. "When asked to hold their breath, their heart rates lowered before or immediately as they began the breath-hold. We also observed that the dolphins reduced their heart rates faster and further when preparing for the long breath-hold, compared to the other holds."The results reveal that dolphins, and possibly other marine mammals, may consciously alter their heart rate to suit the length of their planned dive. "Dolphins have the capacity to vary their reduction in heart rate as much as you and I are able to reduce how fast we breathe," suggests Fahlman. "This allows them to conserve oxygen during their dives, and may also be key to avoiding diving-related problems such as decompression sickness, known as "the bends." "Understanding how marine mammals are able to dive safely for long periods of time is crucial to mitigate the health impacts of man-made sound disturbance on marine mammals. "Man-made sounds, such as underwater blasts during oil exploration, are linked to problems such as "the bends" in these animals," continues Fahlman. "If this ability to regulate heart rate is important to avoid decompression sickness, and sudden exposure to an unusual sound causes this mechanism to fail, we should avoid sudden loud disturbances and instead slowly increase the noise level over time to cause minimal stress. In other words, our research may provide very simple mitigation methods to allow humans and animals to safely share the ocean."The practical challenges of measuring a dolphin's physiological functions, such as heart rate and breathing, have previously prevented scientists from fully understanding changes in their physiology during diving. "We worked with a small sample size of three trained male dolphins housed in professional care," Fahlman explains. "We used custom-made equipment to measure the lung function of the animals, and attached electrocardiogram (ECG) sensors to measure their heart rates.""The close relationship between the trainers and animals is hugely important when training dolphins to participate in scientific studies," explains Andy Jabas, Dolphin Care Specialist at Siegfried & Roy's Secret Garden and Dolphin Habitat at the Mirage, Las Vegas, United States, home of the dolphins studied here. "This bond of trust enabled us to have a safe environment for the dolphins to become familiar with the specialized equipment and to learn to perform the breath-holds in a fun and stimulating training environment. The dolphins all participated willingly in the study and were able to leave at any time."
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November 24, 2020
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https://www.sciencedaily.com/releases/2020/11/201124190527.htm
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T. rex had huge growth spurts, but other dinos grew slow and steady
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<em>Tyrannosaurus rex</em>
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"We wanted to look at a wide swath of different theropods, two-legged, carnivorous dinosaurs, in order to understand broader patterns of growth and evolution in the group," says Tom Cullen, the lead author of a new study in Cullen, a scientific affiliate of Chicago's Field Museum who worked on the study as a postdoctoral researcher at the Field with the museum's then-curator of dinosaurs, Pete Makovicky, explains, "We particularly wanted to understand how some of them got so big -- is the way Makovicky, a scientific affiliate of the Field and professor of geology at the University of Minnesota and the paper's senior author, says, "We also wanted to see if we got the same growth record when we sampled a variety of different bones from the same skeleton. All these questions about how theropods grew could impact our understanding of the evolution of the group." Makovicky developed the idea for the project and also discovered several of the dinosaurs whose fossils were analyzed in the study.The question of how an animal gets big is a surprisingly tricky one. Mammals like us tend to go through a period of extreme growth when we're young and then stay the same size once we reach adulthood. In other animal groups, that's not always the case. "Growth rate really varies, there's no one size fits all," says Cullen, who is now a postdoctoral researcher at the North Carolina Museum of Natural Sciences. "Birds have super growth spurts and reach adult size really fast, while reptiles like alligators and various lizards and snakes have extended growth. With them, a really, really big individual is probably really old."Theropod dinosaurs like The central struggle in studying extinct animals is that we can never know exactly what their lives were like. Since we can't directly observe a dinosaur growing the way you can a living animal today, it's hard to know for sure how they grew. But there are clues in the fossil record that reveal growth patterns.""Inside the bones as an animal grows, there are markings like tree rings that record roughly how old the animal is, how much it's growing each year, and a number of other factors," says Cullen. To find these growth rings, Cullen and his colleagues sliced into fossils from dozens of dinosaurs, from ones the size of dogs and ostriches all the way up to SUE the "The very first specimen that the Field Museum let me sample was SUE the Back in the lab, Cullen sliced samples of bone so thin that light could pass through them and examined them under a microscope."Most animals have a period every year when they stop growing, traditionally suggested to be in times like winter when food is more scarce. It shows up in the bones as a line, like a tree ring," says Cullen. By analyzing these growth lines and examining the bones for new regions of growth, scientists can get a rough estimate of an animal's age and how much it grew every year. There are also clues in the bone structure."You can see all the little areas where the bone cells have grown, and the structure of the blood vessels that passed through the bone," says Cullen. "These vascular canals tell you roughly how fast the bone was growing. If the canals are more organized, the bone was being laid down more slowly, and if the structure is chaotic, it grew more quickly."Cullen found that the dinosaurs' growth patterns depended on their family. The discovery opens up questions about how these predatory dinosaurs interacted with the animals around them. The plant-eating dinosaurs that lived alongside "We can't say for sure, but there could be some kind of a selection pressure for the coelurosaurs to grow quickly to keep up with their prey, or pressure for the allosauroids to keep growing in size since their prey were also increasing in size," says Cullen. "But it's pretty speculative. It could be that even if the sauropods kept growing their whole lives, they had so many offspring that there was always something small to eat."But while the research hasn't answered all the questions about why dinosaurs like
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November 23, 2020
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https://www.sciencedaily.com/releases/2020/11/201123161038.htm
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Big cats and small dogs: Solving the mystery of canine distemper in wild tigers
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If you think getting your cat to the veterinarian is tricky, new Cornell Wildlife Health Center research has revealed that vaccination of endangered Amur (Siberian) tigers is the only practical strategy to protect them from a dangerous disease in their natural habitat in the Russian Far East.
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Canine distemper virus (CDV) causes a serious disease in domestic dogs, and also infects other carnivores, including threatened species like the Amur tiger, which numbers fewer than 550 individuals in the Russian Far East and neighbouring China. It is often assumed that domestic dogs are the primary source of CDV, but in a new study published in the "Understanding how tigers are catching distemper is absolutely crucial to helping us design effective measures to minimize the conservation impact of the virus," said Gilbert. "Vaccinating tigers is hard to do, but our research shows that immunizing just two tigers within a small population each year can reduce the risk that CDV will cause extinction by almost seventy-five percent. At least in the Russian Far East, vaccinating local domestic dogs would not be an effective strategy to protect tigers."The research, led by Cornell University, the Wildlife Conservation Society and the University of Glasgow, relied on several lines of evidence to build a picture of CDV epidemiology in the tigers' habitat. Using samples from domestic dogs, tigers, and other wild carnivores, they compared viral genetic sequence data and used antibodies to assess patterns of exposure in each population."The taiga forest where the tigers live supports a rich diversity of 17 wild carnivore species" said study co-author Dr. Nadezhda Sulikhan with the Federal Scientific Center of the East Asia Terrestrial Biodiversity of Russian Academy of Sciences. "Our findings suggest that more abundant small-bodied species like martens, badgers and raccoon dogs are the most important contributors to the CDV reservoir."Controlling CDV in these abundant wild carnivore populations is not possible, as there are no CDV oral vaccines that could be distributed to these populations through baited food.That left only one viable possibility -- using an injectable vaccine on the tigers themselves. To determine whether currently available CDV vaccines could protect wild tigers, the researchers showed in the laboratory that serum from tigers vaccinated in captivity was able to neutralize the strain of CDV that they had detected in Russia. They then developed a computer model to show that even a low rate of vaccination (two tigers per year) could reduce the tigers' risk of extinction significantly, at a cost of only US $30,000 per year or less if vaccines are given opportunistically when tigers are captured for routine radio collaring studies. Gilbert and his colleagues contend that vaccination can be a valuable conservation strategy. As wildlife populations become more fragmented through the effects of habitat destruction, poaching and climate change, they become increasingly vulnerable to local extinctions caused by infectious diseases like distemper.According to study contributor Dr. Sarah Cleaveland of the University of Glasgow, "This work shows that CDV in the Amur tiger is a solvable problem -- a rare piece of good news for the tiger conservation community."
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November 23, 2020
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https://www.sciencedaily.com/releases/2020/11/201123112510.htm
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True origin of oldest evidence of animals
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Two teams of scientists have resolved a longstanding controversy surrounding the origins of complex life on Earth.
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The joint studies found molecular fossils extracted from 635-million-year-old rocks aren't the earliest evidence of animals, but instead common algae.The researchers from The Australian National University (ANU), Max Planck Institute and Caltech say the finding has big implications for our understanding of evolution."It brings the oldest evidence for animals nearly 100 million years closer to the present day," Dr Lennart van Maldegem from ANU, co-author author of one study, said."We were able to demonstrate that certain molecules from common algae can be altered by geological processes -- leading to molecules which are indistinguishable from those produced by sponge-like animals.Professor Jochen Brocks, also based at ANU, said the mystery of when our very earliest animal ancestors emerged and became abundant in the oceans has puzzled palaeontologists for more than a century."Ten years ago, scientists discovered the molecular fossils of an animal steroid in rocks that were once at the bottom of an ancient sea in the Middle East," Professor Brocks said."The big question was, how could these sponges have been so abundant, covering much of the seafloor across the world, but leave no body fossils?"Dr Ilya Bobrovskiy, lead author of the other study, said the researchers have been able to "solve this mystery.""While it holds true sponges are the only living organism which can produce these steroids, chemical processes can mimic biology and transform common and abundant algae sterols into 'animal' sterols," he said."These molecules can be generated in the lab when simulating geological time and temperatures, but we also showed such processes did happen in ancient rocks."The two complementary studies have been published in
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November 23, 2020
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https://www.sciencedaily.com/releases/2020/11/201123085328.htm
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Coppery titi monkeys do not deceive their partners
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Since methods for genetic paternity analyses were introduced it became clear that many pair-living animal species, including humans, do not take partnership fidelity that seriously. In most species there is some proportion of offspring that is not sired by their social father. Coppery titi monkeys living in the Amazon lowland rainforest seem to be an exception. Scientists from the German Primate Center (DPZ) -- Leibniz Institute for Primate Research in Göttingen could not find evidence for extra-pair paternity in their study population in Peru. Mate choice seems to be so successful that a potential genetic advantage does not outweigh the social costs of infidelity (
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Offspring resulting from extra-pair copulations but raised by the social partner are surprisingly common in pair-living species. Various reasons are discussed for this behavior. For instance, mate choice is often limited and sometimes it only turns out later that the chosen partner is not the genetically best one. In order to ensure the best possible genes for your own children, you may use the genes of a neighbor or a floating male without giving up the security of your own territory and the caring social father.Coppery titi monkeys live in small family-groups, consisting of male, female and offspring, who defend a territory. Usually, a single infant is born per year, that leaves the group when it reaches sexual maturity or shortly after and searches a partner, with whom it occupies an own territory. The pair-partners maintain a strong relationship, spend day and night in close proximity and groom each other. Fourteen groups of coppery titi monkeys were studied at the field station of the German Primate Center "Estación Biológica Quebrada Blanco" and its surroundings in northeastern Peru. Forty-one individuals could be genotyped using faecal samples from which DNA was extracted and sequenced at the Genetics Laboratory of the German Primate Center in Göttingen. None of the 18 offspring examined were not sired by the social father, i.e. genetic monogamy could be confirmed. In addition, it turned out that the adult animals showed a high genetic diversity and that the mating partners were on average unrelated. "Extra-pair breeding would therefore not have provided a genetic advantage for the animals studied, so that they presumably rather avoided the risks of 'infidelity'," says Sofya Dolotovskaya, who studied the animals and their behavior for 14 months of field research as a doctoral student of the German Primate Center."In an undisturbed ecosystem, as at our field station, young coppery titi monkeys obviously migrate far enough from their natal group to find a suitable partner without incurring the risk of inbreeding," Eckhard W. Heymann, scientist at the German Primate Center and head of the field station in Peru, concludes from the study. "Further studies must show whether genetic monogamy also prevails in other populations of coppery titi monkeys, especially in fragmented habitats."
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November 23, 2020
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https://www.sciencedaily.com/releases/2020/11/201123101009.htm
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How ancient fish may have prepared for life on land
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A new study adds another layer to the remarkable evolutionary transition of life from water to land on Earth.
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The international study of the prehistoric 'relic' tetrapods, including salamander and lobe-finned lungfish and coelacanths, adds another perspective to the evolution of other four-legged land animals, including related animals such as frogs and reptiles which live in both terrestrial and aqueous environments.Using micro-CT and MRI scans to make 3D models of small animal heads, palaeontology researchers from the University of Edinburgh, University of Calgary and Flinders University shone a light on how the eating habits and brains of the some of the first land-based lifeforms prepared them for life on dry land.The study published in the journal "Coelacanth and lungfish are the only lobe-finned fish alive today, but their relatives were the lineage of fish that first left the water to colonise land," Dr Clement says."Soft tissue, such as brains and muscles, doesn't survive in fossil records so we studied the brains of living animals, and the internal space of the skull or 'endocast' to figure out what brains of fossils animals must have looked like."Our main finding is that salamanders and lungfish have brains quite similar in size and shape to each other, while the coelacanth is a real outlier with a tiny brain."University of Edinburgh researcher Dr Tom Challands says the high-tech scanning of braincase and jaw structure in six sarcopterygians shows a correlation between how tight or loose the brain fills the skull."For the first time, we have been able to demonstrate the interplay between how the jaw muscles affect how the brain sits inside the brain cavity," says first author Dr Tom Challands, from University of Edinburgh's Grant Institute of Earth Sciences."As animals made their way out of water and on to land, their food sources changed and the brain had to adapt to a completely new way of living -- different sensory processing, different control for movement, balance, and so on," he says."Each of these plays against each other and our work basically shows the effect of masticatory (eating) changes are balanced with maintaining a skull that can support and protect the brain."He says some of the features of these earliest land animals is reflected in other modern animals."Moreover we see similarities between the fish and land animals, suggesting that some muscle-brain-skull arrangements were already primed for living on land."
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November 21, 2020
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https://www.sciencedaily.com/releases/2020/11/201121104309.htm
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Zebra finches amazing at unmasking the bird behind the song
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If songbirds could appear on "The Masked Singer" reality TV competition, zebra finches would likely steal the show. That's because they can rapidly memorize the signature sounds of at least 50 different members of their flock, according to new research from the University of California, Berkeley.
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In findings recently published in the journal Like humans who can instantly tell which friend or relative is calling by the timbre of the person's voice, zebra finches have a near-human capacity for language mapping. Moreover, they can remember each other's unique vocalizations for months and perhaps longer, the findings suggest."The amazing auditory memory of zebra finches shows that birds' brains are highly adapted for sophisticated social communication," said study lead author Frederic Theunissen, a UC Berkeley professor of psychology, integrative biology and neuroscience.Theunissen and fellow researchers sought to gauge the scope and magnitude of zebra finches' ability to identify their feathered peers based purely on their unique sounds. As a result, they found that the birds, which mate for life, performed even better than anticipated."For animals, the ability to recognize the source and meaning of a cohort member's call requires complex mapping skills, and this is something zebra finches have clearly mastered," Theunissen said.A pioneer in the study of bird and human auditory communication for at least two decades, Theunissen acquired a fascination and admiration for the communication skills of zebra finches through his collaboration with UC Berkeley postdoctoral fellow Julie Elie, a neuroethologist who has studied zebra finches in the forests of their native Australia. Their teamwork yielded groundbreaking findings about the communication skills of zebra finches.Zebra finches usually travel around in colonies of 50 to 100 birds, flying apart and then coming back together. Their songs are typically mating calls, while their distance or contact calls are used to identify where they are, or to locate one another."They have what we call a 'fusion fission' society, where they split up and then come back together," Theunissen said. "They don't want to separate from the flock, and so, if one of them gets lost, they might call out 'Hey, Ted, we're right here.' Or, if one of them is sitting in a nest while the other is foraging, one might call out to ask if it's safe to return to the nest."These days, Theunissen keeps a few dozen zebra finches in aviaries on and around campus, 20 of which were used in this latest experiment.In a two-part experiment, 20 captive zebra finches were trained to distinguish between different birds and their vocalizations. At first, half the birds were tested on memorizing songs, while the other half were assessed on distance or contact calls. They then switched those tasks.Next, the zebra finches were placed, one at a time, inside a chamber and listened to sounds as part of a reward system. The goal was to train them to respond to particular zebra finches by hearing several different renditions of those birds' distinct vocalizations and memorizing them.By pecking a key inside the chamber, the bird subjects triggered an audio recording of a zebra finch vocalization. If they waited until the six-second recording ended, and it was part of the reward group, they received birdseed. If they pecked before the recording was finished, they moved to the next recording. Over several trials, they learned which vocalizations would yield birdseed, and which ones to skip.Next, the zebra finches were introduced to more audio recordings from new zebra finches, to teach them to distinguish which vocalizations belonged to which bird. They soon learned to differentiate between 16 different zebra finches.In fact, the zebra finches, both male and female, performed so well in the tests that four of them were given the more challenging task of distinguishing between 56 different zebra finches. On average, they succeeded in recognizing 42 different zebra finches, based on their signature sounds. Plus, they were still able to identify the birds based on their unique sounds a month later."I am really impressed by the spectacular memory abilities that zebra finches possess in order to interpret communication calls," Theunissen said. "Previous research shows that songbirds are capable of using simple syntax to generate complex meanings and that, in many bird species, a song is learned by imitation. It is now clear that the songbird brain is wired for vocal communication."In addition to Theunissen, co-authors of the study are Kevin Yu and Willam Wood at UC Berkeley.
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November 19, 2020
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https://www.sciencedaily.com/releases/2020/11/201119153954.htm
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Elephant genetics guide conservation
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A large-scale study of African elephant genetics in Tanzania reveals the history of elephant populations, how they interact, and what areas may be critical to conserve in order to preserve genetic diversity for species conservation. The study, by researchers at Penn State, appears online in the journal
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"Elephants are a hallmark of the savannah, but poaching and habitat loss and fragmentation have led to major population declines across Africa," said George Lohay, postdoctoral scholar in biology at Penn State and first author of the paper. "Human activities accelerate the loss of elephant habitat, as well as the land between protected areas. Maintaining connectivity between protected areas may be especially important for this far-ranging species, particularly with regard to gene flow, which can improve genetic diversity and help buffer small populations against disease and other threats."The researchers compared both nuclear and mitochondrial DNA of 688 elephants across Tanzania from 4 major areas with large elephant populations. These include the Serengeti and Tarangire-Manyara in north-east Tanzania, Ruaha in south-central Tanzania, and Selous in southeast Tanzania. Each contains several areas with varying levels of protection, including national parks, game reserves, and private land conserved for livestock and wildlife tourism. Many of the wildlife corridors -- the areas between these protected areas -- have closed completely due to human activity.The researchers suspected that the East African Rift Valley that runs between several protected areas would prevent gene flow between elephant populations. But, interestingly, they found that elephants from Lake Manyara National Park were in some ways more genetically similar to elephants across the rift in the Ngorongoro Conservation Area -- in the Serengeti region -- compared to elephants in the closer Tarangire National Park."Even though there are no physical barriers between elephants in Lake Manyara and Tarangire, there is very limited gene flow between the two populations," said Douglas Cavener, professor of biology at Penn State and an author of the paper. "It may be that cultural or behavioral barriers play a role instead. Other studies have tracked elephants moving between the two areas, but they don't appear to be mating with each other."The similarities among the two groups across the rift suggests that there was gene flow between Ngorongoro and Lake Manyara sometime in the past."There is anecdotal evidence from the 1970s of elephants actually climbing across the rift, but most of the corridors connecting Ngorongoro and Lake Manyara have since become occupied by humans," said Cavener. "The Lake Manyara population is now almost completely isolated and contains only about a hundred individuals. The loss of gene flow through these corridors may lead to negative consequences due to inbreeding over the next few generations."The researchers also found that elephants in Tarangire were genetically similar to those more than 400 km to the south in Ruaha. This suggests extensive gene flow between the two populations before the corridors were closed between them."Because elephants are long-lived and because mutation is a slow process, it can take multiple generations to see genetic differences between populations," said Cavener."We know there was significant gene flow between elephants in Tarangire and Ruaha in the recent past, but the corridors between the areas are currently blocked. Opening up these corridors could encourage gene flow, which can help maintain more genetically robust populations," added LohayThe researchers also suspected that the Eastern Arc Mountains in southern Tanzania could prevent gene flow between populations on opposite sides of the mountains in Ruaha and Selous. But while the populations had somewhat similar nuclear DNA, their mitochondrial DNA, which is passed on primarily through the maternal line, was much more varied."While female elephants tend to remain in the groups where they were born, males are ejected from the herd when they reach sexual maturity, which can facilitate gene flow between groups," said Lohay. "When you see lots of differences in mitochondrial DNA markers but relatively few differences in nuclear markers, it can be a hint that males are migrating but females are not. It's a crude measurement, but that might be what are seeing here. In the future, we'd like ascertain the parentage and relationships between individuals so we can better understand the role of males in gene flow in these populations."The study also sheds light onto the history of recolonization of the Serengeti, where elephant populations were almost completely wiped out due to poaching in the late 1800s and, after rebounding somewhat in the 1960s, drastically declined again in the 1980s. The researchers found that mitochondrial DNA of elephants in the northern Serengeti differed from those in the southern Serengeti, suggesting that two distinct groups of elephants arrived from outside the area in the early 1960s when recolonizing the area."Understanding these relationships and population histories can help inform future conservation efforts," said Lohay. "This study provides a baseline for future genetic studies on these remarkable animals. We also provide recommendations for wildlife corridors that should be prioritized for conservation in order to maintain potential gene flow between populations. Although we can't be certain elephants will use certain corridors, at the moment they have limited options and are facing serious habitat losses due to human encroachment."
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November 19, 2020
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https://www.sciencedaily.com/releases/2020/11/201119141729.htm
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Very hungry and angry, caterpillars head-butt to get what they want
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Inspired by his own butterfly garden at home, a Florida Atlantic University neuroscientist got a unique look at how monarch butterfly (Danaus plexippus) caterpillars behave when food is scarce. The results look something like a combination of boxing and "bumper" cars.
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With less access to their favorite food -- milkweed -- they go from docile to domineering, aggressively head-butting, lunging and knocking aside other caterpillars to ensure their own survival. And, they are most aggressive right before the final stages of their metamorphosis. A lack of nutrition during larval stages has been shown to delay larval development as well as reduce adult body size, reproductive performance and lifespan."Aggression is common in insects, including fruit flies, where single-pheromone receptors or single genes have been shown to trigger their aggression," said Alex Keene, Ph.D., lead author and a professor of biological sciences, FAU's Charles E. Schmidt College of Science. "I decided to investigate monarch caterpillars because I was intrigued by their combative behavior, which I observed first-hand in my own garden. They are large and easily recognizable compared to many other insects. These are charismatic animals that everyone loves, and there's a growing appreciation for their potential to tell us about how the brain controls behavior."For the study, published in the journal The process of getting to that result also was challenging. The researchers had difficulty breeding the monarchs in the lab, and found that almost every nursery sells their milkweed with pesticides. That's why they ended up growing their own milkweed.To examine whether caterpillars display aggressive behavior, Keene and collaborators quantified the presence of aggressive lunges under a number of conditions, as well as the effect of attacks on target conspecifics. Monarch caterpillars predominantly feed on milkweed and often strip entire plants bare of leaves over a two-week period. In many locations, milkweed is only available for part of the year, placing a significant constraint on monarch development. Monarchs also impact the milkweed plants they consume -- at their largest and hungriest phase, a single caterpillar may devour an entire milkweed leaf in under five minutes."If you compare a monarch caterpillar to a fruit fly where there are lot of larvae on one piece of rotting fruit, you'll find that they feed socially with little evidence of territoriality," said Keene. "But each of these caterpillars will at some point in their developmental cycle encounter resource limitation because they can strip an entire milkweed of leaves."While observing the caterpillars, researchers noticed that the monarch's tentacles, large mechanosensory appendages, were not utilized when they were being combative. This finding suggests that alternative sensory modalities, such as pheromonal, olfactory or tactile cues that are independent of the tentacles initiate aggression. The researchers believe that aggression induced by limited food availability in monarch caterpillars are likely present in many different species throughout the animal kingdom."While our research showed that the caterpillars respond aggressively to limited food, we still hope to learn more about what drives this response in their brains, which is important for learning more about how these responses work outside the lab," said Keene. "One of the fundamental problems with work like this is that we're testing animals in a very derived setting. And that's not what brains evolved to do. So now that we have this invertebrate model in a relatively controlled setting, but doing an ecologically relevant behavior, that becomes important in terms of looking at the mechanism and function of this behavior in more complex organisms."Beyond the study of aggression in caterpillars, monarchs present an emerging model for studying the molecular mechanisms underlying behavior and set the stage for future investigations into the neuroethology of aggression in this system.
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Animals
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November 19, 2020
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https://www.sciencedaily.com/releases/2020/11/201119135403.htm
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The secret social lives of giant poisonous rats
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The African crested rat (
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"It's considered a 'black box' of a rodent," said Sara Weinstein, lead author and Smithsonian-Mpala postdoctoral fellow and postdoctoral researcher at the University of Utah. "We initially wanted to confirm the toxin sequestration behavior was real and along the way discovered something completely unknown about social behavior. Our findings have conservation implications for this mysterious and elusive rat."People in East Africa have long suspected the rat to be poisonous. A 2011 paper proposed these large rodents sequester toxins from the poison arrow tree ("The initial 2011 study observed this behavior in only a single individual. A main goal of our study was to determine how common this exceptional behavior was," said co-author Denise Dearing from the University of Utah.When threatened, the African crested rat lives up to its name and erects a crest of hair on its back to reveal a warning on its flanks -- black and white stripes running from neck-to-tail on each side of its body. The 2011 study hypothesized that the rats chew the Acokanthera bark and lick the plant toxins into specialized hairs at the center of these stripes.In the new study, researchers trapped 25 African crested rats, the largest sample size of the species ever trapped. Using motion-activated cameras, they documented nearly 1,000 hours of rat behavior. For the first time, they recorded multiple rats sequestering Acokanthera toxins and discovered many traits that suggest the are social, and likely monogamous."Everyone thought it was a solitary animal. I've been researching this rat for more than ten years, so you would expect there to be fewer surprises," said Bernard Agwanda, curator of Mammals at the Museums of Kenya, co-author of this study and the 2011 paper. "This can carry over into conservation policy."As a postdoctoral fellow at the Mpala Research Centre, Weinstein first searched for the rats with camera traps, but found that they rarely triggered the cameras. Weinstein was then joined by Katrina Nyawira, the paper's second author and now a graduate student at Oxford Brookes University. Together, they spent months experimenting with live traps to capture the elusive rodents."We talked to rangers and ranchers to ask whether they'd seen anything." said Nyawira. Eventually they figured out that loading the traps with smelly foods like fish, peanut butter and vanilla, did the trick. "Out of 30 traps, we finally got two animals. That was a win. This thing is really rare."Those two animals changed the course of the study. They first caught an individual female, then caught a male at the same site two days later."We put these two rats together in the enclosure and they started purring and grooming each other. Which was a big surprise, since everyone we talked to thought that they were solitary," Weinstein said. "I realized that we had a chance to study their social interactions."Weinstein and Nyawira transformed an abandoned cow shed into a research station, constructing stalls equipped with ladders and nest boxes to simulate their habitat in tree cavities. They placed cameras in strategic spots of each pen and then analyzed every second of their footage, tracking the total activity, movement and feeding behavior. The aim was to build a baseline of normal behavior before testing whether behavior changed after the rats chewed the toxin cardenolides from the poison arrow tree."They're herbivores, essentially rat-shaped little cows," Weinstein said. "They spend a lot of time eating, but they walk around, mate, groom, climb up the walls, sleep in the nest box."The footage and behavioral observations strongly support a monogamous lifestyle. They share many of the traits common among monogamous animals: large size, a long life span and a slow reproductive rate. Additionally, the researchers trapped a few large juveniles in the same location as adult pairs, suggesting that offspring spend an extended period of time with their parents. In the pens, the paired rats spent more than half of their time touching each other, and frequently followed each other around. The researchers also recorded special squeaks, purrs and other communicative noises making up a wide vocal repertoire. Further behavioral studies and field observation would uncover more insights into their reproductive and family life.After the researchers established a baseline of behavior, they offered rats branches from the poison arrow tree. Although rats did not sequester every time the plant was offered, 10 rats did at least once. They chewed it, mixed it with spit, and licked and chewed it into their specialized hairs. Exposure to the Acokanthera toxins did not alter rat behavior, and neither did eating milkweed, the same cardenolide-enriched plant used as chemical defense by monarch butterflies. Combined, these observations suggest that crested rats are uniquely resistant to these toxins."Most people think that it was a myth because of the potency of the tree," said Nyawira. "But we caught it on video! It was very crazy."The rats were selective about using Acokanthera cardenolides, suggesting that rats may be picky about their toxin source, or that anointed toxins remain potent on the fur a long time, just like traditional arrow poisons from the same source.The African crested rat is listed as IUCN species of least concern, but there's little actual data on the animals. Agwanda has studied African crested rats for more than a decade -- and sees indications that they're in trouble."We don't have accurate numbers, but we have inferences. There was a time in Nairobi when cars would hit them and there was roadkill everywhere," said Agwanda, who continues to monitor the populations. "Now encountering them is difficult. Our trapping rate is low. Their population is declining."The research team is planning future studies to better understand their physiology and behavior. "We are particularly interested in exploring the genetic mechanisms that allow the crested rats and their parasites to withstand the toxic cardenolides" said co-author Jesús Maldonado of the Smithsonian Conservation Biology Institute and Weinstein's Smithsonian-Mpala Postdoctoral fellowship co-advisor."We are looking at a broad range of questions influenced by habitat change. Humans have cleared forests to make farms and roads. We need to understand how that impacts their survival," Agwanda said. Additionally, Agwanda is building an exhibit at the Museums of Kenya to raise awareness about this unique poisonous animal.
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November 19, 2020
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https://www.sciencedaily.com/releases/2020/11/201119103052.htm
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Can animals use iridescent colors to communicate?
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A new paper from the University of Melbourne reveals how animals use beautiful but unreliable iridescent colours as communication signals. Special adaptations enable animals to control how these shifting colours appear so that they can convey reliable information.
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The new work now published in "Iridescence is tricky to study because the hue that you see depends on the position of the viewer and the direction of light," said senior author, Dr Amanda Franklin from the School of BioSciences."That means that iridescent colors change constantly, so it's hard to see how they can convey reliable information. The number one rule for communication is that the information must be reliable -- it's the same for both animals and humans!"But paradoxically, iridescent colours, like dazzling butterfly wings or dramatic peacock feathers, are widespread in the natural world.Co-author and PhD student Leslie Ng explains: "By studying how animals detect and process iridescence, we can get a better idea of when iridescence is actually a useful communication signal."Reliable iridescent signals usually come with behavioural or physical adaptations that help animals control the visual effect. For example, male Anna's hummingbirds precisely control their courtship flights so that their iridescent throats appear a constant bright pink colour to watchful females."Dr Franklin said organisms can do beautiful things with light."Through evolution, they have adapted microstructures to produce specific effects. Some use microstructures to control the precise angle at which the hue of iridescent colours appears to shift. In this way, they control the information they communicate with color."Ms Ng said many studies suggest iridescent colours are important for courtship or camouflage but rarely consider how these flashy signals are actually seen by animals. "Because of this, we know very little about how iridescence is processed in the animal's brain."The detection of iridescent signals also depends on how organisms display their colour patches, and the physical position of both the signaler and viewer. For example, an iridescent colour can be processed differently if it is flashed quickly, or if the colours are fast-moving.Lead author, Professor Devi Stuart-Fox, said the insights shed new light on the colourful world of animal communication and highlight the challenges of studying accurately how iridescent colours work in nature."Nature provides a testing ground for the detection and processing of dynamic and colourful signals," she said. "Understanding how animals reliably use and produce these shifting signals can help the development of bio-inspired iridescent materials designed for human observers."
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Animals
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November 18, 2020
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https://www.sciencedaily.com/releases/2020/11/201118141737.htm
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The single X chromosome of male fruit flies can be just as active as the two X chromosomes of females thanks to two sticky molecules
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Human females have two X chromosomes, and males only one. This chromosome imbalance also extends to other branches of the animal kingdom. Interestingly, the humble fruit fly has devised a different way to "equalize" these differences. Whereas human and mouse females shut down one of their X chromosomes, in fruit flies it instead the male doing the work. An epigenetic factor known as the MSL complex binds to the single male X chromosome and uses its histone acetylation function to hyperactivate the X to try to reach RNA production levels equivalent to those achieved by the two X chromosomes carried by females. If this process fails, male flies die.
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"One aspect that had always baffled researchers is how the MSL complex knows which of the 8 chromosomes carried by every fly cell is the X," explains Asifa Akhtar, Director at the MPI of Immunobiology and Epigenetics in Freiburg. This question motivated researchers in her team to design a novel and elaborate strategy to dissect how the MSL complex could identify the X. Instead of studying the fly MSL complex in its "native habitat," the researchers decided to transplant the complex into a totally foreign environment -- a mouse cell.The researchers decided to go back to basics and reverse engineer the mechanism of recognizing the X chromosome one component at a time. They started by expressing a single protein from the fly MSL complex, MSL2, in mice. At this point, they could not see anything happening. Based on previous work in flies, they hypothesized that another MSL complex component, the roX1 and roX2 long noncoding RNAs, might also be required. They, therefore, decided to throw one of these RNAs into the pot. After providing mouse cells with fly MSL2 and roX2 RNA, the researchers now observed distinct nuclear foci marked by roX2.Furthermore, the condensation of MSL2 and roX2 at these foci appeared to upregulate the expression of genes. The discrete nature and activation potential of these foci are strongly reminiscent of the X-chromosomal territories marked by the MSL complex in the "native" situation of the male fly. Fascinatingly, these experiments indicate that supplementing mouse cells with fly MSL2 and roX2 appears to be sufficient to recreate a mini fly X chromosome in mouse cells. This innovative approach thereby illuminated the minimal molecular components required for the first steps in recognition and activation of the fly X chromosome by the MSL complex.Now that the team had figured out the exact recipe for forming a mini fly X chromosome, they combined the two ingredients, roX RNA and MSL2, together in a test tube. They noted that these components took on a unique state. "When we mixed MSL2 and the roX RNA, we noticed something interesting. Both components -- although they were liquid in isolation -- started to form spherical particles and transitioned into a different phase that looked like a gel," says Claudia Keller-Valsecchi, co-first author of the study. Interestingly, both roX1 and roX2 RNAs are encoded by genes located on the X chromosome.The team speculated about a model where roX RNAs synthesized from the X chromosome induce the nearby "trapping" of MSL2 via their interaction and propensity to assemble into a gel-like state. "Levels of roX RNAs are predictive of how well the MSL complex is able to find the X chromosome. The more roX is synthesized from the X, the better the complex can distinguish the X from autosomes," added co-first author of the work Felicia Basilicata. On the other hand, other chromosomes do not produce the roX RNAs, and therefore have little chance of efficiently trapping the MSL complex in their vicinities.With their results, the team uncovered a new mechanism utilized by male flies to distinguish and mark the single X chromosome based on the assembly of a two-component roX-MSL2 gel. Male flies that fail to assemble this gel will die. "It is possible that the gel state also helps attract and trap other important components for dosage compensation, such as the transcription machinery required for increased RNA production," Asifa Akhtar explains future research questions.
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Animals
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November 18, 2020
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https://www.sciencedaily.com/releases/2020/11/201118141712.htm
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Studies focus on SARS-CoV-2 transmission in domestic cats, pigs
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Two recently published studies from Kansas State University researchers and collaborators have led to two important findings related to the COVID-19 pandemic: Domestic cats can be asymptomatic carriers of SARS-CoV-2, but pigs are unlikely to be significant carriers of the virus. SARS-CoV-2 is the coronavirus responsible for COVID-19.
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"Other research has shown that COVID-19-infected human patients are transmitting SARS-CoV-2 to cats; this includes domestic cats and even large cats, such as lions and tigers," said Jürgen A. Richt, the Regents distinguished professor at Kansas State University in the College of Veterinary Medicine. "Our findings are important because of the close association between humans and companion animals."There are about 95 million house cats in the U.S. and about 60 million to 100 million feral cats, Richt said.Richt is the senior author on the two recent collaborative publications in the journal Through their in-depth study at the K-State Biosecurity Research Institute, or BRI, at Pat Roberts Hall, the researchers studied susceptibility to infection, disease and transmission in domestic cats. They found that domestic cats may not have obvious clinical signs of SARS-CoV-2, but they still shed the virus through their nasal, oral and rectal cavities and can spread it efficiently to other cats within two days. Further research is needed to study whether domestic cats can spread the virus to other animals and humans."This efficient transmission between domestic cats indicates a significant animal and public health need to investigate a potential human-cat-human transmission chain," said Richt, who is also the director of the university's Center of Excellence for Emerging and Zoonotic Animal Diseases, known as CEEZAD, and the Center on Emerging and Zoonotic Infectious Diseases, known as CEZID.For the study involving pigs, the researchers found that SARS-CoV-2-infected pigs are not susceptible to SARS-CoV-2 infection and do not appear to transmit the virus to contact animals."Pigs play an important role in U.S. agriculture, which made it important to determine the potential SARS-CoV-2 susceptibility in pigs," Richt said. "Our results show that pigs are unlikely to be significant carriers of SARS-CoV-2."The BRI has provided the high-security laboratories for Richt and collaborators to study SARS-CoV-2. It is a biosafety level-3 and biosafety level-3 agriculture facility that houses important multidisciplinary research, training and educational programs on pathogens that affect animals, plants and insects, as well as food safety and security.Richt and his collaborators plan further studies to understand SARS-CoV-2 transmission in cats and pigs. They also plan to study whether cats are immune to SARS-CoV-2 reinfection after they have recovered from a primary SARS-CoV-2 infection."This research is important for risk assessment, implementing mitigation strategies, addressing animal welfare issues, and to develop preclinical animal models for evaluating drug and vaccine candidates for COVID-19," Richt said.The research has involved other K-State researchers from the department of diagnostic medicine and pathobiology in the College of Veterinary Medicine: Natasha N. Gaudreault, Jessie D. Trujillo, David A. Meekins, Igor Morozov, Daniel W. Madden, Sabarish V. Indran, Dashzeveg Bold, Velmurugan Balaraman, Taeyong Kwon, Bianca L. Artiaga, Konner Cool, Wenjun Ma and Jamie Henningson, also director of the Kansas State Veterinary Diagnostic Laboratory.Other researchers involved include Mariano Carossino and Udeni B. R. Balasuriya from Louisiana State University; William C. Wilson with the U.S, Department of Agriculture's Arthropod-Borne Animal Disease Research Unit; Adolfo García-Sastre with Icahn School of Medicine at Mount Sinai; and Heinz Feldmann with the National Institutes of Health's National Institute of Allergy and Infectious Diseases.
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Animals
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November 18, 2020
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https://www.sciencedaily.com/releases/2020/11/201118141636.htm
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The bull Y chromosome has evolved to bully its way into gametes
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In a new study, published Nov. 18 in the journal
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"When you have an X and a Y chromosome, it's a setup for conflict," said Page, who is also a professor of biology at the Massachusetts Institute of Technology and investigator with the Howard Hughes Medical Institute. "Seeing this full blown competition between the cattle X and Y means we have to think more deeply about this conflict as a constant and general feature of sex chromosomes in mammals."This insight into the forces that govern sex chromosome behavior and evolution will help scientists in Page's lab study genetic differences between males and females and how they play out in health and disease across every part of the body, Page added.Sex chromosomes -- the X and the Y -- evolved from a regular pair of symmetrical chromosomes some 200 million years ago. Those born biologically female have two X chromosomes. Those born biologically male have one X and one Y.Page's lab successfully sequenced the human Y chromosome in 2003, and afterwards the researchers wanted to be able to compare the sequence to its counterparts in other animals in order to help understand how they have evolved and diverged over time.To make these comparisons, researchers in Page's lab laid out a list of several mammals -- including chimps, opossums, and mice -- that occupied different branches of the mammalian family tree. One after another, the scientists began sequencing these creatures' Ys, using a high-resolution sequencing method called SHIMS -- short for Single-Haplotype Iterative Mapping and Sequencing -- to obtain a level of detail that other techniques, like shotgun sequencing, can't.This powerful sequencing technology allowed the researchers to observe a strange peculiarity of Y chromosomes: in some species, nearly all of the genetic material on the Y is made up of sequences of DNA that have been amplified dozens or hundreds of times over -- "like a hall of mirrors," Page said.In mice, for example, repeats of just a few testis-specific genes make up nearly 98 percent of the Y chromosome. In humans, however, repeats make up only about 45 percent. "We wanted to know if this was just a peculiarity of rodents, or if other Y chromosomes might come close," Page said.That's where the bull came in. "Outside of primates and rodents, the next branch off the mammalian tree includes bull," said Jennifer Hughes, a researcher in Page's lab and the first author of the paper. "We didn't know if the bull's Y chromosome would look like a mouse Y or a human Y or something else entirely."It took the Page Lab and collaborators at Baylor College of Medicine's Human Genome Sequencing Center, the McDonnell Genome Institute at Washington University, Texas A&M University, and other institutions more than a decade to tease apart the complexities of the bull Y chromosome. In fact, it turned out to be the most gene-dense of any Y chromosome ever mapped -- largely due to the fact that 96 percent of its genetic material was made up of repetitive sequences.As in the mouse, most of the bull's "hall of mirrors" repeats appeared to be expressed in the testis. But the question remained: Why? "What drives it can't just be purely making more sperm, because that's just overkill, right?" Hughes said. "You don't really need hundreds of copies of a gene to accomplish that task."The researchers found a clue when they took a closer look at the bovine X chromosome: the female-determining sex chromosome also had a few copies of these testis-specific genes. "We don't really know the mechanism in the bull, but the thought is that somehow the amplification of these genes in the Y has to do with helping the Y get passed on -- and the X copies are amplified to compete against that tendency and help the X," Hughes said.This X-Y arms race has been proven to happen in mice: somehow, repetitive genes on the Y chromosome give it an extra edge when it comes to ending up in the sperm during gamete formation. In a 2012 study, researchers knocked out the Y-chromosome repeats. Without the extra genes, more X chromosomes than Ys ended up in sperm cells, and the sex ratio of offspring skewed female. Over years of evolution, the X has developed repeats as well -- its own way to get a leg up in the race.Competition between X and Y chromosomes is selfish, Hughes said, because it's not a good thing for the species to have a skewed sex ratio. Thus, these alterations benefit only the lucky chromosome that ends up in the fertilized egg. The fact that a selfish -- and even detrimental -- mechanism would continue for millions of years in disparate branches of the evolutionary tree suggests that these conflicts may be an inevitable side effect of having a pair of asymmetrical sex chromosomes. "These X-Y arms races have probably been around for as long as mammals have been around," Page said.Evolutionary theory aside, knowing the mechanisms controlling the sex ratios of cattle could be of practical use in the coming years. "It could be of great interest to breeders, because they would love to be able to manipulate the sex of cattle offspring," Hughes said. "For example, dairy farmers would prefer more females and meat farmers would prefer more males."Right now, the lab is working on leafing out the branches of their Y chromosome evolutionary tree. The bull's is the seventh sex chromosome to be completely sequenced using the SHIMS method. Hughes, Page and the lab are also eyeing members of other animal groups, including reptiles."Our lab is focused on sex differences across the human body, and all of that work really is inspired by lessons that we've learned by comparing the Y chromosomes of different animals with our own," Page said. "It's like when you go to an art gallery and just sit on a bench and look and feel inspired -- these sequences are an infinite source of inspiration in the work we are doing. And we can now add the bull to our gallery."
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Animals
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November 17, 2020
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https://www.sciencedaily.com/releases/2020/11/201117192600.htm
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A Hox paradigm for studying protein evolution
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In a new study, researchers at the Stowers Institute for Medical Research have identified a handful of variations in an amino acid sequence critical for retaining the ancestral function of a gene over the course of 600 million years of evolution.
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The breakthrough discovery detailed in an article published online November 12, 2020, in "It's generally understood that gene duplication and divergence allow genes to take on new functions, while essential genes are conserved and remain unchanged during evolution," says Stowers Investigator Robb Krumlauf, PhD. "But how variation in proteins, the building blocks of life, affects this process has been unclear."The Krumlauf Lab at the Stowers Institute used a cross-species functional analysis of the The study used modern gene editing technologies, including CRISPR/CAS9, to replace the "In 600 million years of evolutionary time, only one gene has retained the ancestral activity," says Narendra Pratap Singh, PhD, a senior research associate in the Krumlauf Lab and first author of the article. "The other genes evolved and have taken on a new function. This was a great surprise."The researchers pinpointed a six amino acid sequence critical for the ancestral function of A1, which is important for modulating interactions with other proteins. Also surprising was the fact that the sequence makes up only 2% of total amino acids in the protein, suggesting that tiny differences in certain key regions can have a big impact on protein function."Subtle and seemingly innocuous differences in protein sequence can profoundly impact the course of evolution," says Stowers Investigator Kausik Si, PhD, an author on the study. "Also, in the evolution of protein function, we tend to focus on what is conserved. This study suggests we should start paying attention to small differences, because some of the most interesting biology is hidden in the tiny differences."In mice, HOXB1 appears to have evolved to have a new function in vertebrates to allow for greater diversity in facial expression and feeding behavior not found in invertebrates. Mutations in B1 in mice and humans affect facial morphology, neuronal development, and nerve function. In humans, Mobius syndrome, a neurological condition that results in lack of facial expressions, is sometimes associated with B1 mutations.The study builds on more than three decades of work on Hox genes, a family of "master planner" genes that control the layout of the developing embryo from head to tail. Krumlauf's seminal discovery that Hox genes are essentially the same in mice and fruit flies helped establish the idea that there is a common genetic tool kit and that many organisms have surprisingly similar genes. The lab's comparative studies in mouse, chick, and zebrafish, and more recently sea lamprey, continue to provide critical information on how different species use the same genetic toolkit to form diverse structures. Hox transcription factors are well-suited for investigations into gene duplication and divergence because of their expansion from invertebrates to mammals.The work paves the way for additional studies on the evolution of protein activity as well as further exploration into the role of conserved toolkit genes following gene duplication and divergence."I think we are poised to exploit the emerging strengths of structural biology, functional analyses, and genome engineering," Krumlauf says. "We can really ask, 'Is this role preserved in other invertebrates? Is this gene or protein really doing the same thing or has it evolved completely new functions?' I think there's a new era of analysis now feasible because of the power of gene editing."Additional contributors to the study include Bony De Kumar, PhD, Ariel Paulson, Mark E. Parrish, PhD, Ying Zhang, PhD, Laurence Florens, PhD, and Joan Conaway, PhD. This work was funded by the Stowers Institute for Medical Research.
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Animals
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November 17, 2020
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https://www.sciencedaily.com/releases/2020/11/201117113054.htm
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Abundance of prey species is key to bird diversity in cities
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Urbanisation represents a drastic change to natural habitats and poses multiple challenges to many wildlife species, thereby affecting the occurrence and the abundance of many bird species. A team of scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) and the Technische Universität Berlin (TUB) collaborated to analyse breeding bird data from the Senate of Berlin gathered by citizen scientists. They found that the abundance of invertebrates such as insects or spiders as prey is a key factor affecting bird diversity in the city. The more prey is available, the more diverse the urban bird communities are. This demonstrates the importance of species interactions for explaining urban biodiversity in addition to impacts of anthropogenic disturbance and habitat structure. The results are published in the scientific journal
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Species interactions profoundly shape the composition of wildlife communities, determining which species and how many individuals are found within given habitats. For example, the presence of strong competitors may result in a diminished abundance or exclusion of particular species. Similarly, prey abundance and distribution affect the numbers of predators in a community. "Although the importance of species interactions for generating biodiversity is widely recognized, studies of urban biodiversity usually focus on the impacts of anthropogenic disturbance and habitat structure, neglecting species interactions," says Stephanie Kramer-Schadt, head of the Leibniz-IZW Department of Ecological Dynamics and Professor at TUB.To assess to what extent species interactions affect avian diversity in cities, the team led by Aimara Planillo from Leibniz-IZW analysed breeding bird monitoring data and related them to invertebrate data. Bird data were collected by citizen scientists and provided by the Senate of Berlin, and invertebrate data were collected within a collaborative project of Berlin research institutions (BBIB-BIBS) funded by the German Ministry of Education and Research (BMBF). They investigated the impact of both food-related (prey availability) and non-food related (e.g. competition) species interactions on the responses of bird species to a gradient of increasing urbanisation, using data from 66 breeding bird species in the city of Berlin."By applying sophisticated modelling techniques to the biodiversity data, we demonstrated that prey invertebrate abundance is one of the most important factors affecting the urban bird biodiversity," says Planillo. Senior author Radchuk adds: "Importantly, the impact of prey abundance depends on the level of urbanisation. Prey abundance had a positive effect on bird diversity under low to medium urbanisation levels. For the highly urbanised areas, prey abundance does not affect bird community, as the bird species inhabiting such areas are those adapted to persist in urban environments and often benefit from human resources."Through these analyses the scientists were able to distinguish three different groups of bird species in Berlin, which differ in how they respond to environmental variables and to prey abundance. "We found urban species, woodland species and nature-area species in Berlin's bird community," Radchuk explains. "Urban species are akin to urban exploiters as they persisted at high abundance at high levels of anthropogenic disturbance. Woodland species are akin to urban adapters, they responded strongly to the urbanisation gradient and were favoured by high tree cover and invertebrate abundance. Finally, nature-area species were strongly negatively affected by urbanisation and positively by tree cover and open green area. They were also the least abundant of the three groups."This categorisation of bird species will allow the design of customised conservation strategies for target species. "Our findings point out that managing urban areas in a way that maintains and increases invertebrate biodiversity is very important for supporting bird diversity in cities," Planillo concludes. "In particular, in order to maintain or increase insect survival we suggest extensive or reduced mowing, leaving dead wood and stones in place, the preservation of set-aside lands and decreased use -- or preferably avoidance -- of pesticides."
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November 13, 2020
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https://www.sciencedaily.com/releases/2020/11/201113154620.htm
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Parasitic worms offer 'the missing link' on the dual nature of a key immune regulator
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De'Broski Herbert has a philosophy that's guided his career researching helminths, or parasitic worms, and their interaction with their hosts' immune systems: "Follow the worm."
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"The mantra of my lab since its inception has been that parasitic worms manipulate their hosts in very interesting ways to maintain their survival," says Herbert, an associate professor of pathobiology in Penn's School of Veterinary Medicine. "SARS-CoV-2 doesn't care about staying in your body very long because it is transmitted so easily. Worms aren't spread so easily, so they have to figure out how to persist."That focus has revealed a key insight about an immune signaling molecule, the cytokine IL-33, that is important not only in parasite infections, but in a range of other health conditions, such as asthma, obesity, and eczema. In a new study published in "Lots of people have been interested in IL-33 ever since two big genomic association studies implicated it and its receptor in the pathogenesis of asthma," Herbert says. "Other researchers have looked at it in the context of infections and others in the context of the brain and development. And everyone knew this protein was in the nucleus, but no one understood how it got out of the cell to accomplish all of these things."I'm excited for this work because not only do we find this cytokine in a cell type that nobody was expecting, but we also present a mechanism that no one was expecting for how it could come out."IL-33 has been of major interest to immunologists focused on what are known as type 2 immune responses, typically associated with parasite infections or asthma and allergies. On the parasite front, researchers knew that IL-33 acted in part to "wake up" the immune system to the presence of a worm infection. In a mouse model, animals lacking IL-33 sustain worm infections much longer than those with IL-33 intact.To find out whether it mattered which cell type was releasing the IL-33 signaling molecule, Herbert and colleagues used special mouse model in which only myeloid antigen-presenting cells (immune cells), or epithelial cells (those that line mucosal surfaces), failed to release IL-33."Sure enough, we found that when animals lacking the myeloid-derived IL-33 experienced a hookworm infection, they eliminated those hookworms quite fast," Herbert says. Mice lacking IL-33 in the epithelial cells, however, were not able to readily clear the infection. The same results held up in another rodent model, this one of roundworm infection.Dendritic cells, a type of myeloid antigen-presenting cell, produce IL-33, and further experiments showed that the cytokine produced by these cells supported a specific population of regulatory T cells (Tregs), which are cells "whose whole purpose is to suppress the immune response," Herbert says.Now understanding that dendritic cells were key to supporting Tregs, the researchers wanted to understand how the dendritic cells were delivering the IL-33. The team screened dendritic cells from mice with and without IL-33, identifying a protein called perforin-2 to be suppressed in expression from myeloid cells lacking IL-33.Perforin-2, as its name suggests, forms a pore that spans the cell membrane, like a tunnel in a hillside, allowing the transport of proteins in and out. The find made complete sense to the researchers, providing an explanation for how dendritic cells could promote the release of IL-33 into the tissues to interact with Tregs. And when Herbert and colleagues experimentally eliminated perforin-2 from dendritic cells, they saw a subsequent lack of Treg growth.To connect the findings in their animal model and lab dishes to humans, the team utilized patient samples from Penn otolaryngologist Noam Cohen. They found perforin-2 at the plasma membrane of cells from polyps removed from patients with chronic rhinosinusitis, suggesting that the significance of the findings extends to human health.The study paves the way for even more translational work in immunology -- and worms are to thank. "It's kind of the missing link," Herbert says. "It opens up a whole new direction for understanding how this cytokine could be involved in obesty, inflammatory bowel disease, Crohn's, asthma, and development."
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November 12, 2020
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https://www.sciencedaily.com/releases/2020/11/201112113141.htm
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Rats are capable of transmitting hantavirus
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A group of researchers from Charité -- Universitätsmedizin Berlin have confirmed Germany's first-ever case of animal-to-human transmission involving a specific species of virus known as the 'Seoul virus'. Working alongside colleagues from Friedrich-Loeffer-Institut (FLI), the researchers were able to confirm the presence of the virus in a young female patient and her pet rat. Their findings, which have been published in
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Following multiple outbreaks earlier in the 21st century, hantavirus disease syndromes have gained increasing levels of public attention and were made notifiable in Germany in 2001. The Puumala and Dobrava-Belgrade viruses, for instance, which are common across central Europe and can be spread by numerous types of mice, usually cause acute fever. Occasionally, infection may result in HFRS (hemorrhagic fever with renal syndrome), an illness characterized by fever, low blood pressure and acute kidney failure. The Seoul virus, in contrast, which is mainly found in Asia and transmitted exclusively by rats, is far more likely to cause severe disease. Even outside Asia, however, there have been numerous reports of rat-to-human transmission of this highly virulent virus.For the first time, a team of researchers led by Prof. Dr. Jörg Hofmann, Head of the National Consultant Laboratory for Hantaviruses at Charité's Institute of Virology, has been able to describe an autochthonous (i.e. acquired in Germany) case of Seoul virus infection transmitted by a rat. Working in close collaboration with a team of researchers led by Prof. Dr. Rainer G. Ulrich at the Friedrich-Loeffler-Institut (FLI) in Greifswald and colleagues at both local and regional health authorities, the researchers were able to identify the virus in samples from a young female patient from Lower Saxony and her pet rat. "The virus originally comes from Asia and was probably carried to Europe by wild rats on ships. However, it had not previously been observed in Germany," says the study's first author, Prof. Hofmann. The infected rat, which had been bred for domestic life, is likely to have been imported from a different country.After developing symptoms of acute kidney failure, the young patient required intensive care treatment and was hospitalized for several days. Serology testing quickly confirmed a suspected diagnosis of hantavirus infection. The species of hantavirus responsible, however, remained unclear.Working at Charité's specialist hantavirus laboratory, Prof. Hofmann and his team of researchers developed a special molecular diagnostic technique capable of identifying the Seoul virus in samples collected from the patient. Using the same technique, experts at the Friedrich-Loeffler-Institut were able to confirm that the patient's pet rat had been infected by the same virus. Explaining the results, Prof. Hofmann says: "Both viral sequences -- the patient's and the rat's -- were identical. This confirms that the disease was transmitted by an animal to a person -- which means it is a zoonotic disease.""Until now, only contact with mice would result in a suspected diagnosis of hantavirus infection. It will now be necessary to consider the possibility of infection after contact with either wild or domesticated rats as well," caution the study's authors. "The fact that this pathogen has been confirmed in a pet rat also means that the virus is capable of being exported, via the trade in these animals, practically anywhere in the world." Those keeping rats are therefore advised to exercise caution.
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November 11, 2020
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https://www.sciencedaily.com/releases/2020/11/201111153113.htm
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Wrinkle-faced male bats lower face masks to copulate
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The first behavioral observations of wrinkle-faced bats in their natural habitat reveal that this elusive species uses the rarest form of bat courtship behavior, according to a study published November 11 in the open-access journal
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This species appears to use lek courtship, in which females choose mates from clusters of sexually displaying presumably territorial males. Among mammals, lek courtship is known to be used by only 12 species, mainly seals and hoofed mammals. When females approached, the perched males beat their wings and emitted very loud, low-frequency whistling calls. The males lowered their masks immediately before copulation, then sang enthusiastically and raised their masks again after mating.According to the authors, future encounters with The authors add: "[
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November 11, 2020
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https://www.sciencedaily.com/releases/2020/11/201111144405.htm
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Compounds block stress-enhanced nicotine intake in rats
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Stress is a major cause of relapse after people quit smoking. Worrying situations, such as money or relationship problems, can affect neurotransmitter levels in the brain, leading former smokers to reach for a cigarette. Now, researchers reporting in
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GABA is an inhibitory neurotransmitter that decreases nerve signaling in the brain. When a person experiences stress, their GABA levels can decrease, causing some neurons to become hyperactive. Using an animal model, Burt Sharp and colleagues wanted to find out if giving rats compounds that stimulate GABAIn the animal model, rats were taught to press a lever to self-administer nicotine. After a week, the animals were withdrawn from nicotine for 8 days. To cause stress, the researchers confined the rats in a small space. After releasing the rodents, the team injected one of three compounds, called positive allosteric modulators of GABAThe authors acknowledge the gift of NS16085 from Karin S. Nielsen at Saniona AB, Denmark and partial funding from Lohocla Research, Inc.
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November 11, 2020
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https://www.sciencedaily.com/releases/2020/11/201111122830.htm
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New genome alignment tool empowers large-scale studies of vertebrate evolution
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Three papers published November 11 in
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Comparative genomics uses genomic data to study the evolutionary relationships among species and to identify DNA sequences with essential functions conserved across many species. This approach requires an alignment of the genome sequences so that corresponding positions in different genomes can be compared, but that becomes increasingly difficult as the number of genomes grows.Researchers at the UC Santa Cruz Genomics Institute developed a powerful new genome alignment method that has made the new studies possible, including the largest genome alignment ever achieved of more than 600 vertebrate genomes. The results provide a detailed view of how species are related to each other at the genetic level."We're literally lining up the DNA sequences to see the corresponding positions in each genome, so you can look at individual elements of the genome and see in great detail what has changed and what's stayed the same over evolutionary time," explained Benedict Paten, associate professor of biomolecular engineering at UC Santa Cruz and a corresponding author of two of the new papers.Identifying DNA sequences that are conserved, remaining unchanged over millions of years of evolution, enables scientists to pinpoint elements of the genome that control important functions across a wide range of species. "It tells you something is important there -- it hasn't changed because it can't -- and now we can see that with higher resolution than ever before," Paten explained.The previous generation of alignment tools relied on comparing everything to a single reference genome, resulting in a problem called "reference bias." Paten and coauthor Glenn Hickey originally developed a reference-free alignment program called Cactus, which was state-of-the-art at the time, but worked only on a small scale. UCSC graduate student Joel Armstrong (now at Google) then extended it to create a powerful new program called Progressive Cactus, which can work for hundreds and even thousands of genomes."Most previous alignment methods were limited by reference bias, so if human is the reference, they could tell you a lot about the human genome's relationship to the mouse genome, and a lot about the human genome's relationship to the dog genome -- but not very much about the mouse genome's relationship to the dog genome," Armstrong explained. "What we've done with Progressive Cactus is work out how to avoid the reference-bias limitation while remaining efficient enough and accurate enough to handle the massive scale of today's genome sequencing projects."Armstrong is a lead author of all three papers, and first author of the paper that describes Progressive Cactus and presents the results from an alignment of 605 genomes representing hundreds of millions of years of vertebrate evolution. This unprecedented alignment combines two smaller alignments, one for 242 placental mammals and another for 363 birds. The other two papers focus separately on the mammal and bird genome alignments.This international collaborative effort was coordinated by an organizing group led by coauthors Guojie Zhang at the University of Copenhagen and China National GeneBank, Elinor Karlsson at the Broad Institute of Harvard and MIT, and Paten at UCSC. The genomic data used in these analyses were generated by two broad consortia: the 10,000 Bird Genomes (B10K) project for avian genomes and the Zoonomia project for mammalian genomes.Scientists have been making plans for years to sequence and analyze the genomes of tens of thousands of animals. Coauthor David Haussler, director of the UCSC Genomics Institute, helped initiate the Genome 10K project in 2009. Related efforts include the Vertebrate Genome Project and the Earth BioGenome Project, and all of these projects are now gathering steam."These are very much forward-looking papers, because the methods we've developed will scale to alignments of thousands of genomes," Paten said. "As sequencing technology gets cheaper and faster, people are sequencing hundreds of new species, and this opens up new possibilities for understanding evolutionary relationships and the genetic underpinnings of biology. There is a colossal amount of information in these genomes."
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November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110190930.htm
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New fossil seal species rewrites history
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The discovery, published today in the
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It came after researchers examined seven preserved fossil specimens, including a complete skull, found by local fossil hunters on south Taranaki beaches in New Zealand between 2009 and 2016.The new species is named Eomonachus belegaerensis, (meaning 'dawn monk seal from Belegaer') after the sea of Belegaer, which lies west of Middle Earth in J.R.R. Tolkien's Lord of the Rings.Around 2.5 metres in length and weighing around 200 -- 250kg, Eomonachus belegaerensis lived in the waters around New Zealand some 3 million years ago.It was previously thought that all true seals originated in the North Atlantic, with some later crossing the equator to live as far south as Antarctica.Eomonachus now shows that many ancient seals, including the ancestors of today's monk, elephant and Antarctic seals, actually evolved in the Southern Hemisphere.Monash palaeontologist James Rule, a PhD candidate at the Biomedicine Discovery Institute, led the research as part of a trans-Tasman collaboration involving Monash University and Museums Victoria in Australia, and Te Papa and Canterbury Museum in New Zealand. The study was supervised and co-authored by Dr Justin Adams (Monash Biomedicine Discovery Institute), Dr Erich Fitzgerald (Museums Victoria), and Associate Professor Alistair Evans (School of Biological Sciences)."This new species of extinct monk seal is the first of its kind from the Southern Hemisphere. Its discovery really turns seal evolution on its head," Mr Rule said."Until now, we thought that all true seals originated in the Northern Hemisphere, and then crossed the equator just once or twice during their entire evolutionary history. Instead, many of them appear to have evolved in the southern Pacific, and then criss-crossed the equator up to eight times."Te Papa Museum of New Zealand curator of marine mammals and study collaborator Dr Felix Marx said the discovery was a triumph for citizen science."This new species has been discovered thanks to numerous, exceptionally well-preserved fossils -- all of which were found by members of the public."Dr Marx is hopeful about future discoveries of new species in New Zealand's ancient past."New Zealand is incredibly rich in fossils, and so far we have barely scratched the surface. Who knows what else is out there?" Dr Marx said.
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November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110133202.htm
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Animal groups consider multiple factors before fighting
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Groups of animals consider multiple factors before deciding whether to fight rivals, researchers say.
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Before one-on-one fights, animals are known to make decisions based on factors including the size and strength of the opponent, the outcome of recent fights and the importance of the prize.But scientists from the universities of Exeter and Plymouth say previous research has often overlooked complexity in group conflicts and assumed that larger groups will always win.Instead, they say factors like group cohesion and teamwork, the strength of individual members and the location of battle all likely play a part -- and animal groups weigh up the situation before fighting."Any potential fight -- whether between humans or animals -- gets more complex if there are multiple individuals on each side," said lead author Dr Patrick Green, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus in Cornwall."Groups may assess both the importance of whatever they're fighting about, and a range of factors about their own group and the opponent."Research on dyadic (one-on-one) fights has developed an advanced framework on 'assessment' -- how animals gather information and decide whether to fight, how much effort to put in, and if and when to give up."However, studies on group contests among social-living animals haven't generally focused on assessment."Understanding more about this can teach us not only about evolution, but also about conflict in humans."Fights between social groups are common in nature.Groups with more members are often assumed to be the likely winners of any fight, and indeed studies of animals including primates, lions, birds and ants show this is often correct.However, the study highlights other factors that can play a part:Co-author Mark Briffa, Professor of Animal Behaviour at the University of Plymouth, said: "Researchers have spent years wondering about the extent to which individual fighting animals use 'assessment' -- effectively, sizing their opponent up."In this paper, we explore the scope for groups of rivals to do a similar thing."This could be a possibility in many examples across the animal kingdom where individuals work collectively, such as battles between rival groups of ants or even warfare between rival groups in humans."Funders of the study included the Human Frontiers Science Program and the Natural Environment Research Council.
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November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110133150.htm
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Dietary overlap of birds, bats and dragonflies disadvantageous in insect decline
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According to a new Finnish study, different groups of insectivores compete for the same type of food. Researchers of the University of Turku, Finland, and the Finnish Museum of Natural History made a discovery by comparing birds, bats and dragonflies that forage in the same area in Southwest Finland. These very distantly related predators consumed the same insect groups, such as flies, mosquitoes, and other dipterans. The results shed new light on the decline in insect populations, because a remarkable portion of insectivores may actually be in greater danger than previously believed.
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According to the study, one common source of food for birds, bats and dragonflies is chironomids. These mosquito-lookalikes do not consume anything as adults and can be found in great masses on the surfaces of lakes and other water systems. In Finland alone, there are up to 800 species of chironomids. Chironomids are a very substantial and diverse family, and many insectivores have taken to their flavour. If an important group of insects like this dies out, the cascading effect on the nature and humans may be considerable.- This is exactly what causes deeper concern. If many predators consume roughly the same food, the decline of chironomids, for example, could lead to an unprecedented ecocatastrophe, explains University Lecturer Eero Vesterinen from the Department of Biology at the University of Turku.Eero Vesterinen, who designed the study, has studied interspecific interaction for over a decade, focusing on food chains, or more specifically food webs.- I compared the material I had collected along the years with the studies I had published, and noticed an exciting pattern. It seemed that even though predators that prey on insects are placed in different parts of the animal kingdom, and therefore do not share the same evolutionary history, there are clear similarities in their diet.A more precise analysis was conducted on insectivores that were collected from the same area in order for the available prey taxa to be comparable. The insectivores from Southwest Finland selected for the study were the European pied flycatcher, northern bat, brown long-eared bat, Daubenton's bat, whiskered bat, Brandt's bat, black darter, common spreadwing, northern bluet, spearhead bluet, crescent bluet, and variable bluet.- It is striking how similar the dietary composition between the invertebrates, such as dragonflies and the vertebrates, was in the study. These results also raise concerns about what would happen if the small dipterans that all our focal predators harvest would decline, says Senior Researcher Kari Kaunisto from the Biodiversity Unit at the University of Turku.- The majority of all the bats in the world are insectivores, and our previous studies have already revealed many significant details about their diet, notes Academy Research Fellow Thomas Lilley from the Finnish Museum of Natural History.The mass decline of insects has received extensive coverage in the recent years, and several reports based on long-term observations have been published on the topic. In places, the insect population has collapsed to under 50 percent, and news across the world is reporting similar events.- The situation may be worse than previously estimated, if the results of the new study can be generalised inter-continentally. Our study seems to have produced different and elaborated data that helps us focus our future research on the phenomenon's cascade effect higher in the food chain, ponders Vesterinen.
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November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110112508.htm
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Swedish, Finnish and Russian wolves closely related
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The Scandinavian wolf originally came from Finland and Russia, and unlike many other European wolf populations its genetic constitution is virtually free from dog admixture. In addition, individuals have migrated into and out of Scandinavia. These findings have emerged from new research at Uppsala University in which genetic material from more than 200 wolves was analysed. The study is published in the journal
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The origin of the Scandinavian wolf strain has long been a controversial topic. Previous genetic studies have indicated migration from the east, without being able to give unequivocal answers about the geographical provenance of this population. The new survey provides a clearer picture of how it formed."We can see that those wolves that founded the Scandinavian population in the 1980s were genetically the same as present-day wolves in Finland and Russian Karelia," says Hans Ellegren, professor of evolutionary biology at Uppsala University.These results are a culmination of earlier research. In 2019, the same research group published a study in which they had analysed wolves' Y-chromosome DNA only -- that is, the male-specific genes that can be passed on solely from fathers to their male offspring, showing paternal lineages over past generations. In the new, much more extensive study, also led by Hans Ellegren and Linnéa Smeds at Uppsala University, whole-genome sequences were analysed.From time to time, new wolves migrate into Sweden from the east. Now, on the other hand, the scientists found genetic evidence for migration in the opposite direction: Scandinavian-born wolves among animals found in Finland."We've probably never had a specific Scandinavian population. Throughout the ages, wolves have likely moved back and forth between the Scandinavian peninsula and regions to the east," Ellegren says.The researchers also sought answers to the question of whether there has been genetic mixing of dogs and Scandinavian wolves. Hybridisation between feral dogs and wolves is common in many parts of the world, and may be difficult to avoid. As late as in 2017, a hybrid wolf-dog litter was found in the county of Södermanland, southwest of Greater Stockholm. If such crossbreeds were allowed to reproduce, they would constitute a threat to the genomic integrity of the wolf strain.When genetic material from Scandinavian and Finnish wolves was compared with that from some 100 dogs of various breeds, however, the scientists were unable to find any evidence that wolf-dog hybridisation has left its mark on the genetic composition of this wolf population -- at least, no signs that recent crossbreeding has affected the wolves.
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November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110081548.htm
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Researchers develop DNA approach to forecast ecosystem changes
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When wolves returned to Yellowstone in 1995, no one imagined the predators would literally change the course of rivers in the national park through cascading effects on other animals and plants. Now, a Stanford University-developed approach holds the promise of forecasting such ecosystem changes as certain species become more prevalent or vanish altogether.
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Outlined in "It's not just that we can rapidly capture the biodiversity of an area," said study lead author Jordana Meyer, a biology PhD candidate in the Stanford School of Humanities and Sciences. "We can also quantify the extent of indirect links among species, such as how a specific predator's behavior affects vegetation in an area. This allows us to measure impacts on species that are essential to the system or particularly vulnerable."Just as the introduction of species, such as Yellowstone's wolves, can have widespread effects, their disappearance can be devastating in ways that are hard for scientists to predict. Meyer, whose work focuses primarily on African wildlife, has seen the impact first-hand in the Democratic Republic of Congo. There, the loss of large herbivores, such as rhinos and elephants, has led to the shrinking of once-massive grassland savannahs the creatures once grazed.As human impacts on wild places accelerate, effective conservation and ecosystem management will require more rapid, inexpensive and non-invasive technologies for capturing changes in biodiversity and quantifying species interactions. One of the most promising tools is the study of so-called environmental DNA in left-behind animal materials, such as hair and skin. After extracting the DNA, scientists sequence and compare it to online databases to identify the organisms present in a certain area. It's a relatively fast, low-maintenance process compared to traditional approaches, such as live-trapping, animal-tracking and camera trapping.Working at Stanford's 1,193-acre Jasper Ridge Biological Preserve, the researchers used their technique to analyze feces from carnivores such as mountain lions, omnivores such as gray foxes and herbivores such as black-tailed deer. By identifying the DNA in the diets of these animals, the researchers constructed an extraordinarily detailed, data-rich food web and accurately captured the biodiversity of the area when compared against other animal surveys and a long-term camera trap study in the preserve.Among other surprises, the new analysis revealed the indirect effects of a predator cascade on vegetation and allowed the researchers to determine exactly how predators competed with each other. These results were validated against evidence from camera trap data gathered at Jasper Ridge over the past seven years in which the return of mountain lions, the ecosystem's top predator, caused a decline in deer and coyote occurrence. Without its coyote competitor, the formerly rare gray fox returned to Jasper Ridge. Gray foxes subsist more on plants, namely fruits and seeds, than do coyotes. Thus, the rise in gray foxes can lead to alterations in the distribution and abundance of fruit plants at the preserve because seeds often remain viable after being digested by mammals. Armed with this type of knowledge, managers can predict the impacts of shifting animal and plant communities, which can, in turn, provide a framework for conservation-relevant decisions.The DNA the researchers collected in animal feces also identified plant and animal species not known to occur within the preserve, providing an early warning of invasive species."We are excited about this approach because it will not only help us to understand how and why species survive in protected areas based on what they eat, but also whether animals are able to capitalize on non-native plant and animal species," said study senior author Elizabeth Hadly, the Paul S. and Billie Achilles Professor in Environmental Biology in Stanford's School of Humanities and Sciences. Hadly's lab has pioneered work with left-behind and ancient DNA in the U.S., South America and India.These methods could aid in rewilding protected areas by allowing researchers to model how ecosystems will respond to certain species before they are actually reintroduced. For example, before reintroducing the African lion to protected parts of Africa, scientists could first study the biodiversity and connectivity of the areas and predict how the lions could impact prey populations and other knock-on effects they might trigger throughout the entire ecosystem.The researchers plan to scale-up their model across protected areas in Africa to assist in strategic adaptive management and rewilding strategies. "I am hopeful that techniques like this can help us secure and monitor natural spaces on a global scale," Meyer said.Hadly is also a faculty director of Stanford's Jasper Ridge Biological Preserve, a member of Stanford Bio-X and a senior fellow at the Stanford Woods Institute for the Environment. Co-authors of the study include Kevin Leempoel and Gianalberto Losapio, biology postdoctoral research fellows at Stanford at the time of the research.Video:
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November 10, 2020
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https://www.sciencedaily.com/releases/2020/11/201110102555.htm
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Female mongooses start battles for chance to mate
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Female banded mongooses lead their groups into fights then try to mate with enemy males in the chaos of battle, new research shows.
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Mongooses rarely leave the group into which they are born, meaning members are usually genetically related -- and the new study reveals how females get round the problem of inbreeding.The research team -- led by the University of Exeter and the University of Cambridge -- say females start fights for the genetic benefits of finding unrelated males.Meanwhile, males bear the costs of these fights, in which injuries and deaths are common.The researchers say "exploitative leadership" of this kind, which is also seen in human warfare, leads to frequent and damaging conflicts."We've known for some time that banded mongoose groups often engage in violent battles -- and now we know why," said Professor Michael Cant, of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall."Females start fights between groups to gain genetic benefits from mating with outsiders, while the males within their group -- and the group as a whole -- pay the costs."A classic explanation for warfare in human societies is leadership by exploitative individuals who reap the benefits of conflict while avoiding the costs."In this study, we show that leadership of this kind can also explain the evolution of severe collective violence in certain animal societies."Dr Faye Thompson, from the University of Exeter, added: "We tested our model using long-term data from wild banded mongooses in Uganda."The findings do not fit a heroic model of leadership, in which leaders contribute most to aggression and bear greatest costs, but rather an exploitative model, in which the initiators of conflict expose others to greater risks while contributing little to fighting themselves."The findings suggest that "decoupling" leaders from the costs of their choices "amplifies the destructive nature of intergroup conflict."Professor Rufus Johnstone of the University of Cambridge, who led the theoretical research, said: "Exploitative leadership in banded mongooses helps to explain why intergroup violence is so costly in this species compared to other animals."The mortality costs involved are similar to those seen in a handful of the most warlike mammals, including lions, chimpanzees and of course humans."
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November 9, 2020
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https://www.sciencedaily.com/releases/2020/11/201109184912.htm
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Researchers identify new Rickettsia bacteria species in dogs
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Researchers at North Carolina State University have identified a new species of Rickettsia bacteria that may cause significant disease in dogs and humans. This new yet unnamed species, initially identified in three dogs, is part of the spotted-fever group Rickettsia which includes Rickettsia rickettsii, the bacteria that cause Rocky Mountain Spotted Fever (RMSF).
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Rickettsia pathogens are categorized into four groups; of those, spotted-fever group Rickettsia (which are transmitted by ticks) is the most commonly known and contains the most identified species. There are more than 25 species of tick-borne, spotted-fever group Rickettsia species worldwide, with R. rickettsii being one of the most virulent and dangerous.For dogs, R. rickettsii is the only known spotted fever group Rickettsia that causes clinical disease in North America. Symptoms of RMSF in dogs and people are similar, including fever, lethargy, weight loss and symptoms related to vascular inflammation, like swelling, rash and pain.In 2018 and 2019, three dogs from three different states (Tennessee, Illinois and Oklahoma) with exposure to ticks and RMSF-associated symptoms had blood samples taken, to test them for R. rickettsii. While the samples reacted positively to antibody tests for R. rickettsii, when researchers at NC State utilized polymerase chain reaction (PCR) to amplify the pathogen's DNA from the samples, the DNA they retrieved was only 95% similar to R. rickettsii."Often, antibodies from other spotted fever group Rickettsia will cross-react in antibody tests for RMSF," says Barbara Qurollo, associate research professor at NC State and corresponding author of a paper describing the work. "So to be sure what we're dealing with, we also look at the genetic information via PCR and that's how we found that this is a new organism."The initial PCR work led Qurollo and James Wilson, a PCR technician at NC State and first author of the study, to pursue the new bacteria further. They performed additional PCRs to amplify different genes and examined five different regions of the bacteria's DNA, comparing it to the sequenced DNA from other spotted fever group Rickettsia. They also performed a phylogenetic tree analysis, which allowed them to place the new Rickettsia firmly within the spotted fever group.Before naming this new Rickettsia species, Qurollo and colleagues want to culture the organism, which would allow for better characterization of the new species. Culturing Rickettsia species from small amounts of a clinical sample has been difficult to do thus far."We're going to continue looking for this Rickettsia species, determine its geographical range and try to better characterize it -- it's a slow process, but high on our radar," Qurollo says. "So far in 2020 we've detected this new Rickettsia species in four more dogs residing in the southeastern and midwestern U.S. We're also asking veterinarians to collect the ticks associated with dogs who show symptoms when possible, and we're collaborating with researchers in Oklahoma to collect ticks in the environment for testing. This will help us determine what tick species may be transmitting this particular bacteria."Another question we would like to answer is whether this new Rickettsia species also infects people. Dogs are great sentinels for tick-borne diseases -- they have high rates of exposure to ticks and the ability to become infected with many of the same tick-borne pathogens that infect people. We hope to take a 'One Health' approach to this new pathogen and collaborate with scientists in human medicine as well."
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November 7, 2020
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https://www.sciencedaily.com/releases/2020/11/201107133915.htm
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Migration and molt affect how birds change their colors
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In late summer and autumn, millions of birds fly above our heads, often at night, winging their way toward their wintering grounds.
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Before the journey, many birds molt their bright feathers, replacing them with a more subdued palette. Watching this molt led scientists to wonder how feather color changes relate to the migrations many birds undertake twice each year. Molt matters -- not only because replacing worn feathers is necessary for flight, but because molt is the catalyst for plumage changes that affect whether birds find mates and reproduce."We're really blessed here, as nature lovers and birdwatchers, that we have lots of species of warblers here, which come in blues, greens, red and yellows," said Jared Wolfe, assistant professor in Michigan Technological University's College of Forest Resources and Environmental Science and one of the founders of the Biodiversity Initiative. "These brightly colored birds migrate and nest here and then leave for the winter. Everyone is so focused on the coloration, but the mechanism of the change of coloration is the process of molt, of replacing feathers."While migration distances vary, many species fly thousands of miles each year, chasing summer as the planet tilts toward and away from winter. These lengthy journeys tend to wear out feathers. In research published in the journal Ecology and Evolution, Wolfe and co-authors analyzed the variation in distances traveled against the extent of molt in a particular species. "Birds that go farther distances replace more feathers," said Wolfe."Sun is the primary reason feathers degrade, and harsh environments," he said. "In northerly latitudes in the summer, it's sunny all day. As the birds move south, tracking the sun, they are maximally exposing themselves to sun all year."Feathers must be replaced because of wear and tear; what's the significance of brightly colored plumage? Wouldn't black be more protective against sunburn, or white better at deflecting heat?For birds, like many animals, an attention-getting physical appearance plays a crucial role in attracting a mate. As stylish haircuts and makeup are to humans, beautiful feathers are to birds. But a spectacular plumage is also pragmatic; it broadcasts age and health, which determine who gets to mate and who doesn't."Bright plumages are signals of habitat quality in the tropics," Wolfe said. "Acquiring mates is based on a signal of habitat quality from the wintering grounds. Undergoing a second molt on the wintering grounds before migrating north allows the birds to become colorful. Color is a signal to potential mates in places like the Midwest what jungle wintering habitats are like."Experiences during the winter months affect how colorful birds become, which affects how successful they are at finding mates and breeding in North America. Scientists call these carryover effects. "It's so elegant, but we're just now starting to understand it," Wolfe said.Growing vibrant feathers is a physically taxing activity, and the easier a bird has it during the winter, the more brightly colored their plumage during the summer. This makes quality and availability of food, places to shelter and safety from predators important components of a wintering habitat.Like humans seeking out coveted locations to live, birds flock to the best habitats. In both cases, resources are finite. What might have been an ideal wintering ground one year might be depleted of food sources or other important attributes the next."The best habitats offer resource stability over time, versus poorer quality habitats which are variable month-to-month, year-to-year," he said.But what about birds that don't migrate, preferring to spend their lives within a single home range? For them, it turns out molt is comparable to changing one's clothes on a regular basis rather than changing appearances to impress someone. Molting and breeding are constricted by multiple factors: Seasons, food abundance and size of home range play major roles in plumage and feather replacement."Birds here in the temperate zones are restricted in when they can breed and undergo their annual molt by winter," Wolfe said. "In the tropics, there are wet and dry seasons, but there is less constraint from a real absence of food sources. Molt is an expensive process calorically; birds need lots and lots of food while they're molting."Wolfe and his collaborators found that adjusting the time it takes Amazonian birds to complete their annual molt affects how they go about making a living. For example, ant-following birds in Brazil eat insects that are trying to outrun army ants. One tiny species, the white-plumed antbird, opportunistically darts ahead of the ants -- not your garden variety ant but a species that can overpower and eat lizards, birds and small mammals in addition to insects -- to take advantage of a moveable feast."Its molt is crazy slow; it takes an entire year," Wolfe said, noting that the bird essentially lives in a constant state of molt, dropping one feather at a time.Obligate antbirds have huge home ranges that overlap with multiple army ant colonies, which means they spend a large part of their day flying around the jungle in search of army ants. The bird's lengthy daily commute is a problem when they molt wing feathers, which creates gaps in their wings and compromises their ability to fly. How do they get around this problem? A very slow molt."A single feather at a time to minimize gaps thereby improving their ability to fly and maintain large home ranges," Wolfe said. "This unique adaptation has made the white-plumed antbird the slowest-molting songbird on Earth."Despite the predilection of migrant birds to return to the same breeding territory year after year, Wolfe and collaborators note that not all birds return to the same molting grounds. This finding confounds the assumption of home field advantage, where birds benefit from completing their annual molt in a familiar location. But it appears there isn't much of a relationship between molting activity and what Wolfe calls "site fidelity.""Until our research, it had remained a mystery whether or not migratory songbirds return to the same site to molt," Wolfe said. "This is an important question because there is growing evidence that mortalities accrued after the breeding season -- during molt, migration and overwintering periods -- is responsible for the continued loss of migratory songbirds. In fact, bird abundance has decreased by 29% since 1970. Understanding where and why birds molt is an important step towards protecting vulnerable populations of songbirds."Wolfe and colleagues used 31 years of bird banding data from northern California and southern Oregon to measure the site fidelity of 16 species of songbird during molt. While the researchers did find that breeding activity strongly correlated with site fidelity, molt did not appear to influence a bird's decision to return to a particular place or not. It appears that birds, like humans, tend to splurge on fine feathers -- and then go home to show them off.
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November 6, 2020
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https://www.sciencedaily.com/releases/2020/11/201106134327.htm
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Ancient crocodiles' family tree reveals unexpected twists and turns
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Scientists probing a prehistoric crocodile group's shadowy past have discovered a timeless truth -- pore over anyone's family tree long enough, and something surprising will emerge.
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Despite 300 years of research, and a recent renaissance in the study of their biological make-up, the mysterious, marauding teleosauroids have remained enduringly elusive.Scientific understanding of this distant cousin of present day long snouted gharials has been hampered by a poor grasp of their evolutionary journey -- until now.Researchers from the University of Edinburgh have identified one previously unknown species of teleosauroid and seven of its close relatives -- part of a group that dominated Jurassic coastlines 190 to 120 million years ago.Their analysis offers tantalising glimpses of how teleosauroids adapted to the momentous changes that occurred during the Jurassic period, as the earth's seas experienced many changes in temperature."Our study just scratches the surface of teleosauroid evolution," says study lead Dr Michela M. Johnson, of the University's School of GeoSciences. "But the findings are remarkable, raising interesting questions about their behaviour and adaptability."These creatures represented some of the most successful prehistoric crocodylomorphs during the Jurassic period and there is so much more to learn about them."The study reveals that not all teleosauroids were engaged in cut and thrust lifestyles, snapping at other reptiles and fish from the seas and swamps near the coast.Instead, they were a complex, diverse group that were able to exploit different habitats and seek out a variety of food sources. Their physical make-up is also more diverse than was previously understood, the scientists say.Previous research had provided insights into the origins and evolution of this fossilised croc's whale-like relatives metriorhynchids, but less was known about teleosauroids.To address this, the expert team of palaeontologists examined more than 500 fossils from more than 25 institutions around the world.Cutting edge computer software enabled the team to glean swathes of revealing data regarding their anatomical similarities and differences, by examining the entire skeleton, teeth and bony armor, which indicated whether species were closely related or not.This information enabled the team to create an up-to-date family tree of the teleosauroids group from which emerged two new large groups, whose anatomy, abundance, habitat, geography and feeding styles differ from one another significantly.The first group, teleosaurids, were more flexible in terms of their habitat and feeding. The second group known as machimosaurids -- which included the fearsome turtle crushers, Lemmysuchus and Machimosaurus -- were more abundant and widespread.Names given by the team to seven newly described fossils, found in both teleosaurids and machimosaurids, reflect a curious range of anatomical features -- among them Proexochokefalos, meaning 'large head with big tuberosities' and Plagiophthalmosuchus, the 'side-eyed crocodile'.There are even hints of their diverse behavioural characteristics and unique locations -- Charitomenosuchus, meaning 'graceful crocodile' and Andrianavoay, the 'noble crocodile' from Madagascar.Researchers have named the newly discovered species, Indosinosuchus kalasinensis, after the Kalasin Province in Thailand, where the fossil -- now housed in Maha Sarakham University -- was found.The recognition of I. kalasinensis shows that at least two species were living in similar freshwater habitats during the Late Jurassic -- an impressive feat as teleosauroids, with the exception of Machimosaurus, were becoming rare during this time.Dr Steve Brusatte, Reader in Vertebrate Palaentology, at the School of Geosciences, University of Edinburgh, said: "The same way family trees of our own ancestors and cousins tell us about our history, this huge new family tree of teleosauroids clarifies their evolution. They were some of the most diverse and important animals in the Jurassic oceans, and would have been familiar sights along the coastlines for tens of millions of years."The study, published in the scientific journal PeerJ, was funded by the Natural Sciences and Engineering Council of Canada, SYNTHESYS Project and Leverhulme Trust Research. The Palaeontological Association and Paleontological Society provided travel grants.
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November 5, 2020
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https://www.sciencedaily.com/releases/2020/11/201105183832.htm
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Earliest example of a rapid-fire tongue found in 'weird and wonderful' extinct amphibians
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Fossils of bizarre, armored amphibians known as albanerpetontids provide the oldest evidence of a slingshot-style tongue, a new Science study shows.
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Despite having lizardlike claws, scales and tails, albanerpetontids -- mercifully called "albies" for short -- were amphibians, not reptiles. Their lineage was distinct from today's frogs, salamanders and caecilians and dates back at least 165 million years, dying out only about 2 million years ago.Now, a set of 99-million-year-old fossils redefines these tiny animals as sit-and-wait predators that snatched prey with a projectile firing of their tongue -- and not underground burrowers, as once thought. The fossils, one previously misidentified as an early chameleon, are the first albies discovered in modern-day Myanmar and the only known examples in amber.They also represent a new genus and species: Yaksha perettii, named after treasure-guarding spirits known as yakshas in Hindu literature and Adolf Peretti, the discoverer of two of the fossils."This discovery adds a super-cool piece to the puzzle of this obscure group of weird little animals," said study co-author Edward Stanley, director of the Florida Museum of Natural History's Digital Discovery and Dissemination Laboratory. "Knowing they had this ballistic tongue gives us a whole new understanding of this entire lineage."The discovery began with a bumble.In 2016, Stanley and Juan Diego Daza, lead author of the Science study and assistant professor of biological sciences at Sam Houston State University, published a paper presenting a dozen rare amber fossil lizards -- or so they thought. One juvenile specimen possessed a hodgepodge of bewildering characteristics, including a specialized tongue bone. After much debate and consultation with colleagues, the scientists finally labelled it an ancient chameleon, about 99 million years old, an estimate based on radiometric dating of crystals at the site where the fossil was found.When she read the study, Susan Evans, professor of vertebrate morphology and paleontology at University College London and an albie expert, instantly recognized the puzzling specimen. It was no chameleon. She emailed Daza."I remember that as one of the worst days of my life," he said.But the paper also attracted the attention of an unexpected collaborator: Peretti, a gemologist who contacted Daza about another collection of amber fossil lizards from the same region of Myanmar. (Note: The mining and sale of Burmese amber are often entangled with human rights abuses. Peretti acquired the fossils legally from companies that follow a strict ethical code. More details appear in an ethics statement at the end of this story).Per Daza's recommendation, Peretti sent the collection to the University of Texas at Austin for CT scanning, a way of clarifying what lies inside. As Daza began cleaning up the scans, one fossil in particular caught his eye -- the complete skull of an adult albie.Most fossil albies are crushed flat or a jumble of bones in disarray. In 1995, Evans published the first description of a complete specimen, excavated in Spain, but "it was very much roadkill," she said. Even amber fossils suffer degradation, and soft tissues can mineralize, becoming difficult to work with.This specimen, however, was not only three-dimensional, "it was in mint condition," Stanley said. "Everything was where it was supposed to be. There was even some soft tissue," including the tongue pad and parts of the jaw muscles and eyelids.It was also the adult counterpart to the juvenile albie that had been mistaken for a chameleon.When Daza sent the scan to Evans, she was dazzled by its rich detail."All my Christmases have come at once!" she wrote back.Once classified as salamanders, albies' stippled, reinforced skulls led many scientists to hypothesize they were diggers. No one imagined them as having chameleonlike lifestyles, Stanley said. But, he added, "if you're going to misidentify an albie as any kind of lizard, a chameleon is absolutely what you would land on."Even though one is an amphibian and the other a reptile, they share several features, including claws, scales, massive eye sockets and -- we now know -- a projectile feeding mechanism.The chameleon tongue is one of the fastest muscles in the animal kingdom and can rocket from 0 to 60 mph in a hundredth of a second in some species. It gets its speed from a specialized accelerator muscle that stores energy by contracting and then launching the elastic tongue with a recoil effect. If the earliest albies also had ballistic tongues, the feature is much older than the first chameleons, which may have appeared 120 million years ago. Fossil evidence indicates albies are at least 165 million years old, though Evans said their lineage must be much more ancient, originating more than 250 million years ago.While armed with a rapid-fire tongue, Y. perettii was tiny: Based on the fossil skull, Daza estimates the adult was about 2 inches long, not including the tail. The juvenile was a quarter that size."We envision this as a stocky little thing scampering in the leaf litter, well hidden, but occasionally coming out for a fly, throwing out its tongue and grabbing it," Evans said.The revelation that albies had projectile tongues helps explain some of their "weird and wonderful" features, such as unusual jaw and neck joints and large, forward-looking eyes, a common characteristic of predators, she said. They may also have breathed through their skin, as salamanders do.Even though the specimens are remarkably preserved, Stanley said CT scanning was essential to the analysis, revealing fine-scale features obscured in the cloudy amber."They only come to life with CT scanning," he said. "Digital technology is really key with this amber material."Digitization also enabled the researchers, scattered around the world and hunkered down during COVID-19 quarantines, to collaboratively analyze and describe the specimens -- and then make the same material digitally available to others.Despite the level of preservation and completeness of the Y. perettii specimens, albies' exact place in the amphibian family tree remains a mystery. The researchers coded the specimens' physical characteristics and ran them through four models of amphibian relationships with no clear results. The animals' unusual combination of features is likely to blame, Evans said."In theory, albies could give us a clue as to what the ancestors of modern amphibians looked like," she said. "Unfortunately, they're so specialized and so weird in their own way that they're not helping us all that much."But Y. perettii does put albies on a new part of the map. Northwest Myanmar was likely an island 99 million years ago and possibly a remnant from Gondwana, the ancient southern continental landmass. With two exceptions in Morocco, all other fossil albies have been found in North America, Europe and East Asia, which formerly formed a northern continental landmass. Daza said Y. perettii may have rafted to the island from mainland Asia or could represent a new southern record for the group.With such a wide distribution, why did albies vanish into extinction while frogs, salamanders and caecilians still exist today?We don't know. Albies almost survived to the present, fading out about 2 million years ago, possibly late enough to have crossed paths with our earliest hominid relatives, Evans said."We only just missed them. I keep hoping they're still alive somewhere."
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November 4, 2020
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https://www.sciencedaily.com/releases/2020/11/201104194703.htm
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Eradicating black rats on Palmyra Atoll uncovers eye-opening indirect effects
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The black rats weren't supposed to be there, on Palmyra Atoll. Likely arriving at the remote Pacific islet network as stowaways with the U.S. Navy during World War II, the rodents, with no natural predators, simply took over. Omnivorous eating machines, they dined on seabird eggs, native crabs and whatever seed and seedling they could find.
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When the atoll's managers -- the U.S. Fish and Wildlife Service, The Nature Conservancy and Island Conservation -- were planning to conduct a rat eradication project, UC Santa Barbara community ecologist Hillary Young and her research group saw it as an unusual opportunity. They had already been visiting Palmyra regularly to track another non-native species -- the coconut palm -- to see whether it was spreading invasively in the area, potentially impacting the nesting seabird population and changing the island's soil composition. They had plots where they were monitoring trees in various stages of growth and survival; how would the vegetation respond to the eradication of the island's main seed and seedling eater?"Prior to the eradication, most of the understory of Palmyra was either bare ground -- sandy soil or coral rubble -- or covered in a carpet of ferns," said Ana Miller-ter Kuile, a graduate student researcher in the Young Group and lead author of a study that appears in the journal Eradication of the rats -- which was conducted in 2011 -- did in fact result in a resurgence of vegetation on Palmyra. And not only that. The Asian tiger mosquito was wiped out, while two species of land crab emerged, adding to the atoll's biodiversity.But rarely is ecology easily untangled. In the years that followed eradication, Palmyra's understory did indeed fill with juvenile trees as seeds that hit the ground were allowed to take root. Only they were often not the Pisonia or other native trees that would have been the more ideal forests for the native seabirds and animals of Palmyra."I was on the island in 2012, just after the eradication and could easily navigate through the open jungle understory," Miller-ter Kuile said. "Two years later when I went back, I was wading through an infuriating carpet of seedlings that were taller than me, tripping over piles of coconuts." While the researchers found a 14-fold increase in seedling biomass, most of these new seedlings were juvenile coconut palms, their proliferation left unchecked by the removal of the rats."Rats were basically eating almost every nut before it even reached the forest floor," Miller-ter Kuile said. "I knew that rats could have an impact, I just didn't expect it to be this large." In the absence of rats, according to a population model the researchers built based on a decades' worth of data on coconut seed production, growth and survival, the coconut palms' population growth rate increased by 10% -- enough to eventually overtake the island, had the managers not stepped in with an aggressive coconut palm removal project.The coconut palm invasion is a problem for places like Palmyra Atoll, as it shifts the island's ecology away from native plants and animals."Coconuts have a very different 'nutritional' profile from the native tree species on this island, with much more carbon and less nitrogen," Miller-ter Kuile said. "When these trees die, because they have different nutrient profiles from native plants, they are likely to break down differently -- and more slowly -- and influence rates of decomposition." In addition, she said, native seabirds do not nest in coconut palms, which would deprive the atoll of the nutrients in their guano, which, in turn, "would lead to what would likely be a fairly nutrient-poor system, which discourages other native plants from growing in those areas."Continuing their restoration of the island, Palmyra's managers were working to remove the vast majority of the island's millions of coconut palms to give local species a chance to dominate, a project that is currently on hold due to the COVID-19 pandemic.Anticipating the indirect downstream effects, such as potential shifts in ecology toward other invasive species, could become part of a more holistic island rodent eradication effort, Miller-ter Kuile said."Wildlife management, in particular, has a history of being single-species focused, which often means that a lot of time and energy is put into producing or controlling a species without considering the broader effects of that management effort on all of the rest of the species in that ecosystem," she said. According to the study, "documenting the variation in invasive rodent diet items, along with long-term surveys, can help prioritize island eradications where restoration is most likely to be successful.""The 'accidental experiment' of our long-term monitoring of trees in this project I think provides a rare opportunity to quantify the immediate and longer-term effects of eradication," she said.
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Animals
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November 4, 2020
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https://www.sciencedaily.com/releases/2020/11/201104114728.htm
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Scientists find Ebola virus antibodies in people before 2018 DRC outbreak
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Scientists found antibodies to Ebola virus in people up to a year before the 2018 Ebola virus disease outbreak began in the Eastern Democratic Republic of Congo, or DRC. This suggests that either early cases may have been missed or that exposure occurs more commonly than previously thought, according to a study led by the University of California, Davis.
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The study, published today in the journal "This study highlights that, yes, these are lethal diseases, but there's a range of severity -- not everyone who is exposed dies," said lead author Tracey Goldstein, an associate director of the One Health Institute at the UC Davis School of Veterinary Medicine. "Spillover doesn't always cause lethal outbreaks. To prevent outbreaks, we need a better understanding of what's happening between them. If you really are trying to understand how a virus works, you need to study it at all times, not just during an outbreak."For the study, scientists collected and tested biological samples from 272 people seeking care in the Rutshuru Health Zone of North Kivu Province over the year before the start of the outbreak that killed nearly 2,300 people. Antibodies, which indicate past exposure to a virus, were found in 10 percent of patients.Scientists also administered questionnaires to patients to collect demographic and behavioral information, and to better understand their interactions with domestic animals and wildlife.While people of both sexes and all ages tested positive for antibodies, women had a significantly increased risk of exposure. This is consistent with other studies and may be due to the larger role women play in preparing food and caring for livestock and sick family members."These findings are important for those of us who live in eastern Congo, because it shows that people may become exposed to Ebola virus without becoming ill," said Jean-Paul Kabemba Lukusa, the Gorilla Doctors' medical technologist who coordinated human surveillance for this study. "It helps reinforce the work we do to explain to people how important it is to limit direct contact with wild animals and to follow hygiene and safety best practices."The study also demonstrates the need to address how humans come into contact with wildlife and the viruses they exchange.Co-author Kirsten Gilardi directs the UC Davis Karen C. Drayer Wildlife Health Center and the Gorilla Doctors program, which provides veterinary care to wild mountain and eastern lowland gorillas in Rwanda, Uganda and DRC. As the region's country lead for the USAID PREDICT Project, Gorilla Doctors sampled both wildlife and humans for viruses that may be circulating among them."These findings suggest there are more spillover events than we realize," Gilardi said. "This may not happen once in a while and then the virus disappears. Preventing spillover means understanding and minimizing high-risk human-to-wildlife interactions."Funding for the study was provided by the U.S. Agency for International Development, or USAID, Emerging Pandemic Threats PREDICT Project.
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November 4, 2020
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https://www.sciencedaily.com/releases/2020/11/201104001259.htm
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Death from below: Parasitic wasp attacking caterpillar underwater
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A very few species of parasitoid wasps can be considered aquatic. Less than 0.1% of the species we know today have been found to enter the water, while searching for potential hosts or living as endoparasitoids inside of aquatic hosts during their larval stage.
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Within the subfamily Microgastrinae (family Braconidae), only two species have previously been recorded to be aquatic, based on their parasitism of aquatic caterpillars of moths. However, none has been known to actually dive in the water.Recently, during their research work in Japan, Dr. Jose Fernandez-Triana of the Canadian National Collection of Insects and his team found and recorded on camera the first microgastrine parasitoid wasp that dives underwater for several seconds, in order to attack and pull out caterpillar hosts, so that it can lay its eggs inside them before releasing them back in the water.Interestingly, the wasp, which was described as a new to science species in the open-access, peer-reviewed scientific In the video, the female wasp can be seen walking over floating plants as it searches for hosts, specifically larvae of the moth species As for the curious choice of name for the new species, Dr. Jose Fernandez-Triana explains:"The reasons why we decided to use the name of Godzilla for the wasp species are interesting. First, being a Japanese species, it respectfully honours Godzilla, a fictional monster (kaiju) that became an icon after the 1954 Japanese film of the same name and many remakes afterwards. It has become one of the most recognizable symbols of Japanese popular culture worldwide. Second, the wasp's parasitization behaviour bears some loose resemblance to the kaiju character, in the sense that the wasp suddenly emerges from the water to parasitize the host, similar to how Godzilla suddenly emerges from the water in the movies. Third, Godzilla has sometimes been associated, albeit in different ways, with Mothra, another kaiju that is typically portrayed as a larva (caterpillar) or an adult moth. As you can see, we had biological, behavioural and cultural reasons to justify our choice of a name. Of course, that and having a bit of fun, because that is also an important part of life and science!"Beyond unusual behaviours and funny names, Dr. Fernandez-Triana wants to emphasize the importance of multidisciplinary work and collaboration. The team that published this paper got to know each other at an international meeting devoted to biological control (The 5th International Entomophagous Insects Conference in Kyoto, Japan, 2017)."I was very impressed by several presentations by Japanese grad students, which included video recordings of parasitoid wasp biology. As a taxonomist, I am always impressed with the quality of research done by colleagues in other fields. In this case, we saw an opportunity to combine our efforts to study the wasp in detail and, when we found that it was a new species, we described it together, including adding the filmed behaviour to the original description. Usually, taxonomic descriptions of parasitoid wasps are based on dead specimens, with very few details -- often none -- on its biology. Thanks to my biocontrol colleagues, we could add more information to what is known about the new species being described. Hopefully we can continue this collaboration and combined approach for future studies."
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November 9, 2020
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https://www.sciencedaily.com/releases/2020/11/201109132445.htm
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Fossil feces hows fishy lunches from 200 million years ago
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A new study of coprolites, fossil feces, shows the detail of food webs in the ancient shallow seas around Bristol in south-west England. One hungry fish ate part of the head of another fish before snipping off the tail of a passing reptile.
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Marie Cueille, a visiting student at the University of Bristol's School of Earth Sciences, was working on a collection of hundreds of fish fecess from the Rhaetian bone bed near Chipping Sodbury in South Gloucestershire, dated at 205 million years ago.She applied new scanning technology to look inside these coprolites and found an amazing array of food remains.Marie said: "The ancient fishes and sharks of the Rhaetian seas were nearly all carnivores. Their coprolites contain scales, teeth, and bones, and these tell us who was eating whom. In fact, all the fish seem to have been snapping at each other, although the general rule of the sea probably applied: if it's smaller than you, eat it."The CT scans of one tiny coprolite, measuring only a centimetre or so in length, contained only three bones, one a highly tuberculated skull bone of another fish, and two vertebrae from the tail of a small marine reptile called Pachystropheus.Dr Chris Duffin, who collaborated on the project added: "This shark probably snapped at another fish or scavenged some flesh from the head region of a dead fish. But it didn't just strip off the flesh but swallowed great chunks of bone at the same time. Then it snapped at a Pachystropheus swimming by and had a chunk of its tail."Professor Mike Benton, who co-supervised the study, said: "What amazed us was that the bones and scales inside the coprolites were almost completely undamaged. Today, most predators that swallow their prey whole, such as sharks, crocodiles or killer whales, have powerful stomach acids that dissolve the bone away. These ancient fishes must have had a painful time passing their faeces which were absolutely bristling with relatively large chunks of bone."The researchers also identified for the first time some coprolites of crabs and lobsters, so this completes the food web. The marine reptiles and sharks were feeding on smaller fishes, which in turn fed on even smaller fishes and lobsters. Some also had crushing teeth adapted to feeding on oysters and other molluscs.The study has a classical resonance as well, because Rhaetian coprolites from bonebeds near Bristol were some of those studied by William Buckland (1784-1856) in the 1820s when he invented the name 'coprolite'. Buckland was Professor of Geology at Oxford University, but also Dean of Christ Church, and known for his unusual eating habits. Possibly his interest in eating exotic animals (he would serve his guests roasted dormice or potted panther but declared that moles and house flies were inedible) gave him an interest in animal diets.Buckland pioneered the use of coprolites to reconstruct ancient food webs. He also collected specimens from the Jurassic around Lyme Regis, and many were supplied by famous fossil collector Mary Anning (1799-1847). Buckland even had these larger coprolites cut across and set into the top of a table, which was highly polished and doubtless formed a conversation opener during lunch and tea parties in the Dean's lodgings.The new work also sheds light on the Mesozoic Marine Revolution, the time when marine ecosystems modernised. The coprolites from Bristol show a complex, modern-style ecosystem with lobsters, bony fishes, sharks and marine reptiles at the top of the food web. Reconstructing the timing of the event is of current interest, and the new work suggests the process began earlier than had been thought.
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November 4, 2020
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https://www.sciencedaily.com/releases/2020/11/201104001309.htm
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New species of ancient cynodont, 220 million years old, discovered
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Fossilized jaw bone fragments of a rat-like creature found at the Petrified Forest National Park in Arizona last year by a Virginia Tech College of Science Ph.D. candidate are in fact a newly discovered 220-million-year-old species of cynodont or stem-mammal, a precursor of modern-day mammals.
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The finding of this new species, Kataigidodon venetus, has been published today in the journal "This discovery sheds light on the geography and environment during the early evolution of mammals," Kligman said. "It also adds to evidence that humid climates played an important role in the early evolution of mammals and their closest relatives. Kataigidodon was living alongside dinosauromorphs and possibly early dinosaurs related to Coelophysis -- a small bipedal predator -- and Kataigidodon was possibly prey of these early dinosaurs and other predators like crocodylomorphs, small coyote-like quadrupedal predators related to living crocodiles."Kligman added that finding a fossil that is part of Cynodontia, which includes close cousins of mammals, such as Kataigidodon, as well as true mammals, from Triassic rocks is an extremely rare event in North America. Prior to Kligman's discovery, the only other unambiguous cynodont fossil from the Late Triassic of western North America was the 1990 discovery of a braincase of Adelobasileus cromptoni in Texas. Note that 220 million years ago, modern day Arizona and Texas were located close to the equator, near the center of the supercontinent Pangaea. Kataigidodon would have been living in a lush tropical forest ecosystem.Kligman made the discovery while working as a seasonal paleontologist at Petrified Forest National Park in 2019. The two fossil lower jaws of Kataigidodon were found in the Upper Triassic Chinle Formation. Because only the lower jaws were discovered and are quite small -- half an inch, the size of a medium grain of rice -- Kligman only has a semi-picture of how the creature looked, roughly 3.5 inches in total body size, minus the tail.Along with the jawbone fossils, Kligman found incisor, canine, and complex-postcanine teeth, similar to modern day mammals. Given the pointed shape of its teeth and small body size, it likely fed on a diet of insects, Kligman added. (Why are jaw fossils commonly found, even among small specimens? According to Kligman, the fossil record is "biased" toward only preserving the largest and most robust bones in a skeleton. The other smaller or more fragile bones -- ribs, arms, feet -- disappear.)Kligman carried out field work, specimen preparation, CT scanning, conception, and design of the study and drafting of the manuscript. He added that he and his collaborators only discovered the fossils were of a new species after reviewing the CT scan dataset of the jaws and comparing it to other related species."It likely would have looked like a small rat or mouse. If you were to see it in person you would think it is a mammal," Kligman added. Does it have fur? Kligman and the researchers he worked with to identify and name the creature actually don't know. "Triassic cynodonts have not been found from geological settings which could preserve fur if it was there, but later nonmammalian cynodonts from the Jurassic had fur, so scientists assume that Triassic ones did also."The name Kataigidodon venetus derives from the Greek words for thunderstorm, "kataigidos," and tooth, "odon," and the Latin word for blue, "venetus," all referring to the discovery location of Thunderstorm Ridge, and the blue color of the rocks at this site. Kligman didn't name the creature, though. That task fell to Hans Dieter-Sues, coauthor and curator of vertebrate paleontology at the Smithsonian National Museum.Additional collaborators include Adam Marsh, park paleontologist at Petrified Forest National Park, who found the jaw fossils with Kligman, and Christian Sidor, an associate professor at the University of Washington's Department of Biology. The research was funded by the Petrified Forest Museum Association, the Friends of Petrified Forest National Park, and the Virginia Tech Department of Geosciences."This study exemplifies the idea that what we collect determines what we can say," said Michelle Stocker, an assistant professor of geosciences and Kligman's doctoral advisor. "Our hypotheses and interpretations of past life on Earth depend on the actual fossil materials that we have, and if our search images for finding fossils only focuses on large-bodied animals, we will miss those important small specimens that are key for understanding the diversification of many groups."With Kataigidodon being only the second other unambiguous cynodont fossil from the Late Triassic found in western North America, could there be more new species out there waiting to be found?Kligman said most likely. "We have preliminary evidence that more species of cynodonts are present in the same site as Kataigidodon, but we are hoping to find better fossils of them," he added.
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