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June 11, 2020
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https://www.sciencedaily.com/releases/2020/06/200611152417.htm
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'Matador' guppies trick predators
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Trinidadian guppies behave like matadors, focusing a predator's point of attack before dodging away at the last moment, new research shows.
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The tiny fish (10-40mm) draw attention by turning their irises black, which makes their eyes very conspicuous.This encourages pike cichlids -- a large fish that is the guppies' main predator -- to charge at their head rather than their body.The international study, led by the University of Exeter, found guppies then use their lightning reflexes to whip their head out of the way, causing the predators to miss, before swimming away.Many fish, including guppies, often approach their predators to find out if they are hungry and thus a current threat."We noticed that guppies would approach a cichlid at an angle, quickly darkening their eyes to jet-black, and then waiting to see if it would attack," said lead author Dr Robert Heathcote, who undertook the experimental work at Exeter and is now at the University of Bristol."Cichlids are ambush predators, lying in wait like a coiled spring before launching themselves at their prey."The guppies actually use their eyes to get the predator's attention, causing them to lunge at a guppy's head rather than its body."Whilst it seems completely counterintuitive to make a predator attack your head, this strategy works incredibly well because guppies wait until the predator commits to its attack before pivoting out of the way."The speed of the whole interaction is extraordinary -- at around three hundredths of a second -- so was only observable using a high-speed camera."Many animals are known to use "conspicuous colouration" for purposes such as communication, attracting mates, startling predators and advertising toxicity.This paper demonstrates a previously unknown divertive strategy -- but the researchers think it may be used by other species too."We don't know for sure, but it seems highly likely that other animals also use a 'matador' strategy like the one we have identified in guppies," said Professor Darren Croft, of the University of Exeter."Eyes are one of the most easily recognised structures in the natural world and many species go to great lengths to conceal and camouflage their eyes to avoid unwanted attention from predators."Some species, however, have noticeable or prominent eyes and, for the most part, it has remained a mystery as to why this would be."Our latest research gives new insight into why 'conspicuous' and colourful eyes have evolved."The study was conducted in several stages:"This project presented a wonderful range of technological challenges, including the creation of robotic guppies matched to the colour vision of pike cichlids, and high-speed computer tracking of guppies as they escaped," said Dr Jolyon Troscianko, of the University of Exeter."These advances allowed us to work out whether an attack would have been successful without needing to run life-and-death experiments with fish."One surprising finding was that larger guppies were better than smaller ones at escaping using this method."As animals become larger, they generally become less agile. If larger prey don't have weapons or other ways of defending themselves, this can result in them being easier for predators to catch," said Dr Heathcote."By turning their eyes black, larger guppies actually reverse this phenomenon."Bigger guppies with black eyes are better at diverting and escaping predator attacks."Since bigger animals produce more or larger offspring, it would be really exciting to find out if the animals that use these kinds of strategies have evolved to become larger."Professor Indar Ramnarine, of the University of the West Indies, St Augustine Campus, said: "We first discovered this particular behaviour in guppies several years ago and wondered what was the significance of this. Now we know."Previous research has shown that guppies also turn their eyes black to display aggression towards each other.Dr Safi K. Darden, of the University of Exeter, said: "We knew that changing iris colour was somehow involved in interactions with with other guppies, but when we saw that guppies performing predator inspections were also changing the colour of their irises, we figured that something really interesting must be going on."It is thrilling to have had such a skilled team with diverse expertise come together to be able to investigate this behaviour in such detail."
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Animals
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June 11, 2020
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https://www.sciencedaily.com/releases/2020/06/200611114542.htm
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Ancient crocodiles walked on two legs like dinosaurs
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An international research team has been stunned to discover that some species of ancient crocodiles walked on their two hind legs like dinosaurs and measured over three metres in length.
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University of Queensland palaeontologist Dr Anthony Romilio said the researchers first thought the similar-shaped fossilised footprints were from another ancient animal known as the pterosaurs."At one site, the footprints were initially thought to be made by a giant bipedal pterosaur walking on the mudflat, we now understand that these were bipedal crocodile prints," Dr Romilio said."The footprints measure around 24 centimetres, suggesting the track-makers had legs about the same height as human adult legs."These were long animals that we estimate were over three metres in length."And while footprints were everywhere on the site, there were no handprints."The research team, led by Professor Kyung Soo Kim from Chinju National University of Education, soon found clues as to why there were no handprints."Typical crocodiles walk in a squat stance and create trackways that are wide," Professor Kim said."Oddly, our trackways are very narrow looking -- more like a crocodile balancing on a tight-rope."When combined with the lack of any tail-drag marks, it became clear that these creatures were moving bipedally."They were moving in the same way as many dinosaurs, but the footprints were not made by dinosaurs."Dinosaurs and their bird descendants walk on their toes."Crocodiles walk on the flat of their feet leaving clear heel impressions, like humans do."The footprints dated between 110-120 million years ago and were discovered after analysing animal track sites in what is now known as South Korea.Researchers initially questioned the absence of hand impressions from the trackways, given that today's typical crocodiles are 'four-legged' or quadrupedal."Fossil crocodile tracks are quite rare in Asia, so finding an abundance of nearly one hundred footprints was extraordinary," Dr Romilio said."As an animal walks, the hind feet have the potential of stepping into the impression made by the hand and 'over-printing' it, but we find no evidence of this at these Korean sites."It isn't due to poor preservation either, because these fossils are spectacular, they even have the fine details of the toe-pads and scales on their soles preserved."
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Animals
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June 11, 2020
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https://www.sciencedaily.com/releases/2020/06/200611094156.htm
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Baboon model could aide in Alzheimer's disease interventions
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Scientists at Texas Biomedical Research Institute's (Texas Biomed) Southwest National Primate Research Center (SNPRC) recently published findings indicating the baboon could prove to be a relevant model to test therapeutics and interventions for neurodegenerative diseases, such as early stage Alzheimer's and related dementias. The scientists observed a steep age-related cognitive decline in baboons about 20-years-old, which is the equivalent of a 60-year-old human. The team of scientists, led by Dr. Marcel Daadi, Associate Professor at Texas Biomed's SNPRC, published their findings in the May issue of
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According to the Alzheimer's Association, more than five million Americans are living with Alzheimer's, and one in three seniors die from the disease or related dementias. Dr. Daadi explained that early detection of age-associated cognitive dysfunction is crucial and may provide an understanding of the breakdown of brain systems, leading to better interventions."We don't know how Alzheimer's disease starts, and if you are trying to treat a patient already with advanced disease, it is nearly impossible to treat them because of the significant loss in brain cells" said Dr. Daadi. "If we detect early on pathology in the brain then we can target interventions to prevent it from progressing, and we are in a better position to help. This is the first time a naturally-occurring model for early-stage Alzheimer's has been reported. This model could be relevant to test promising drugs, to better understand how and why the disease develops and to study the areas of the brain affected in order to determine how can we impact these pathways."Aging is currently irreversible and a significant reason for the gradual deterioration of general health and function. Neurodegenerative diseases, in particular, are related to the aging of brain cells and synaptic loss, which is a loss of the lines of communications inside the brain. As noted in the paper, humans and nonhuman primates (NHP) share many similarities, including age-dependent changes in gene expression and a decline in neural and immune functions. Previous studies have pinpointed the prefrontal cortex (PFC) of the brain as one of the regions most affected by age. The PFC plays an important role in working memory function, self-regulatory and goal-directed behaviors, which are all vulnerable to aging. To observe whether these PFC functions are impacted by aging in baboons and determine whether the baboons at varying ages could discern and learn new tasks, Dr. Daadi and his team separated the baboons into two groups based on age (adult group and aged group). Four cognitive tests were performed to observe novel learning, motor function and memory and shape association."What we found is that aged baboons lagged significantly in performance among all four tests for attention, learning and memory" Dr. Daadi said. "The delay or inability to collect rewards (response latency) also increased in older baboons, suggesting a decline in motivation and/or motor skills. The team then used a more complex task requiring integration of several cognitive processes and demonstrated that aged subjects actually have deficiencies in attention, learning and memory. Human studies have suggested a precipitous decline in brain systems function and cognition with 60 years as the potential breakpoint. These findings are consistent with our results."Rodents have been the primary lab model to test therapeutic interventions for neurodegenerative diseases. However, mice do not always reflect human processes, so while this animal model has been integral to understanding neurodegenerative disease processes, it has not proven as effective in translating promising therapies to the clinic."The failure rate in clinical trials of Alzheimer's disease therapeutics is extremely high at about 99.6%, and we need to change that" said Dr. Daadi.A nonhuman primate, or monkey, which is more similar to humans in terms of genetics, physiology, cognition, emotion and social behavior, could prove to be a more effective model to test therapeutic interventions.Dr. Daadi and his team are moving forward and plan to submit a National Institutes of Health grant to allow for further research. This published study was funded by the Marmion Family Fund, the Worth Family Fund, The Perry and Ruby Stevens Charitable Foundation and The Robert J., Jr. and Helen C. Kleberg Foundation, The William and Ella Owens Medical Research Foundation, the NIH Primate Center Base grant (Office of Research Infrastructure Programs/OD P51 OD011133), the National Institute on Aging R56 AG059284."Our next step is to investigate the neuropathologies behind this cognitive decline and perform imaging to understand what happens to the neural connections and determine where defects may be," he said. "We will also look at biomarkers that can give us an idea of why this steep decline is happening. All this data will enable us to further characterize the baboon as a naturally-occurring model that may prove useful for testing early therapeutic interventions."
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Animals
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June 11, 2020
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https://www.sciencedaily.com/releases/2020/06/200611094152.htm
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Surface disturbance can limit mule deer migration
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A new study shows that surface disturbance from energy development can hinder mule deer migrations when it exceeds 3 percent.
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Researchers from the University of Wyoming and Western Ecosystems Technology used 15 years of movement data collected from GPS-collared mule deer in western Wyoming to evaluate how much disturbance mule deer could withstand during migration. The study was conducted in the Pinedale Anticline -- the sixth-largest natural gas field in the nation and home to one of the largest deer herds in West.The findings were published in the Researchers used 145 migrations from 56 individual deer to examine disturbance effects at various scales. Results consistently showed that mule deer use of migration corridors steeply declined when surface disturbance from roads and well pads surpassed 3 percent. Mule deer were able to migrate through areas where surface disturbance was lower."Better understanding the relationship between surface disturbance and migratory behavior can help managers identify trade-offs and potential mitigation measures associated with mineral leasing and energy development that overlap with the migratory routes of big game," research biologist and co-author Hall Sawyer says.The authors note that similar disturbance thresholds likely vary across development types -- such as wind, solar and residential -- as well as geographic regions and species."There is a growing need to understand and predict how our migratory animals respond to disturbed landscapes, so we hope to expand this type of work in the future," says Jerod Merkle, who is the Knobloch Professor of Migration and Conservation Ecology at UW.Mallory Lambert, a UW graduate student and study co-author, says the next steps will be identifying disturbance thresholds for migrating pronghorn and wintering mule deer.This study was funded, in part, by the Wyoming Game and Fish Department.Visit the Wyoming Game and Fish Department and Wyoming Migration Initiative websites for information on big-game migrations in Wyoming.
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Animals
| 2,020 |
June 10, 2020
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https://www.sciencedaily.com/releases/2020/06/200610135101.htm
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Roadkill study identifies animals most at risk in Europe
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Around 194 million birds and 29 million mammals are thought to be killed each year on European roads, according to a new study that has ranked the most vulnerable species. An international research team used 90 roadkill surveys from 24 European countries to create a new method of estimating both the birds and mammal species killed most often on roads, and the species most vulnerable to being wiped out of certain areas. The research, published in
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Dr Manuela Gonzalez-Suarez, an ecologist at the University of Reading, and co-author of the study, said: "Road densities in Europe are among the world's highest, with 50% of the continent within 1.5km of a paved road or railway. Roads are therefore a significant threat to wildlife, and evidence shows deaths on them could even cause some species to disappear completely."Despite this, the long-term vulnerability of species is not currently considered when assessing the impact of new roads on wildlife, meaning we risk channeling support to the wrong species, doing nothing to help those most at risk. Better understanding which species are most vulnerable to roads is therefore important if we are to take more effective conservation action."The research team, led by the Centre for Environmental and Marine Studies (CESAM) in Lisbon, calculated roadkill rates for 423 bird species and 212 mammal species. They found that small animals with high population densities and which reach maturity at an early age were most likely to be killed on roads. Nocturnal mammals and birds with a diet of predominantly of plants and seeds were also shown to have higher death rates.The animals with the highest predicted roadkill rates were the common blackbird (11.94 per km/yr) and soprano pipistrelle bat (1.76 per km/yr). Roads in Central Europe, such as in Germany, Austria and Czech Republic, were found to be the most deadly.The study also used the roadkill surveys to rank the bird and mammal species whose long-term survival was most threatened by roadkill.The hazel grouse and russet ground squirrel were found to be the most at-risk of local extinction. Both are common in Europe but are classified as species of Least Concern in the International Union for Conservation of Nature's (IUCN) Red List of Threatened Species.The most vulnerable animals classified as Threatened by the IUCN were the red-knobbed coot, and the Balcan mole and Podolian mole.The study revealed that the roadkill hotspots did not correlate with the areas with the highest populations of vulnerable species.For example, house sparrows had a high roadkill rate projection (2.7 per km/yr) but were ranked 420th of 423 bird species for vulnerability. Conversely, the hazel grouse had a low predicted roadkill rate (0.2 per km/yr) but was most vulnerable of all birds studied.The areas with the highest concentrations of vulnerable bird species were the Iberian Peninsula, Balkan Peninsula and Eastern European countries. Vulnerable mammals were concentrated in northern Spain, Italy, Austria and the Balkan Peninsula.Dr Clara Grilo, researcher at CESAM and lead author of the study, said: "We wanted to get the big picture of which species are more roadkilled and also map the regions that can be a threat for wildlife conservation in Europe. We used modeling to estimate roadkill for the unstudied species and also to identify which species are vulnerable to local extinction due to roads."From a conservation perspective, we need to go beyond the quantification of roadkill by applying population models to identify which species can be vulnerable to additional loss of individuals, which will provide more accurate information to target road segments that require mitigation."Members of the public can contribute roadkill reports to improve studies like this one by visiting 1 Bonasa bonasia, Hazel grouse2 Circaetus gallicus, Short-toed snake eagle3 Phylloscopus borealis, Artic warbler4 Lanius nubicus, Masked shrike5 Anthus cervinus, Red-throated pipit6 Loxia leucoptera, Two-barred crossbill7 Buteo rufinus, Long-legged buzzard8 Gelochelidon nilotica, Common gull-billed tern9 Ardeola ralloides, Squacco heron10 Glaucidium passerinum, Eurasian pygmy-owl1 Spermophilus major, Russet ground squirrel2 Spalax graecus, Balkan mole rat3 Spalax zemni, Podolian mole rat4 Spalax microphthalmos, Greater blind mole rat5 Spalax arenarius, Sandy mole rat6 Pygeretmus pumilio, Dwarf fat-tailed jerboa7 Rhinolophus blasii, Blasius' horseshoe bat8 Rhinolophus Euryale, Mediterranean horseshoe bat9 Sorex alpinus, Alpine shrew10 Ellobius talpinus, Northern mole vole
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Animals
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June 10, 2020
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https://www.sciencedaily.com/releases/2020/06/200610135022.htm
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Population ecology: Origins of genetic variability in seals
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A new study led by Ludwig-Maximilians-Universitaet (LMU) in Munich researchers shows that fluctuations in population sizes in the past have had a significant effect on contemporary seal populations, and estimates the risk of genetic impoverishment in the species investigated.
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In the course of Earth's history, evolution has given rise to an enormous range of biological diversity, which in turn enabled the emergence of complex, species-rich ecosystems. The availability of adequate levels of genetic variation is a basic prerequisite for evolution. Higher levels of genetic variability therefore increase the probability that any given population will be able to adapt to new environmental conditions and remain evolutionarily flexible. Scientists led by LMU evolutionary biologist Jochen Wolf have examined the genetic variability of multiple seal species and show that a large part of today's variation is due to historical fluctuations in population sizes. In addition, the authors use the results of their genomic analyses to derive a parameter that allows them to assess the risk that genetic impoverishment and inbreeding pose to seal populations today. The new study appears in the journal Genetic variation is the product of random mutations, which are passed down from generation to generation. However, mutations can also be lost, owing to the effects of 'genetic bottlenecks', for instance. Such bottlenecks can occur when a large fraction of the population is lost. "It is generally assumed that populations that are made up of many individuals are likely to exhibit high levels of genetic variability," says Wolf. "We have now tested this assumption for 17 species of seals, by analyzing the genetic differences between 458 animals from 36 populations."Since the genetic variation found in present-day populations can tell us a great deal about the genetic make-up of their ancestors, the authors of the study were able to deduce from their data how different populations have changed with time. "Genetic data are like a microscope that allows us to peer into the past," says Wolf. "The greater the differences between the genomic sequences, the farther back in time their last common ancestor lived. Our analyses enable us to look back thousands and even millions of years, and we can see that many populations must have gone through very narrow genetic bottlenecks -- in other words, were drastically reduced in size -- while others experienced significant expansions."The researchers use the 'effective population size' as a measure of the extent of genetic variation within a population. This parameter is defined as the number of individuals that, under theoretically ideal conditions, would be expected to exhibit the same level of genetic variance as the real population of interest. The effective population size is related to, but much smaller than, the actual size of the real population, because the parameter includes the effects of factors such as reproductive behavior. Male seals in some species compete aggressively for females. That implies that the less dominant males may have no chance to reproduce, which in turn reduces the range of genetic variation in the following generation. "We assessed the impact of such effects, but our analyses indicate that the amounts of genetic variation in modern seals have been influenced mainly by historical fluctuations in population sizes, which are probably related to changes in the climate," says Wolf.The ratio of the effective to the actual population size is often used to infer whether or not a given population possesses enough genetic variability to survive in the longer term. A very low quotient serves as a warning signal, since populations with low levels of variation are especially susceptible to inbreeding effects which, among other things, increase the risk of disease. "Most genetic studies undertaken in the context of conservation assess the level of genetic variability only across a few generations," says Wolf. "Our investigation, on the other hand, extends much further back in time. So we were able to take fluctuations in population sizes into account, and could calculate the population sizes we would expect to find today due to the genetic variability."The expected population sizes were then compared with their actual sizes by means of a complex statistical procedure, which reveals whether the extant population is larger or smaller than the expected value. "This then tells us if a population is at risk because its current size is much too small to sustain that particular species in the longer term," says Wolf. In this context, the absolute number of individuals can be misleading. For instance, only 400 Saimaa ringed seals survive in the wild, and the species is regarded as endangered." From a genetic point of view, however, despite their small number, we do not expect them to run into problems in the near future, as the animals are highly variable," says Wolf. The indications are that they settled in their present habitat only a short time ago -- in evolutionary terms -- and they retain the full range of variation that characterized their ancestors. The situation in the Galapagos is quite different. There too, seal and sea lion populations are small, but their levels of genetic variability are also low -- a factor which is not reflected in the value of the conventional ratio of effective to actual population size. The study shows that comparative genomic analyses of animal populations constitute an important tool for the identification of vulnerable populations in order to take protective measures.
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Animals
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June 10, 2020
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https://www.sciencedaily.com/releases/2020/06/200610120958.htm
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What makes a giant jellyfish's sting deadly?
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With summer on the way, and some beaches reopening after COVID-19 shutdowns, people will be taking to the ocean to cool off on a hot day. But those unlucky enough to encounter the giant jellyfish
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Found in coastal waters of China, Korea and Japan, Nomura's jellyfish can grow up to 6.6 feet in diameter and weigh up to 440 pounds. This behemoth stings hundreds of thousands of people per year, causing severe pain, redness, swelling, and in some cases, even shock or death. The jellyfish's venom is a complex brew of numerous toxins, some of which resemble poisons found in other organisms, such as snakes, spiders, bees and bacteria. Rongfeng Li, Pengcheng Li and colleagues wanted to determine which of the many toxins in the jellyfish's venom actually cause death. The answer could help scientists develop drugs to counteract jellyfish stings.The researchers captured
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Animals
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June 10, 2020
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https://www.sciencedaily.com/releases/2020/06/200610112055.htm
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Beavers are diverse forest landscapers
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Beavers are ecosystem engineers that cut down trees to build dams, eventually causing floods. Beaver-induced floods make forest landscapes and habitats increasingly diverse, but very little is known about the long-term effects of beavers on European landscapes. Researchers at the University of Eastern Finland and the University of Helsinki examined the history and occurrence of beaver-induced floods and patch dynamics in southern Finland. They used a unique dataset of field observations from 1970 to 2018.
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Floods caused by beavers over the course of history form a network of different habitats that remain interconnected even for long periods of time."Beavers can help to restore wetland ecosystems and entire boreal forests, and they also help in conserving the biodiversity of these environments," Researcher Sonja Kivinen from the University of Eastern Finland says.The European beaver was hunted to extinction in the 19th century Finland. Nowadays, the study area is home to the American beaver, which was introduced there in the 1950s. The American beaver builds similar dams as the European one."The spread of the beaver in our study area has created a diverse and constantly changing mosaic of beaver ponds and beaver meadows of different ages," Kivinen says.In 49 years, number of beaver-induced flood sites grew 11-fold.The researchers observed that the number of beaver-induced flood sites grew by more than 11-fold over the study period. In addition to creating new flood sites, beavers also often use old sites to cause new floods. The duration of an individual flood and the frequency of floods can vary greatly between different flood sites, resulting in an abundance of habitat patches with different environmental conditions."Thanks to beaver activity, there is a unique richness of wetlands in the forest landscape: flowages dominated by bushes, beaver meadows, and deadwood that can be used by various other species," University Lecturer Petri Nummi from the University of Helsinki says.Indeed, beaver-induced disturbances are more predictable in diversifying the forest landscape than for example forest fires or storms.
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Animals
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June 10, 2020
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https://www.sciencedaily.com/releases/2020/06/200610094045.htm
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A rare heart bone is discovered in chimpanzees
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Experts from the University of Nottingham have discovered that some chimpanzees have a bone in their heart, which could be vital in managing their health and conservation.
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Very few species of animals have this bone -- called an os cordis -- therefore this is a particularly rare find.The exciting research, which was carried out by experts from the University's School of Veterinary Medicine and Science, is published today in Wild chimpanzees are endangered and cardiovascular disease is very common in this species. Understanding their hearts is vital in making medical advances and managing their health and conservation.The tiny 'os cordis' heart bones, measuring a few millimetres in size, were more likely to be present in chimps with idiopathic myocardial fibrosis -- a type of heart disease found in chimps and people. Myocardial fibrosis is the most common type of heart disease in chimpanzees and has been linked to the occurrence of cardiac arrhythmias and sudden death."The discovery of a new bone in a new species is a rare event, especially in chimps which have such similar anatomy to people. It raises the question as to whether some people could have an os cordis too,' said lead author Dr Catrin Rutland from the University.This astonishing new find was made possible using several techniques including an advanced imaging method called micro-computed tomography. This enabled the hearts to be scanned at much higher magnifications than standard hospital or veterinary CT scans."Looking for ways to help chimps with heart disease is essential. Understanding what is happening to their hearts helps us manage their health" Said Dr Sophie Moittié, from the University.The heart bone is present in many bovines (cattle, ox and buffalo), and is often quite large, butchers even remove it some that meat can be used for soups. Sheep, otters, dogs and camels sometimes have the heart bone too. Sometimes the os cordis is present in most animals of a species but in other cases it is associated with heart disease.The function of an os cordis is still being researched, but this work shows that cartilage was present in addition to bone, which gives insight into the mechanisms via which bone growth started. The scientists also showed that the heart bone was present in male and female chimps of differing ages.Many suggestions have been given for the reasons behind an os cordis developing. The bone may support the essential heart valves, develop due to heart disease or even alter the electrical system which controls the heart."This research has brought together researchers and veterinary professionals, working on a common aim to advance chimpanzee health and conservation," adds Dr Rutland.
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Animals
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June 10, 2020
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https://www.sciencedaily.com/releases/2020/06/200610093549.htm
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Bees? Please. These plants are putting ants to work
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In a world first, Edith Cowan University (ECU) researchers have discovered a plant that has successfully evolved to use ants -- as well as native bees -- as pollinating agents by overcoming their antimicrobial defences.
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ECU PhD student Nicola Delnevo discovered the trait in a group of shrubs found the Swan Coastal Plain in Western Australia.Mr Delnevo said ant pollination of plants was incredibly rare."Ants secrete an antimicrobial fluid that kills pollen grain," he said."So ants have traditionally been considered to be a menace -- nectar thieves whose aggression keeps other potential pollinating insects at bay."However this group of plants in WA, commonly known as the Smokebush family (Conospermum), has evolved a way to use ants to their advantage."Mr Delnevo tested the effect of the antimicrobial secretion from three ant species found locally on the flowers of six WA plant species, with startling results."We found evidence that Conospermum plants have adapted the biochemistry of their pollen grains to cope with the antimicrobial properties of the ants."This is the first plant species found to have adapted traits that enables a mutually beneficial relationship with ants," Mr Delnevo said."About 46 examples of ant pollination have been documented around the world, but these have been due to the ants producing less toxic secretions that allow them to pollinate."Mr Delnevo said the pollination by ants was particularly good news for these plants as they were unable to rely on honeybees."Conospermum plants have unscented tubular flowers that are too narrow for honeybees wriggle inside to pollinate," Mr Delnevo explained."They rely on native insects carrying a suitable pollen load from visiting other flowers for pollination to occur."They have co-evolved with a native bee (Leioproctus conospermi) that has evolved as a specialist feeder of these flowers."This relationship is mutually beneficial, but it would be risky in an evolutionary sense for the plant to rely solely on the native bee for pollination."Future research will explore how common ant pollination is amongst the flora of south-western Australia and exactly how this trait of overcoming ant defences has evolved.
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Animals
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June 9, 2020
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https://www.sciencedaily.com/releases/2020/06/200609190723.htm
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Twitter fight: Birds use social networks to pick opponents wisely
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Knowing when to fight and when to flee is a big part of many animal societies, including our own.
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University of Cincinnati biologist Elizabeth Hobson says some animals make the call based on a sophisticated understanding of social standing and their place in it."We have a phrase: Choose your battles wisely. Animals do that. People do that," said Hobson, an assistant professor in UC's College of Arts and Sciences.In a new article published in the journal Dominance hierarchies are common social organizations in nature. They're found in everything from hermit crabs to human society, Hobson said."Understanding how information is perceived, processed and used by individuals in hierarchical systems is critical to understanding how animals make aggression decisions because different types of information can underlie different kinds of aggression strategies," she said in the article.The most basic understanding comes from firsthand experience."The low-information case is when animals only perceive and remember things that happened to them. A good example of this is if you are beaten in a fight. You remember that you lost but not to whom you lost," she said.Biologists say these battles can have a lasting impact on the combatants called winner effects and loser effects. Winners are more likely to be aggressive in future conflicts while losers are less likely to meet aggression with aggression or pick a new fight."With a strong loser effect, if you got beaten, you're less likely to fight again in the future," Hobson said.Other animals might remember losing to a particular foe and be less inclined to challenge that foe in the future."What if you don't just remember the outcome but you remember who beat you? You can build on that," she said. "Going forward, you'll be less aggressive with the individual who beat you. It's a different social dynamic."But some animals can make judgments not just through their own direct interactions but by observing other animals and making inferences about where those would-be opponents stand in the hierarchy.This ability, known as transitive inference, goes like this: If animal A beats animal B and animal B beats animal C, you know animal A can beat animal C. It's a logical conclusion some animals seem to understand, Hobson said."Maybe they never have to fight C or they'll know they can beat C," she said.Hobson is putting her ideas to the test with captive parakeets."This paper is setting up a perspective I want to push in my research program. It will be an exciting time," Hobson said.
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Animals
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June 9, 2020
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https://www.sciencedaily.com/releases/2020/06/200609095016.htm
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Human presence weakens social relationships of giraffes
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The effects of human presence on the social relationships of wild animals have rarely been studied. Even if the animals are not hunted or killed, increasing contact with humans could have profound indirect impacts. This is because proximity to humans could disturb the animals' ability to perform at tasks that are important for survival -- such as feeding together or rearing young.
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Researchers from the Department of Evolutionary Biology and Environmental Studies at the University of Zurich (UZH) have now taken a closer look at this topic by studying Masai giraffes in Tanzania. The study, carried out with researchers from the Max Planck Institute of Animal Behavior, the University of Konstanz and Pennsylvania State University, provides the first robust evidence that human presence affects the social structure in this iconic herbivore.For their study, the scientists first needed to obtain large amounts of data from field research. "Detecting signals of natural versus human-caused influences on social relationships among wild animals is challenging," says Monica Bond, PhD candidate at the University of Zurich and first author of the study.Over a period of six years, Bond and her research collaborators collected photographic data spanning 540 adult female Masai giraffes that live in a large, unfenced landscape in the Tarangire Ecosystem of Tanzania -- an environment that features varying levels of anthropogenic (human-caused) disturbance. The researchers were able to identify individual giraffes by their unique and unchanging spot patterns. This resulted in one of the largest-scale social networks ever studied in a wild mammal.The field research sheds new light on the social relationships of giraffes: The female giraffes in Tarangire live in a complex multilevel society, with individuals preferring to associate with some females while avoiding others. These preferences result in discrete social communities of 60 to 90 females with little mixing among the groups, even when these share the same general area. "The study reveals that social structuring is clearly an important feature of female giraffe populations," says Barbara König, UZH professor and co-author of the study.The data analysis also revealed that the social networks exhibit signs of disturbance when groups of giraffes are exposed to humans: Giraffes living closer to traditional compounds of indigenous Masai people have weaker relationship strengths and more exclusive social associations.The researchers suspect that giraffes living near traditional human settlements are more likely to encounter livestock and humans. This potentially causes groups of giraffes to split up, even though they are tolerated by the Masai people. This disruption to the giraffes' social system -- in addition to poaching, loss of habitat and changes in food supply -- could be a reason why Masai giraffe populations have declined 50% in recent years.In other research, the team found that groups of female giraffes with calves were more likely to occur closer to human settlements -- possibly because this provides better protection from lions and hyenas. "It seems that female giraffes face a trade-off between maintaining important social bonds and reducing risk to their calves near these traditional settlements," explains Bond.Overall, the study's results suggest that human presence could play an important role in determining the conservation future of this species of giraffe. Moreover, the study's leading-edge methodology highlights the importance of using the social network approach to reveal otherwise hidden potential causes of population declines.
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Animals
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June 8, 2020
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https://www.sciencedaily.com/releases/2020/06/200608132459.htm
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Monkeys appreciate lifelike animation
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Monkeys can overcome their aversion to animated monkeys through a more realistic avatar, according to research recently published in
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Humans feel more comfortable toward life-like humanoid robots, but if a robot gets too life-like, it can become creepy. This "uncanny valley" effect plagues monkeys, too, which becomes a problem when scientists use animated monkey faces to study social behavior. However, monkeys overcome the uncanny valley when presented with a sufficiently realistic monkey avatar created using movie industry animation technology.Siebert et al. compared how Rhesus monkeys reacted toward five types of monkey faces: video footage from real monkeys, a natural looking avatar with fur and facial details, a furless avatar, a greyscale avatar, and a wireframe face. The monkeys looked at the wireframe face but avoided looking at the furless and greyscale avatars, showing the uncanny valley effect at work. However, the natural looking avatar with fur overcame this effect. The monkeys looked at the model and made social facial expressions, comparable to how they would act around real monkeys. Using this type of avatar will make social cognition studies more standardized and replicable.
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Animals
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June 8, 2020
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https://www.sciencedaily.com/releases/2020/06/200608122336.htm
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Temperate insects as vulnerable to climate change as tropical species
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In previous research, it has been assumed that insects in temperate regions would cope well with or even benefit from a warmer climate. Not so, according to researchers from the Universities of Uppsala and Lund in Sweden and Oviedo, Spain, in a new study. The earlier models failed to take into account the fact that insects in temperate habitats are inactive for much of the year.
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The research group's study, published in the journal "Insects in temperate zones might be as threatened by climate change as those in the tropics," says Uppsala University professor Frank Johansson.The researchers found new, disturbing patterns in a modified analysis of a previously used dataset on insects' critical temperature limits and their survival. Their conclusion is that temperate insects might be just as sensitive to climate change as tropical ones. The previous studies showed that tropical insects are severely threatened by climate change since they already live very close to their optimal temperature and "critical thermal maximum." However, the scientists responsible for those previous studies also assumed that temperate insects live far below their own optimal and maximum temperatures, and might therefore benefit from climate change.The problem is that the earlier studies used mean annual temperatures for all their estimates. In so doing, they failed to consider that the vast majority of insects in temperate latitudes remain inactive in cold periods -- that is, for much of the year.When more biological details about the various insect species, and only the months in which the species are active, are entered in the models, the new estimates show that in temperate insects' habitats, too, the temperatures are close to the insects' optimal and critical maximum. This is because the average temperature for the months when the insects are active clearly exceeds the mean year-round temperature. Temperate insects are thus as vulnerable as tropical species to temperature increasesWhen the temperature is close to insects' optimal temperature or critical upper limit, there is a great risk of their numbers declining. The decreases in insect populations would also affect humans, since many insect species provide ecosystem services, such as pollination of fruit, vegetables and other plants we eat.
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Animals
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June 8, 2020
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https://www.sciencedaily.com/releases/2020/06/200608093000.htm
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Protected areas worldwide at risk of invasive species
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Protected areas across the globe are effectively keeping invasive animals at bay, but the large majority of them are at risk of invasions, finds a China-UK research team involving UCL.
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The research, led by the Chinese Academy of Science and published in Co-author Professor Tim Blackburn (UCL Genetics, Evolution & Environment and the Institute of Zoology, ZSL) said: "One of the most harmful ways that people are impacting the natural environment is through the introduction of 'aliens' -- species that do not occur naturally in an area, but have been taken there by human activities."These species may kill or compete with native species, or destroy habitats, amongst other impacts. Invasions by alien species are regarded as one of the top five direct drivers of global biodiversity loss, and aliens are establishing themselves in new areas at ever increasing rates. Protected areas are a cornerstone of biodiversity conservation, but aliens don't know where their boundaries lie. It's important to know whether these areas might protect against the spread of invasive species."The researchers investigated 894 terrestrial animal species (including mammals, birds, reptiles and invertebrates) that are known to have established alien populations somewhere in the world.They then assessed whether these species occurred within, or near, the boundaries of 199,957 protected areas across the globe, as defined by the International Union for Conservation of Nature (IUCN), including wilderness areas, national parks, and natural monuments or features.The team found that less than 10% of the protected areas are currently home to any of the invasive species surveyed, suggesting that protected areas are generally effective in protecting against invasive species.But almost all of those areas may be at risk of invasion, as an invasive species was found within 100km of the boundaries of 99% of the protected areas. For 89% of the protected areas, there was an alien species resident within 10km of the boundaries.More than 95% of the protected areas were deemed to be environmentally suitable for the establishment of at least some of the alien species under investigation.The researchers also investigated common factors among the protected areas that are already home to alien species. They found that protected areas tend to have more alien animal species if they have a larger human footprint index, due to factors such as transport links and large human populations nearby.The researchers also found that larger, and more recently established protected areas, tend to have more alien species. Older protected areas tend to be in more remote areas, so they are less exposed to human impacts.Senior author Dr Li Yiming (Institute of Zoology, Chinese Academy of Sciences) said: "At the moment most protected areas are still free of most animal invaders, but this might not last. Areas readily accessible to large numbers of people are the most vulnerable.""We need to increase efforts to monitor and record invasive alien species that people may bring into protected areas, deliberately or by accident, especially damaging species like the American bullfrog, brown rat and wild boar."The findings do not suggest that the rich existing biodiversity in protected areas acts as a barrier to invasions, as they found mixed evidence on the relationships between existing native biodiversity and presence of invasive species.Professor Blackburn concluded: "If alien species continue to spread -- and we would expect many to do that -- many more protected areas will have their boundaries reached, and potentially breached, by these alien species."The research was supported by the Second Tibetan Plateau Scientific Expedition and Research (STEP) Programme, National Science Foundation of China and Youth Innovation Promotion Association of Chinese Academy of Sciences. Alien species commonly found in protected areas include:The most invaded parks were all found in Hawaii: Volcanoes National Park (80 species): Hakalau Forest National Wildlife Refuge (63 species) and Kipuka Ainahou (62 species)
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Animals
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June 7, 2020
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https://www.sciencedaily.com/releases/2020/06/200607131646.htm
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Great white shark diet surprises scientists
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The first-ever detailed study of the diets of great white sharks off the east Australian coast reveals this apex predator spends more time feeding close to the seabed than expected.
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"Within the sharks' stomachs we found remains from a variety of fish species that typically live on the seafloor or buried in the sand. This indicates the sharks must spend a good portion of their time foraging just above the seabed," said lead author Richard Grainger, a PhD candidate at the Charles Perkins Centre and School of Life and Environmental Sciences at the University of Sydney."The stereotype of a shark's dorsal fin above the surface as it hunts is probably not a very accurate picture," he said.The study, published today on World Oceans Day in the journal Dr Vic Peddemors a co-author from the NSW Department of Primary Industries (Fisheries), said: "We discovered that although mid-water fish, especially eastern Australian salmon, were the predominant prey for juvenile white sharks in NSW, stomach contents highlighted that these sharks also feed at or near the seabed."Mr Grainger said: "This evidence matches data we have from tagging white sharks that shows them spending a lot of time many metres below the surface."The study examined the stomach contents of 40 juvenile white sharks (Carcharodon carcharias) caught in the NSW Shark Meshing Program. The scientists compared this with published data elsewhere in the world, mainly South Africa, to establish a nutritional framework for the species."Understanding the nutritional goals of these cryptic predators and how these relate to migration patterns will give insights into what drives human-shark conflict and how we can best protect this species," said Dr Gabriel Machovsky-Capuska, an adjunct Senior Research Fellow at the Charles Perkins Centre and a co-author of the study.Mr Grainger said: "White sharks have a varied diet. As well as east Australian salmon, we found evidence of other bony fish including eels, whiting, mullet and wrasses. We found that rays were also an important dietary component, including small bottom-dwelling stingrays and electric rays."Eagle rays are also hunted, although this can be difficult for the sharks given how fast the rays can swim."The study found that based on abundance, the sharks' diet relied mostly on:- Bottom-dwelling fish, such as stargazers, sole or flathead: 17.4%- Reef fish, such as eastern blue gropers: 5.0%- Batoid fish, such as stingrays: 14.9%The remainder was unidentified fish or less abundant prey. Mr Grainger said that marine mammals, other sharks and cephalopods (squid and cuttlefish) were eaten less frequently."The hunting of bigger prey, including other sharks and marine mammals such as dolphin, is not likely to happen until the sharks reach about 2.2 metres in length," Mr Grainger said.The scientists also found that larger sharks tended to have a diet that was higher in fat, likely due to their high energy needs for migration."This fits with a lot of other research we've done showing that wild animals, including predators, select diets precisely balanced to meet their nutrient needs," said co-author Professor David Raubenheimer, Chair of Nutritional Ecology in the School of Life and Environmental Sciences.Tracking of white sharks shows that they migrate seasonally along Australia's east coast from southern Queensland to northern Tasmania, and the range of movement increases with age.Protecting this species and safely managing its interactions with humans is a priority for scientists and the NSW Department of Primary Industries."This study will give us a lot of information to assist in this management process," Dr Peddemors said.
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Animals
| 2,020 |
June 4, 2020
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https://www.sciencedaily.com/releases/2020/06/200604152053.htm
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Sleep, death and ... the gut?
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The first signs of insufficient sleep are universally familiar. There's tiredness and fatigue, difficulty concentrating, perhaps irritability or even tired giggles. Far fewer people have experienced the effects of prolonged sleep deprivation, including disorientation, paranoia and hallucinations.
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Total, prolonged sleep deprivation, however, can be fatal. While it has been reported in humans only anecdotally, a widely cited study in rats conducted by Chicago-based researchers in 1983 showed that a total lack of sleep inevitably leads to death. Yet, despite decades of study, a central question has remained unsolved: why do animals die when they don't sleep?Now, Harvard Medical School neuroscientists have identified an unexpected, causal link between sleep deprivation and premature death. In a study on sleep-deprived fruit flies, researchers found that death is always preceded by the accumulation of molecules known as reactive oxidative species (ROS) in the gut.When fruit flies were given antioxidant compounds that neutralize and clear ROS from the gut, sleep-deprived flies remained active and had normal lifespans. Additional experiments in mice confirmed that ROS accumulate in the gut when sleep is insufficient.The findings, published in "We took an unbiased approach and searched throughout the body for indicators of damage from sleep deprivation. We were surprised to find it was the gut that plays a key role in causing death," said senior study author Dragana Rogulja, assistant professor of neurobiology in the Blavatnik Institute at HMS."Even more surprising, we found that premature death could be prevented. Each morning, we would all gather around to look at the flies, with disbelief to be honest. What we saw is that every time we could neutralize ROS in the gut, we could rescue the flies," Rogulja said.Scientists have long studied sleep, a phenomenon that appears to be fundamental for life, yet one that in many ways remains mysterious. Almost every known animal sleeps or exhibits some form of sleeplike behavior. Without enough of it, serious consequences ensue. In humans, chronic insufficient sleep is associated with heart disease, type 2 diabetes, cancer, obesity, depression and many other conditions.Previous research has shown that prolonged, total sleep restriction can lead to premature death in animal models. In attempts to answer how sleep deprivation culminates in death, most research efforts have focused on the brain, where sleep originates, but none have yielded conclusive results.Spearheaded by study co-first authors Alexandra Vaccaro and Yosef Kaplan Dor, both research fellows in neurobiology at HMS, the team carried out a series of experiments in fruit flies, which share many sleep-regulating genes with humans, to search for signs of damage caused by sleep deprivation throughout the body. To monitor sleep, the researchers used infrared beams to constantly track the movement of flies housed in individual tubes.They found that flies can sleep through physical shaking, so the team turned to more sophisticated methods. They genetically manipulated fruit flies to express a heat-sensitive protein in specific neurons, the activity of which are known to suppress sleep. When flies were housed at 29 degrees C (84 degrees F), the protein induced neurons to remain constantly active, thus preventing the flies from sleeping.After 10 days of temperature-induced sleep deprivation, mortality spiked among the fruit flies and all died by around day 20. Control flies that had normal sleep lived up to approximately 40 days in the same environmental conditions.Because mortality increased around day 10, the researchers looked for markers of cell damage on that and preceding days. Most tissues, including in the brain, were indistinguishable between sleep-deprived and non-deprived flies, with one notable exception.The guts of sleep-deprived flies had a dramatic buildup of ROS -- highly reactive, oxygen-containing molecules that in large amounts can damage DNA and other components within cells, leading to cell death. The accumulation of ROS peaked around day 10 of sleep deprivation, and when deprivation was stopped, ROS levels decreased.Additional experiments confirmed that ROS builds up in the gut of only those animals that experienced sustained sleep loss, and that the gut is indeed the main source of this apparently lethal ROS."We found that sleep-deprived flies were dying at the same pace, every time, and when we looked at markers of cell damage and death, the one tissue that really stood out was the gut," Vaccaro said. "I remember when we did the first experiment, you could immediately tell under the microscope that there was a striking difference. That almost never happens in lab research."The team also examined whether ROS accumulation occurs in other species by using gentle, continuous mechanical stimulation to keep mice awake for up to five days. Compared to control animals, sleep-deprived mice had elevated ROS levels in the small and large intestines but not in other organs, a finding consistent with the observations in flies.To find out if ROS in the gut play a causal role in sleep deprivation-induced death, the researchers looked at whether preventing ROS accumulation could prolong survival.They tested dozens of compounds with antioxidant properties known to neutralize ROS and identified 11 that, when given as a food supplement, allowed sleep-deprived flies to have a normal or near-normal lifespan. These compounds, such as melatonin, lipoic acid and NAD, were particularly effective at clearing ROS from the gut. Notably, supplementation did not extend the lifespan of non-deprived flies.The role of ROS removal in preventing death was further confirmed by experiments in which flies were genetically manipulated to overproduce antioxidant enzymes in their guts. These flies had normal to near-normal lifespans when sleep-deprived, which was not the case for control flies that overproduced antioxidant enzymes in the nervous system.The results demonstrate that ROS buildup in the gut plays a central role in causing premature death from sleep deprivation, the researchers said, but cautioned that many questions remain unanswered."We still don't know why sleep loss causes ROS accumulation in the gut, and why this is lethal," said Kaplan Dor. "Sleep deprivation could directly affect the gut, but the trigger may also originate in the brain. Similarly, death could be due to damage in the gut or because high levels of ROS have systemic effects, or some combination of these."Insufficient sleep is known to interfere with the body's hunger signaling pathways, so the team also measured fruit fly food intake to analyze whether there were potential associations between feeding and death. They found that some sleep-deprived flies ate more throughout the day compared with non-deprived controls. However, restricting access to food had no effect on survival, suggesting that factors beyond food intake are involved.The researchers are now working to identify the biological pathways that lead to ROS accumulation in the gut and subsequent physiological disruptions.The team hopes that their work will inform the development of approaches or therapies to offset some of the negative consequences of sleep deprivation. One in three American adults gets less than the recommended seven hours of sleep per night, according to the U.S. Centers for Disease Control and Prevention, and insufficient sleep is a normal part of life for many around the world."So many of us are chronically sleep deprived. Even if we know staying up late every night is bad, we still do it," Rogulja said. "We believe we've identified a central issue that, when eliminated, allows for survival without sleep, at least in fruit flies.""We need to understand the biology of how sleep deprivation damages the body, so that we can find ways to prevent this harm," she said.The study was supported by the New York Stem Cell Foundation, the Pew Charitable Trusts and the National Institutes of Health (R73 NSO72030). Additional support includes an EMBO long-term fellowship, a Fondation Bettencourt Schueller fellowship, an Edward R. and Anne G. Lefler Center postdoctoral fellowship, an Alice and Joseph E. Brooks Postdoctoral Fellowship and a Life Sciences Research Foundation fellowship.
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Animals
| 2,020 |
June 4, 2020
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https://www.sciencedaily.com/releases/2020/06/200604095646.htm
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Alien frog invasion wreaks havoc on natural habitat
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Indiscriminate feeding by an alien population of the carnivorous spotted-thighed frog -- could severely affect the native biodiversity of southern Australia according to a new study by the University of South Australia.
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The invasive amphibian -- This is the first study of the spotted-thighed frog's diet in its invaded range with the findings providing important biological information about the impact of the alien species on natural ecosystems.Ecology experts, UniSA's Associate Professor Gunnar Keppel and Christine Taylor, say the potential of the spotted-thighed frog spreading to other parts of Australia is very concerning given its destructive eating patterns."This frog is an indiscriminate eating machine that will devour just about anything it can fit into its mouth," Taylor says."We're talking about a relatively large, predatory tree frog that, as a species is alien to South Australia, and it could have devastating impact on invaded habitats."As it eats away at local species, it's impacting the natural ecosystem, which can displace or destroy local food webs, outcompete native birds, reptiles and mammals for resources, and potentially change natural biodiversity."Biodiversity is the theme of this year's United Nations World Environment Day.Published in the On average, each frog had at least six prey items in its stomach, with prey estimated to include 200 different species, 60 per cent of which were beetles, spiders and insects. Native geckos, young frogs and mice were also identified as prey.Introduced species can have terrible outcomes for Australia, if not understood well. The infamous introduction of the cane toad in the 1930s as a mechanism to control sugar cane beetles, is just one example. The failure of that initiative continues to ravage Australia's ecology, with the cane toad now listed as a threatening pest under the Environment Protection and Biodiversity Conservation Act.Assoc Prof Keppel says it is important that people understand how detrimental introduced species can be for whole environments. He warns that if the spread of the spotted-thighed frog is not kept under control they could dominate many ecosystems in south-east Australia, at the expense of the local flora and fauna."The spotted-thighed frog is obviously very mobile. Already it's managed to travel more than 2000 kilometres and set up a colony in Streaky Bay. But its considerable tolerance of salinity and potential ability to withstand high temperatures could lead to further geographic spread, and if not controlled, it could extend further eastward into the Murray-Darling Basin," Assoc Prof Keppel says."It's vital that we continue to protect Australia's biodiversity. Preventing further dispersal of the spotted-thighed frog is a high conservation priority."The state government should consider managing the invasive population of spotted-thighed frogs at Streaky Bay. This should include education programs to inform people about what to do if they find a frog, as well as the feasibility of exterminating the population in South Australia."Importantly, if you do see one of these critters in your travels -- leave it be. We don't want it hitchhiking any further."
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Animals
| 2,020 |
June 3, 2020
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https://www.sciencedaily.com/releases/2020/06/200603104550.htm
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Scientists discover what an armored dinosaur ate for its last meal
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More than 110 million years ago, a lumbering 1,300-kilogram, armour-plated dinosaur ate its last meal, died, and was washed out to sea in what is now northern Alberta. This ancient beast then sank onto its thorny back, churning up mud in the seabed that entombed it -- until its fossilized body was discovered in a mine near Fort McMurray in 2011.
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Since then, researchers at the Royal Tyrrell Museum of Palaeontology in Drumheller, Alta., Brandon University, and the University of Saskatchewan (USask) have been working to unlock the extremely well-preserved nodosaur's many secrets -- including what this large armoured dinosaur (a type of ankylosaur) actually ate for its last meal."The finding of the actual preserved stomach contents from a dinosaur is extraordinarily rare, and this stomach recovered from the mummified nodosaur by the museum team is by far the best-preserved dinosaur stomach ever found to date," said USask geologist Jim Basinger, a member of the team that analyzed the dinosaur's stomach contents, a distinct mass about the size of a soccer ball."When people see this stunning fossil and are told that we know what its last meal was because its stomach was so well preserved inside the skeleton, it will almost bring the beast back to life for them, providing a glimpse of how the animal actually carried out its daily activities, where it lived, and what its preferred food was."There has been lots of speculation about what dinosaurs ate, but very little known. In a just-published article in Royal Society Open Science, the team led by Royal Tyrrell Museum palaeontologist Caleb Brown and Brandon University biologist David Greenwood provides detailed and definitive evidence of the diet of large, plant-eating dinosaurs -- something that has not been known conclusively for any herbivorous dinosaur until now."This new study changes what we know about the diet of large herbivorous dinosaurs," said Brown. "Our findings are also remarkable for what they can tell us about the animal's interaction with its environment, details we don't usually get just from the dinosaur skeleton."Previous studies had shown evidence of seeds and twigs in the gut but these studies offered no information as to the kinds of plants that had been eaten. While tooth and jaw shape, plant availability and digestibility have fuelled considerable speculation, the specific plants herbivorous dinosaurs consumed has been largely a mystery.So what was the last meal of "The last meal of our dinosaur was mostly fern leaves -- 88 per cent chewed leaf material and seven per cent stems and twigs," said Greenwood, who is also a USask adjunct professor."When we examined thin sections of the stomach contents under a microscope, we were shocked to see beautifully preserved and concentrated plant material. In marine rocks we almost never see such superb preservation of leaves, including the microscopic, spore-producing sporangia of ferns."Team members Basinger, Greenwood and Brandon University graduate student Jessica Kalyniuk compared the stomach contents with food plants known to be available from the study of fossil leaves from the same period in the region. They found that the dinosaur was a picky eater, choosing to eat particular ferns (leptosporangiate, the largest group of ferns today) over others, and not eating many cycad and conifer leaves common to the Early Cretaceous landscape.Specifically, the team identified 48 palynomorphs (microfossils like pollen and spores) including moss or liverwort, 26 clubmosses and ferns, 13 gymnosperms (mostly conifers), and two angiosperms (flowering plants)."Also, there is considerable charcoal in the stomach from burnt plant fragments, indicating that the animal was browsing in a recently burned area and was taking advantage of a recent fire and the flush of ferns that frequently emerges on a burned landscape," said Greenwood."This adaptation to a fire ecology is new information. Like large herbivores alive today such as moose and deer, and elephants in Africa, these nodosaurs by their feeding would have shaped the vegetation on the landscape, possibly maintaining more open areas by their grazing."The team also found gastroliths, or gizzard stones, generally swallowed by animals such as herbivorous dinosaurs and today's birds such as geese to aid digestion."We also know that based on how well-preserved both the plant fragments and animal itself are, the animal's death and burial must have followed shortly after the last meal," said Brown. "Plants give us a much better idea of season than animals, and they indicate that the last meal and the animal's death and burial all happened in the late spring to mid-summer.""Taken together, these findings enable us to make inferences about the ecology of the animal, including how selective it was in choosing which plants to eat and how it may have exploited forest fire regrowth. It will also assist in understanding of dinosaur digestion and physiology."Other members of the team include museum scientists Donald Henderson and Dennis Braman, and Brandon University research associate and USask alumna Cathy Greenwood.Research continues on The research was funded by Canada Foundation for Innovation, Research Manitoba, Natural Sciences and Engineering Research Council of Canada, National Geographic Society, Royal Tyrrell Museum Cooperating Society, and Suncor Canada, as well as in-kind support from Olympus Canada.
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Animals
| 2,020 |
June 2, 2020
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https://www.sciencedaily.com/releases/2020/06/200602110140.htm
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On the hunt for megafauna in North America
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Research from Curtin University has found that pre-historic climate change does not explain the extinction of megafauna in North America at the end of the last Ice Age.
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The research, published today in The research was an international collaboration between Curtin University, University of Texas-Austin, Texas A&M University and Stafford Research Labs.Lead researcher Mr Frederik Seersholm, Forrest Foundation Scholar and PhD candidate from Curtin's School of Molecular and Life Sciences, said the analysis tracks how biodiversity in Texas changed as temperatures dropped, and then recovered around 13,000 years ago."At the end of the last ice-age, Earth experienced drastic climate changes that significantly altered plant and animal biodiversity. In North America these changes coincided with the arrival of humans," Mr Seersholm said."When we combined our new data with existing fossil studies in the region, we obtained a detailed picture of the biodiversity turnover against the backdrop of both human predation and pre-historic climate changes."Our findings show that while plant diversity recovered as the climate warmed, large animal diversity did not recover."Of the large-bodied animals, known as megafauna, identified at the cave, nine became extinct and five disappeared permanently from the region."In contrast, small animals which are not believed to have been hunted intensely by humans, adapted well to the changing climate by migrating. Hence, the data suggests a factor other than climate may have contributed to the extinction of the large mammals."While the research team acknowledges it is difficult to assess the exact impact of human hunting on the megafauna, they believe there is now sufficient evidence to suggest our ancestors were the main driver of the disappearance of ice age species such as the mammoth and sabre-toothed cat.Mr Seersholm said the findings demonstrate how much information is stored in seemingly insignificant bone fragments."The study builds on years of research at Hall's cave, which have helped shape our understanding of the North American megafauna since the first analyses were conducted in the 1990s," Mr Seersholm said."By combining new genetic methods with classic stratigraphy and vertebrate palaeontology, our research adds to this story."We found that while small mammals and plants in the region seemed to be able to cope fine with the changing climate, the megafauna did not. Because humans are the only other major factor, we hypothesise that human hunting of megafauna was the driving force of the animals' decline."
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Animals
| 2,020 |
May 29, 2020
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https://www.sciencedaily.com/releases/2020/05/200529161221.htm
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Evolution of pandemic coronavirus outlines path from animals to humans
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A team of scientists studying the origin of SARS-CoV-2, the virus that has caused the COVID-19 pandemic, found that it was especially well-suited to jump from animals to humans by shapeshifting as it gained the ability to infect human cells.
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Conducting a genetic analysis, researchers from Duke University, Los Alamos National Laboratory, the University of Texas at El Paso and New York University confirmed that the closest relative of the virus was a coronavirus that infects bats. But that virus's ability to infect humans was gained through exchanging a critical gene fragment from a coronavirus that infects a scaly mammal called a pangolin, which made it possible for the virus to infect humans.The researchers report that this jump from species-to-species was the result of the virus's ability to bind to host cells through alterations in its genetic material. By analogy, it is as if the virus retooled the key that enables it to unlock a host cell's door -- in this case a human cell. In the case of SARS-CoV-2, the "key" is a spike protein found on the surface of the virus. Coronaviruses use this protein to attach to cells and infect them."Very much like the original SARS that jumped from bats to civets, or MERS that went from bats to dromedary camels, and then to humans, the progenitor of this pandemic coronavirus underwent evolutionary changes in its genetic material that enabled it to eventually infect humans," said Feng Gao, M.D., professor of medicine in the Division of Infectious Diseases at Duke University School of Medicine and corresponding author of the study publishing online May 29 in the journal Gao and colleagues said tracing the virus's evolutionary pathway will help deter future pandemics arising from the virus and possibly guide vaccine research.The researchers found that typical pangolin coronaviruses are too different from SARS-CoV-2 for them to have directly caused the human pandemic.However, they do contain a receptor-binding site -- a part of the spike protein necessary to bind to the cell membrane -- that is important for human infection. This binding site makes it possible to affix to a cell surface protein that is abundant on human respiratory and intestinal epithelial cells, endothelial cell and kidney cells, among others.While the viral ancestor in the bat is the most closely related coronavirus to SARS-CoV-2, its binding site is very different, and on its own cannot efficiently infect human cells.SARS-CoV-2 appears to be a hybrid between bat and pangolin viruses to obtain the "key" necessary receptor-binding site for human infection."There are regions of the virus with a very high degree of similarity of amino acid sequences among divergent coronaviruses that infect humans, bats and pangolins, suggesting that these viruses are under similar host selection and may have made the ancestor of SARS-CoV-2 able to readily jump from these animals to humans," said lead co-author Xiaojun Li from Duke."People had already looked at the coronavirus sequences sampled from pangolins that we discuss in our paper, however, the scientific community was still divided on whether they played a role in the evolution of SARS-CoV-2," said study co-lead author Elena Giorgi, staff scientist at Los Alamos National Laboratory."In our study, we demonstrated that indeed SARS-CoV-2 has a rich evolutionary history that included a reshuffling of genetic material between bat and pangolin coronavirus before it acquired its ability to jump to humans," Giorgi said.In addition to Gao, Li and Giorgi, study authors include, Manukumar Honnayakanahalli Marichannegowda, Brian Foley, Chuan Xiao, Xiang-Peng Kong, Yue Chen, S. Gnanakaran and Bette Korber.
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May 29, 2020
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https://www.sciencedaily.com/releases/2020/05/200529150656.htm
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'Single pixel' vision in fish helps scientists understand how humans can spot tiny details
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Recently discovered 'single-pixel vision' in fish could help researchers understand how humans are able to spot tiny details in their environment -- like stars in the sky.
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In a paper published this week, researchers at the University of Sussex found that zebrafish are able to use a single photoreceptor to spot their tiny prey.This photoreceptor is like an 'eye pixel' and seems to provide enough of a signal for the fish to go and investigate the stimulus.Professor Tom Baden and his co-authors believe that this could provide insights as to how animals, including humans, are able to process tiny details in their environment.Professor of Neuroscience Tom Baden, said: "Zebrafish have what's known as an 'acute zone' in their eyes, which is basically an evolutionary forerunner to the fovea that we have in the retina of our own. In both the zebrafish acute zone and the human fovea, visual acuity is at its highest."Because of this similarity, zebrafish are really good models to help us understand how the human eye might work."We found that, in this acute zone, zebrafish are using single photoreceptors to spot their tiny prey -- the equivalent of us spotting a star in the sky. These photoreceptors are a little bit like pixels -- but 'special' pixels at that: They have been specifically tuned to be sensitive to prey-like stimuli."There have been suggestions that primates and therefore humans too, use similar tricks to enhance our own foveal vision."The paper, published in the journal Prof Baden added: "This is effectively super-vision.""Zebrafish prey is really hard to see with human vision, which ranges from 'red' to 'blue'. However, beyond blue, zebrafish can also see UV, and as it turns out their prey is easily spotted when illuminated with the UV component in natural sunlight. Our research found that without UV-vision, zebrafish have a much harder time spotting their prey."While humans don't have this skill, the similarities between the zebrafish' acute zone and our own fovea has provided researchers with a model to further investigate how our eyes work and how we're able to see in such high detail.Scientists now have the possibility to manipulate visual functions in the zebrafish acute zone to see how this affects their sense of sight. These sorts of tests aren't possible in humans so doing them in fish will give researchers new insights into the function and dysfunction of extreme spatial acuity vision.
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May 28, 2020
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https://www.sciencedaily.com/releases/2020/05/200528160514.htm
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Reintroduction of wolves tied to return of tall willows in Yellowstone National Park
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The reintroduction of wolves into Yellowstone National Park is tied to the recovery of tall willows in the park, according to a new Oregon State University-led study.
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Wolves were reintroduced to the park in 1995. The new study shows their predation on elk is a major reason for an increase in the height of willows in northern Yellowstone, said Luke Painter, a wildlife ecologist at Oregon State University and lead author on the study.There's been a debate among scientists over the degree to which willows may have recovered from decades of suppression by elk following the restoration of wolves and subsequent reductions in elk numbers, Painter said."Our results demonstrate that the reduction of elk browsing over the last two decades in northern Yellowstone has allowed willows to grow taller in many places, despite a warming and drying climate," Painter said, adding that willows aren't recovering in some areas due to continued browsing by increased numbers of bison.Following wolf restoration in the 1990s, elk numbers decreased, and some researchers reported willows growing taller with reductions in elk browsing, evidence of a shift toward willow recovery.The new study compared data from three time periods: 1988-1993, when elk densities were high and most willows very short; 2001-04, when willows may have begun to recover; and 2016-18.The researchers confirmed that willows have indeed increased in height and cover in response to a reduction in browsing by elk.The study is published in the journal Elk numbers in northern Yellowstone have declined from a high of nearly 20,000 in 1995 -- the year wolves were restored to the park -- to 4,149 counted over two days in March 2019 by biologists with Montana Fish, Wildlife, and Parks; U.S. Forest Service and U.S. Geological Survey.Painter and co-author Michael Tercek of Walking Shadow Ecology in Montana found a strong contrast between sites along streams compared to wet meadows. Willows in meadow sites did not increase in height, but willows in stream sites increased significantly, exceeding 200 centimeters, or 6 feet -- a height accessible to elk -- in the summers of 2001-04 and in the spring of 2016.They also found a significant change in willow thickets at least 200 centimeters in height along streams, with thickets occupying about 80% of willow patches in some sites, but as little as 22% in others. Tall willow thickets are an important habitat feature and an indicator of willow recovery, Painter said.Thus, passive restoration through the return of predators has begun to reverse the loss of willows, something active culling of elk in the past was unable to accomplish, he said."Wolves didn't do it all by themselves," Painter said. "Other predators and hunters also affected elk, but this would not have happened without the wolves."This does not mean a wider expanse of willow habitat has been restored as existed in the early days of the park when beavers created large wetland expanses. This may eventually happen as beavers return but could take a long time to develop."This is the latest OSU study led by Painter that examines the effects of wolf reintroduction to Yellowstone on trees. In 2018, he published a study that showed that aspen is recovering in areas around the park, as well as inside the park boundary.Painter teaches ecology and conservation in the OSU College of Agricultural Sciences and College of Forestry.
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May 28, 2020
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https://www.sciencedaily.com/releases/2020/05/200528115827.htm
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Sea snakes have been adapting to see underwater for 15 million years
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Sea snakes first entered the marine environment 15 million years ago and have been evolving ever since to survive in its changing light conditions, according to a new study.
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Research led by the University of Plymouth (UK) has for the first time provided evidence of where, when and how frequently species have adapted their ability to see in colour.It suggests sea snakes' vision has been modifying genetically over millions of generations, enabling them to adapt to new environments and meaning they can continue to see prey -- and predators -- deep below the sea surface.In an unexpected twist, the study published in The research was led by Dr Bruno Simões, Lecturer in Animal Biology at the University of Plymouth, and involved scientists from the UK, Australia, Denmark, Bangladesh and Canada.Dr Simões, formerly a Marie Sk?odowska-Curie Global Fellow at the University of Bristol (UK) and University of Adelaide (Australia), said: "In the natural world, species obviously have to adapt as the environment around them changes. But to see such a rapid change in the sea snakes' vision over less than 15 million years is truly astonishing. The pace of diversification among sea snakes, compared to their terrestrial and amphibious relatives, is perhaps a demonstration of the immensely challenging environment they live in and the need for them to continue to adapt in order to survive."Our study also shows that snake and mammal vision has evolved very differently in the transition from land to sea. Sea snakes have retained or expanded their colour vision compared to their terrestrial relatives, whereas pinnipeds and cetaceans underwent a further reduction in the dimensions of their colour vision. This contrast is further evidence of the remarkable evolutionary diversity of snake eyesight."In the study, scientists say that despite being descended from highly visual lizards, snakes have limited (often two-tone) colour vision, attributed to the dim-light lifestyle of their early snake ancestors.However, the living species of front-fanged and venomous elapids are ecologically very diverse, with around 300 terrestrial species (such as cobras, coral snakes and taipans) and 63 fully marine sea snakes.To try and establish how this diversity occurred, scientists analysed various species of terrestrial and sea snakes from sources including fieldwork in Asia and Australia and historical museum collections.They investigated the evolution of spectral sensitivity in elapids by analysing their opsin genes (which produce visual pigments that are responsible for sensitivity to ultra-violet and visible light), retinal photoreceptors and eye lenses.Their results showed that sea snakes had undergone rapid adaptive diversification of their visual pigments when compared with their terrestrial and amphibious relatives.In one specific example, a particular lineage of sea snake had expanded its UV-Blue sensitivity. Sea snakes forage on the sea floor in depths exceeding 80metres, yet must swim to the surface to breathe at least once every few hours. This expanded UV-Blue sensitivity helps the snakes to see in the variable light conditions of the ocean water column.Also, most vertebrates have pairs of chromosomes resulting in two copies of the same genes. In some fruit-eating primates, the two copies might be slightly different (alleles) resulting in visual pigments with different spectral properties, expanding their colour vision. This study suggests that some sea snakes used the same mechanism to expand their underwater vision with both UV sensitive and blue-sensitive alleles.Dr Kate Sanders, Associate Professor of the University of Adelaide and senior author, said: "Different alleles of the same gene can be used by organisms to adapt new environmental conditions. The ABO blood types in primates are a result of different alleles of the same gene. However, despite being very important for the adaptation of species this mechanism is still poorly reported. For vision, it has been only reported on the long-wavelength opsin of some primates but our study suggests an intriguing parallel with diving sea snakes."
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May 27, 2020
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https://www.sciencedaily.com/releases/2020/05/200527123337.htm
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Fishing less could be a win for both lobstermen and endangered whales
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A new study by researchers at Woods Hole Oceanographic Institution (WHOI) found that New England's historic lobster fishery may turn a higher profit by operating with less gear in the water and a shorter season. The findings could provide a path forward for the lobster fishing industry, which is under pressure to move away from traditional pot fishing that uses long vertical lines of rope known to entangle and kill endangered North Atlantic right whales and other protected species. The study was published this week in the journal
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"The story the data tells is optimistic," says lead author Hannah Myers, a graduate student at the University of Alaska Fairbanks and a guest student at WHOI. "We know that taking rope out of the water column is the best way to protect whales, and that can likely be done in a way that could benefit fishers as well."American lobsters (In order to maintain healthy fish stocks, many fisheries have a limited season, catch quotas and/or gear restrictions. These measures often reduce associated fishing costs, such as for bait and fuel, while also ensuring that the available fish are bigger and more abundant. Although the U.S. lobster fishery has some restrictions, the trap limit is very high and for the most part fishers can operate year-round.By evaluating three different scenarios to understand the connection between lobster fishing effort and catch, the researchers found that tightening restrictions could make the industry more profitable in the long run.In Massachusetts, where a three-month fishing closure was implemented in 2015 in Cape Cod Bay and surrounding areas where North Atlantic right whales come to feed each winter and spring, fishers caught significantly more lobster since the closure was implemented -- particularly in the areas most affected by it.Further north, Canadian fishers in the Gulf of Maine operate with far fewer traps and a six-month season, and catch about the same amount of lobster as their American counterparts with 7.5 times less fishing effort. In Maine, a 10 percent drop in the number of lobster traps fished in recent years has not prevented fishers from bringing in record landings.Fishing gear entanglements are the most serious threat to the survival of endangered North Atlantic right whales, only about 400 of which are alive today. During peak lobster season, right whales must navigate through more than 900,000 endlines -- ropes that connect surface buoys to traps on the seafloor -- in waters off the northeastern U.S. coastline, which is an important area for their feeding and migratory habitat."Entanglements often cause chronic injury, stress, and even starvation if the animal doesn't immediately drown," says Michael Moore, a coauthor of the paper and director of WHOI's Marine Mammal Center. "If the public could see the trauma these entangled animals endure, they would be extremely concerned."Understanding the economic implications that right whale protection measures may have is important to the lobster fishing industry and the many communities along New England's coast that it supports, the researchers say. This study shows that reducing the amount of gear in the water or shortening the season does not necessarily mean fishers will catch less, and is in fact likely to benefit the industry in the long-term. This is especially important, given the economic devastation of the COVID-19 crisis.Overall, their findings were consistent across the board: fishing with less gear and a shorter season corresponded with higher landings and higher profits.
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May 26, 2020
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https://www.sciencedaily.com/releases/2020/05/200526203557.htm
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Scientists reveal new fundamental principles governing diving in animals
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Diving as a lifestyle has evolved many times in the animal kingdom, and the ecology of all diving animals is essentially shaped by how long they can hold their breaths.
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According to new research, the world's diving animals -- from small insects to giant whales -- are all governed by a number of similar principles.Using the largest dataset ever compiled, an international team of scientists has examined how metabolic constraints govern the diving performance of air-breathing aquatic species, all of which have evolved to maximise the amount of time they can spend underwater.They discovered that maximum dive duration increases predictably with body mass in all animals, but the rate at which this happens depends on metabolic mode.Ectotherms -- cold-blooded creatures such as amphibians, reptiles and insects -- can remain submerged for longer at a given body mass, but the impact of an increase in body mass on dive duration in warm-blooded endotherms -- including birds and mammals -- is far more pronounced.Writing in They also say it may partly explain why many warm-blooded diving animals -- including modern whales but also extinct reptiles such as ichthyosaurs and plesiosaurs -- evolved relatively large body sizes, as increases in size led to greater relative increases in dive duration.The research was completed at the University of Plymouth (UK), and led by an international team of scientists now based at Radboud University (Netherlands), Université du Québec à Rimouski (Canada) and Plymouth's School of Biological and Marine Sciences.They compiled and analysed 1,792 records for 286 species, including 62 ectotherms and 224 endotherms, and tested whether the globally recognised oxygen store/usage hypothesis -- which suggests that larger animals are able to dive for longer and deeper -- applies to all diving animals, irrespective of their evolutionary origin and metabolic mode.Lead author Dr Wilco Verberk, an Assistant Professor at Radboud University, said: "Our work provides an unprecedented analysis of the ecology of diving behaviour from a metabolic perspective, with far-reaching implications. It demonstrates that body mass and temperature affect dive duration in a similar manner in species as evolutionarily distant as insects, reptiles, birds and mammals. This shows the same general physical and physiological principles have shaped the evolution of diving in all animal groups, both ancient and modern, constituting a new fundamental principle for evolutionary physiology."Senior author David Bilton, Professor of Aquatic Biology at the University of Plymouth and an expert on aquatic beetles, added: "Our results change our understanding of diving in animals significantly, and help us better disentangle what shapes the ecology and evolution of both extant and extinct divers. It shows that large body size and the increased oxygen storage capacity that goes with it, permit longer dives, opening many previously inaccessible aquatic ecosystems to large bodied air breathers and provides a possible explanation as to why many warm-blooded diving animals tend to be relatively large."
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May 26, 2020
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https://www.sciencedaily.com/releases/2020/05/200526203555.htm
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Chimpanzees help trace the evolution of human speech back to ancient ancestors
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One of the most promising theories for the evolution of human speech has finally received support from chimpanzee communication, in a study conducted by a group of researchers led by the University of Warwick.
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The evolution of speech is one of the longest-standing puzzles of evolution. However, inklings of a possible solution started emerging some years ago when monkey signals involving a quick succession of mouth open-close cycles were shown to exhibit the same pace of human spoken language.In the paper 'Chimpanzee lip-smacks confirm primate continuity for speech-rhythm evolution', published today, the 27th May, in the journal Just like each and every language in the world, monkey lip-smacks have previously shown a rhythm of about 5 cycles/second (i.e. 5Hz). This exact rhythm had been identified in other primate species, including gibbon song and orangutan consonant-like and vowel-like calls.However there was no evidence from African apes, such as gorillas, bonobos and chimpanzees -- who are closer related to humans, meaning the plausibility of this theory remained on hold.Now, the team of researchers using data from 4 chimpanzee populations have confirmed that they too produce mouth signals at a speech-like rhythm. The findings show there has been most likely a continuous path in the evolution of primate mouth signals with a 5Hz rhythm. Proving that evolution recycled primate mouth signals into the vocal system that one day was to become speech.African great apes, the closest species to humans, had never been studied for the rhythm of their communication signals. Researchers investigated the rhythm of chimpanzee lip-smacks, produce by individuals while they groom another and found that chimpanzees produce lip-smacks at an average speech-like rhythm of 4.15 Hz.Researchers used data across two captive and two wild populations, using video recordings collected at Edinburgh Zoo and Leipzig Zoo, and recordings of wild communities including the Kanyawara and the Waibira community, both in Uganda.Dr Adriano Lameira, from the Department of Psychology at the University of Warwick comments:"Our results prove that spoken language was pulled together within our ancestral lineage using "ingredients" that were already available and in use by other primates and hominids. This dispels much of the scientific enigma that language evolution has represented so far. We can also be reassured that our ignorance has been partly a consequence of our huge underestimation of the vocal and cognitive capacities of our great ape cousins."We found pronounced differences in rhythm between chimpanzee populations, suggesting that these are not the automatic and stereotypical signals so often attributed to our ape cousins. Instead, just like in humans, we should start seriously considering that individual differences, social conventions and environmental factors may play a role in how chimpanzees engage "in conversation" with one another."If we continue searching, new clues will certainly unveil themselves. Now it's a matter of mastering the political and societal power to preserve these precious populations in the wild and continue enabling scientists to look further."
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May 26, 2020
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https://www.sciencedaily.com/releases/2020/05/200526145300.htm
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Similar to humans, chimpanzees develop slowly
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Few species develop as slowly as humans, both in terms of developing adult skills and in terms of brain development. Human infants are born so underdeveloped that they cannot survive without adult care and feeding for some years after birth. Children still need to learn fundamental skills such as walking, eating, talking, using tools and much more. The timing of when these developmental milestones emerge is used by doctors to determine if your child and your child's brain are developing normally. However, we know little about the timing of when motor and social developmental milestones emerge in other long-lived, closely-related species, such as chimpanzees; nor what this means for their brain development. For example, when do chimpanzees start to walk, feed themselves, groom others and use tools? Fully charting development milestones in wild chimpanzees and other species can help us understand the evolutionary basis of such extended developmental periods.
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Researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig have now systematically mapped a wide array of behavioural skills and determined at which point during development these skills emerge in wild chimpanzees. For this study, the researchers observed 19 chimpanzee infants (eight females and 11 males) from the Taï National Park, Côte d'Ivoire, from the first month after they were born until five years of age. The results showed that gross motor skills begin to emerge at around four months, communication traits at 12 months, social interaction skills at 14 months and fine motor skills at 15 months. "Not only the time frame, but also the order of emergence of the different skills is very similar to what we see in humans, reflecting a shared evolutionary history," says first author Aisha Bründl. "Our findings are in line with the delayed benefits hypothesis, which states that extended development is necessary for acquiring adult skills.""Such developmental milestones may shed light on the maturation of the brain," says senior author Catherine Crockford, a co-leader of the Evolution of Brain Connectivity (EBC) project of the Max Planck Society. "Our findings suggest that some parts of the chimpanzee brain may develop slowly like in humans." This remains to be investigated as part of this new EBC-project, a collaboration between the Max Planck institutes for Evolutionary Anthropology and for Human Cognitive and Brain Sciences, in the context of which researchers collect, scan and analyse post mortem brains of great apes and relate these findings to ape behaviour.In addition, the researchers found that more complex skills, like tool use and social interactions, emerge later, with larger differences between individual chimpanzees in when they emerge than less complex skills. "This variation may be caused by underlying differences in the social environment a chimpanzee is growing up in, but also other factors such as nutrition, and remains to be investigated further," explains co-author Patrick Tkaczynski."Such a developmental study requires long-term data, since chimpanzees have a similarly slow life history as humans," Roman Wittig, another senior author on the study and director of the Taï Chimpanzee Project points out. "We are lucky to have 40 years of observations on the same wild chimpanzees." Overall, this study is the most extensive description of developmental milestones in chimpanzees to date and brings us a step closer to shedding light on shared developmental pathways of great ape species.
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Animals
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May 26, 2020
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https://www.sciencedaily.com/releases/2020/05/200526115048.htm
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Cultural diversity in chimpanzees
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The transmission of cultures from generation-to-generation is only found in a few species besides humans. Chimpanzees are one such species and exhibit a large diversity of cultural and tool use behaviours. Although these behaviours have been well documented at a handful of long term research sites, the true cultural repertoire of chimpanzees across populations is still poorly understood. To better understand this diversity, researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, initiated the 'Pan African Programme: The Cultured Chimpanzee' (PanAf) in 2010. Using a standardized protocol, researchers set up camera traps, collected samples and recorded ecological data at over 40 temporary and long-term research sites across Africa.
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Prior to this study, termite fishing was thought to occur in only two forms with one or multiple tools, from either above-ground or underground termite nests. By carefully observing the techniques required to termite fish at ten different sites, lead author Christophe Boesch created a catalogue of behaviours (ethogram) for each chimpanzee in the study.What was found was 38 different technical elements making up the various termite fishing techniques, all of which were combined in different ways in each of the chimpanzee communities. In addition, individuals in the same community shared more of the termite fishing technical elements, and unique combinations of the technical elements, when compared to chimpanzees from other groups."The diversity of techniques seen in chimpanzee termite fishing was a huge surprise to me. Not only does each community have a very unique way of fishing, they also combine a number of different elements into specific termite fishing etiquettes," explains Christophe Boesch."The most striking examples of this are how the Wonga Wongue chimpanzees of Gabon usually lie down on their sides to termite fish, while the Korup chimpanzees in Cameroon lean on their elbows, and the ones from Goualougo in the Republic of Congo sit while fishing."Because the communities of chimpanzees live in similar habitats with access to the same resources, ecological differences could mostly be ruled out to explain the observed differences. "This supports the idea that chimpanzees are capable of imitating social techniques in 'how to termite fish' which goes beyond alternative explanations such as each individual reinventing termite fishing each time they learn it," explains co-author Ammie Kalan.Much like in human etiquette, not everything is about increased efficiency but rather about conforming to what the rest of the group is doing. In humans, this is observed in the different chopstick cultures across Asia. "For example, in Thailand and Japan not only are chopsticks somehow shaped differently, but the way they hold them differ as well, and this is very reminiscent of what we see here with chimpanzees. In La Belgique in Cameroon, chimpanzees fashion their stick by opening the fibers to obtain a long brush and then rest the termite-covered stick on their wrist while they eat. On the other hand, at another site in Cameroon called Korup, the chimpanzees do not make a brush at all and use their mouth to shake the inserted stick while it is in the mound," explains Christophe Boesch.In humans, cultural variation has been documented in hundreds of different populations which is one explanation for why chimpanzee culture seems so limited in comparison. "What we knew before about chimpanzees came from at most 15 communities," notes co-author Hjalmar Kuehl. "Through the PanAf we have been able to study many more communities and by this we are able to learn more about the richness of chimpanzee diversity and culture and could demonstrate that there is so much more to discover out there."Further analyses of videos and other data collected from the PanAf are currently underway. "Termite fishing and other cultural behaviours of wild chimpanzees can be observed first hand by signing onto our citizen science platform Chimp&See," says co-author Mimi Arandjelovic. "At Chimp&See citizen scientists can watch the over one million video clips the PanAf has recorded from all across Africa of chimpanzees, gorillas, elephants, buffalo, leopards and many more species.
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May 26, 2020
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https://www.sciencedaily.com/releases/2020/05/200526091326.htm
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Early African Muslims had a halal -- and cosmopolitan diet -- discovery of thousands of ancient animal bones shows
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Early Muslim communities in Africa ate a cosmopolitan diet as the region became a trading centre for luxury goods, the discovery of thousands of ancient animal bones has shown.
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Halal butchery practices became common when Islam spread through Ethiopia as vibrant communities developed because of the import and export of products around the Red Sea, and to Egypt, India, and the Arabian Peninsula, archaeologists have found.New excavations at three sites in the east of the country completed by the University of Exeter and the Ethiopian Authority for Research and Conservation of Cultural Heritage have uncovered around 50,000 animal bones dating from the eighth/ninth centuries onwards, and showing people living there at this early time ate a Muslim diet 400 years before major Mosques or burial sites were built in the 12th century.The team, led by Professor Timothy Insoll, and involving archaeozoologist Jane Gaastra from the University of Exeter's Institute of Arabic and Islamic Studies, found the first evidence in Africa for ancient halal butchery during the excavations, at Harlaa, Harar, and Ganda Harla.Previous excavations led by Professor Insoll have revealed the Mosques and burial sites, as well as the remains of luxury materials such as ceramics from China and Egypt, marine shell from the Red Sea and beads from India.Harlaa was established in the 6th and 7th centuries before Islam arrived in Ethiopia. It was abandoned in the 15th century when Harlaa and Ganda Harlaa were established, possibly because of plague or environmental change, and with the increasing spread of Islam better places to farm could be lived in.During the period from which the animal bones date people may have been using smaller Mosques not yet discovered by archaeologists, and built larger buildings for worship as Muslim communities grew.Professor Insoll said: "We didn't expect to find bones of this quality and quantity. They are so well preserved that we can clearly see both cuts and evidence of wear. We've also found bones in both residential areas and places of work."This is significant new information about people's religious identity at the time. It shows in the early days of Islam in the region people were just starting to adopt religious practices, so were sometimes pragmatic and didn't follow all of them."Analysis of wear on the bones show cattle were used for ploughing and turning grinding stones, and other species such as camels, horses, and donkeys, may have been used as pack animals to carry trade goods and other commodities. Analysis of the age data of cattle bones at Harlaa indicated 80 to 90 per cent of animals survived beyond 3 years of age, showing they were kept for milk or for work rather than bred to eat.Archaeologists found the remains of pigs in Harlaa and Ganda Harlaa, which could have been domesticated or wild, unexpected in an Islamic area, as pigs are haram, ot forbidden in Islamic halal diet. This suggests the region was cosmopolitan, with visitors and residents from different areas and with different religions. Another explanation could be that early Muslims in the area ate pork during this period for practical reasons. No pig remains were found at Harar, which was a city of Muslim scholarship and pilgrimage. Similar halal butchery techniques were used in all three sites, showing the influence of Muslim traders who arrived in the area and the spread of Islam to first Harlaa, and then Harar and Ganda Harla.People also ate and hunted warthog, bushpig, aardvark, porcupine, hare, gennet, mongoose and leopard.At Harlaa researchers also found evidence of marine fish imported from the Red Sea some 120 kilometres away. These had all been processed prior to being sent to Harlaa, either in dried or salted form to preserve them. This was indicated by the complete absence of fish heads showing these had been removed, probably at the Red Sea coast. No local freshwater fish species were found suggesting the people eating the fish were used to a sophisticated diet.Similar animal body portions were found at each site, indicating wealth or status may not have been a factor in access to meat.The study, published in the
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May 22, 2020
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https://www.sciencedaily.com/releases/2020/05/200522102315.htm
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How the darter got stripes: Expanding a sexual selection theory explains animal patterns
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Samuel Hulse, a Ph.D. candidate at UMBC, spent a lot of time in waders over the last two years. He traipsed from stream to stream across the eastern U.S., carefully collecting live specimens of small, colorful freshwater fish known as darters and taking photos of their habitats. Then he brought them back to the lab to capture high-quality images of their coloration patterns.
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Hulse developed a precise, quantitative analysis of those visual patterns, such as stripes, spots, and various mottled looks. His work shows, for the first time, a strong correlation between the complicated patterns on male fish and the fishes' highly variable environments. The results were published today in These findings represent a major expansion of a theory in sexual selection known as "sensory drive," which emphasizes how an animal's environment can influence what sexual signals -- like visual patterns -- are selected for over time.So far, sensory drive has successfully explained examples such as coloration in cichlids, a group of freshwater fish in Africa. Hulse was working to expand on this research.Different species of cichlids live at different depths, and which colors the fish can easily see changes as you go deeper and there is less light. Why does this matter? The idea of sensory drive is that animals perceive visual signals, like colors, as more attractive when they are easier for their brains to process. And which signals are easier to process is dependent on the environment. When male fish are perceived as more attractive, they are more likely to reproduce, and their colors are more likely to be passed to the next generation of fish. So, if the theory of sensory drive is true, eventually, most male fish will have colors that are easy for mates to perceive in their particular environment.In cichlid fish, "you see this depth-dependent change in the male colors as you go deeper," Hulse says. With the new work, "we were able to expand on this theory to explain more complicated traits, such as visual patterns," like stripes and spots.Hulse, who is also taking courses toward an M.S. in mathematics at UMBC, brought his quantitative skills to bear on this research. He used a measure called Fourier analysis to examine his fish images, looking at variations in color contrast.For example, if you were to look at a photo of a grassy hill under a bright blue sky, the greatest contrast in brightness would be between the large areas above and below the horizon line. That contrast is on a larger scale than the differences in brightness between, say, tiny blades of grass. The differences between each blade are small, but occur frequently across the image.Fourier analysis can translate the contrast patterns in an image into a representative set of mathematical sine and cosine waves. The low-frequency waves, which only swoop up and down once or twice across the entire image, represent large-scale differences, like above and below the horizon. High-frequency waves swoop up and down many times across an image and represent small-scale differences, like between blades of grass.Researchers can look at the relationships between those waves -- how much high-frequency versus low-frequency contrast there is in the image. Hulse's work looked at that measure to examine the visual relationship between a habitat and the fish that lived in it. And sure enough, his calculations revealed a strong correlation, providing evidence of sensory drive in male darters.One argument against the idea that these patterns are attractive to females is the idea of camouflage. Wouldn't it make sense for animals to match the visual patterns of their environment to avoid getting eaten rather than to attract females? Darters are under strong predation pressure, so, Hulse says, it's a valid point.However, the fact that he found that only male fish match their environment is a strong argument in favor of sensory drive. Predators don't discriminate between males and females, so you would expect females to also match their environment if camouflage was the reason."Quantitatively describing visual patterns is a big challenge, and there's not one easy way to do that, so being able to use tools like Fourier analysis is wonderful," Hulse says. "That actually lets us quantify some of these things that have historically been very hard to describe other than with wishy-washy terminology."Tamra Mendelson, professor of biological sciences, is Hulse's advisor and a co-author on the new paper. She had just begun formulating the ideas for this research with visual ecologist Julien Renoult, a colleague at Centre National de la Recherche Scientifique (CNRS) in Montpellier, France, and another co-author, when Hulse joined her laboratory in 2016."Julien had inspired me to take concepts from a field called human empirical aesthetics, which is the mathematical and biological basis of human appreciation of art, and apply them to animals' appreciation of other animals," Mendelson says. "I was super excited about it, but I didn't have the mathematical chops to really take it as far as it could go."So, when Hulse arrived, "It was a perfect match. Sam is the ideal student to be doing this project."Hulse also spent several months in France working with Renoult to iron out some of the statistical challenges of the work -- which were many. "The data analysis became a lot more complicated than we thought, and there were a lot of technical snags," Hulse says. "So it was really great to be able to be there working directly with Julien, who has a lot of background with these sorts of methods."Hulse was drawn to this work by the unique blend of skills it requires. "I love the interdisciplinary nature of it. We're bringing together field biology, sensory biology, a little bit of neurobiology, and image analysis," he says. "That's one of the most attractive things about this project for me -- how much I get to learn and how much I get to take little pieces from so many different areas."Now, Hulse, Mendelson, and Renoult are excited to see where their new work leads. "There's not a lot of theory in sexual selection that can be used to explain why you see one pattern evolve in one animal where you see a different one evolve in a closely related species," Hulse says.The new findings open the door to much more exploration with different species, including animals that live on land. In any group of animals that relies on vision, has visually distinct environments, and where the animals have distinct habitat preferences, Hulse argues, "this theory should hold."
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May 22, 2020
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https://www.sciencedaily.com/releases/2020/05/200522095500.htm
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New to science newts from Vietnam
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In time for the International Day for Biological Diversity 2020, the date (22 May) set by the United Nations to recognise biodiversity as "the pillars upon which we build civilizations," a new study, published in the peer-reviewed open-access journal
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Until recently, the Black knobby newt (Tylototriton asperrimus) was known to be a common species inhabiting a large area stretching all the way from central and southern China to Vietnam. Much like most of the other members of the genus Tylototriton, colloquially referred to as crocodile newts or knobby newts, it has been increasingly popular amongst exotic pet owners and traditional Chinese medicine practitioners. Meanwhile, authorities would not show much concern about the long-term survival of the Black knobby newt, exactly because it was found at so many diverse localities. In fact, it is still regarded as Near Threatened, according to the International Union for Conservation of Nature's Red List.However, over the past decade, the increasing amount of research conducted in the region revealed that there are, in fact, many previously unknown to science species, most of which would have been assumed to be yet another population of Black knobby newts. As a result, today, the crocodile newts represent the most species-rich genus within the whole family of salamanders and newts (Salamandridae).Even though this might sound like great news for Earth's biodiversity, unfortunately, it also means that each of those newly discovered species has a much narrower distributional range, making them particularly vulnerable to habitat loss and overcollection. In fact, the actual Black knobby newt turns out to only exist within a small area in China. Coupled with the high demand of crocodile newts for the traditional Chinese medicine markets and the exotic pet trade, this knowledge spells a worrying threat of extinction for the charming 12 to 15-centimetre amphibians.In order to help with the answer of the question of exactly how many Vietnamese species are still being mistakenly called Black knobby newt, the German-Vietnamese research team of the Cologne Zoo (Germany), the universities of Hanoi (Vietnam), Cologne and Bonn (Germany), and the Vietnam Academy of Science and Technology analysed a combination of molecular and detailed morphological characters from specimens collected from northern Vietnam. Then, they compared them with the Black knobby newt specimen from China used to originally describe the species back in 1930.Thus, the scientists identified two species (Tylototriton pasmansi and Tylototriton sparreboomi) and one subspecies (Tylototriton pasmansi obsti) previously unknown to science, bringing the total of crocodile newt taxa known from Vietnam to seven. According to the team, their discovery also confirms northern Vietnam to be one of the regions with the highest diversity of crocodile newts."The taxonomic separation of a single widespread species into multiple small-ranged taxa (...) has important implications for the conservation status of the original species," comment the researchers.The newly discovered crocodile newts were named in honour of the specialist on salamander chytrid fungi and co-discoverer Prof. Dr. Frank Pasmans and, sadly, the recently deceased salamander enthusiasts and experts Prof. Fritz-Jurgen Obst and Prof. Dr. Max Sparreboom.In light of their findings, the authors conclude that the current and "outdated" Near Threatened status of the Black knobby newt needs to be reassessed to reflect the continuous emergence of new species in recent years, as well as the "severe threats from international trade and habitat loss, which have taken place over the last decade."Meanwhile, thanks to the commitment to biodiversity conservation of Marta Bernardes, lead author of the study and a PhD Candidate at the University of Cologne under the supervision of senior author Prof Dr Thomas Ziegler, all crocodile newts were included in the list of internationally protected species by the Convention on International Trade in Endangered Species (CITES) last year.Today, some of the threatened crocodile newt species from Vietnam are already kept at the Cologne Zoo as part of conservation breeding projects. Such is the case for the Ziegler's crocodile newt (Tylototriton ziegleri), currently listed as Vulnerable on the IUCN Red List and the Vietnamese crocodile newt (
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Animals
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May 21, 2020
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https://www.sciencedaily.com/releases/2020/05/200521161220.htm
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CRISPR a tool for conservation, not just gene editing
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The gene-editing technology CRISPR has been used for a variety of agricultural and public health purposes -- from growing disease-resistant crops to, more recently, a diagnostic test for the virus that causes COVID-19.
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Now a study involving fish that look nearly identical to the endangered Delta smelt finds that CRISPR can be a conservation and resource management tool, as well. The researchers think its ability to rapidly detect and differentiate among species could revolutionize environmental monitoring.The study, published in the journal As a proof of concept, it found that the CRISPR-based detection platform SHERLOCK (Specific High-sensitivity Enzymatic Reporter Unlocking) was able to genetically distinguish threatened fish species from similar-looking nonnative species in nearly real time, with no need to extract DNA."CRISPR can do a lot more than edit genomes," said co-author Andrea Schreier, an adjunct assistant professor in the UC Davis animal science department. "It can be used for some really cool ecological applications, and we're just now exploring that."The scientists focused on three fish species of management concern in the San Francisco Estuary: the U.S. threatened and California endangered Delta smelt, the California threatened longfin smelt and the nonnative wakasagi. These three species are notoriously difficult to visually identify, particularly in their younger stages.Hundreds of thousands of Delta smelt once lived in the Sacramento-San Joaquin Delta before the population crashed in the 1980s. Only a few thousand are estimated to remain in the wild."When you're trying to identify an endangered species, getting it wrong is a big deal," said lead author Melinda Baerwald, a project scientist at UC Davis at the time the study was conceived and currently an environmental program manager with California Department of Water Resources.For example, state and federal water pumping projects have to reduce water exports if enough endangered species, like Delta smelt or winter-run chinook salmon, get sucked into the pumps. Rapid identification makes real-time decision making about water operations feasible.Typically to accurately identify the species, researchers rub a swab over the fish to collect a mucus sample or take a fin clip for a tissue sample. Then they drive or ship it to a lab for a genetic identification test and await the results. Not counting travel time, that can take, at best, about four hours.SHERLOCK shortens this process from hours to minutes. Researchers can identify the species within about 20 minutes, at remote locations, noninvasively, with no specialized lab equipment. Instead, they use either a handheld fluorescence reader or a flow strip that works much like a pregnancy test -- a band on the strip shows if the target species is present."Anyone working anywhere could use this tool to quickly come up with a species identification," Schreier said.While the three fish species were the only animals tested for this study, the researchers expect the method could be used for other species, though more research is needed to confirm. If so, this sort of onsite, real-time capability may be useful for confirming species at crime scenes, in the animal trade at border crossings, for monitoring poaching, and for other animal and human health applications."There are a lot of cryptic species we can't accurately identify with our naked eye," Baerwald said. "Our partners at MIT are really interested in pathogen detection for humans. We're interested in pathogen detection for animals as well as using the tool for other conservation issues."This study was funded with support from the California Department of Water Resources.
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Animals
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May 21, 2020
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https://www.sciencedaily.com/releases/2020/05/200521151917.htm
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The European viper uses cloak-and-dazzle to escape predators
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Research of the University of Jyväskylä demonstrate that the characteristic zig-zag pattern on a viper's back performs seemingly opposing functions during a predation event. At first, the zig-zag pattern helps the snake remain undetected. But upon exposure, it provides a conspicuous warning of the snake's dangerous defense. Most importantly the zig-zag can also produce an illusionary effect that may hide the snake's movement as it flees. The research, published in
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Protective coloration is one of the simplest but most effective tools that prey species use to evade predators. Typically, different color patterns are useful at different stages of a predation event. Some color patterns are cryptic, obscuring the prey from being detected -- think chameleons. Other patterns are aposematic, which blatantly advertise a warning to predators -- think wasps. Finally, some patterns can produce optical illusions to startle or confuse predators and give the prey an escape opportunity -- think zebras.But a recent series of experiments, by a team headed by Janne Valkonen and Johanna Mappes at the University of Jyväskylä (Finland), suggests that European vipers (At first, the zig-zag pattern helps the viper to hide. The researchers hid plasticine models of snakes with different color patterns along paths and noted how often they were detected by people walking the trail. Models with the zig-zag pattern were detected less often than plainly colored models. This is the first confirmation that the viper's zig-zag pattern provides a cryptic function. But even if the viper is detected, the zig-zag can still work its magic -- instead of hiding the snake, the pattern now functions to make it more obvious. Previous research has already established that the pattern warns predators about the snake's dangerous bite.The most significant contribution from Dr. Janne Valkonen's study deals with a particular class of illusion generated by the zig-zag pattern. Just as how a rapid series of still pictures can produce a smooth animation, the rapid flickering from the zigs and zags of a fleeing snake can produce a solid shape.Team measured the speed of fleeing snakes and calculated the flicker rate of the zig-zag. To an observer, a rapidly changing stimulus (such as a moving zig-zag, or spinning helicopter blade) is perceived as continuous if the flicker rate exceeds a threshold in the visual system.The researchers found that the zig-zag moved quickly enough to produce such a 'flicker-fusion effect' to mammalian predators, although the quicker eyes of a raptor won't be fooled. The effect of this illusion may change the appearance of the moving snake, making it harder to catch. So, like a skilled illusionist, the viper hides by revealing.The viper's zig-zag seems to be a simple pattern, but it is a masterful illusion that can hide, reveal, and paradoxically achieve both at the same time. Similarly, this research resolves theoretical tensions between apparently opposing functions of color patterns. That is, crypsis and aposematism seem mutually exclusive: one is meant to blend an animal into its surroundings, the other to make it stand out.However, through the magic of movement and optics, both functions can be gained through the same pattern at different stages in the predation sequence. Furthermore, the one-to-many aspect of the zig-zag to its antipredator functions implies a far broader scope for the evolution of color patterns and antipredator adaptations than simple one pattern-to-one function relations.
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Animals
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May 21, 2020
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https://www.sciencedaily.com/releases/2020/05/200521112605.htm
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Environmental contaminants alter gut microbiome, health
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The microbes that inhabit our bodies are influenced by what we eat, drink, breathe and absorb through our skin, and most of us are chronically exposed to natural and human-made environmental contaminants. In a new paper, scientists from the University of Illinois at Urbana-Champaign review the research linking dozens of environmental chemicals to changes in the gut microbiome and associated health challenges.
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The review is published in the journal The paper includes sections on compounds used in manufacturing consumer goods, including the bisphenols found in plastic food packaging, and phthalates, which are used in everything from vinyl flooring to plastic films. It also describes the science associated with exposure to persistent organic pollutants and heavy metals. POPs include chemicals like PCBs; perfluorochemicals, which are used in nonstick cookware and food packaging; flame retardants known as polybrominated diphenyl ethers; and pesticides and herbicides."More than 300 environmental contaminants or the metabolic byproducts of those contaminants have been measured in human urine, blood or other biological samples," said Jodi Flaws, a U. of I. professor of comparative biosciences who led the analysis with Ph.D. student Karen Chiu. "Chemicals such as bisphenols, phthalates and some pesticides, persistent organic pollutants and heavy metals can alter hormone metabolism and are associated with adverse health outcomes."The negative health effects linked to these chemicals include reproductive and developmental defects, Type 2 diabetes, cardiovascular dysfunction, liver disease, obesity, thyroid disorders and poor immune function, the researchers report.Dozens of studies have explored how chemical exposures affect health, and scientists are now turning their attention to how these chemicals influence gut microbes. The studies reviewed in the new paper were conducted in rats, mice, fish, dogs, chickens, cows, human adults and infants, honey bees and other organisms.Studies have found that exposure to bisphenols, which are detectable in the urine of more than 90% of adults in the United States, increases levels of Methanobrevibacter bacteria in the male gut. These microbes have been shown -- in humans and in mice -- to boost their host's ability to extract more energy from food."This raises a strong possibility that BPA-induced weight gain is caused at least partially by BPA-induced changes in the gut microbiome," the researchers wrote.Phthalates are plasticizers and stabilizers that easily leach into foods. Eating phthalate-contaminated foods is the primary route of exposure in humans. Like bisphenols, phthalates are endocrine disruptors, meaning that they interfere with normal hormone-signaling in the body.High phthalate exposure in human newborns is associated with changes in the gut microbiome and altered immune responses to vaccination. In mice, exposure to phthalates during puberty appears to inhibit the microbial synthesis of butyrate, a metabolite that is essential for intestinal health, immune regulation and neurological function.Persistent organic pollutants are oily organic chemicals that can persist in the environment for years or decades."Recent studies have investigated the impact of POP exposure on the gut microbiota during developmental, juvenile and adult stages in a variety of animals, including mice, fish and humans," the researchers wrote.Studies have found that exposure to PCBs is associated with microbial shifts in the gut and increased gut permeability, intestinal inflammation and cognitive problems. Once used as coolants, PCBs were banned in the U.S. in 1978 but persist in the environment.Perfluorochemicals are used in nonstick cookware, food packaging and stain-resistant carpets. One study linked PFCs to changes in the gut microbiome and impaired lipid metabolism in female -- but not male -- fish and their offspring. The microbiome shifts persisted in the offspring, and the young fish suffered higher mortality than those whose mothers were not exposed to PFCs.Studies have found that exposure to glyphosate herbicides alters the bacterial makeup of the gut microbiome in cattle, rodents and honey bees. It increased anxious and depressive symptoms in mice and was associated with an increase in pathogenic bacteria in cattle. The pesticide chlorpyrifos affects microbial populations in male rodents and fish exposed during development and adulthood, and also causes inflammation and oxidative stress in the gut."All of these data together suggest that exposure to many of these environmental chemicals during various stages of life can alter the gut microbiome in ways that influence health," Chiu said. "The pathologies associated with altered microbiomes after exposure to environmental chemicals include immune dysfunction, altered carbohydrate and lipid metabolism, and neurological and behavioral impairments. We are also seeing that these effects highly depend on an individual's sex and age."
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Animals
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May 19, 2020
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https://www.sciencedaily.com/releases/2020/05/200519204121.htm
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Ancient giant armored fish fed in a similar way to basking sharks
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Scientists from the University of Bristol and the University of Zurich have shown that the
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Where the lower jaw of Consequently, However, this has remained uncertain, as no fossilised evidence of suspension-feeding structures such as elongate projections that cover the gills in modern suspension-feeding fish has ever been found.Instead, the team sought to investigate the question indirectly, using biomechanical analysis to compare the lower jaw of Lead author Sam Coatham carried out the research while studying for his masters in palaeobiology at the University of Bristol's School of Earth Sciences.He said: "We have found that "Consequently, those feeding strategies (common amongst its relatives) would probably have not been available for The fossils of The team tested the resilience of the jaws by virtually applying forces to the jaws, using a technique called Finite Element Analysis (FEA) to assess how likely each jaw was to break or bend.This revealed that the lower jaw of This pattern was consistent in both sharks and whales, with the suspension-feeder proving less resistant to stress than the other species within the same lineage. Further analyses comparing the distribution of stress across the jaws showed similar patterns in It has been established that there were almost certainly giant suspension-feeding vertebrates living 380 million years ago, at least 150 million years before the suspension-feeding Pachycormidae (previously the earliest definitive example) and about 350 million years before the first baleen whales.The research team believes that there are other extinct species that would have filled a similar ecological role, including other placoderms (armoured fish) and at least one species of plesiosaur.Sam Coatham added: "Our methods could be extended to identify other such species in the fossil record and investigate whether there were common factors driving the evolution and extinction of these species."We suggest a link between oceanic productivity and the evolution of
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Animals
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May 19, 2020
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https://www.sciencedaily.com/releases/2020/05/200519204113.htm
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Scientists dissect the complex choices of animals
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What is important when you choose a home? Space, security, light -- or a combination of these? Like humans, animals make choices about where to live that have important implications for their livelihoods. But unlike humans, animals do not easily reveal the basis of their choice.
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Now, researchers from the Max Planck Institute of Animal Behavior in Konstanz and the University of Konstanz have created a paradigm that can disentangle the strands of animal decision-making. By using CT scanning, 3D modelling and 3D printing, they have created artificial shelters that vary in precise ways, and used these structures to reveal the underlying preferences of animals.The findings are reported in Aneesh Bose, a postdoc in Jordan's lab and co-first author of the study points out that the choices an animal makes, especially when it comes to choosing a home, can have major implications for the choosing animal. "A shelter can serve many ecological roles, a place to rear babies, hide from predators, perform social behaviour," says Bose. "But just looking at the choices animals make doesn't give us a correct answer of what they want because they are constrained by what's available to them."The problem with studying shelter selection in the wild is that many traits in nature are linked. A bigger shelter (for example a burrow, den, hole, or shell), could be better for rearing off-spring, while a bigger shelter entrance opens the way for more predators to enter. However, bigger shelters often have bigger entranceways, and many animals are unable to physically alter the structures they encounter and choose amongst in the wild. Therefore, pinpointing the function behind an animal's preferences for shelter structures requires circumventing the constraints of the natural world where traits are often correlated.The researchers devised an experimental framework that enabled methodical appraisal of the possible traits of importance. Selecting a species of shell-dwelling cichlid fish (Neolamprologus multifasciatus) from Lake Tanganyika, Africa, they used high resolution CT scanning on a range of the snail shells that the fish use as shelters. From the scans, 3D models of the structures were created wherein certain features of the shells were manipulated independently of each other. The models were 3D printed to create accurate shell replicas and then offered to fish in choice experiments.Fish showed preferences for exaggerated shells that bore dimensions that do not exist, or rarely exist, in nature. Fish preferred shells that were fully intact and either enlarged, lengthened, or had widened apertures. Notably, fish were able to distinguish chirality -- the direction of coiling -- in the shells provided, always favouring shells with the same chirality as those that exist in their natural habitat. The important finding was that, for fish, not every home structural feature is equal. In fact, they preferred shell intactness more than shell length, which was itself preferred more heavily than entrance size. These are facets of the fish's decision-making process that could not be ascertained without such a controlled, manipulative experiment."The innovation of our study is that we have been able to 3D print a biological structure with precisely controlled dimensions, rather than using samples of real shells, which are limited in how they can be manipulated," says Windorfer, a bachelor student and co-lead author on the study. "And that way we escape the confines of the natural world."Jordan, senior author on the study says: "Our ultimate goal is to understand why animals choose the things they do, so first we have be certain we know what they choose. For example, I choose my beer based on taste, and I don't really care about the bottle it comes in. But someone watching me might notice that all my favourite beers come in green bottles, and conclude I prefer green bottles.""If we are to avoid making the same mistake in animal behaviour, we need to figure out a different way. Our study shows how you can experimentally dissociate linked traits and gives us a very powerful experimental framework to explore the ultimate basis of animal decision-making."- A shell-dwelling cichlid fish (Neolamprologus multifasciatus) from Lake Tanganyika, Africa, were given artificial shells to choose from in experiments.
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Animals
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May 19, 2020
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https://www.sciencedaily.com/releases/2020/05/200519165838.htm
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Fishing rod 'selfie stick' and scientific sleuthing turn up clues to extinct sea reptile
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A Russian paleontologist visiting the Natural History Museum in London desperately wanted a good look at the skeleton of an extinct aquatic reptile, but its glass case was too far up the wall. So he attached his digital camera to a fishing rod and -- with several clicks -- snagged a big one, scientifically speaking.
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Images from the "selfie stick" revealed that the creature, whose bones were unearthed more than a century ago on a coast in southern England, seemed very similar to a genus of ichthyosaurs he recognized from Russian collections.He emailed the photos of the dolphin-like ichthyosaur to fellow paleontologist Megan L. Jacobs, a Baylor University doctoral candidate in geosciences. She quickly realized that the animal's skeletal structure matched not only some ichthyosaurs she was studying in a fossil museum on the English Channel coast, but also some elsewhere in the United Kingdom.Jacobs and paleontologist Nikolay G. Zverkov of the Russian Academy of Sciences -- who "fished" for the ichthyosaur -- merged their research, studying their collective photos and other materials and ultimately determining that the Russian and English ichthyosaurs were of the same genus and far more common and widespread than scientists believed.Their study is published in the "Ichthyosaurs swam the seas of our planet for about 76 million years," Jacobs said. "But this 5-foot ichthyosaur from some 150 million years ago was the least known and believed to be among the rarest ichthyosaurs. The skeleton in the case, thought to be the only example of the genus, has been on display in the Natural History Museum in London since 1922."Nikolay's excellent detailed photos significantly expand knowledge of Nannopterygius enthekiodon," she said. "Now, after finding examples from museum collections across the United Kingdom, Russia and the Arctic -- as well as several other Nannopterygius species -- we can say Nannopterygius is one of the most widespread genera of ichthyosaurs in the Northern Hemisphere."Additionally, the study described a new species, Nannopterygius borealis, dating from about 145 million years ago in a Russian archipelago in the Arctic. The new species is the northernmost and youngest representative of its kind, Jacobs said.Previously, for the Middle and Late Jurassic epochs, the only abundant and most commonly found ichthyosaur was Ophthalmosaurus, which had huge eyes and was about 20 feet long. It was known from hundreds of specimens, including well-preserved skeletons from the Middle Jurassic Oxford Clay Formation of England, Jacobs said."For decades, the scientific community thought that Nannopterygius was the rarest and most poorly known ichthyosaur of England," Zverkov said. "Finally, we can say that we know nearly every skeletal detail of these small ichthyosaurs and that these animals were widespread. The answer was very close; what was needed was just a fishing rod."
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Animals
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May 19, 2020
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https://www.sciencedaily.com/releases/2020/05/200519153506.htm
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Ribs evolved for movement first, then co-opted for breathing
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When early tetrapods transitioned from water to land the way they breathed air underwent an evolutionary revolution. Fish use muscles in their head to pump water over their gills. The first land animals utilized a similar technique -- modern frogs still use their head and throat to force air into their lungs. Then another major transformation in vertebrate evolution took place that shifted breathing from the head to the torso. In reptiles and mammals, the ribs expand to create a space in the chest that draws in breath. But what caused the shift?
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A new study published on May 12 in When lizards walk, they bend side-to-side in a sprawling gait. The ribs and vertebrae are crucial to this movement, but it was unclear how until now. Researchers captured the 3-D motion of lizard ribs and vertebrae using XROMM, a combination of CT scans and X-ray videos. They recorded three savannah monitor lizards and three Argentine black and white tegus walking slowly on a treadmill. The resulting images revealed that while the spine is bending, every rib in both species rotated substantially around its vertebral joint, twisting forward on one side of the body and backward on the other side alternatively with each stride. The mechanics follow nearly the same pattern as when the reptiles inhale and exhale."It's really exciting because we didn't previously have plausible hypotheses for how rib-breathing evolved," said first author Robert Cieri, a postdoc at the University of the Sunshine Coast and who conducted the research while at the University of Utah, where he is still affiliated. "We're proposing that these rib movements first started to facilitate locomotion, then were co-opted for breathing."The work also included John Capano and Elizabeth Brainerd at Brown University, and undergraduate Samuel Hatch at the U.Reptiles, birds and mammals, all considered amniotes, use costal aspiration where the ribs and vertebrae control breathing by expanding and contracting. The motion is facilitated by the ribs rotating around the vertebrocostal joints -- where the ribs and vertebrae meet. It's possible that an early amniote ancestor first used these rib movements to enhance its lateral undulation, the side-to-side trunk motion that helps propel lizards forward. During locomotion, each limb has two phases: First is propulsion, which is when the foot is pushing against the ground. Second is swing, which is when the foot is in the air. The new research found that during the arm's propulsion phase, the ribs on the same side of the body rotate towards the head, and while it's in the swing phase, they rotate towards the tail. This mimics what the scientists previously found the ribs doing inhalation and exhalation -- but this time simultaneously on both sides.Early tetrapods used sprawling, undulatory locomotion, but likely still had a head-driven breathing system. The authors propose that rib movements and increased costal joint mobility evolved during locomotion to increase stride length, hold the thorax steady, or as the passive result of the ribs moving to prevent being bunched together as the animals bended. At some point, early amniotes evolved the ability to express these rib movements on both sides simultaneously, which allowed for the expansion and contraction of the trunk that support inhalation and exhalation."Aspiration breathing was one of the key innovations that allowed amniotes to diversify on land. We were surprised and thrilled to find clues to how it evolved from a study on locomotion," co-author Brainerd said.
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Animals
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May 19, 2020
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https://www.sciencedaily.com/releases/2020/05/200519144454.htm
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Observing the freely behaving brain in action
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Scientists working at caesar have developed a small head-mounted microscope that allows access to the inner workings of the brain. The new system enables measurement of activity from neuronal populations located in the deep cortical layer with single-cell resolution, in an animal that is freely behaving.
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Understanding how animals use their brain circuitry to generate behavior in response to their environment is one of the central goals of neuroscience. While it is possible to study animal behavior by observing how an animal solves problems, to gain an understanding of the brain's role in generating the behavior the brain circuit activity must be measured at the same time.In vivo imaging is, of course, nothing new in biology: it dates back to the very beginnings of microscopy. To look inside the brain, special microscopes can be used that can see through the tissue enabling the observation of neuronal circuits at work. Using a microscope to image neural activity has the advantage of being relatively non-invasive. Mounted outside the brain, the microscope simply sends light into the brain, in turn receiving the light emitted out of the brain. While conventional microscopes are too heavy to enable functional imaging from freely behaving animals, over the last years significant effort has gone into developing head-mounted miniaturized microscopes.In 2009, Jason Kerr's group, in collaboration with the group of Winfried Denk at the Max Planck Institute of Neurobiology (Martinsried), established a miniaturized head-mounted multiphoton microscope. It enabled recording of activity from neuronal populations located in the upper few layers in visual cortex of awake, freely moving rats. While this 'two-photon fiberscope' was a breakthrough in measuring brain activity from freely behaving animals, most of the cortical layers remained out of reach. To image the deeper layers of the cortex on a cellular level, a new approach was needed.In collaboration with Philip Russell's group at the Max Planck Institute for the Science of Light, Kerr's group has now developed a small head-mounted multiphoton microscope, capable of imaging all cortical layers in a freely moving rat. Light is delivered through a custom designed and manufactured glass fiber, utilizing the 'three-photon effect' to image neuronal activity located in deep cortical layers. Compared to two-photon or one-photon fluorescence microscopy, three-photon is ideal for imaging deeper in scattering tissue, and enables clearer images of single cells deep in the tissue. The new microscope allows for continuous imaging of neuron populations, even when the animal runs or performs complex behavioral tasks, over extended periods of time.The researchers expect the fiberscope to be widely applicable to behavioral research, as previous microscopes were limited in their imaging depth and unsuitable for use over extended periods of time, restricting the types of behaviors that could be observed. With this new approach, researchers are now able to understand the complex network dynamics that underlie neural computation which, in turn, forms the basis of perception and behavior.
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May 19, 2020
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https://www.sciencedaily.com/releases/2020/05/200519114218.htm
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How do birds understand 'foreign' calls?
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<em> Fais attention! Serpent!</em>
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You may not speak French, but if someone behind you in a forest shouted this, you'd likely understand and become instantly alert.And according to a new report from Kyoto University's Hakubi Center for Advanced Research, the same thing happens in birds.Previous reports have shown that animals with shared predators can eavesdrop on and respond to each other's calls, indicating that they can partly understand other species. Toshitaka Suzuki, publishing in "Many birds have specific alarm calls, warning others about a predator," explains Suzuki. "I was studying how a specific call of a small bird named the Japanese tit, But he then observed that another bird, the coal tit or "I wondered if these other birds also mentally retrieve 'snake' images from these calls. While they are in the same taxonomic group their calls are otherwise vastly different."To demonstrate this, Suzuki set up an experiment under controlled conditions to investigate if the coal tits can anticipate and react appropriately even when they have not yet seen the predator in question. Snake-specific warning calls of the Japanese tit were played, and a stick was moved to mimic a snake gliding across the ground or up a tree."A variety of bird calls were played, but it was only the snake-specific ones which caused the coal tits to approach and inspect the stick," states Suzuki. "Additionally, when the stick was moved unlike a snake, such as in a rocking motion, none of the birds approached even when the warning calls were played."These results show that the birds likely visualize a snake and react appropriately when they hear the snake-specific call from the other species, supported by visual confirmation. This work therefore represents the first evidence of visual search activity evoked via eavesdropping on another animal's alarm calls.Suzuki intends to pursue this study to further explore how birds associate another species' calls with predators, hoping eventually to provide the basis for a new model for speech acquisition that may even be applicable to humans.
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May 18, 2020
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https://www.sciencedaily.com/releases/2020/05/200518184916.htm
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Why cats have more lives than dogs when it comes to snakebite
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Cats are twice as likely to survive a venomous snakebite than dogs, and the reasons behind this strange phenomenon have been revealed by University of Queensland research.
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The research team, led by PhD student Christina Zdenek and Associate Professor Bryan Fry, compared the effects of snake venoms on the blood clotting agents in dogs and cats, hoping to help save the lives of our furry friends."Snakebite is a common occurrence for pet cats and dogs across the globe and can be fatal," Dr Fry said."This is primarily due to a condition called 'venom-induced consumptive coagulopathy' -- where an animal loses its ability to clot blood and sadly bleeds to death."In Australia, the eastern brown snake (Pseudonaja textilis) alone is responsible for an estimated 76 per cent of reported domestic pet snakebites each year."And while only 31 per cent of dogs survive being bitten by an eastern brown snake without antivenom, cats are twice as likely to survive -- at 66 per cent."Cats also have a significantly higher survival rate if given antivenom treatment and, until now, the reasons behind this disparity were unknown.Dr Fry and his team used a coagulation analyser to test the effects of eastern brown snake venom -- as well as 10 additional venoms found around the world -- on dog and cat plasma in the lab."All venoms acted faster on dog plasma than cat or human," Mrs Zdenek said."This indicates that dogs would likely enter a state where blood clotting fails sooner and are therefore more vulnerable to these snake venoms."The spontaneous clotting time of the blood -- even without venom -- was dramatically faster in dogs than in cats."This suggests that the naturally faster clotting blood of dogs makes them more vulnerable to these types of snake venoms."And this is consistent with clinical records showing more rapid onset of symptoms and lethal effects in dogs than cats."Several behavioural differences between cats and dogs are also highly likely to increase the chances of dogs dying from venomous snake bite."Dogs typically investigate with their nose and mouth, which are highly vascularised areas, whereas cats often swat with their paws," Dr Fry said."And dogs are usually more active than cats, which is not great after a bite has taken place because the best practice is to remain as still as possible to slow the spread of venom through the body."The researchers hope their insights can lead to a better awareness of the critically short period of time to get treatment for dogs envenomed by snakes."As dog lovers ourselves, this study strikes close to home but it also has global implications," Dr Fry said."I've had two friends lose big dogs to snakebites, dying in less than ten minutes even though the eastern brown snakes responsible were not particularly large specimens."This underscores how devastatingly fast and fatal snake venom can be to dogs."
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May 18, 2020
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https://www.sciencedaily.com/releases/2020/05/200518144958.htm
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Even biodiverse coral reefs still vulnerable to climate change and invasive species
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A new study reveals clear evidence highlighting the importance of fish biodiversity to the health of spectacular tropical coral reef ecosystems.
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This is the case for reefs that are pristine and also those that have been affected by stresses, such as bleaching events caused by warming oceans.However, the study's results show that even though strong relationships between diversity and a healthy ecosystem persist, human-driven pressures of warming oceans and invasive species still diminish ecosystems in various ways.This highlights that protecting fish biodiversity is a key factor for improving the survival chances of coral reef ecosystems in the face of rapid environmental change. But the researchers caution that without removing human-driven stressors, protecting biodiversity alone might not be enough.Dr Casey Benkwitt, of Lancaster Environment Centre and lead author of the study, said: "Our study, which is the first of its kind to look at relatively pristine coral, reveals the strong link between rich biodiversity and a thriving ecosystem. This relationship is still evident even when an ecosystem has been degraded and provides further clarity on just how crucial it is to maintain biodiversity to give tropical coral reefs a fighting chance to thrive in an uncertain future."However, the bad news is that the functioning of these fragile ecosystems is still vulnerable and was impaired in different ways by climate change and invasive species on nearby islands."A team of researchers conducted surveys on coral reefs around ten islands in the remote Chagos Archipelago -- the largest uninhabited and unfished coral reef area in the Indian Ocean.Their surveys counted the number of different fish species on reefs as a measure of biodiversity. They also measured how well an ecosystem was functioning relative to fish biodiversity at different islands using two key indicators -the biomass of fish living on a reef, and a measure of productivity, which is the rate at which biomass is produced.Dr Benkwitt, said: "We were surprised that the positive effects of biodiversity on ecosystem functions were so strong because such clear patterns are rare in ecological data. These results match previous studies on less pristine coral reefs, and in other terrestrial and marine systems. To see the same patterns in so many places suggests the positive relationship between diversity and ecosystem function may be one of the few general rules in ecology."Importantly, the researchers also looked at coral reefs under pressure from multiple human-driven factors. This is the first time scientists have measured these kinds of effects outside of a lab.The scientists had data from before and after a major heatwave in 2016 that caused bleaching and death of corals. This coral loss caused biodiversity to plummet by 17 per cent. Because of the strong relationship between biodiversity and ecosystem function, such losses in biodiversity caused by warming oceans will result in coral ecosystems that are not able to function as well.Professor Nick Graham of Lancaster University and co-author of the study said: "The large negative effects of coral bleaching on biodiversity is worrisome as warming events are becoming more and more common. Because high diversity is key to ecosystem function, this means that preserving biodiversity may be increasingly important, but also increasingly challenging, in the future."The scientists also studied coral reefs experiencing a reduction in nutrients caused by invasive rats on nearby islands. The rats, which arrived with people on boats decades ago, decimate wild bird populations, resulting in fewer droppings. These bird droppings act as fertiliser for the reefs when washed off into the sea, increasing fish growth rates and the amount of fish on a reef.The researchers found that the coral reefs near islands with rats, and therefore with fewer seabird nutrients washing off to reefs, experienced lower levels of biomass. This shows that even when maintaining biodiversity, coral reef ecosystems are still vulnerable to human-caused stressors.Dr Benkwitt said: "The bleaching event and loss of nutrients each reduced ecosystem functions in different ways. This means that managing each stressor will have complementary benefits for coral reefs. While biodiversity is clearly important to ecosystem function, biodiversity conservation may become more difficult and may not fully sustain ecosystems unless underlying stressors, such as climate change, are reduced."The findings are outlined in the paper 'Biodiversity increases ecosystem functions despite multiple stressors on coral reefs', which has been published in the journal
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May 18, 2020
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https://www.sciencedaily.com/releases/2020/05/200518090026.htm
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Fish feces reveals which species eat crown-of-thorns
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Crown-of-thorns starfish are on the menu for many more fish species than previously suspected, an investigation using fish poo and gut goo reveals.
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The finding suggests that some fish, including popular eating and aquarium species, might have a role to play in keeping the destructive pest population under control.The native starfish (Increasing the amount of predation on starfish has long been touted as a potential solution to preventing outbreaks. However, aside from a mollusc called the Giant Triton (Now, a team of scientists led by Dr Frederieke Kroon from the Australian Institute of Marine Science in Townsville, Australia, has applied a genetic marker unique for crown-of-thorns, developed at AIMS, to detect the presence of starfish DNA in fish poo and gut contents.Over three years, Dr Kroon's team used it on samples taken from 678 fish from 101 species, comprising 21 families, gathered from reefs experiencing varying levels of starfish outbreak."Our results strongly indicate that direct fish predation on crown-of-thorns may well be more common than is currently appreciated," said Dr Kroon.The study, published in the journal Among the species were nine which had not been previously reported to feed on crown-of-thorns. These include the Neon Damsel ("Our findings might also solve a mystery -- why reef areas that are closed to commercial and recreational fishing tend to have fewer starfish than areas where fishing is allowed," said Dr Kroon.She and colleagues from AIMS worked with researchers from CSIRO Land and Water and managers from the Great Barrier Reef Marine Park Authority to conduct the study."This innovative research sheds new light on the extent that coral reef fishes eat crown-of-thorns starfish," said Mr Darren Cameron, co-author of the paper, and Director of the COTS Control Program at the Great Barrier Reef Marine Park Authority."A number of the fish species shown to feed on these starfish are caught by commercial and recreational fisheries, highlighting the importance of marine park zoning and effective fisheries management in controlling crown-of-thorns starfish across the Great Barrier Reef."
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May 18, 2020
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https://www.sciencedaily.com/releases/2020/05/200518090022.htm
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Analysis of bird species reveals how wings adapted to their environment and behavior
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Bird wings adapted for long-distance flight are linked to their environment and behaviour, according to new research on an extensive database of wing measurements, led by the University of Bristol.
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The Arctic tern flies from the Arctic to the Antarctic and back again each year, while the Inaccessible Island rail -- the world's smallest flightless bird -- never leaves its five-square-mile island.The way different organisms vary in how much they move around is a key factor in understanding and conserving biodiversity. Yet since tracking animal movement is difficult and expensive, there are still huge gaps in knowledge about animal movements and dispersal, particularly in more remote parts of the world. The good news is that bird wings offer a clue.Measurements of wing shape -- particularly a metric called the 'hand wing index', which reflects the elongation of the wing -- can quantify how well the wing is adapted for long-distance flight and is easily measured from museum specimens.New research published today in A global team of researchers, led by the University of Bristol and Imperial College London, measured the wings of 45,801 birds in museums and field sites around the world.From these, the team created a map of the global variation in wing shape, showing that the best-adapted fliers were primarily found in high latitudes while birds adapted to more sedentary lifestyles were generally found in the tropics.By analysing these values along the bird family tree, together with detailed information about each species' environment, ecology, and behaviour, the authors found that this geographical gradient is primarily driven by three key variables: temperature variability, territory defence, and migration.The study's lead author, Dr Catherine Sheard from the University of Bristol's School of Earth Sciences, said: "This geographic pattern is really striking. Given the role we know dispersal plays in evolutionary processes, from speciation to species interactions, we suspect this relationship between behaviour, the environment, and dispersal may be shaping other aspects of biodiversity."Examples of fundamental patterns potentially explained by variation in dispersal include the smaller geographical ranges noted in tropical species.Dr Joseph Tobias, senior author of the study, based at Imperial College London, added: "We hope our measures of wing shape for over 10,000 bird species will have numerous practical applications, particularly in ecology and conservation biology, where so many important processes are regulated by dispersal."
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May 18, 2020
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https://www.sciencedaily.com/releases/2020/05/200518090035.htm
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Eavesdropping crickets drop from the sky to evade capture by bats
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Researchers have uncovered the highly efficient strategy used by a group of crickets to distinguish the calls of predatory bats from the incessant noises of the nocturnal jungle. The findings, led by scientists at the Universities of Bristol and Graz in Austria and published in
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Sword-tailed crickets of Barro Colorado Island, Panama, are quite unlike many of their nocturnal, flying-insect neighbours. Instead of employing a variety of responses to bat calls of varying amplitudes, these crickets simply stop in mid-air, effectively dive-bombing out of harm's way. The higher the bat call amplitude, the longer they cease flight and further they fall. Biologists from Bristol's School of Biological Sciences and Graz's Inst of Zoology discovered why these crickets evolved significantly higher response thresholds than other eared insects.Within the plethora of jungle sounds, it is important to distinguish possible threats. This is complicated by the cacophony of katydid (bush-cricket) calls, which are acoustically similar to bat calls and form 98 per cent of high-frequency background noise in a nocturnal rainforest. Consequently, sword-tailed crickets need to employ a reliable method to distinguish between calls of predatory bats and harmless katydids.Responding only to ultrasonic calls above a high-amplitude threshold is their solution to this evolutionary challenge. Firstly, it allows the crickets to completely avoid accidentally responding to katydids. Secondly, they do not respond to all bat calls but only sufficiently loud ones, which indicates the bat is within seven metres of the insect. This is the exact distance at which a bat can detect the echo of the crickets, which ensures the crickets only respond to bats that have already detected them when trying to evade capture.This type of approach is rare in nature with most other eavesdropping insects living in less noisy environments being able to rely on differences in call patterns to distinguish bat predators.Dr Marc Holderied, senior author on the study from Bristol's School of Biological Sciences, explained: "The beauty of this simple avoidance rule is how the crickets respond at call amplitudes that exactly match the distance over which bats would detect them anyway -- in their noisy world it pays to only respond when it really counts."The study was supported by the Austrian Science Foundation and Leverhulme Trust.
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May 15, 2020
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https://www.sciencedaily.com/releases/2020/05/200515144654.htm
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Ocean 'breathability' key to past, future habitat of West Coast marine species
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Marine life off the West Coast, from Mexico up through Canada, inhabit the California Current. The cool, nutrient-rich water supports life from invisible phytoplankton to the economically important salmon, rockfish and Dungeness crab to the majestic orcas.
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A new study led by the University of Washington finds that the animals' ability to breathe in that water may be key to where and when they thrive. The study, published May 15 in "If you're worried about marine life off the west coast of North America, you're worried about anchovies and other forage fish in the California Current. Ultimately it's what underpins the food web," said lead author Evan Howard, a UW postdoctoral researcher in oceanography.The study shows that species respond to how breathable the water is -- a combination of the oxygen levels in the water and the species' oxygen needs, which are affected by water temperature. The anchovy historical data matches this pattern, and it suggests that the southern part of their range could be uninhabitable by 2100."Climate change isn't just warming the oceans -- it is causing oxygen to decrease, which could force fish and other ocean animals to move away from their normal range to find higher-oxygen waters," Howard said.Anchovy populations are known to cycle through time, but the reasons have been mysterious. Other explanations -- that drew on food supplies, predator-prey interactions, competition with other species, and temperature preferences -- failed to fully explain the anchovy populations cycles from the1950s to today, which have been carefully recorded.Since the late 1940s, the California Cooperative Oceanic Fisheries Investigations, or CalCOFI, a partnership between California state and federal agencies, has monitored marine life and conditions offshore. It was established after the economically devastating crash of the sardine fishery in the 1940s with the goal of avoid another fisheries collapse and better understanding marine populations."They weren't just measuring anchovies, they were measuring everything they could get their hands on," Howard said. Because the anchovies are numerous and their populations soared after the sardine collapse, these fish provide a good record over time and space for the past half-century.Previous research by the UW group showed that water "breathability," the combined effects of temperature and oxygen levels, are key for marine animals' survival. The 2015 research used models to combine the effects of warmer seawater that can hold less oxygen with marine animals' increased metabolic needs in a warmer environment.The new study also drew on a 2018 paper that analyzed the oxygen needs for various types of marine animals at different water temperatures. The two previous studies focused on the future, under climate change, and the distant past, for a major extinction event.Researchers combined observations with ocean models to fill gaps in the data and showed that the breathability index changes over time and corresponds with when anchovy populations rise and fall, and when they move deeper or closer to shore."This study is the first one that demonstrates on a timescale of decades that a species is responding in really close alignment with this metabolic index -- how breathable the ocean in its habitat has become," said senior author Curtis Deutsch, a UW associate professor of oceanography. "It adds a new, independent line of verification that species in the ocean are arranged in accordance with how breathable their habitats are."The authors then looked at the extent of anchovy habitat in the future under climate change. Projected changes in the water conditions will likely make the southern part of the anchovies' range, off the coasts of Mexico and Southern California, uninhabitable by 2100."We expect habitats to shift for all species that depend on oxygen for survival," Howard said. "If we understand how these animals are responding to their environment, we can better predict how these populations will be affected as the conditions change."
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May 15, 2020
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https://www.sciencedaily.com/releases/2020/05/200515144652.htm
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Food webs determine the fate of mercury pollution in the Colorado River, Grand Canyon
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In the Grand Canyon reach of the Colorado River, two species play an outsized role in the fate of mercury in the aquatic ecosystem, and their numbers are altered by flood events. So reports new research, published in Science Advances, that is among the first to meld ecotoxicology and ecosystem ecology to trace how mercury flows through aquatic food webs and then spreads to land.
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Mercury is an environmental contaminant that occurs in ecosystems globally. In its organic form, it is a potent neurotoxin that can harm people and wildlife. Mercury accumulation in animals and how it magnifies along food chains is well studied. Less well understood are the pathways mercury takes through food webs to reach top predators, such as fish and birds, and how those pathways might change after large ecosystem disturbances, such as floods.Emma Rosi is an aquatic ecologist at Cary Institute of Ecosystem Studies and co-lead author on the paper. She explains, "By combining data on mercury concentrations in aquatic life with well-studied food webs, we were able to reveal how mercury moves through an ecosystem. We found that flooding and an invasive species both influenced the flow of this contaminant of global concern."The traits of organisms living in an ecosystem -- their physiology, what they eat, and what eats them -- determine contaminant movement and exposure. These factors have rarely been included in models of contaminant flux and fate. "Pairing contaminant concentrations and highly detailed food webs has the potential to improve the management of contaminants in ecosystems," Rosi notes.To study these pathways, the research team developed mercury-based food webs for six sites spanning 225 miles of the Colorado River, extending downstream from the Glen Canyon Dam in Grand Canyon National Park. Food web sampling took place seasonally over two years. At each site, they measured algae, invertebrates, and fish to determine who was eating what -- and what that meant for mercury exposure at each level of the food web.Insects (blackflies and midges) and invasive New Zealand mudsnails were the dominant invertebrates in the river. These animals play a vital role in moving energy and contaminants from the bottom of the food web to fish predators at the top. Fish included native Bluehead Sucker, Flannelmouth Sucker, Speckled Dace, and Humpback Chub, as well as non-native species such as Common Carp, Fathead Minnow, and Rainbow Trout.The stomach contents of invertebrates and fish were assessed to identify what they ate and in what amounts. Algae, detritus, and animals were analyzed for mercury concentrations and, combined with the diet data, the team estimated the amount of mercury that animals were consuming throughout the year.Food web complexity varied across the study sites. Just below the Glen Canyon Dam, food webs were simple with few species and food web connections. Further downstream, food webs had higher species diversity and more connections. Across the study sites, regardless of food web complexity, relatively few species were key players in the movement of mercury.Algae and tiny particles of detritus were the source of 80% of mercury flowing to invertebrates. In sites closest to the dam, invasive mudsnails dominated the food webs. Trout were the only fish in this part of the river, and they are unable to digest mudsnails. Mercury accumulated by the snails did not move up the food chain. Because the snails are fully aquatic, mercury cycled back into the river's detrital food web when they died.Blackfly larvae were the source of 56-80% of the mercury flowing to fish. Blackflies are preferred prey for fish, such as Rainbow Trout, and blackflies had higher mercury contaminations compared to other invertebrates. Blackflies that escape predation and emerge from the river as flying adults move mercury from the river to land. This can expose terrestrial predators, such as birds and bats, to mercury that started out in the river.The amount of mercury that blackflies moved to land was dependent on the number of hungry fish in any part of the river. At some sites, fish ate nearly 100% of the blackfly larvae, leaving few left to emerge. At other sites, there were a lot more blackflies than the fish could eat. When these blackflies emerged as adults, the mercury inside them hitched a ride to terrestrial food webs along the river.One year into sampling, the study sites were flooded as part of a planned dam release. The team was able to explore the effects of the flood on mercury movement in the food webs. At sites near the dam, the flood washed away large numbers of New Zealand mudsnails and led to a boom in blackfly populations. With the rise in blackflies, more mercury flowed to trout. Because trout gobbled up nearly all the blackflies in their larval form, very little of the mercury accumulated in these abundant insects was transported to land by the flying adults.Rosi explains, "Changes to the animal populations in an ecosystem will impact how mercury moves through a food web. This was especially apparent at sites where flooding changed the proportion of blackflies relative to fish. Flooding dramatically altered mercury pathways in the simple tailwater food web near the dam, but not in the more complex food webs downstream.""Invasive species and dams are common in rivers globally, and both factors were at play in the Grand Canyon reach of the Colorado River," Rosi says. "We found that flooding changed the species present at our study sites, and mercury flow changed with those shifts.""Understanding the factors that control the movement of mercury through food webs can help resource managers protect ecosystems that are susceptible to mercury pollution," says David Walters, USGS scientist and co-lead author of the study.Rosi concludes, "This study is exciting because it sheds light on the depth of understanding we can achieve when we merge ecological and ecotoxicological thinking. Species traits, animal populations, predator-prey interactions, and disturbance can all influence the movement of contaminants in the environment. Understanding the complex interplay of these factors can improve risk management of animal exposures in the environment."
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May 14, 2020
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https://www.sciencedaily.com/releases/2020/05/200514164236.htm
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Genetic origins of hybrid dysfunction
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In a small pool nestled between two waterfalls in Hidalgo, Mexico, lives a population of hybrid fish -- the result of many generations of interbreeding between highland and sheepshead swordtails. The lab of Molly Schumer, assistant professor of biology at Stanford University, has been collecting these fish for years to study the evolution of hybrids.
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"We're just realizing that hybridization affects species all across the tree of life, including our own species -- many of us carry genes from Neanderthals and Denisovans," said Schumer, referring to two ancient human species that interbred with our ancestors. "Understanding hybridization and the negative and positive effects that can come from genes that have moved between species is important in understanding our own genomes and those of other species with which we interact."In a new paper, published May 14 in People have long known that the offspring of two different species tend to have genetic flaws. For example, mules -- which are donkeys-horse hybrids -- are infertile. Ironically, in order to find the genes responsible for such dysfunctions, researchers need hybrids that are fit enough to breed for several generations after the initial hybridization. Otherwise, the pieces of their genomes that come from the parental species are so large that it is nearly impossible to trace the influence of any one gene.This is what makes the highland-sheepshead hybrids an exceptional case study. They have been interbreeding for about 45 generations, resulting in genomes that contain smaller chunks of parental DNA, which are easier to inspect at a single-gene level."We've known about genetic incompatibility between the genes of two species since the 1940s. Despite that, we don't know many of the genes that cause these negative interactions," said Daniel Powell, a postdoctoral fellow in the Schumer lab and lead author of the paper. "Our lab has clearly defined natural hybrids and we've developed the genomic resources for both parental species. These fish represent a unique system for addressing this question."In order to home in on the genes responsible for melanoma in hybrids, the researchers first turned their attention to the pure sheepshead swordtails and the genetic origin of a black spot some of these fish develop -- which is non-cancerous but found in the same location as the hybrids' melanoma. Analyzing the genomes of nearly 400 individual fish, they linked the black spot with the presence of a gene called xmrk. Following that lead, the researchers concluded that xmrk was also more highly expressed in hybrids with melanoma compared to those without it -- altogether, it could explain 75 percent of all variation in the spotting they studied in both the pure sheepshead and hybrid fishes.The researchers also found that another gene called cd97 -- which some hybrids inherit from their highland swordtail ancestors -- was more highly expressed in the highland swordtails and in hybrids than in sheepshead swordtails. Further genetic evidence suggests that cd97 and xmrk interact in some way to produce melanoma in the hybrids.Interestingly, even though neither gene is associated with melanoma in the parental swordtails species, they're both linked to cancer in other animals. In a distantly related swordtail hybrid, for example, xmrk interacts with another gene -- not cd97 -- to cause melanoma, and a gene related to cd97 has been associated with cancer in humans.Taken together, these findings yield a puzzling picture. "We've ended up with competing but not mutually exclusive ideas about hybrid incompatibility and disease," said Powell. "We've lent credibility to the idea that some genes might be vulnerable to breaking down in different species -- which is surprising, given the randomness of evolution. But we also have evidence for the idea that there is a diversity of genetic causes for similar dysfunctions."Schumer says she took a bit of a gamble when she focused her studies on hybridization, but her bet is paying off."When I started my PhD in 2011, it was really not accepted that hybridization was common in animals. The best-known examples were mules and fruit flies. It's been such a massive shift and a fun time to be working on this question," said Schumer, who is senior author of the paper and a member of Stanford Bio-X. "What we've arrived at now is the best kind of project in science: one that raises way more questions than answers and spins you off in a bunch of different directions."Through future work, the researchers want to figure out why hybrid swordtails with melanoma are less likely to survive in the wild and in captivity. They are also curious to know why so many of these fish have the melanoma -- it's possible that, when it comes to mate selection, females prefer males with the large black spots generated by melanoma. Already, they have lined up several ideas to further understand whether genes go wrong in a repeatable way in hybrids, or if what they've found in xmrk and cd97 is closer to coincidence.
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May 14, 2020
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https://www.sciencedaily.com/releases/2020/05/200514143546.htm
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Newly emerged coronavirus did not spill over from scaly anteaters, researchers say
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Mammals known as scaly anteaters are natural hosts of coronaviruses, but are not likely the direct source of the recent outbreak in humans, according to a study published May 14 in the open-access journal
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Last December, an outbreak of the coronavirus disease (COVID-19) emerged in Wuhan, China. Recent studies have shown that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) -- the virus that causes COVID-19 -- could have originated in bats. But SARS-CoV-2 may have spilled over to humans from another intermediate host, and the source of this virus is still unknown. To effectively control the disease and prevent new spillovers, it is critical to identify the animal origin of this newly emerging coronavirus. In the new study, Chen and colleagues examined whether pangolins could be an intermediate host for SARS-CoV-2.The researchers assembled the whole genome of a coronavirus identified in two groups of sick Malayan pangolins. The results suggest that the pangolin coronavirus is genetically associated with SARS-CoV-2 and a group of bat coronaviruses. But further analysis suggests that SARS-CoV-2 did not arise directly from the pangolin coronavirus. Although this study does not support the idea that pangolins are an intermediate host directly responsible for the emergence of SARS-CoV-2, it is possible that other coronaviruses could be circulating in pangolins. According to the authors, wildlife conservation and limited exposure to wildlife will be important to minimize the risk that coronaviruses will spill over from wild animals to humans.The authors state, "Pangolins could be natural hosts of Betacoronaviruses with an unknown potential to infect humans. However, our study does not support that SARS-CoV-2 evolved directly from the pangolin-CoV."
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May 14, 2020
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https://www.sciencedaily.com/releases/2020/05/200514143521.htm
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Mouse and human eye movements share important similarity
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In a study published today in
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The researchers identified two types of mouse eye movement coupled to head movement with different functions: 'head tilt compensation' and 'saccade and fixate' eye movements. 'Head tilt compensation' allows mice to maintain a consistent view of the world by compensating for slow changes in head tilt, and results in the two eyes moving in opposite directions, which is typically not observed in humans. 'Saccade and fixate' eye movements allow animals to stabilise their view during fast head rotations and shift their gaze in the direction of the head rotation. These 'saccade and fixate' movements are similar to those seen in humans and monkeys, which often sample their environment by a sequence of stable images (fixations) and result in the two eyes moving in the same direction. 'Fixate' eye movements keep the flow of visual information steady while 'saccade' movements allow the animal to select relevant visual information to focus on.The mouse is an important species to help understand how the human brain functions. First, the organisation and function of the mouse and human brain is similar in many ways, although there are also important differences. Second, scientists can use unique genetic research tools in mice to study brain circuits at a level of detail not possible in other mammals. Third, scientists use genetic tools in mice to model human brain disorders.The traditional approach to studying vision in humans, monkeys and mice involves restraining head movement. While this facilitates the interpretation of data and allows researchers to use a wider range of experimental measuring methods, it has been unclear whether the results can be generalised to naturalistic behaviours where both head and eyes are free to move. Understanding how mice visually sample their surroundings is also crucial to further close the gap between vision and navigation which has traditionally been studied in freely moving rodents.This research validates using mice to study important aspects of how humans select visual features that are most important for navigation and decision-making. This visual process is impaired in multiple neurological and neuropsychiatric disorders, including schizophrenia, Alzheimer's disease and stroke. These impairments are currently difficult to treat, and using mice to model these conditions will allow scientists to study the underlying brain mechanisms to help identify and develop new treatments.
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https://www.sciencedaily.com/releases/2020/05/200514115800.htm
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Reptile poaching in Balochistan (Pakistan) is on a decreasing trend but still troublesome
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Since 2013, following strict enforcement of provincial wildlife legislation in the less studied regions of Asia, the overall trend of illegal reptile poaching is steadily decreasing. But it's too early to claim that the issue is solved. Poached reptiles are largely destined not only for the pet trade, but also folk medicines and snake charmer shows, according to the recent study led by the scientists from the Pakistan Museum of Natural History and the University of Peshawar published in the open-access journal
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For the first time, the exploitation of reptiles for the pet trade has come to the attention of the public in the late 1960s. In general, illegal poaching is one of the problems we still face a lot all over the world, despite strict restrictions which are coming in force massively over the last decades. The wildlife trade leads not only to biodiversity loss (through the capture of protected species), but also threatens with a possible spread of animal-borne diseases, due to interspecies contact at pet and folk medicine markets. The case of the recent COVID-19 pandemic gives a lesson to learn, and in order to stop further occurrences, a focus on law-enforcement activities should be brought to wildlife trade hotspots.In the particular case of Pakistan, a country with high species diversity of reptiles, still very little is known about the links between illegal wildlife trade and wildlife decline. The illegal poaching and trade in Pakistan are largely undocumented and it's difficult to bring accurate data since the trade involves many channels and follows informal networks. There is marginal information available about the medicinal use of wild flora and fauna for some parts of Pakistan, but there is no report on the commercialisation, harvest, market dynamics and conservation impact of these activities.Since 2013, a number of confiscations of different reptile species and their parts from Pakistani nationals have been reported widely from across the country, which resulted in the enforcement of legislations regarding the wildlife trade in Pakistan.An international team of researchers, led by Dr. Rafaqat Masroor from Pakistan Museum of Natural History investigated the extent of illegal reptile collection in southwestern Balochistan. Scientists tried to determine what impact these activities might have on the wild populations.The field trips, conducted in 2013-2017, targeted Chagai, Nushki, Panjgur, Kharan and Washuk districts in Balochistan province. Over those years, scientists interviewed 73 illegal collectors. Most of the collectors worked in groups, consisting of males aged between 14 to 50 years."They were all illiterate and their sole livelihood was based on reptile poaching, trade, and street shows. These collectors were well-organized and had trapping equipment for the collection of reptiles. [...] These groups were locally known as "jogeez," who mainly originated from Sindh Province and included snake charmers, having their roots deep with the local hakeems (herbal medicine practitioners) and wildlife traders, businessmen and exporters based at Karachi city. [...] We often observed local people killing lizards and snakes, mostly for fear of venom and part for fun and centuries-old myths," share Dr. Masroor.A total number of illegally poached reptiles, recorded during the investigation, results in 5,369 specimens representing 19 species. All of them had already been declared Protected under Schedule-III of the Balochistan Provincial Wildlife Act.Amongst the reasons for the province of Balochistan to remain unexplored might have been the lack of government environmental and wildlife protection agencies, lack of resources and specialists of high qualification in the provincial wildlife, forest and environment departments, as well as geopolitical position and remoteness of vast tracts of areas.Scientists call for the provincial and federal government to take action and elaborate a specific strategy for the conservation of endemic and threatened species as a part of the country's natural heritage both in southwestern Balochistan and whole Pakistan. The conservation plan needs to be consulted with specialists in the respective fields, in order to avoid incompetence.Also, the research group suggests to strictly ban illegal poaching of venomous snakes for the purpose of venom extraction.What is important to remember is that Balochistan represents one of the most important areas of Asia with a high number of endemic reptile species. The illegal capture of these species presents a threat to the poorly documented animals. Even though the current trend for captured reptiles is decreasing, more actions are needed, in order to ensure the safety of the biodiversity of the region.
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https://www.sciencedaily.com/releases/2020/05/200514115749.htm
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Beads made of boa bones identified in lesser Antilles
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Today Boa snakes have a patchy distribution in the islands that form the Lesser Antilles in the Caribbean Sea, but the constrictors are nearly absent from archaeological deposits in the region. Whether this scarcity is due to past species distribution, poor preservation conditions, or a lack of interaction with human communities, remains unknown.
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To find out why boas occur sparsely in the Lesser Antilles today but hardly at all in archaeological contexts, Corentin Bochaton of the Max Planck Institute for the Science of Human History and the University of Bordeaux, conducted a multidisciplinary study combining archaeological evidence with historical and biological data sources. The study, published in To conduct the study, Bochaton investigated the animal remains from three sites: Dizac Beach on Martinique, Basse-Terre Cathedral on Basse-Terre (Guadeloupe) and Pointe Gros Rampart on La Désirade (Guadeloupe). Using a binocular microscope, Bochaton observed the surface condition and taxonomic features of the finds, eventually identifying eight vertebrae from the Boa genus.Despite the presence of many other snake species in the archeological assemblages of the Lesser Antilles, these Boa remains are the only snake bones that appear to have been made into beads, an important clue as to their cultural significance. "The extreme scarcity of Boa in zooarchaeological assemblages, combined with the fact that these are the only snake bones to be modified, reflects the prominent status Boa had in Pre-Columbian Amerindian communities," says Bochaton.The fact that Boa are largely absent from archaeological finds suggests they probably weren't hunted or eaten by human populations, at least not near their settlements, and evidence from historical records further points to an elevated status of Boa snakes. A chronicle of a 17th century voyage to the Caribbean in a document known as Carpentras Anonymous describes the indigenous people of the islands as unwilling to kill Boas, believing the harm they did to the snakes would also be done to their grandchildren. Further, an account by Charles de Rochefort (1658) retells a story told by the people of Dominica of a monstrous snake who carried on its head a stone of great worth that would glow when it drank or moved in the abyss."These documents show us that Boa snakes had, among all snakes, a special status and were especially feared and respected, which could help explain their scarcity in archaeological deposits," says Bochaton.The islands of the Lesser Antilles were first colonized by Amerindian groups between 7,000 and 5,500 years ago, but molecular evidence and the presence of Boa in fossil deposits show that the snakes colonized these islands thousands, if not millions of years before. Approximately 2,500 years ago, ceramic producing cultures arrived and evolved until the first European contact. At this point a ceramic style known as Cayo emerges.Western colonization in the 17th century almost completely depopulated the Lesser Antilles of Amerindians and wiped out indigenous cultural practices. It also brought about the extinctions of a long list of species, ranging from terrestrial and flying mammals to birds and scaled reptiles -- a list this paper shows to remain incomplete."Because of their absence in the archaeological record, Boa snakes were presumed absent from Guadeloupe," Bochaton explains. "These remains not only show that Boas were here, they remind us how much of the cultural and natural history of these islands has been lost, and how important it is to use different lines of evidence to discover and interpret the past."
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May 14, 2020
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https://www.sciencedaily.com/releases/2020/05/200514092555.htm
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Scientists discover why some birds live fast and die young
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Size, safety and parenting all have an impact on how quickly a species of bird matures, according to new research from the University of Sheffield that could help scientists to understand and predict how animals will respond to climate breakdown and the destruction of habitats.
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The team of scientists has studied thousands of species of birds to understand why there is so much diversity in the length of time they take to grow from a fertilised egg to an independent adult.The research, published in All organisms face a trade-off between reproducing and surviving and they solve this problem in different ways. The team found that bird species with a 'live fast die young' strategy develop quicker, allowing them to maximise the number of offspring they can produce in the short time they have available.Findings showed that birds that breed and live in safer environments with fewer predators typically took longer to develop, possibly because they can afford to spend longer in a vulnerable state.They also found that migratory birds develop much quicker, which may ensure they are ready to return to their winter habitats at the end of the summer.As expected, the research showed that bigger birds took longer to develop -- but even among birds of a similar size there was variation in development times.Dr Chris Cooney, from the University of Sheffield's Department of Animal and Plant Sciences and lead author of the research, said: "The amount of time it takes for a fertilised egg to develop into a fully grown adult varies hugely across the animal kingdom. For instance, it takes an elephant almost 10 years to reach independence, whereas a fruit fly is fully grown after only a matter of days."This extraordinary diversity is also encapsulated within birds, where albatrosses can take almost a year to develop from an embryo to an independent adult, but a typical UK garden songbird takes little more than a month. We found that certain aspects of a species' lifestyle and environment are important in explaining how long they take to develop."Dr Alison Wright, co-author of the research from the University of Sheffield, said: "Our study on birds gives us some clues about the type of factors that may be important in other species. However, it may be that different factors are important for determining development length in other animal groups."The next step is therefore to address these questions using data that covers the breadth of the animal kingdom -- from fish to mammals to insects -- to gain an even broader insight into the factors shaping these fundamental differences across species."Dr Nicola Hemmings, co-senior author of the research from the University of Sheffield, said: "The insights from our research may prove crucial in understanding and even predicting how organisms may respond when conditions change, for instance as our climate warms and habitats become modified."The Department of Animal and Plant Sciences at the University of Sheffield is home to one of the biggest communities of whole-organism biologists in the UK. Our research covers animals, plants, humans, microbes, evolution and ecosystems, in habitats ranging from the polar regions to the tropics. This work aims to shed new light on the fundamental processes that drive biological systems and help solve pressing environmental problems.
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May 14, 2020
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https://www.sciencedaily.com/releases/2020/05/200514115836.htm
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Study confirms cats can become infected with and may transmit COVID-19 to other cats
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In a study published today (May 13, 2020) in the
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Professor of Pathobiological Sciences at the University of Wisconsin School of Veterinary Medicine Yoshihiro Kawaoka led the study, in which researchers administered to three cats SARS-CoV-2 isolated from a human patient. The following day, the researchers swabbed the nasal passages of the cats and were able to detect the virus in two of the animals. Within three days, they detected the virus in all of the cats.The day after the researchers administered virus to the first three cats, they placed another cat in each of their cages. Researchers did not administer SARS-CoV-2 virus to these cats.Each day, the researchers took nasal and rectal swabs from all six cats to assess them for the presence of the virus. Within two days, one of the previously uninfected cats was shedding virus, detected in the nasal swab, and within six days, all of the cats were shedding virus. None of the rectal swabs contained virus.Each cat shed SARS-CoV-2 from their nasal passages for up to six days. The virus was not lethal and none of the cats showed signs of illness. All of the cats ultimately cleared the virus."That was a major finding for us -- the cats did not have symptoms," says Kawaoka, who also holds a faculty appointment at the University of Tokyo. Kawaoka is also helping lead an effort to create a human COVID-19 vaccine called CoroFlu.The findings suggest cats may be capable of becoming infected with the virus when exposed to people or other cats positive for SARS-CoV-2. It follows a study published in Science by scientists at the Chinese Academy of Agricultural Sciences that also showed cats (and ferrets) could become infected with and potentially transmit the virus. The virus is known to be transmitted in humans through contact with respiratory droplets and saliva."It's something for people to keep in mind," says Peter Halfmann, a research professor at UW-Madison who helped lead the study. "If they are quarantined in their house and are worried about passing COVID-19 to children and spouses, they should also worry about giving it to their animals."Both researchers advise that people with symptoms of COVID-19 avoid contact with cats. They also advise cat owners to keep their pets indoors, in order to limit the contact their cats have with other people and animals.Kawaoka is concerned about the welfare of animals. The World Organization for Animal Health and the Centers for Disease Control and Prevention say there is "no justification in taking measures against companion animals that may compromise their welfare."Humans remain the biggest risk to other humans in transmission of the virus. There is no evidence cats readily transmit the virus to humans, nor are there documented cases in which humans have become ill with COVID-19 because of contact with cats.There are, however, confirmed instances of cats becoming infected because of close contact with humans infected with the virus, and several large cats at the Bronx Zoo have also tested positive for the virus.For instance, according to an April 22 announcement from the U.S. Department of Agriculture, two cats in two private homes in New York state tested positive for COVID-19. One had been in a home with a person with a confirmed case of the viral disease. The cats showed mild signs of respiratory illness and were expected to make a full recovery.Additional cats have also tested positive for COVID-19 after close contact with their human companions, says Sandra Newbury, director of the UW-Madison Shelter Medicine Program. Newbury is leading a research study in several states in the U.S. to test animal-shelter cats that might have previously been exposed to human COVID-19 cases."Animal welfare organizations are working very hard in this crisis to maintain the human-animal bond and keep pets with their people," says Newbury. "It's a stressful time for everyone, and now, more than ever, people need the comfort and support that pets provide."Newbury has worked with the CDC and the American Veterinary Medical Association to develop recommendations for shelters housing potentially exposed pets, which they may do while owners are hospitalized or otherwise unable to provide care because of their illness. The UW-Madison study helps confirm experimentally that cats can become infected, though the risk of natural infection from exposure to SARS-CoV-2 seems to be quite low, Newbury says. Of the 22 animals the program has tested, none have had positive polymerase chain reaction tests for the virus, she adds."Cats are still much more likely to get COVID-19 from you, rather than you get it from a cat," says Keith Poulsen, director of the Wisconsin Veterinary Diagnostic Laboratory, who recommends that pet owners first talk to their veterinarians about whether to have their animals tested. Testing should be targeted to populations of cats and other species shown to be susceptible to the virus and virus transmission.With respect to pets, "we're targeting companion animals in communal residences with at-risk populations, such as nursing homes and assisted living facilities," Poulsen says. "There is a delicate balance of needing more information through testing and the limited resources and clinical implications of positive tests."So, what should pet owners do?Ruthanne Chun, associate dean for clinical affairs at UW Veterinary Care, offers the following advice:"As always, animal owners should include pets and other animals in their emergency preparedness planning, including keeping on hand a two-week supply of food and medications," she says. "Preparations should also be made for the care of animals should you need to be quarantined or hospitalized due to illness."The study was supported by the U.S. National Institute of Allergy and Infectious Diseases and by the Japan Agency for Medical Research and Development.
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May 13, 2020
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https://www.sciencedaily.com/releases/2020/05/200513143402.htm
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Microscopic feather features reveal fossil birds' colors and explain why cassowaries shine
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Cassowaries are big flightless birds with blue heads and dinosaur-looking feet; they look like emus that time forgot, and they're objectively terrifying. They're also, along with their ostrich and kiwi cousins, part of the bird family that split off from chickens, ducks, and songbirds 100 million years ago. In songbirds and their relatives, scientists have found that the physical make-up of feathers produce iridescent colors, but they'd never seen that mechanism in the group that cassowaries are part of -- until now. In a double-whammy of a paper in
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"A lot of times we overlook these weird flightless birds. When we're thinking about what early birds looked like, it's important to study both of these two sister lineages that would have branched from a common ancestor 80 million or so years ago," says Chad Eliason, a staff scientist at the Field Museum and the paper's first author."Understanding basic attributes -- like how colors are generated -- is something we often take for granted in living animals. Surely, we think, we must know everything there is to know? But here, we started with simple curiosity. What makes cassowaries so shiny? Chad found an underlying mechanism behind this shine that was undescribed in birds. These kinds of observations are key to understanding how color evolves and also inform how we think about extinct species," says Julia Clarke, a paleontologist at the Jackson School of Geosciences at the University of Texas at Austin and the paper's senior author. Eliason began conducting research for this paper while working with Clarke at the University of Texas as part of a larger project funded by the National Science Foundation (NSF EAR 1355292) to study how flightless birds like cassowaries have evolved their characteristic features.In humans and other mammals, color mostly comes from pigments like melanin that are in our skin and hair. Birds' colors don't just come from pigment -- some of their coloration, like the rainbow flecks on hummingbirds and the shiny, glossy black on crows, is due to the physical makeup of their feathers. The parts of their cells that produce pigment, called melanosomes, affect the feathers' color based on how light bounces off those melanosomes. Different shapes or arrays of melanosomes can create different structural colors, and so can the layers of keratin making up the birds' feathers. They can reflect a rainbow of light, and they can make the difference between dull, matte feathers and feathers with a glossy shine.Scientists had never found structural colors in the feathers of paleognaths like cassowaries and ostriches -- only in the neognath group of birds like songbirds. But paleognaths can make structural colors: the blue skin on cassowaries' heads is due to structural color, and so is the shiny sheen on eggs laid by their cousins, the tinamous. Eliason and Clarke, who study structural colors in birds and dinosaurs, wanted to see if structural color was also present in paleognath feathers.A bird's feather is structured a little like a tree. The long trunk running through the middle is called the rachis, and it has branches called barbs. The barbs are covered with tiny structures called barbules, akin to the leaves on tree branches. In other shiny birds, glossiness is produced by the shape of the barbs and layers of melanosomes in barbules. Eliason and Clarke didn't find that in cassowary feathers, though. Instead, they discovered that the shiny black color came from the rachis running down the middle of the feathers. Since the fluffy barbules on cassowary feathers are pretty sparse, the rachis gets more exposure to light than in "thick-feathered" birds, giving it a chance to literally shine.In addition to finding structural color in cassowary feathers, Eliason and Clarke also explored the feathers of a cousin of the cassowary that lived 52 million years ago. The extinct bird "You can look at a fossil slab and see an outline of where their feathers were, because you kind of see the black stain of melanin that's left over, even after you 50 million years or so," explains Eliason. "We peeled off little flakes of the fossil from the dark spots of melanin, and then we used scanning electron microscopes to look for remnants of preserved melanosomes."By examining these feather imprints on a microscopic level, the researchers were able to see the shape of the pigment-producing melanosomes in the leaf-like barbules of the feathers. The melanosomes were long, skinny, and green bean-shaped, which in modern birds is associated with iridescence.Before this study, scientists had never found evidence of structural color in paleognath feathers -- now, they've got two different examples. The researchers aren't sure why cassowaries and the fossil birds evolved two different ways to build shiny feathers -- why reinvent the wheel? Eliason suspects that flightlessness might have given cassowaries more room to experiment with their feathers. In flighted birds, including the fossil birds in this study, the number one priority for feather structure is being aerodynamic. Since cassowaries don't need to worry about flying, they had more evolutionary leeway to develop their oddly-shaped, thick-spined feathers. "Needing to be able to fly is a very strong stabilizing force on wing shape," says Eliason. "Losing that constraint, that need to fly, might result in new feather morphologies that produce gloss in a way that a flying bird might not."In addition to the questions this study poses about why these birds' feathers evolved so differently, Eliason and Clarke note that it gives us a better overall understanding of life on Earth. "It gives us a glimpse into the time when dinosaurs were going extinct and the birds were rising," says Eliason. "Studying these paleognaths gives us a better understanding of what was happening there, because you can't just study neognaths; you need to study both sister clades to understand their ancestors."
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May 13, 2020
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https://www.sciencedaily.com/releases/2020/05/200513143357.htm
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T. rex was a champion walker, highly efficient at lower speeds
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Long legs may make good runners, but they're great for walking, too. Scientists have generally assumed that long-limbed dinosaurs evolved their leggy proportions for speed to catch prey and avoid predators.
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But a new study by the University of Maryland's Thomas Holtz and his colleagues suggests that long legs evolved among the biggest dinosaurs to help them conserve energy and go the distance as they ambled along searching for prey. The study was published in the journal "The assumption tends to be that animals with adaptations for running, such as long legs, are adapted for a higher maximum speed, but this paper shows that there's more to running than top speed," said Thomas Holtz, principal lecturer in the UMD Department of Geology. "When you're a bigger animal, those adaptations may also be for endurance and efficiency. It may be about being a marathoner rather than a sprinter."Holtz and his colleagues analyzed a variety of metrics like limb proportions, size ratio, body mass and gaits to estimate the top speeds of more than 70 species from a group of dinosaurs called theropods. Theropods ranged in size from less than a half-pound to more than nine tons. They included Tyrannosaurus rex and the many other two-legged predators that dominated the age of dinosaurs for 180 million years. Bipedalism and running speed have often been cited as major contributors to their success.The study revealed a more nuanced story. According to the new analysis, longer legs were associated with higher top speeds in small and medium-sized dinosaurs, but that didn't hold true for dinosaurs weighing over 2,200 pounds. Scientists have known that larger body size can limit speed, and the study showed that large dinosaur species with longer legs were no faster than their stubby-limbed brethren. But they moved more efficiently.By calculating how much energy each dinosaur expended while moving at walking speeds, the researchers found that among the largest dinosaurs, those with longer legs needed less energy to cruise around."That's actually a very beneficial savings, because predators tend to spend a great deal of their time foraging, searching for prey," Holtz said. "If you are burning less fuel during the foraging part of the day, that's an energy savings that dinosaurs with shorter leg forms didn't get."These results highlight the often-overlooked impact of body proportions on running ability and the limiting effect of large body size on running speed. Clearly, there are different kinds of runners. This work should broaden the discussion about what it means to be adapted for running.
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May 13, 2020
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https://www.sciencedaily.com/releases/2020/05/200513081759.htm
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'Pingers' could save porpoises from fishing nets
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Underwater sound devices called "pingers" could be an effective, long-term way to prevent porpoises getting caught in fishing nets with no negative behavioural effects, newly published research suggests.
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The study of harbour porpoises off Cornwall found they were 37% less likely to be found close to an active pinger.Concerns have been raised about porpoises becoming used to pingers and learning to ignore them, but the eight-month study -- by the University of Exeter and Cornwall Wildlife Trust -- found no decrease in effectiveness.There have also been worries that continual pinger use could affect porpoise behaviour by displacing them from feeding grounds, but when pingers were switched off the animals returned "with no delay."The effect was found to be "very localised" -- the 37% reduction in porpoise detection at the active pinger compared to a drop of 9% just 100 metres away.Harbour porpoises are the most common cetaceans (whales, dolphins and porpoises) seen at the Cornish coast, where accidental catching by fishing boats ("bycatch") is a persistent problem."Cornwall Wildlife Trust have been monitoring local dolphin and porpoise deaths through our standings scheme for over 25 years, and bycatch is still the biggest threat to these animals in the South West with large numbers washing ashore every year," said Ruth Williams, of Cornwall Wildlife Trust."Together with other NGOs we have campaigned to try to find a solution to reduce bycatch, that will work in our inshore fisheries."The results of this latest research show that there is a practical solution that is both effective and does not impact or change the animals' behaviour, a positive result for both conservation and fishermen alike." Lead author Dr Lucy Omeyer, of the University of Exeter and Fishtek, said: "Based on our findings, it seems likely that pingers would reduce harbour porpoise bycatch in gill-net fisheries with no negative consequences."Indeed, we found no evidence that long-term and continual use decreased the effectiveness of pingers or affected harbour porpoise behaviour."Pingers are acoustic deterrent devices which are fitted on to fishing nets.They work by emitting a randomised sonic noise, or "ping," which can be heard by dolphins and porpoises and highlights the presence of the nets, thereby preventing accidental entanglement.The porpoises' own click sounds can be way above 100 times louder than the pings from the pinger.In the study, Fishtek Banana Pingers were placed in the water along with two acoustic loggers (one beside the pinger and one 100m away) to record cetacean activity.With small-scale operations the main form of fishing in UK waters, the researchers say there is an "acute need" for cost-effective strategies to prevent bycatch, such as pingers.The study was partly funded by Whale and Dolphin Conservation.Cornwall Wildlife Trust's marine strandings report recorded 245 cetacean strandings in Cornwall in 2019.
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May 12, 2020
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https://www.sciencedaily.com/releases/2020/05/200512151958.htm
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Alaskan rainforests are a global lichen hotspot
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The rainforest fjords of Southeastern Alaska harbour one of the highest concentrations of lichen diversity found anywhere on Earth, according to a new study spearheaded by University of Alberta scientists.
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An international team of researchers led by Toby Spribille, assistant professor in the Department of Biological Sciences at the Faculty of Science, details the names and habitats of lichens, a symbiosis of fungi and algae in Alaska's Glacier Bay National Park.The researchers found more than 900 species of lichen, including 27 new, never-seen-before species "This level of novelty biodiversity is usually associated with 'lost valleys' in the tropics," says Spribille, Canada Research Chair in Symbiosis. "To find this in Southeast Alaska really speaks to how little we still know about coastal rainforests. There are so many new species to science that if you know what to look for, you can average one new species to science per day of field work."The authors compared cumulative numbers of lichens in four different national parks in southern Alaska and found that together, the parks contain more than 1300 species. This work highlights the importance of understanding local biodiversity for nature conservation. Each national park is home to many species not found in the other parks.Within Glacier Bay National Park alone, each fjord was different. "Of 950 species, we found only 14 species common to all sectors of Glacier Bay," added Spribille. "It makes you wonder what remains to be discovered in all the areas we couldn't get to."The research team expresses hope that the insights from Glacier Bay National Park will help guide decision-making in other parts of the coastal rainforest ecosystem."At high latitudes, biodiversity is locked up in other groups of organisms -- and in Alaska, lichens are clearly one of those groups," said Spribille. "This ecosystem is clearly very old and very diverse for some species groups. Each island and valley is different. As ecosystems go, it is definitely one that I'd label 'handle with care.'"The study was funded by the National Park Service Cooperative Ecosystem Studies Unit in the United States in collaboration with the University of Montana, Michigan State University, and the University of Graz in Austria.
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May 12, 2020
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https://www.sciencedaily.com/releases/2020/05/200512151943.htm
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Dogs can detect traces of gasoline down to one billionth of a teaspoon
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Trained dogs can detect fire accelerants such as gasoline in quantities as small as one billionth of a teaspoon, according to new research by University of Alberta chemists. The study provides the lowest estimate of the limit of sensitivity of dogs' noses and has implications for arson investigations.
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"During an arson investigation, a dog may be used to identify debris that contains traces of ignitable liquids -- which could support a hypothesis that a fire was the result of arson," explained Robin Abel, graduate student in the Department of Chemistry and lead author of the study. "Of course, a dog cannot give testimony in court, so debris from where the dog indicated must be taken back to the laboratory and analyzed. This estimate provides a target for forensic labs when processing evidence flagged by detection dogs at sites of potential arson."The study involved two dog-and-handler teams. The first was trained to detect a variety of ignitable liquids, while the other was trained primarily with gasoline. Results show that the dog trained on a variety of liquids performed well detecting all accelerants, while the dog trained on gasoline was not able to generalize to other accelerants at extremely low concentrations.Another outcome of the study was the development of a protocol that can be used to generate suitable ultra-clean substrates necessary for assessing the performance of accelerant-detection dogs for trace-level detection."In this field, it is well-known that dogs are more sensitive than conventional laboratory tests," said James Harynuk, associate professor of chemistry and Abel's supervisor. "There have been many cases where a dog will flag debris that then tests negative in the lab. In order for us to improve laboratory techniques so that they can match the performance of the dogs, we must first assess the dogs. This work gives us a very challenging target to meet for our laboratory methods."So, just how small a volume of gasoline can a dog detect?"The dogs in this study were able to detect down to one billionth of a teaspoon -- or 5 pL -- of gasoline," added Harynuk. "Their noses are incredibly sensitive."This research was conducted in collaboration with Jeff Lunder, vice president of the Canine Accelerant Detection Association (CADA) Fire Dogs. Funding was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC).
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May 12, 2020
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https://www.sciencedaily.com/releases/2020/05/200512134526.htm
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Early experiences determine how birds build their first nest
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Early life experiences of zebra finches have a big effect on the construction of their first homes, according to a new study by researchers at the University of Alberta's Faculty of Science and the University of St Andrews' School of Biology.
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The study shows that the presence of an adult bird as well as the types of materials available in early adolescence influence two key aspects of first-time nest building: material preference and construction speed."Interestingly, we noted that the preference for different materials, differentiated by colour in our study, is shaped by the juvenile experience of this material -- but only in the presence of an adult," said Lauren Guillette, assistant professor in the Department of Psychology and project lead."This work is important because it debunks the long-held myth that birds build nests that look like the nest in which they hatched -- making nest-building a useful model system to experimentally test how animals learn about physical properties of the world."In this study, the researchers controlled the environment in which zebra finches grew up. Each bird hatched into a nest of a specific colour -- pink or orange. As the birds grew up, they were paired with another bird of the same age. Then, some pairs were grouped with an adult bird in an environment that contained a different colour of nest material than the colour in which they hatched. Other young pairs of birds experienced only an adult as company, or only nest material and no adult, other pairs just had each other.Using these methods the researchers could determine if birds build their first nest with a colour that matches their natal nest, or the colour they experienced while growing up.The results show that as juvenile zebra finches embarked on building their first nest, most birds preferred to use materials to which they'd had access to while growing up -- but only if an adult had also been present during this time. Further, birds who had not had juvenile access to an adult or material were between three and four times slower at nest building."Together, these results show that juvenile zebra finches combine relevant social and ecological cues -- here, adult presence and material colour -- when developing their material preference," explained Alexis Breen, lead author on the study who recently obtained a PhD at the University of St Andrews in Scotland.
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May 12, 2020
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https://www.sciencedaily.com/releases/2020/05/200512134450.htm
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More than the sum of their genes
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Reproducing efficiently in captivity is crucial for the survival of many wildlife species, yet reproductive success is often lower than in the wild. Currently, many zoo population management strategies prioritise the genetic diversity of captive populations. Scientists now argue that a broader perspective is required which also includes behaviour, life-history, husbandry and environmental considerations. This would improve breeding success in zoos and the maintenance of the diversity of traits, behaviours, and phenotypes of threatened species. In a paper published recently in the scientific "
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Many species of birds and mammals reproduce better in the wild than in captivity. When wild populations are threatened, it is of utmost importance to conservation that captive populations are healthy and sustainable. In a new paper, wildlife biologists Werner Kaumanns (LTM-Research and Conservation), Nilofer Begum (Freie Universität Berlin) and Heribert Hofer (Leibniz Institute for Zoo and Wildlife Research) evaluate decades of scientific literature on the reproduction of captive populations and compared two well-known population management paradigms. The "small population paradigm" focuses on the genetic reservoir of the species and attempts to maximise genetic diversity within the captive populations, for example by exchanging mating partners frequently or by avoiding groups of closely related individuals. In the "declining population paradigm" on the other hand measures target the causes of population decline and thereby reproduction processes and conditions. "We argue that under the latter paradigm better management options can be developed without necessarily contradicting genetic assessments and their relevance to population management," says lead author Kaumanns.The authors argue that, next to survival, evolution places a heavy emphasis on reproduction, the success of which profoundly affects the animal's contribution to future generations. "This means that many key traits and evolutionary adaptations are linked to reproduction," senior author Hofer explains. "It is evident that animals are designed for breeding, which means that group sizes, socialisation and learning repertoires, behaviours, spatial requirements and other traits and contexts usually contribute to reproductive success." For example, the behavioural skills and experience of a primate female in infant rearing are as relevant to reproductive success and recruitment for population management as her genetic status. "It is necessary that appropriate conditions are provided in zoos to ensure that females can acquire these skills," Hofer says. This can require the presence of aunts, mothers or other group members, an appropriate demography and group composition.This perspective is not restricted to primates: providing the setting for mothers to gain the necessary experience would also be beneficial in elephants and other species with complex societies, such as spotted hyenas. "It is, therefore, recommended that key traits play a dominant role in management plans and husbandry guidelines," Nilofer Begum, a doctoral student at Freie Universität Berlin, adds. If captive breeding conditions do not respect natural breeding conditions, traits can function as constraints and the diversity of traits, behaviours and phenotypes may be threatened. This may mean that in practice, zoos might sometimes concentrate on fewer animals, develop a more flexible husbandry system that better incorporates essentials of a species' niche or habitat, and ensure that social groups foster generational learning, problem solving and the resolution of conflicts.
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Animals
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May 12, 2020
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https://www.sciencedaily.com/releases/2020/05/200512092805.htm
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Can we really tell male and female dinosaurs apart?
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Scientists worldwide have long debated our ability to identify male and female dinosaurs. Now, research led by Queen Mary University of London has shown that despite previous claims of success, it's very difficult to spot differences between the sexes.
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In the new study, researchers analysed skulls from modern-day gharials, an endangered and giant crocodilian species, to see how easy it is to distinguish between males and females using only fossil records.Male gharials are larger in size than females and possess a fleshy growth on the end of their snout, known as a ghara. Whilst the ghara is made from soft tissue, it is supported by a bony hollow near the nostrils, known as the narial fossa, which can be identified in their skulls.The research team, which included Jordan Mallon from the Canadian Museum of Nature, Patrick Hennessey from Georgia Southern University and Lawrence Witmer from Ohio University, studied 106 gharial specimens in museums across the world. They found that aside from the presence of the narial fossa in males, it was still very hard to tell the sexes apart.Dr David Hone, Senior Lecturer in Zoology at Queen Mary University of London and author of the study, said: "Like dinosaurs, gharials are large, slow growing reptiles that lay eggs, which makes them a good model for studying extinct dinosaur species. Our research shows that even with prior knowledge of the sex of the specimen, it can still be difficult to tell male and female gharials apart. With most dinosaurs we don't have anywhere near that size of the dataset used for this study, and we don't know the sex of the animals, so we'd expect this task to be much harder."In many species, males and females can look very different from each other. For example, antlers are largely only found in male deer and in peacocks, males are normally brightly-coloured with large, iridescent tail feathers whereas females are much more subdued in their colouration. This is known as sexual dimorphism and is very common within the animal kingdom. It is expected that dinosaurs also exhibit these differences, however this research suggests that in most cases this is far too difficult to tell from the skeleton alone.Dr Hone said: "Some animals show extraordinarily high levels of sexual dimorphism, for example huge size differences between males and females. Gharials sit somewhere in the middle as they do possess these large narial fossa that can help with identification. Our study suggests that unless the differences between the dinosaurs are really striking, or there is a clear feature like the fossa, we will struggle to tell a male and female dinosaur apart using our existing dinosaur skeletons."The new research also challenges previous studies that have hinted at differences between the sexes in popular dinosaur species such as the "Many years ago, a scientific paper suggested that female
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May 12, 2020
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https://www.sciencedaily.com/releases/2020/05/200512093952.htm
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Waiting game: Testing the patience of predators and prey
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'Like a frog stared down by a snake', goes an old Japanese expression, descrbing an animal petrified with fear.
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However, it now seems that this freeze in action may not be about fear at all, but rather a delicate waiting game of life and death.A new report from researchers at Kyoto University's Graduate School of Science shows that this common interaction is all about patience, with each animal waiting for and anticipating its opponent's actions."When predator and prey face each other, it is generally thought that the initiator has the advantage that would mediate successful capture or escape," explains Nozomi Nishiumi, corresponding author of the report published in the "However, in cases involving snakes and frogs, they occasionally move extremely slowly -- or almost not at all. It looks like they purposely avoid taking preemptive action."Nishiumi, together with colleague Akira Mori, examined how the animals' behaviors affected the consequences of their interaction by focusing specifically on the kinematics of the snakes' strikes and the frogs' flight behavior.The team analyzed the movement patterns of the Japanese striped snake, "In the staged encounters we wanted to look at the disadvantages of preemptive actions by analyzing the kinematic characteristics of each animal's movements," explains Nishiumi."The field observations, on the other hand, were designed to follow the consequences of the animals' actions and survival."The team found that the counteractions of each animal were often effective because the initiator's actions were difficult to change once started. For example, if the snake initiated a strike action first, the frog would evade the attack because the trajectory of the strike could not be changed mid-movement, allowing the frog to escape safely while the snake spent time resetting its lunge posture.Alternatively, if the frog first attempted an escape, the snake would start lunging immediately, and occasionally be able to adjust its strike direction in anticipation of the frog's direction of movement."The efficacy of this waiting tactic depends on the distance between them: the closer they are the less likely the counteraction succeeds," continues Nishiumi."In this regard, when approaching this critical distance, the animals appropriately switch their behaviors from waiting to taking action."These results suggest that a game of patience occurs between the animals, providing insight on predicting the decision-making of predators and prey.
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Animals
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May 11, 2020
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https://www.sciencedaily.com/releases/2020/05/200511112549.htm
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Flying foxes in South Australia exposed to zoonotic viruses
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University of Adelaide researchers have found that South Australia's population of Grey-headed flying foxes, which took up residence in 2010, has been exposed to a number of viruses, including Hendra virus that can be transmitted to humans via horses. But they have not found evidence of exposure to Australian bat lyssavirus.
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The research, published today in Hendra virus and Australian bat lyssavirus are classified as zoonotic viruses. Hendra virus for example can be transmitted to horses and then to humans by airborne droplets causing acute respiratory diseases and death. In the case of Australian bat lyssavirus, humans and other animals need to be bitten or scratched by a carrier. The risks posed by Hendra virus are extremely low with only seven cases in humans, all of whom had been in contact with infected horses, never directly from bats.Dr Wayne Boardman from the University of Adelaide's School of Animal and Veterinary Sciences says given the Grey-headed flying foxes are known carriers of viruses, they wanted to understand if the local population of flying foxes had been exposed to them."Grey-headed flying foxes are essential ecosystem service providers contributing to large-scale pollination and seed dispersal and are a nationally threatened species," Dr Boardman said."They have this extraordinary ability to be infected with viruses but don't show any ill effects, except for one virus; the Australian bat lyssavirus. It's important to understand what risks they pose to humans."We have found the local population has developed antibodies for the Hendra, Cedar and Tioman viruses, meaning they have been exposed at some stage in their lives."What's good news for South Australia is that the local population has not shown exposure to Australian bat lyssavirus, which in humans causes serious illness including paralysis, delirium, convulsions and death."It's positive to discover that the risk of lyssavirus transmission in South Australia is lower than anticipated."However, this doesn't mean that flying foxes are safe to touch; only people with experience in handling these animals should ever come into contact with them."The Grey-headed flying fox has made the Botanic Gardens in Adelaide home for the past 10 years, having come to South Australia from New South Wales and Victoria in search of a suitable climate and food.The research on the local population has also revealed that Hendra virus levels were significantly higher in pregnant females; results that align with findings interstate. However, good body condition is a risk factor for a bigger proportion of the population being exposed to Hendra virus because the flying foxes are in better condition in winter than summer, which is the opposite of what has been found in the eastern states.Dr Boardman said this means the flying foxes are finding plenty to eat here in winter time specifically, enjoying the introduced foods that are planted in gardens, along roads and in parklands, similar to the normal food source for those in the eastern states."The Grey-headed flying fox is certainly enjoying the local environment during the South Australian winter, but we have seen on numerous occasions that the heat in summer certainly knocks the population around so we are looking at ideas to help support them during heatwaves in summer using high level misters and sprinklers."The research was carried out in partnership with CSIRO's Animal Health Laboratory in Geelong, South Australian Museum and Zoos South Australia.
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Animals
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May 11, 2020
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https://www.sciencedaily.com/releases/2020/05/200511112543.htm
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New test identifies lobster hybrids
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Scientists have developed a test that can identify hybrids resulting from crossbreeding between European and American lobsters.
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American lobsters have occasionally escaped or been released into European waters after being imported for the seafood market.Experts have long feared they could threaten European lobsters by introducing disease or establishing as an invasive species.Hybridisation -- when a "pure" species is threatened at a genetic level via interbreeding with a different but related species -- had been less of a concern because lab studies suggested European and American lobsters were reluctant to mate.However, when an American lobster female was found bearing eggs in a fjord in Sweden, University of Exeter researchers tested the offspring and found they were "clearly distinct" from both European and American lobsters."We had just developed a genetic test for seafood traceability that could separate any American lobsters mislabelled as more expensive European equivalents once they've been cooked and shell colouration is no longer a useful indicator of the species," said Dr Charlie Ellis, of the University of Exeter."What we found when we tested these offspring is that they came out exactly in the middle of this separation -- half American and half European -- so these lobsters were hybrids."This has potentially concerning implications for the lobster industry and conservation efforts, and Dr Ellis says further research is required to assess the extent of the threat."Until recently, it was thought that American and European lobsters would avoid crossbreeding, but this introduced American female has mated with a native European male, probably because she was unable to find an American male," he said."We now need to check whether any mature adult hybrids are fertile, because if they are then they have the ability to spread these unwanted American genes far and wide across our native lobster stocks."Working with collaborators from the University of Gothenburg who originally found the hybrid egg clutch, the researchers say their study, published in the journal "It is particularly concerning that we seem to have found American lobster genes in one of our lobster reserves," said Linda Svanberg of the Gothenburg team."The better news is we now have this genetic tool to test lobsters or their eggs for hybridisation," added Dr Jamie Stevens, leader of the research which was funded by an EU grant through the Agritech Cornwall scheme, "so we can use it track the spread of these 'alien' genes to assess how big a threat this presents to our native lobster species."The team advise that, for a range of conservation reasons including potential contact with American lobsters, it is important that the general public never release a marketed lobster back into the wild, even our native species.Dr Tom Jenkins said: "Although we appreciate that all animal-lovers have concern for the fate of individual animals, in this case the rescue of one animal might endanger the health of the entire wild population, so once a lobster has entered the seafood supply chain that's where it should stay."
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May 8, 2020
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https://www.sciencedaily.com/releases/2020/05/200508145331.htm
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Flies sleep when need arises to adapt to new situations
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Flies that cannot take to the air respond by sleeping more as they learn to adapt to their flightlessness, according to a study from Washington University School of Medicine in St. Louis. The findings, published May 8 in
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"We know that sleep is involved in creativity and insight," said senior author Paul Shaw, PhD, a professor of neuroscience. "Have you ever slept on a problem, and when you wake up you've found the answer? Anxiety keeps people up at night, but if you find yourself in a dangerous environment, or in a situation that you don't know how to deal with, sleep may be exactly what you need to respond to it effectively."Fruit flies' sleep looks a lot like people's. Baby flies need a lot of sleep, but as they get older, their need for sleep diminishes. Flies become more alert with caffeine and drowsier with antihistamines. And if you keep a fly awake one day, it will sleep more the next.These similarities suggest that the sleep habits of flies might shed light on the sleep habits of people. To explore the relationship between challenging circumstances and sleep, Shaw and staff scientist and first author Krishna Melnattur, PhD, took away flies' ability to fly.Baby flies must expand their wings in the first half hour or so after emerging from pupal cases, or their wings will not develop properly. The researchers placed some newly emerged flies in tiny containers so they could not expand their wings, and they genetically modified other flies so that the insects' wings failed to expand. Both scenarios rendered the young flies permanently flightless. The researchers also grounded older flies by disabling their wings. In all cases, faced with the inability to fly, the animals slept more than usual.In subsequent experiments, the researchers traced the neurological circuit that signals to the brain that the wings aren't functioning and triggers the impulse to sleep more."When we identified the neurons that were activated when we cut or glued the wings of adult flies, they turned out to be the same neurons involved in the normal developmental process of wing expansion after emergence," Melnattur said.The fact that wing injury and normal wing development are linked to sleep through the same neurological circuitry makes sense from an evolutionary standpoint, the researchers said. The circuit is active in young flies because their developing brains need sleep as the animals expand their wings, learn to fly and begin to navigate the world around them."And then the whole circuit can get reactivated later in life when something happens that forces a fly to adapt to a new normal," Shaw said. "Suddenly, its brain needs to be as flexible as when it was young. It can no longer fly, but it still needs to get food, it needs to compete for mates, it needs to avoid dying. We think that sleep amplifies the brain plasticity the fly needs to survive."Shaw and Melnattur are planning experiments to determine whether increased sleep helps flightless flies survive. Their findings also may provide clues to why some people sleep more than others and why some sleep disorders arise."There's huge variation in sleep time among people," Shaw said. "Some people need five hours a night; some need nine. Sleep is an ancient process, and we've evolved mechanisms to change our sleep-wake balance to help us meet our needs. If these mechanisms get inappropriately activated, say by a traumatic event that triggers post-traumatic stress disorder, it can create a situation in which you're sleeping too much or too little and it's no longer matching up with your needs, and then you have a sleep disorder."
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Animals
| 2,020 |
May 8, 2020
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https://www.sciencedaily.com/releases/2020/05/200508083540.htm
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Prehistoric sea creatures evolved pebble-shaped teeth to crush shellfish
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As bad as things might seem here in 2020, they could be worse: we could be living 252 million years ago during the Permian mass extinction. Volcanic eruptions and dramatic, sudden climate change killed most of the animals on land and almost everything in the oceans, setting the stage for the later rise of the dinosaurs on land and an explosion of new marine life. One kind of marine reptile, the ichthyosaurs, eventually evolved into sleek, dolphin-like predators, but scientists don't know much about early ichthyosaurs. But by CT-scanning the fossil of one of the first ichthyosaurs, scientists discovered pebble-shaped teeth hidden in its short snout. These strange teeth, probably used for crushing the shells of snails and clam-like bivalves, help illuminate the ways that early ichthyosaurs filled different roles in Triassic marine ecosystems.
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"We don't know exactly the ancestry of ichthyosaurs. They're reptiles, and they're probably archosaurs -- that is to say, they're more closely related to crocodiles and dinosaurs and birds than they are to lizards and snakes -- but even that isn't 100%," says Olivier Rieppel, a paleontologist and Rowe Family Curator of Evolutionary Biology at Chicago's Field Museum, who co-authored a new paper on the findings in The paper focuses on This new study builds on the description of These rounded teeth were in the back of the jaws, where our molars are, and were likely used to crush small hard-shelled invertebrates like snails and clam-like bivalves. The teeth also showed wear and tear suggesting that even though the only known specimen of Armed with this new knowledge about These different tooth shapes springing up in different families gives us a glimpse of the world in which ichthyosaurs were evolving. "There were no marine reptiles prior to the Triassic," says Rieppel. "That's what makes these early ichthyosaurs so interesting -- they tell us about the recovery from the mass extinction, because they entered the sea only after it." And, since most sea creatures died in the mass extinction, there was a lot of free real estate, evolutionarily speaking -- lots of niches for new animals to fill. "After the mass extinction, the marine biota was nearly empty and ready to be recolonized," Rieppel explains.Animals' teeth can tell us a lot about their lifestyles: what they were eating and how. The rapid emergence of lots of different kinds of ichthyosaurs with different kinds of teeth points to the way that they took over the oceans and played different ecological roles. It's also likely that the repeated evolution of rounded crushing teeth in ichthyosaurs like "Fossils are clues about what the world was like long ago," says Rieppel. "By gaining a better understanding of how these ichthyosaurs evolved, we get a better sense of how life rebounds after extinctions, and that lesson is still relevant today."This study was contributed to by researchers from Anhui Geological Museum, University of California, Davis, Peking University, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Science, Università degli Studi di Milano, and the Field Museum.
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Animals
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May 6, 2020
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https://www.sciencedaily.com/releases/2020/05/200506162212.htm
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Arctic Edmontosaurus lives again: A new look at the 'caribou of the Cretaceous'
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A new study by an international team from the Perot Museum of Nature and Science in Dallas and Hokkaido University and Okayama University of Science in Japan further explores the proliferation of the most commonly occurring duck-billed dinosaur of the ancient Arctic as the genus
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The scientific paper describing the find -- titled "Re-examination of the cranial osteology of the Arctic Alaskan hadrosaurine with implications for its taxonomic status" -- has been posted in "Recent studies have identified new species of hadrosaurs in Alaska, but our research shows that these Arctic hadrosaurs actually belong to the genus The report states that anatomical comparisons and phylogenetic analyses clearly demonstrate that attribution of the Alaskan hadrosaurines to a unique genus Ugrunaaluk is inappropriate, and they are now considered as a junior synonym of The fossils used for this study were found primarily in the Liscomb Bonebed, Prince Creek Formation of the North Slope of Alaska, the location of the first dinosaur fossils discovered in the Arctic.The team's research also show that the plant-eating hadrosaurs were taking over parts of North America during the Cretaceous, suggesting that "In other words, Members of this team also found ties to "Combined with the newly named "This study is a wonderful example of why paleontologists need to be more aware of how individual growth and life stage of fossils matter when we try to interpret the anatomical features preserved in them. If you don't, you run the risk of erroneously erecting a new 'genus' or species based on juvenile traits that will change or vanish as the individual creature grows up -- and winds up being an adult of an already-known 'genus' or species!," said Tykoski. "Our study shows that was probably the case with these juvenile duck-billed dinosaurs from the ancient Arctic of Alaska."
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Animals
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May 6, 2020
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https://www.sciencedaily.com/releases/2020/05/200506133625.htm
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Fossil reveals evidence of 200-million-year-old 'squid' attack
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Scientists have discovered the world's oldest known example of a squid-like creature attacking its prey, in a fossil dating back almost 200 million years.
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The fossil was found on the Jurassic coast of southern England in the 19th century and is currently housed within the collections of the British Geological Survey in Nottingham.In a new analysis, researchers say it appears to show a creature -- which they have identified as Clarkeiteuthis montefiorei -- with a herring-like fish (Dorsetichthys bechei) in its jaws.They say the position of the arms, alongside the body of the fish, suggests this is not a fortuitous quirk of fossilization but that it is recording an actual palaeobiological event.They also believe it dates from the Sinemurian period (between 190 and 199 million years ago), which would predate any previously recorded similar sample by more than 10 million years.The research was led by the University of Plymouth, in conjunction with the University of Kansas and Dorset-based company, The Forge Fossils.It has been accepted for publication in Proceedings of the Geologists' Association and will also be presented as part of Sharing Geoscience Online, a virtual alternative to the traditional General Assembly held annually by the European Geosciences Union (EGU).Professor Malcolm Hart, Emeritus Professor in Plymouth and the study's lead author, said: "Since the 19th century, the Blue Lias and Charmouth Mudstone formations of the Dorset coast have provided large numbers of important body fossils that inform our knowledge of coleoid palaeontology. In many of these mudstones, specimens of palaeobiological significance have been found, especially those with the arms and hooks with which the living animals caught their prey."This, however, is a most unusual if not extraordinary fossil as predation events are only very occasionally found in the geological record. It points to a particularly violent attack which ultimately appears to have caused the death, and subsequent preservation, of both animals."In their analysis, the researchers say the fossilised remains indicate a brutal incident in which the head bones of the fish were apparently crushed by its attacker.They also suggest two potential hypotheses for how the two animals ultimately came to be preserved together for eternity.Firstly, they suggest that the fish was too large for its attacker or became stuck in its jaws so that the pair -- already dead -- settled to the seafloor where they were preserved.Alternatively, the Clarkeiteuthis took its prey to the seafloor in a display of 'distraction sinking' to avoid the possibility of being attacked by another predator. However, in doing so it entered waters low in oxygen and suffocated.
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Animals
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May 6, 2020
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https://www.sciencedaily.com/releases/2020/05/200506133614.htm
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Bat 'super immunity' may explain how bats carry coronaviruses, study finds
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A University of Saskatchewan (USask) research team has uncovered how bats can carry the Middle East respiratory syndrome (MERS) coronavirus without getting sick -- research that could shed light on how coronaviruses make the jump to humans and other animals.
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Coronaviruses such as MERS, Severe Acute Respiratory Syndrome (SARS), and more recently the COVID19-causing SARS-CoV-2 virus, are thought to have originated in bats. While these viruses can cause serious and often fatal disease in people, for reasons not previously well understood, bats seem unharmed."The bats don't get rid of the virus and yet don't get sick. We wanted to understand why the MERS virus doesn't shut down the bat immune responses as it does in humans," said USask microbiologist Vikram Misra.In research just published in "Instead of killing bat cells as the virus does with human cells, the MERS coronavirus enters a long-term relationship with the host, maintained by the bat's unique 'super' immune system," said Misra, corresponding author on the paper. "SARS-CoV-2 is thought to operate in the same way."Misra says the team's work suggests that stresses on bats -- such as wet markets, other diseases, and possibly habitat loss -- may have a role in coronavirus spilling over to other species."When a bat experiences stress to their immune system, it disrupts this immune system-virus balance and allows the virus to multiply," he said.The research was carried out at USask's Vaccine and Infectious Disease Organization -- International Vaccine Centre (VIDO-InterVac), one of the world's largest containment level 3 research facilities, by a team of researchers from USask's Western College of Veterinary Medicine and VIDO-InterVac."We see that the MERS coronavirus can very quickly adapt itself to a particular niche, and although we do not completely understand what is going on, this demonstrates how coronaviruses are able to jump from species to species so effortlessly," said VIDO-InterVac scientist Darryl Falzarano, who co-led the bat study, developed the first potential treatment for MERS-CoV, and is leading VIDO-InterVac's efforts to develop a vaccine against COVID-19.So far, the SARS-CoV-2 virus has infected more than 3.5 million people worldwide and killed seven per cent of those infected. In contrast, the MERS virus infected nearly 2,500 people in 2012 but killed one in every three people infected. There is no vaccine for either SARS-CoV-2 or MERS. While camels are the known intermediate hosts of MERS-CoV, bats are suspected to be the ancestral host.Coronaviruses rapidly adapt to the species they infect, Misra said, but little is known on the molecular interactions of these viruses with their natural bat hosts. A 2017 USask-led study showed that bat coronaviruses can persist in their natural bat host for at least four months of hibernation.When exposed to the MERS virus, bat cells adapt -- not by producing inflammation-causing proteins that are hallmarks of getting sick, but rather by maintaining a natural antiviral response, a function which shuts down in other species, including humans. Simultaneously, the MERS virus also adapts to the bat host cells by very rapidly mutating one specific gene, he said.Operating together, these adaptations result in the virus remaining long-term in the bat but being rendered harmless until something -- such as disease or other stressors -- upsets this delicate equilibrium.Next, the team will turn its focus to understanding how the bat-borne MERS virus adapts to infection and replication in camelid (a group of even-toed ungulates that includes camels) and human cells."This information may be critical for predicting the next bat virus that will cause a pandemic," said Misra.Lead researchers on the paper were Misra's former PhD students Arinjay Banerjee and Sonu Subudhi who are now at McMaster University and Massachusetts General Hospital respectively. Other team members included researchers Noreen Rapin and Jocelyne Lew, as well as summer student Richa Jain.
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May 6, 2020
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https://www.sciencedaily.com/releases/2020/05/200506123751.htm
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The movie 'Jurassic Park' got it wrong: Raptors don't hunt in packs
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A new University of Wisconsin Oshkosh analysis of raptor teeth published in the peer-reviewed journal
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The raptors (Deinonychus antirrhopus) with their sickle-shaped talons were made famous in the 1993 blockbuster movie Jurassic Park, which portrayed them as highly intelligent, apex predators that worked in groups to hunt large prey."Raptorial dinosaurs often are shown as hunting in packs similar to wolves," said Joseph Frederickson, a vertebrate paleontologist and director of the Weis Earth Science Museum on the UWO Fox Cities campus. "The evidence for this behavior, however, is not altogether convincing. Since we can't watch these dinosaurs hunt in person, we must use indirect methods to determine their behavior in life."Frederickson led the study in partnership with two colleagues at the University of Oklahoma and Sam Noble Museum, Michael Engel and Richard Cifell.Though widely accepted, evidence for the pack-hunting dinosaur proposed by the late famed Yale University paleontologist John Ostrom is relatively weak, Frederickson said."The problem with this idea is that living dinosaurs (birds) and their relatives (crocodilians) do not usually hunt in groups and rarely ever hunt prey larger than themselves," he explained."Further, behavior like pack hunting does not fossilize so we can't directly test whether the animals actually worked together to hunt prey."Recently, scientists have proposed a different model for behavior in raptors that is thought to be more like Komodo dragons or crocodiles, in which individuals may attack the same animal but cooperation is limited."We proposed in this study that there is a correlation between pack hunting and the diet of animals as they grow," Frederickson said.In Komodo dragons, babies are at risk of being eaten by adults, so they take refuge in trees, where they find a wealth of food unavailable to their larger ground-dwelling parents. Animals that hunt in packs do not generally show this dietary diversity."If we can look at the diet of young raptors versus old raptors, we can come up with a hypothesis for whether they hunted in groups," Frederickson said.To do this, the scientists considered the chemistry of teeth from the raptor Deinonychus, which lived in North America during the Cretaceous Period about 115 to 108 million years ago."Stable isotopes of carbon and oxygen were used to get an idea of diet and water sources for these animals. We also looked at a crocodilian and an herbivorous dinosaur from the same geologic formation," he said.The scientists found that the Cretaceous crocodilians, like modern species, show a difference in diet between the smallest and largest teeth, indicating a distinct transition in diet as they grew."This is what we would expect for an animal where the parents do not provide food for their young," Frederickson said. "We also see the same pattern in the raptors, where the smallest teeth and the large teeth do not have the same average carbon isotope values, indicating they were eating different foods. This means the young were not being fed by the adults, which is why we believe Jurassic Park was wrong about raptor behavior."Frederickson added that the method used in this study to analyze carbon in teeth could be applied to see whether other extinct creatures may have hunted in packs.
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May 6, 2020
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https://www.sciencedaily.com/releases/2020/05/200506091541.htm
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Severe coral loss leaves reefs with larger fish but low energy turnover
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Research on the Great Barrier Reef has found severe coral loss to be associated with substantial increases in the size of large, long-living herbivorous fish. However, decreased recycling of this fish biomass could leave the ecosystem vulnerable to crashing. The research is published in the British Ecological Society journal
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By comparing reef surveys from 2003-2004 and 2018, an international team of researchers led by James Cook University, found severe coral loss, of up to 83% in some areas, was associated with increases in fish biomass, productivity and consumed biomass, meaning the reef now has more energy stored in the form of fish weight, is able produce more fish weight and these fish are being consumed by predators.Renato Morais, lead author of the study, said "It's as if the herbivorous fish community has been scaled up, with larger fish growing and providing more food for predators when they die. However, this does not come without a cost."Superficially, the increased biomass may seem positive from a human perspective, with the presence of bigger fish after a coral reef collapse suggesting a stable population. However, the researchers warn that reduced turnover, or recycling of biomass, in the reef could mean that this trend benefiting large fish might not last long."The fish have not multiplied. Instead, there are more bigger fish and less smaller ones." Said Mr Morais "This suggests that many of these long-living herbivorous fishes, such as surgeon fish which can live up to 40 years, could have been there before the corals died, only growing bigger. Eventually, these older fish will die and, if not replaced by young ones, productivity could collapse."The increased growth of large fish like surgeonfish, parrotfish and rabbitfish is likely to have been made possible by the accessibility and quality of algal turf, the preferred food of these herbivores. These algal 'lawns' grow abundantly over the skeletons of dead coral. A recovery of the coral could result in a reduction in this food source and collapse of these herbivores.Erosion of dead coral structures and subsequent loss of refuges for fish could also cause a population crash. Although the researchers did observe a decline in coral structure in the reef area studied, it is possible that it had not reached a level where fish biomass would start to decline.Between 2014 and 2017 the reefs around lizard island, where the research took place, were subjected to two back-to-back mass bleaching events and two severe cyclones that decimated the coral populations. Combined, these events led to an 80% decline in coral cover throughout the islands.Previous research has mainly taken a static look at the impacts of coral loss on fish. In this study the researchers looked at the cumulative effects of coral mortality over time using metrics often absent from coral reef studies: fish growth, mortality and energy turnover.To record the data, the researchers carried out fish and benthic (sea floor) surveys at Lizard Island, on Australia's Great Barrier Reef in 2003 to 2004, and 14 years later in 2018. The benthic surveys quantified live coral cover and algal turf cover. Fish surveys recorded 12 common types of reef fish families.Because the study comprises of two snapshot assessments 15 years apart the researchers were limited to looking at long term trends. "If there were changes to the energetic balance of the fish assemblages at that reef that happened between surveys but did not have a lasting effect, they would have gone unnoticed." Explained Mr Morais.Mr Morais also cautions that the findings apply to the one reef the researchers surveyed and other reefs could behave differently, although a number of features suggest similar changes may have taken place elsewhere. For instance, increases in herbivore populations are common in post-coral reefs. Collecting the same data on other reefs will help to establish if this is the case.The researchers are looking to follow this reef to see if new energetic shifts occur. "Any further shifts will depend on what happens to the reef," said Mr Morais, "Will there be a recovery of corals? Or will this degraded state be maintained? Then, will these large and old herbivorous fishes be replaced by younger ones? There are many aspects in this story to be investigated."
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May 5, 2020
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https://www.sciencedaily.com/releases/2020/05/200505190546.htm
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Amphibian study shows stress increases vulnerability to virus
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Even the anti-freeze frog is not invulnerable to stress, according to a new study led by Washington State University researchers.
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The study, published in "We're seeing these mass mortality events in wildlife that are often due to infectious diseases; while at the same time, we notice an association with some kind of environmental change," said Emily Hall, the lead author on the study, which was part of her dissertation at Washington State University.The researchers studied wood frog larvae in ponds in the northeastern U.S. where the use of salt as a road deicer is common. Originally, Hall was interested in the effect of road salt in ponds on the frog's development, but at some of her study sites, all the tadpoles simply died."It's really dramatic when you go to a pond and suddenly all the little tadpoles are floating on the surface," Hall said. She discovered they had died of ranavirus, a common viral pathogen that healthy wood frogs often survive.Working with her advising professor Erica Crespi, who specializes in stress physiology, and Jesse Brunner, a disease ecologist, Hall started a new study using a combination of field work and lab studies to look at the potential link between the stress of salinity and susceptibility to infection.The researchers found the animals who had been exposed to salt had 10 times more intense infections when exposed to ranavirus. The salt-water tadpoles were also more infectious, shedding five times as much virus into the water as infected animals who had grown up in freshwater without salt added.The researchers did not see an increase in the frogs' corticosteroids, stress hormones, just from salinity. It was only with the virus infection did they see the magnified hormone levels and that inhibited the immune response.This finding has implications beyond the small northeastern ponds, said Crespi."We may be studying an amphibian-pathogen system, but what we saw is being played out right now with the COVID-19 epidemic," Crespi said. "Chronic non-lethal stressors can cause health outcomes that we aren't aware of until a crisis happens. People, who are in constant socioeconomic stress or have higher incidence of metabolic disease or asthma, are experiencing more severe infections and higher incidence of mortality. That's also what we saw in our salty ponds."The WSU study also has implications for how scientists approach wildlife conservation and mass die-offs of species. Unlike other species of amphibians, the wood frog is not experiencing major population declines. It is a common, usually resilient frog with a range that extends from Alabama to the Arctic. Mass mortality events from the virus have been observed in many parts of the world, but why one population experiences a die-off and not another is an open question. Researchers hypothesized that underlying poor conditions that elevate stress could play a role in where these mortality events occur."Since wood frogs are not a species of concern, people might not consider this a conservation story, but I do," Crespi said. "No one predicts die-offs. It's not a linear progression of decline. It's always a confluence of multiple things that act synergistically to cause an outcome that's more severe than expected. We should consider looking at preventative medicine in conservation."Practicing preventative conservation would require monitoring populations, evaluating the complex relationship of stressors and health threats as well as looking for ways to reduce the threats, Crespi said. In this case, the researchers recommended that road crews look for opportunities to reduce the use of salt in winter road treatments while balancing safety, such as using gravel as is done in parts of the Pacific Northwest.This work was supported by funding from the National Science Foundation, an EPA STAR Fellowship, and Sigma Xi Grants in Aid of Research as well as the Elling Endowment and the Natural Resources Conservation Endowment Fund at Washington State University.
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May 4, 2020
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https://www.sciencedaily.com/releases/2020/05/200504150209.htm
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How gene flow between species influences the evolution of Darwin's finches
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Despite the traditional view that species do not exchange genes by hybridisation, recent studies show that gene flow between closely related species is more common than previously thought. A team of scientists from Uppsala University and Princeton University now reports how gene flow between two species of Darwin's finches has affected their beak morphology. The study is published today in
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Darwin's finches on the Galápagos Islands are an example of a rapid adaptive radiation in which 18 species have evolved from a common ancestral species within a period of 1-2 million years. Some of these species have only been separated for a few hundred thousand years or less.Rosemary and Peter Grant of Princeton University, co-authors of the new study, studied populations of Darwin's finches on the small island of Daphne Major for 40 consecutive years and observed occasional hybridisation between two distinct species, the common cactus finch and the medium ground finch. The cactus finch is slightly larger than the medium ground finch, has a more pointed beak and is specialised to feed on cactus. The medium ground finch has a blunter beak and is specialised to feed on seeds."Over the years, we observed occasional hybridisation between these two species and noticed a convergence in beak shape. In particular, the beak of the common cactus finch became blunter and more similar to the beak of the medium ground finch," say Rosemary and Peter Grant. "We wondered whether this evolutionary change could be explained by gene flow between the two species.""We have now addressed this question by sequencing groups of the two species from different time periods and with different beak morphology. We provide evidence of a substantial gene flow, in particular from the medium ground finch to the common cactus finch," explains Sangeet Lamichhaney, one of the shared first authors and currently Associate Professor at Kent State University."A surprising finding was that the observed gene flow was substantial on most autosomal chromosomes but negligible on the Z chromosome, one of the sex chromosomes," says Fan Han, Uppsala University, who analysed these data as part of her PhD thesis. "In birds, the sex chromosomes are ZZ in males and ZW in females, in contrast to mammals where males are XY and females are XX.""This interesting result is in fact in excellent agreement with our field observation from the Galápagos," explain the Grants. "We noticed that most of the hybrids had a common cactus finch father and a medium ground finch mother. Furthermore, the hybrid females successfully bred with common cactus finch males and thereby transferred genes from the medium ground finch to the common cactus finch population. In contrast, male hybrids were smaller than common cactus finch males and could not compete successfully for high-quality territories and mates."This mating pattern is explained by the fact that Darwin's finches are imprinted on the song of their fathers so that sons sing a song similar to their father's song and daughters prefer to mate with males that sing like their fathers. Furthermore, hybrid females receive their Z chromosome from their cactus finch father and their W chromosome from their ground finch mother. This explain why genes on the Z chromosome cannot flow from the medium ground finch to the cactus finch via these hybrid females, whereas genes in other parts of the genome can, because parents of the hybrid contribute equally."Our data show that the fitness of the hybrids between the two species is highly dependent on environmental conditions which affect food abundance," says Leif Andersson of Uppsala University and Texas A&M University. "That is, to what extent hybrids, with their combination of gene variants from both species, can successfully compete for food and territory. Therefore, the long-term outcome of the ongoing hybridisation between the two species will depend on environmental factors as well as competition.""One scenario is that the two species will merge into a single species combining gene variants from the two species, but perhaps a more likely scenario is that they will continue to behave as two species and either continue to exchange genes occasionally or develop reproductive isolation if the hybrids at some point show reduced fitness compared with purebred progeny. The study contributes to our understanding of how biodiversity evolves," Andersson concludes.
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May 4, 2020
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https://www.sciencedaily.com/releases/2020/05/200504114115.htm
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Predators help prey adapt to an uncertain future
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What effect does extinction of species have on the evolution of surviving species? Evolutionary biologists have investigated this question by conducting a field experiment with a leaf galling fly and its predatory enemies. They found that losing its natural enemies could make it more difficult for the prey to adapt to future environments.
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According to many experts, the Earth is at the beginning of its sixth mass extinction, which is already having dire consequences for the functioning of natural ecosystems. What remains unclear is how these extinctions will alter the future ability of remaining species to adapt.Researchers from the University of Zurich have now pursued this question with a field experiment in California. They investigated how the traits of a tiny fly changed when a group of its natural enemies was removed. From their observations, they drew conclusions about changes in the genetic diversity of the flies.The fly Iteomyia salicisverruca lives on willow leaves in tooth-shaped growths called galls, which it induces in its larval stage. The natural enemies of this fly include several species of parasitic wasps. These wasps lay their eggs inside the fly larva within the gall, where they then develop into parasitic predators known as parasitoids. Before the adult wasp leaves the gall, it devours its host, the fly.Some species of these parasitoids attack before the gall is formed, while others parasitize fly larvae later in their development and pierce through the gall. The researchers specifically eliminated the latter group of natural enemies by attaching fine-meshed nets over leaves with galls before they were attacked.After three months, the biologists collected about 600 galls and checked if the fly larvae had survived. They also measured three traits that influence a fly's survival from parasitoid attack: the size of the gall; the number of flies within a gall; and the fly's preference to create galls on particular genetic varieties of willow trees. Using these data they then created "fitness landscapes" using computer models, which visualize the adaptability of a species.It turned out that different combinations of these three traits helped flies survive ? when all of the fly's natural enemies were present. "So there are several equally good solutions that ensure the survival of the fly," says Matt Barbour, the study's lead author. In contrast, after some natural enemies were removed, only one specific combination of traits helped flies survive. "This suggests that the extinction of natural enemies constrains fly evolution toward only one optimal solution." Genetic variations that lead to a different development of the traits could thus be permanently lost in the flies' genome.This loss of diversity might be of consequence: "The diversity of potential solutions for survival acts to preserve genetic variability in the gall's traits," says Barbour. And since genetic variation provides the raw material for evolution, the findings suggest that the extinction of this fly's natural enemies may make it more difficult for it to adapt to a changing environment."Thinking about the big picture, our study hints at a potential insidious side effect of extinctions," says Barbour. "The extinction of natural enemies may compromise the ability of remaining species to adapt and persist in an uncertain and changing world." If this is true, this would put many ecosystems at even greater risk than we currently realize.
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May 4, 2020
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https://www.sciencedaily.com/releases/2020/05/200504114113.htm
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Foraging Drosophila flies are open for new microbial partners
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In a comprehensive ecological study, a team of scientists at the Max Planck Institute for Chemical Ecology in Jena examined three different species of the genus Drosophila and their interactions with their natural food resources, in particular the yeasts associated with these substrates. They found that vinegar flies do not necessarily prefer yeasts they know from their natural environments, but were also attracted by yeasts found in a foreign habitat. Female flies sometimes even decided to lay their eggs in presence of previously unknown yeast communities, although their offspring had less chance of survival there. Such processes in nature could be a key factor that leads to the flies populating new habitats and, provided that the larvae also survive there, the formation of niches and, ultimately, the evolution of new species.
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Everyone knows the common vinegar fly (Researchers at the Max Planck Institute for Chemical Ecology wanted to know more about the role of the yeasts that grow on the respective hosts play in the host selection of the flies, and whether a partnership or mutual dependency between flies and these yeasts had developed in the process of co-evolution. "We asked ourselves: Would the fly species remain faithful to their yeasts, or would they also be attracted towards other yeasts, and would that influence the reproductive success of their species?" Sarah Koerte, first author and doctoral researcher in the Department of Evolutionary Neuroethology, summarizes the initial question.In addition to In behavioral experiments, the scientists tested the preferences of adult flies of all three species for yeasts, which grow either on fruit (the baker's or brewer's yeast Saccharomyces cerevisiae), on cacti (Pichia cactophila) or on fungi (Vanrija humicola), and are thus part of the naturally associated microbial communities for each of the fly species. In addition, the influence of different yeast species on the egg laying behavior of mated female flies was observed.Surprisingly, the flies did not necessarily prefer yeasts from their familiar habitat, but were also attracted towards the other yeasts. Females of the vinegar fly The yeasts help the flies to decompose the plant or fungal substrate. The flies, on the other hand, excrete the yeasts undigested with their frass, and as a consequence the yeasts can spread further. The researchers suspected that the yeasts might be involved to different degrees in the decomposition of the respective substrates. Analyses of the sugar contents and the degradation rates showed that flies and yeasts together accelerated the decomposition. However, there was no evidence that the interaction of a specific fly species with its associated yeast was beneficial."Our results show that flies with a broad host spectrum were also more tolerant to different yeasts in food sources and at oviposition sites. Interestingly, the flies did not care much which yeasts were present when laying their eggs, while the hatching larvae were often only able to grow on the yeasts they would have encountered in nature," said Markus Knaden, head of the study. However, if larvae survive on a new host and the host-specific yeasts, this might enable the flies to adapt to new environments, which might lead to the evolution of new species."The evolutionary success of Drosophila might be linked to the ability to adapt rapidly to new habitats. Insect-associated microbial communities could be the evolutionary keys to unlock new doors and pathways towards conquering unknown environments and establishing new ecological niches," says Sarah Koerte.
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May 4, 2020
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https://www.sciencedaily.com/releases/2020/05/200504114040.htm
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Smart use of genomic data needed in species conservation
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A "step-change" in conservation is needed in order to help save species from extinction in the future, according to an academic at the University of East Anglia (UEA).
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Professor of evolutionary genetics Cock van Oosterhout calls for the smart use of genomic data to make populations more resilient to future genetic drift and inbreeding, and proposes a new 'road map' for what needs to be done in conservation to achieve this.Decades of work by conservation geneticists and international treaties such as the UN Convention on Biological Diversity have attempted to improve the status of biodiversity and maintain genetic diversity across the various forms of life on Earth.However, according to the most recent global assessment report in 2019, the decline in biodiversity is only accelerating, and one million species are threatened with extinction. The Red List of the International Union for Conservation of Nature (IUCN) also shows that 44.3% of species are currently in decline.Contributing to this, recent fires in the Amazon and Australia have transformed vast swathes of habitat, climate change places additional pressures on populations, and globally, approximately 75% of the infrastructure planned for 2050 has yet to be built.Writing in the journal Over the last half century, conservation geneticists have analysed genetic variation and focused on maintaining this in threatened species. While this is important, Prof van Oosterhout says they have ignored an essential part of the genome that is devoid of variation, identical across different species. These are the DNA nucleotides that have been conserved over millions of years of evolution.These parts of the genome are under strong selection and if mutations occur in these so-called 'ultra-conserved elements', they are bad for the fitness of individuals. When a population declines these mutations become exposed by inbreeding, so the already struggling population is even more at risk.However, genomics can reveal the presence of this 'mutation load' at the molecular level using tools developed for humans and model animals, such as mice and rats.Prof van Oosterhout said: "Given that these studies all examine the same ultra-conserved elements, the mutation load can be directly compared between species. Hence, the analyses developed in human genomics could be universally applied across the tree of life, making them very promising tools for conservation genomics."We now know the DNA sequences of these ultra-conserved regions in the genomes of threatened species. This means that we can also identify the bad mutations when we sequence these individuals. This has become relatively cheap and it is quick."Conservation genomics could also help to improve captive breeding in zoos. Rather than just minimising the rate of inbreeding, studbook holders could use the mutation load data of individuals to take on the role of natural selection in the zoo environment."With that data and knowledge of which DNA sequences to look out for, we can select against these bad mutations even before they become 'exposed' by inbreeding," said Prof van Oosterhout."This would help to prevent -- or even turn-back -- the deterioration of genepool of the often small zoo populations. Data on the mutation load could also be used to reduce the risk of inadvertently reintroducing harmful mutations into the wild during genetic rescue. Such genomics-informed conservation would make populations more resilient to genetic drift and inbreeding yet to come."In his paper, Prof van Oosterhout suggests a method that avoids losing valuable genetic variation, an inevitable consequence of selection. It involves selecting the best two offspring of all breeding pairs, so the two with the lowest number of bad mutations. This will reduce the mutation load, maintains the useful genetic variation, and would make the zoo population, and the species, more resilient against current and future inbreeding.Prof van Oosterhout cautions that there is still work to do to make these genomic approaches reliable, practical tools for conservation. "We still don't know how the mutation load affects the fitness of individuals in the natural environment," he said. "Translating this genomic data into metrics that are relevant to conservation is therefore urgently needed.""Fortunately, with thousands of genomes currently being sequenced by consortiums, data is rapidly being generated. Together with the rich sample archives that have been collected for some of our threatened species over decades, such as the pink pigeon and the echo parakeet, this would help to translate genomic data into information that is relevant for conservation, for example around the fitness of individuals in their natural environment, and the viability of their populations."We should be able to rank individuals, and species, according to their mutation load and relative levels of inbreeding, thereby improving the Red List of animals currently in decline."
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May 4, 2020
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https://www.sciencedaily.com/releases/2020/05/200504114035.htm
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Last supper: Fish use sharp barbs and spines to fight off hungry seals
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What price are you willing to pay for food? As humans, we face this challenge each time we shop, but for some seals and dolphins this may be a life or death decision.
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Modern medical scanning reveals the steep price some marine mammals are willing to pay for food, after a stranded fur seal was discovered with more than a dozen facial wounds inflicted by its seafood prey.The extreme dangers facing hungry marine mammals are revealed in a new study published in the journal "Marine mammals like whales, seals and dolphins need to eat seafood to survive," Dr Hocking said. "But, we seldom consider what the fish think of this situation. Obviously, they are less than enthusiastic about being eaten, and some of them have evolved elaborate defence systems to help them fight off would-be predators."The study describes a stranded seal found at Cape Conran in south-eastern Australia, which -- according to Dr Hocking -- "followed its stomach one fish too far." Unusually, a fish spine was seen poking through the seal's cheek, prompting the researchers to CT scan the seal using the cutting-edge facilities at Monash Biomedical Imaging."We were shocked to discover not one, but six fish spines embedded in the seal's face," said Associate Professor Alistair Evans, a co-author on the study, also from the Monash School of Biological Sciences. These were later identified by comparing them with specimens at Museums Victoria."The fish spines turned out to be tail barbs from stingarees [a small type of stingray] and serrated spines from the back fin of Australian ghostsharks."While seals are known to feed on these types of prey, this is the first time that researchers have understood how dangerous this process can be. This raises an interesting question: is the Cape Conran seal just an unusual case, or have similar injuries in other stranded individuals simply been overlooked?"In New Zealand, fur seals target ghostsharks regularly. With that in mind, similar facial wounds may actually be rather common, even though they haven't been recognised much," said co-author Dr Felix Marx from Museum of New Zealand Te Papa Tongarewa. "That's perhaps not surprising, as the injuries could easily have been hidden beneath the seals' thick fur."Animals from future stranding events will be examined using X-ray and medical imaging to look for further evidence of facial injuries -- a unique yet gruesome window into the eternal battle between predator and prey.
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Animals
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May 3, 2020
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https://www.sciencedaily.com/releases/2020/05/200503092739.htm
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Tree trunks take a licking as koalas source water
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Koalas are one of the world's most charismatic animals. But there is a lot we still don't know about them. For example, how do the marsupials access water in the treetops? Do they only absorb moisture from the gum leaves they eat? Or do they come down from the trees to drink from a waterhole? Until now, no one really knew.
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A study published today in The news arrives in time to celebrate Wild Koala Day on Sunday 3 May."For a long time, we thought koalas didn't need to drink much at all because they gained the majority of the water they need to survive in the gum leaves they feed on," said Dr Valentina Mella, in the School of Life and Environmental Sciences. "But now we have observed them licking water from tree trunks. This significantly alters our understanding of how koalas gain water in the wild. It is very exciting."Australia is currently suffering the longest dry period ever documented, with severe rainfall deficits and record maximum temperatures. Koalas experience severe heat-stress and mass mortality events in prolonged hot and dry conditions and they spend more time drinking from artificial water stations if rain is scarce.Further research could investigate when and why koalas from different areas need access to free water -- not contained in the leaves as moisture but available freely as liquid, such as rain, river water or puddles -- and whether water supplementation is necessary for some populations."This type of drinking behaviour -- licking tree trunks -- relies on koalas being able to experience regular rainfall to access free water and indicates that they may suffer serious detrimental effects if lack of rain compromises their ability to access free water," Dr Mella said."We know koalas use trees for all their main needs, including feeding, sheltering and resting. This study shows that koalas rely on trees also to access free water and highlights the importance of retaining trees for the conservation of the species."Each day, wild koalas eat around 510 grams of fresh succulent eucalyptus leaves, and the water in the foliage they feed on is believed to contribute about three quarters of their water intake in both summer and winter.Among their adaptations to the Australian climate, koalas also possess extraordinary urinary concentrating abilities and have restricted respiratory and cutaneous water loss compared to similar-sized mammals.In captivity, koalas have been observed to drink water, but this behaviour has often been considered unusual and attributed to disease or to severe heat stress.However, anecdotal reports suggest that koalas in the wild drink from waterholes in summer when temperatures exceed 40 degrees Celsius.Koalas have also been observed approaching humans to access free water (in bottles, gardens and swimming pools during drought and after fire. But this is considered an unusual occurrence.For this study, Dr Mella collated observations of koalas drinking in the wild made by citizen scientists and independent ecologists between 2006 and 2019 at the You Yangs Regional Park in Victoria and the Liverpool Plains in NSW. Each observation was koala behaviour noticed by chance and reported to Dr Mella.There were 44 observations of free ranging koalas licking water running down a tree trunk during or immediately after rain in the You Yangs Regional Park.The other two observations of koala drinking behaviour were recorded between the towns of Gunnedah and Mullaley, in the Liverpool Plains. One was an adult female, with a joey, who drank profusely and uninterruptedly for 15 minutes. The other was an adult male who drank at a steady pace for 34 minutes."As koalas are nocturnal animals and observation of their behaviour rarely occurs during heavy rainfall, it is likely that their drinking behaviour has gone largely unnoticed and has therefore been underestimated in the past," Dr Mella said. "Our observations probably only represent a minority of the drinking that normally takes place in trees during rainfall."Koalas were observed accessing water in trees by licking the wet surfaces of branches and tree trunks during rain across a range of weather conditions, even when free-standing water was available in dams."This suggests koalas were drinking not as a result of heat stress and that this behaviour is likely to represent how koalas naturally access water," said Dr Mella.
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April 29, 2020
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https://www.sciencedaily.com/releases/2020/04/200429191856.htm
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Thousands of miles of planned Asian roads threaten the heart of tiger habitat
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Nearly 15,000 miles of new Asian roads will be built in tiger habitat by mid-century, deepening the big cat's extinction risk and highlighting the need for bold new conservation measures now, according to a new study.
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University of Michigan conservation ecologist Neil Carter and his colleagues used a recently developed global roads dataset to calculate the extent and potential impacts of existing and planned road networks across the nearly 450,000-square-mile, 13-country range of the globally endangered tiger.Fewer than 4,000 tigers remain in the wild. They are found mainly in South Asia and Southeast Asia, regions that will experience accelerating pressure from human development in coming years.Road construction often exacerbates all three of the main threats to tigers: prey depletion, habitat degradation and poaching.The U-M-led study showed that existing roads are pervasive throughout tiger habitat, totaling 83,300 miles (134,000 kilometers) in Tiger Conservation Landscapes (TCLs), blocks of habitat across the animal's range that are considered crucial for recovery of the species. Carter and his co-authors called this finding "a highly troubling warning sign for tiger recovery and ecosystems in Asia."The researchers calculated three measures -- road density, distance to the nearest road and relative mean species abundance -- to characterize how existing road networks influence tiger habitat. They calculated current road densities for all 76 TCLs and summarized those estimates by country and protection status.In addition, they used published forecasts of global road expansion to calculate the length of new roads that might exist in tiger habitat by 2050, for each of the 13 tiger-range countries.The study, scheduled for publication April 29 in "Our analysis demonstrates that, overall, tigers face a ubiquitous and mounting threat from road networks across much of their 13-country range," said U-M's Carter, an assistant professor at the School for Environment and Sustainability."Tiger habitats have declined by 40% since 2006, underscoring the importance of maintaining roadless areas and resisting road expansion in places where tigers still exist, before it is too late. Given that roads will be a pervasive challenge to tiger recovery in the future, we urge decision makers to make sustainable road development a top priority."The world's remaining tigers are concentrated in a small number of source populations -- areas with confirmed current presence of tigers and evidence of breeding -- across the animal's geographic range. Even a small amount of road construction could disproportionately impact tiger recovery by permanently isolating tiger populations, creating tiger "islands," according to the researchers.Protecting tigers is a global conservation priority, exemplified by a landmark international initiative, called TX2, with the goal of doubling global tiger numbers between 2010 and 2022. And tigers are considered a conservation flagship species, a popular, charismatic animal that serves as a symbol and rallying point to stimulate conservation awareness and action.Even so, few studies have assessed the impacts of roads on tigers and their recovery, limiting the impact of tiger conservation planning.And most previous "road ecology" studies of tigers have focused on localized patterns of wildlife mortality or behavior associated with road design. The new study by Carter and his colleagues, in contrast, estimates road impacts on wildlife at broad scales. It is the first study to include baseline indices on the threat from existing and future roads in tiger habitat."This research opens the door to build partnerships at the regional scale to better mitigate existing roads and to develop greener road designs for the next century of infrastructure development," said study co-author Adam Ford, a wildlife ecologist at the University of British Columbia.The researchers say their metrics provide tools to support sustainable road development, enabling rapid risk assessment for roads passing through tiger habitat, including roads planned as part of the Belt and Road Initiative.The BRI is a global development strategy adopted by the Chinese government in 2013 involving infrastructure projects in dozens of countries in Asia, Europe and Africa. The rush to build major new roads throughout the forested regions of South Asia and Southeast Asia, financed through the initiative, could have severe impacts on tigers, according to Carter and his colleagues.But the BRI could become an important partner in tiger preservation, according to the researchers, by adopting biodiversity conservation as one of its core values. That would set the stage for the BRI to plan and implement a network of protected areas and wildlife corridors to safeguard tigers from road impacts.
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April 29, 2020
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https://www.sciencedaily.com/releases/2020/04/200429155656.htm
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New findings highlight threatened status of forest elephants
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Conservation efforts for the African forest elephant have been hindered by how little is known the large animal, according to researchers.
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A newly published study by a 10-member international research team, including University of Oregon biological anthropologist Nelson Ting, offers new information that could help to understand and protect the elephants amid increasing threats to their existence.The team's study, published in The new findings provide insights into a revised population count and social behavior of the forest elephants, Loxodonta cyclotis. Both factors have been understudied, even as the elephant's population has dramatically declined over recent decades from human-related activities like habitat loss and poaching."Forest elephants are among the most threatened animals, but their biology and behavior remain poorly understood," said Ting, who is also a member of the UO's Institute of Ecology and Evolution. "More information is key to figuring out the best ways to protect them and prevent extinction."Ting had a senior role in the study, which was led by UO graduate student Colin Brand and Gabonese scientist Mireille Johnson. It also featured several collaborators from the Smithsonian Institution.Ting was drawn to studying the elephants' elusive nature in the same Central African jungles where he was studying primates, leading to a partnership with Johnson, who specializes in forest elephants.African elephants often are grouped with the better-known savanna elephants, also known as bush elephants, Loxodonta africana, resulting in less scrutiny. The two tusked animals, however, are actually quite different, Ting said.Reproductive lives, habitat preference, and physical characteristics such as body size, ear shape, and tusk shape and color are among the differences.Savanna elephants roam open landscapes. Forest elephants stay in more densely wooded areas, where they are harder to study and count.The research was done in the southern Industrial Corridor of the Gamba Complex of Protected Areas in southwestern Gabon, a global stronghold for forest elephants.To assess population size, the researchers counted elephants using a method known as genetic capture-recapture -- which involves systematically collecting dung piles and analyzing their genetic composition to match the DNA of each deposit to its owner. The approach is like collecting genetic fingerprints for the elephants, Ting said.In previous methodology, Ting said, researchers also counted dung piles but could not differentiate those deposited by one individual from another. That method can lead to over-counting since the same elephant could be responsible for multiple mounds.Previous methodology had assessed the elephant population size in the Gamba Complex Industrial Corridor to be approximately 10,000 individuals, which would be a substantial proportion of the global forest elephant population, the researchers noted.Ting and team estimated that their sampled region is actually home to 754 to 1,502 elephants or .47 to .80 elephants per square kilometer. That data suggests the population in the corridor is between 3,033 to 6,043 elephants, based on abundance, or 1,684 to 2,832, based on their density -- the two different metrics they used to model the population size."Gabon is thought to be a population stronghold of African forest elephants," Ting said. "But even our most optimistic results suggest a smaller population size than expected. Our research shows how endangered they really are if a region like this one is so overestimated."It is hoped, Ting said, that his team's new findings can help inform government officials and conservation groups as they plan future conservation strategies."Our study emphasizes the threatened status of forest elephants and demonstrates the need for more research," Ting said. "It is imperative that known populations are monitored to provide accurate data on the status of these populations and the global forest elephant population as a whole."
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April 29, 2020
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https://www.sciencedaily.com/releases/2020/04/200429111133.htm
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Marooned on Mesozoic Madagascar
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In evolutionary terms, islands are the stuff of weirdness. It is on islands where animals evolve in isolation, often for millions of years, with different food sources, competitors, predators, and parasites...indeed, different everything compared to mainland species. As a result, they develop into different shapes and sizes and evolve into new species that, given enough time, spawn yet more new species.
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Such is the case with the discovery of a new, bizarre 66-million-old mammal in Madagascar by a team of international researchers led by Dr. David Krause, senior curator of vertebrate paleontology at the Denver Museum of Nature & Science and professor emeritus at Stony Brook University, where part of the research was done. The discovery of this opossum-sized mammal that lived among dinosaurs and massive crocodiles on the fourth largest island on Earth was announced today in the journal The finding of the new mammal, called Krause said that, "knowing what we know about the skeletal anatomy of all living and extinct mammals, it is difficult to imagine that a mammal like In fact, although a life-like reconstruction might lead one to think that "Its nasal cavity exhibits an amazing mosaic of features, some of which are very standard for a mammal, but some that I've never seen in anything before," Rossie declared.The teeth of About the size of a Virginia opossum, Prior to the discovery of the nearly complete skeleton of The completeness and excellent preservation of the skeleton of As Krause's primary collaborator Simone Hoffmann of the New York Institute of Technology put it, "The plate tectonic history of Gondwana provides independent evidence for why The fossil record of early mammals from the northern hemisphere is roughly an order of magnitude better than from the south."More than anything, this discovery underscores to the researchers how much more remains to be learned by making new discoveries of early mammals in Madagascar and other parts of the former Gondwana.In addition to Krause, Hoffmann, and Rossie, other researchers involved in the new discovery -- which was funded by the National Science Foundation and National Geographic Society -- were: the late Yaoming Hu of Stony Brook University; John R. Wible of Carnegie Museum of Natural History; Guillermo W. Rougier of University of Louisville; E. Christopher Kirk of University of Texas at Austin; Joseph R. Groenke of Stony Brook University and Ohio University; Raymond R. Rogers of Macalester College; Julia A. Schultz of Institut für Geowissenschaften der Universität Bonn, Alistair R. Evans of Monash University and Museums Victoria; Wighart von Koenigswald of Institut für Geowissenschaften der Universität Bonn; and Lydia J. Rahantarisoa of Université d'Antananarivo.The new The island itself is filled with animals (and plants) found nowhere else on the planet, including hissing cockroaches, giraffe weevils, tomato frogs, Satanic leaf-tailed geckos, panther chameleons, and streaked tenrecs to name a few. And, of course, there is the signature group of mammals -- lemurs -- made famous in the animated "Madagascar" movies. Only a few thousand years ago, the Madagascar fauna also included 1400-pound elephant birds, gorilla-sized lemurs, and pygmy hippopotamuses.
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April 29, 2020
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https://www.sciencedaily.com/releases/2020/04/200429105838.htm
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Tuning into dolphin chatter could boost conservation efforts
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Tuning in to the signature 'whistles' of dolphins could prove a game-changer in being able to accurately track the movements of this much-loved protected species.
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Researchers from Edith Cowan University (ECU) and Curtin University in Australia have moved an important step closer to using sound rather than sight to track individual dolphin activity.Their study, which has potential implications for dolphin communities around the world, investigated whether there was a way to attribute unique whistles to individual bottlenose dolphins living in Western Australia's Swan River.It is the first time researchers have attempted acoustic tracking dolphins in the Swan River, which is a complicated marine ecosystem due to its high volume of activity and noise.ECU researcher Associate Professor Chandra Salgado Kent said the project could have significant implications for dolphin conservation."Our ultimate aim is to track the movements of individual dolphins through underwater acoustic recorders," Professor Salgado Kent said."Until now researchers around the world have relied on laborious and expensive visual surveys on boats to track individual dolphins."These surveys can only be conducted during the day and rely on photographing the unique nicks and notches in dorsal fins when they come to the surface."We aimed to design a new approach to monitor individual dolphin activity through matching unique sounds, known as signature whistles, to individual dolphins."From April to September 2013 the researchers systemically monitored an area within the eastern part of the Fremantle Inner Harbour where the Swan River narrows.Acoustic recordings were made throughout all observation times with handheld hydrophones deployed over the side of the small craft jetty lowered to 1.5m depth.More than 500 whistles were matched to dolphin photos over the period of the study.Curtin University Professor Christine Erbe said the process presented some unique challenges."Dolphins are social creatures and very frequently seen in groups, which makes the process of matching the whistles to particular individuals very challenging," she said."Based on the presence and absence of dolphins when whistles were recorded, most whistle types were narrowed down to a range of possible dolphins that could have produced it."Our next goal will be to narrow this down to individuals."
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April 29, 2020
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https://www.sciencedaily.com/releases/2020/04/200429105913.htm
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Shrinking instead of growing: How shrews survive the winter
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Last year, about 30 common shrews from the area around Möggingen had an unusual adventure. Researchers at the Max Planck Institute for Animal Behavior in Radolfzell captured the animals, measured their skulls, and examined their metabolism. The animals were then released back into the wild. This all led to an exciting discovery. The measurements revealed that the animals' metabolism is equally active in summer and winter. Animals that do not hibernate usually require more energy in winter in order to maintain a constant body temperature. This gives shrews a survival advantage that has likely enabled them to colonize colder regions.
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Common shrews have one of the highest metabolic rates among mammals. They must therefore consume a considerable amount of energy for their relatively low body weight. Because their fat reserves are quickly used up, they often starve to death after only a few hours without food. Nevertheless, forest shrews and their close relatives are highly evolutionarily successful and quite widespread, especially in the northern hemisphere.Dina Dechmann, a scientist at the Max Planck Institute of Animal Behavior in Radolfzell, hopes to find out how animals deal with large fluctuations in food supply and other resources. For example, how do tiny shrews manage to overcome the cold and food shortages in winter? But studies with wild shrews consume a great deal of time and resources. Because of their strong territorial behaviour, the animals must be kept in large individual enclosures throughout the experiments.Unlike many other animals, common shrews neither store food nor hibernate. Instead, they adapt in a completely different way: After their birth in summer, they grow rapidly to a maximum size. But in autumn, they begin to shrink and lose approximately ten to 20 percent of their body weight. Not only fat and muscle mass is reduced; internal organs such as the brain also shrink. From February onwards, the shrews begin to grow again until they reach their maximum size in spring. However, some tissues, such as the brain, only partially grow again. This seasonal change in body size, which is extremely rare in the animal kingdom, is also known as Dehnel's phenomenon.However, this strategy seems a bit paradoxical. Despite thick winter fur, one would expect the shrews to cool down more easily in winter temperatures because smaller animals have an unfavourable body surface to body mass ratio. Because of this, they lose more heat to the cold ambient air. In fact, the relationship between body weight, temperature, and metabolic rate is a fundamental law of ecology.In order to find out how the seasonal change in body size affects the energy consumption of shrews, Dechmann and her team measured the animals' metabolism at the respective outdoor temperatures of the different seasons. The results were surprising. "The common shrew somehow manages to cheat evolution," says Dechmann. Despite their reduced body size, shrews do not consume more energy per gram of body weight in winter -- even though temperatures can fluctuate by more than 30 degrees. This is not because they are less active in winter. The video recordings of the researcher show that although the shrews rest a little more, this can only explain a small part of the differences in energy requirements.The scientists suspect that shrews constantly produce excessive amounts of heat because of their high metabolic activity and therefore do not need to increase their metabolic rate in winter. A smaller body size simply means that they must consume less energy overall. This is advantageous considering the scarce food supply in winter. "How this works exactly is still unclear. There are still some open questions we would like to investigate in further experiments," says Dechmann. The special metabolism of the forest shrews might even shed light onto research in human diseases in which metabolism plays a role.
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April 29, 2020
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https://www.sciencedaily.com/releases/2020/04/200429105848.htm
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White-faced capuchin monkeys come down from the trees on Panama's Coiba Island
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Crossing a 23-kilometer stretch of ocean from mainland Panama to Coiba, the largest offshore island in the Eastern Pacific, a group of intrepid biologists hoped to find species never reported there before. But in addition to discovering new species, the 2015 Coiba BioBlitz crew was surprised to find that capuchin monkeys spent so much time on the ground there.
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"Most of us have worked on Barro Colorado Island (the Smithsonian's research station in Panama's Lake Gatún) where capuchin monkeys are used to people, but we had never seen them spending so much time on the forest floor," said Claudio Monteza, now doing his PhD at the Max Planck Institute of Animal Behavior and University of Konstanz. "We never saw moms carrying babies come down to the ground like we did on Coiba. Even the most habituated groups on Barro Colorado are very careful with the babies."Meg Crofoot and Mark Grote, then at the University of California, Davis, were intrigued by this shift in behavior and the insight it might provide into why human ancestors originally descended from the trees. They encouraged Claudio to make the unusual behavior of the monkeys on Coiba the subject of his masters' thesis."In the Old World there are lots of primates that have adapted to life on the ground, but no one knows why this behavior is missing in New World primates," Claudio said.Isolated from the mainland between 12-18 thousand years ago, Coiba is home to plant and animal life found nowhere else on Earth. When the Spanish first sailed to Coiba in 1516, chroniclers reported an island densely populated by indigenous peoples, but by 1550, the island had been depopulated, leaving only a small settlement of Spanish colonists. And from 1919 to 2004, the island was a penal colony where prisoners' movements were restricted, leaving most of the island to its wild inhabitants.Claudio suspected that the fearlessness of Coiba's capuchins might have a simple explanation: Coiba lacks jaguars, pumas, tayras (large weasels), coyotes, jaguarundis and ocelots -- all identified as predators based on capuchin remains in fecal samples. One of the reasons that no one has studied this before is because it is nearly impossible for researchers to observe the effects of predators that are frightened away when scientists show up.But Claudio's team got around this problem by using cameras. They set up camera traps at knee height on the bases of trees on Coiba and a on much smaller island nearby called Jicarón. Movement triggers the video recorders in the traps. Then they compared the videos of monkeys on the islands with videos from camera traps at three mainland sites: the STRI research station on Barro Colorado Island, the nearby Gigante Peninsula and in Panama's Soberanía National Park -- part of a study by staff scientist Patrick Jansen as part of the global Tropical Ecology Assessment and Monitoring Network (TEAMS)."We didn't record any mammalian predators on the ocean islands, and there were more predators in Soberanía National Park than on Barro Colorado or Gigante Peninsula," Claudio said. "The results were what we expected in the absence of predators: The party sizes of the monkeys -- the number of individuals on the ground at one time -- on Coiba Island were much bigger than at any of the mainland sites."Monkeys at sites where there were predators also spent more time on the ground during the middle of the day, when predators are less active. In contrast, monkeys on the Pacific islands did not focus their activity at a certain time of day. The longest visits to the ground were made on Jicarón (14.5 minutes) and Coiba Islands (7.9 minutes).Primates coming down from the trees played a significant role in human evolution, but the still-controversial explanations usually involve changes in climate or diet.Millions of years ago, when the Isthmus of Panama rose from the sea to form a land bridge between North and South America, global ocean currents shifted, perhaps causing a drying trend in Africa and the replacement of forests by savannahs, forcing human ancestors to spend more time on the ground.Others suggest that human ancestors came to the ground to forage for fungi."Our study indicates that predators likely play a key role in explaining why there are no terrestrial primates in the Neotropics," said Crofoot, who is now director of the Max Planck Institute of Animal Behavior and professor at the University of Konstanz. "When there are no predators, primates can become more terrestrial, even if they aren't 'forced' to by changes in forest structure. But Coiba is a unique place where we also discovered that these monkeys are using stone tools. Is that a result of the lack of predators, or could the capuchins' ability to use new food source be the explanation in itself?"
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April 28, 2020
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https://www.sciencedaily.com/releases/2020/04/200428225421.htm
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How hero shrews' bizarre backbones evolved
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At first glance, hero shrews don't seem super exciting -- they're small grayish-brown mammals, related to moles and hedgehogs, and they look a little bit like chubby, long-nosed rats. But under their fur, they have some of the strangest skeletons in the animal kingdom. Hero shrews have unique interlocking backbones that make their spines insanely strong -- the shrews only weigh a quarter of a pound, but there are stories that their backs can support the weight of a full-grown man standing on them. Scientists aren't sure why these tiny animals developed such crazy backbones, but researchers looking for clues took CT scans of shrew spines to try to get a better sense of how the spines evolved.
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"Hero shrews have crazy-looking spines -- their vertebrae are squished flat like a pancake, and they have a bunch of extra places where they touch the vertebrae next to them. It makes a really long stiff column along their back, and there aren't good field reports as to what this structure might be useful for," says Stephanie Smith, a postdoctoral researcher at the Field Museum and the University of Chicago and the lead author of a new paper in Western scientists first became aware of hero shrews about a hundred years ago, but the Mangbetu people of the Congo Basin have long known about the shrews' incredible strength. There's a (maybe apocryphal) story about Mangbetu people showing a team of American and European scientists how a grown man could stand on a hero shrew's back without hurting it. A second species of hero shrew, with a spine complexity in between that of the original hero shrew and a regular shrew, was described in 2013. But researchers haven't been able to spot the shrews in the wild putting these backbones to good use -- the shrews are hard to find, and they live in areas where political unrest makes research trips nearly impossible."There are two species of hero shrew, and they're both very poorly known. We have specimens of them at the museum, but we can't see them in action. It's almost like studying an animal in the fossil record, where we have specimens that tell us about their anatomy, but we can't bring a live specimen into the lab and observe it," says Kenneth Angielczyk, a curator of paleontology at the Field Museum and the paper's senior author.The authors of the 2013 paper, including the Field's late head of collections Bill Stanley, posited that the hero shrews' thick spines might be used as a brace as the animals shifted logs and peeled apart palm stems to get at insects. But no one's observed them doing that. All we know for sure is that the shrews' backbones are unique."Their spines are arched, and when they contract their muscles to squeeze their vertebrae together, the bones interlock really tightly. When that happens, it becomes one solid block of vertebrae instead of a bunch of bendy pieces," says Smith.Without any live shrews to observe, Smith and Angielczyk turned to the bones in the Field Museum's collections. They took micro-CT scans of the bones of the two known hero shrew species, as well as a "normal" shrew for comparison. These scans revealed minute details of the bones, but more importantly, they also hinted at how the bones were used in life."Bones contain a record, to some degree, of the forces that are acting on them during life. There are special cells in the bone that detect when pressure is put on it. They send out signals to reorganize the bone to be better at handling the forces they're under, so you have bones responding throughout an animal's life to habitual forces," explains Smith. "My absolute favorite example of this was a paper where they put sheep in tall shoes, like high heels, and the different angle of pressure changed the inner structure of their leg bones."Armed with the knowledge that the inner structure of bone changes depending on the direction of the forces that have acted on the bone, Smith and Angielczyk tried to determine what these shrews had gotten up to. "We found that the two species of hero shrews have really, really thick, dense spongy bone inside their vertebrae. The percentage of bone is high relative to the total volume of the structure compared to other shrews," Smith says. "That makes the bone a lot sturdier. It's like how a chair with thick legs and crossbeams connecting those legs is sturdier than a chair with just four spindly legs and no crossbeams.""That's really interesting because it says that these guys can take a lot of force compressing their spine from head to tail. And that's the main direction that force is applied to the spine in an animal that has four legs," continues Smith. "It doesn't necessarily solve the question of what are they doing, but it does give us an indicator that they're habitually experiencing strong forces in that direction."To sum up: hero shrew spines don't just look tough from the outside, they're also super dense inside, in a way that indicates that they're able to withstand pressure from being scrunched up like an inchworm. It doesn't confirm Stanley's hypothesis that the shrews scrunch up and then extend their spines to wedge apart palm trunks to get at bugs -- only direct observation can do that. But it does indicate that the shrew's backbones could resist the forces such behavior would generate.In addition to studying the forces the hero shrews were exposed to in life, Smith also helped quantify the differences between the two known species. The original hero shrew described in 1910 has a more complex spine than the new species from 2013, although the latter has a more complex spine than regular shrews. This suggests the transitional features of the 2013 species (Thor's hero shrew) can provide information about how the 1910 shrew evolved from a slender-spined ancestor. To help quantify the differences between the shrews' spines, Smith painstakingly counted all the little nodules and tubercles on the specimens' vertebrae. "I think the grand total was something like 17,000," she says. "We found that the Thor's hero shrew was intermediate on both the inside and the outside. Because of the way that bone reacts to load, that means that it could also be functionally intermediate. But that's just a hypothesis at this point."And if this all seems like a lot of time and effort thinking about shrews at a time when the world has bigger fish to fry, the researchers note that it helps answer bigger questions about the evolution of mammals."Small mammals experience the world differently than we do, and we don't have all that much information about the way that being small affects their interaction with the world," says Angielczyk. "Part of what we're interested in is the question of how you can be a small mammal -- what do you need to be effective at that and resist forces that are being applied to your body in different functional contexts. It's something that we don't know very much about, but it's important, because we evolved from small mammals. Better knowledge of what it takes to be a small mammal is important for understanding a lot of weird things about mammals in general, including us."Smith has no plans to move on from studying shrews anytime soon. "Shrews are really interesting ecologically, and they're so small they have almost secret powers," she says. "They're incredibly diverse, and I think they're beautiful. They're dope as hell."
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April 28, 2020
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https://www.sciencedaily.com/releases/2020/04/200428165748.htm
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New insights into how genes control courtship and aggression
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Fruit flies, like many animals, engage in a variety of courtship and fighting behaviors. Now, Salk scientists have uncovered the molecular mechanisms by which two sex-determining genes affect fruit fly behavior. The male flies' courtship and aggression behaviors, they showed, are mediated by two distinct genetic programs. The findings, both published in
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"Courtship and aggression seem to be controlled somewhat separately by these two genes," says Kenta Asahina, an assistant professor in Salk's Molecular Neurobiology Laboratory and senior author of the two papers. "Having behaviors controlled by different genetic mechanisms can have some benefits in terms of evolution." In other words, he explains, a fly population that is under evolutionary pressure to compete more -- perhaps due to limited resources -- can evolve aggressive behaviors without affecting courtship.Male fruit flies' aggression is primarily toward other males, while their courtship behaviors -- which involve a series of movements and songs -- are toward female flies. Both behaviors are reinforced by evolution over time, because the ability of male flies to compete with other males and attract females directly affects their ability to mate and pass on their genes.Researchers already knew which neurons in the brain are important for controlling aggression and courtship. In general, studies had suggested that specialized brain cells called P1/pC1 neurons, promote both courtship and aggression while Tk-GAL4FruM neurons promote aggression specifically. They also knew that the two sex-determining genes fruitless (fru) and doublesex (dsx) played key roles in this behavior. But the connection between the genes and the behaviors hadn't been clear.In the new study, Asahina and his colleagues raised Drosophila fruit flies that contained light-activatable versions of the courtship and aggression neurons. The team could turn the neurons on at any time by shining a light on the flies. The researchers next altered the fru or dsx genes in some of these male flies. They then developed an automated system using machine-learning to analyze videos of the flies and count how often they carried out aggressive or courtship behaviors."We made a computer system to capture aggressive behaviors and courtship behaviors to more quickly and accurately count actions," says Salk postdoctoral fellow Kenichi Ishii, co-first author of both of the new papers. "Getting the program to work was actually difficult and time-consuming but in the end, it made it easier for us to get good data."The team found that dsx was required for the formation of courtship-inducing neurons: when the fruit flies had the female version of dsx, the courtship neurons were no longer present. On the other hand, fru played a different role -- without this gene, flies could still be coaxed to perform courtship behaviors by activating courtship neurons but the courtship was directed at both males and females, suggesting that fru was required for flies to differentiate between the sexes. For aggression, however, the findings were the opposite: fru but not dsx was required for the activation of aggression neurons to cause fighting in male flies."This is an important example of the neurobiological differences between sexes and what kind of approaches we can use to study sexually-linked behaviors," says Asahina, who holds the Helen McLoraine Developmental Chair in Neurobiology."I think the interesting part of this is understanding that sex is really not a binary thing," says UC San Diego doctoral student Margot Wohl, co-first author of both of the new papers. "A lot of factors come together to control behaviors that differ between the sexes."Since sex determination in flies is very different than in humans -- fruit flies don't have sex hormones, for instance -- the new findings don't carry over to how biological sex may impact behavior in people. But Asahina says his approach -- the combination of optogenetics and sex-linked gene manipulation -- may be useful in understanding behaviors that vary by sex in other animals.
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April 28, 2020
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https://www.sciencedaily.com/releases/2020/04/200428112459.htm
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Arctic wildlife uses extreme method to save energy
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The extreme cold, harsh environment and constant hunt for food means that Arctic animals have become specialists in saving energy. Now, researchers at Lund University in Sweden have discovered a previously unknown energy-saving method used by birds during the polar night.
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Researchers from Lund University and the University of Tromsø have examined the immune system strength of the Svalbard rock ptarmigan in the Arctic. This bird lives the farthest up in the Arctic of any land bird, and the researchers have investigated how the immune response varies between winter and late spring."We have discovered that the birds reduce how much they spend on keeping their own immune defence system up and running during the five months of the year when it is dark around the clock, probably to save energy. Instead, they use those resources on keeping warm and looking for food. When daylight returns, their immune response is strengthened again," says Andreas Nord, researcher at Lund University.The researchers found that when the birds become ill in mid-winter, their energy consumption drops compared to when they are healthy. However, when the birds become ill in late spring, their energy consumption increases instead."A weaker immune system is probably a part of all the adaptations that Arctic animals use to save energy in winter. The risk of being infected by various diseases so far north is less in winter than when it becomes warmer towards summer," says Andreas Nord.When Svalbard rock ptarmigan save energy in this manner, they do so by weakening an already weak immune system. According to the researchers, this is probably due to the fact that the species evolved in the Arctic where there has been less of a need for a very strong immune defence system."This may have negative consequences when the climate changes and migratory birds arrive earlier in the Arctic and leave later. More and more tourists also come ashore in places where people have not set foot before. Such a scenario paves the way for an increased risk of disease and may be a threat to animals that have evolved in the Arctic where a strong immune defence system might not have been needed," Andreas Nord concludes.
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April 27, 2020
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https://www.sciencedaily.com/releases/2020/04/200427140510.htm
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Three years of monitoring of Oregon's gray whales shows changes in health
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Three years of "health check-ups" on Oregon's summer resident gray whales shows a compelling relationship between whales' overall body condition and changing ocean conditions that likely limited availability of prey for the mammals, a new study from Oregon State University indicates.
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Researchers from the Geospatial Ecology of Marine Megafauna Laboratory at OSU's Marine Mammal Institute used drones to monitor 171 whales off the Oregon Coast during the foraging season between June and October in 2016, 2017 and 2018.They found that the whales' health declined following a period of relatively poor upwelling -- an ocean condition that brings colder, nutrient-rich water closer to the surface -- compared to previous years."What we see is this compelling relationship between the oceanographic processes that control the quality and quantity of available prey and whale health," said Leigh Torres, an assistant professor with the Marine Mammal Institute and the lab's director. "This research gives us an inclination that changes in ocean conditions might be causing skinny whales."The findings may also provide insight into the unusual gray whale die-off event that occurred in 2019 along the Pacific Coast, Torres said. More than 200 gray whales were reported dead between Mexico and Alaska last year, including six in Oregon. Many of the deceased whales appeared to be in poor body condition, meaning they looked skinny.The study was just published 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. The Pacific Coast Feeding Group, as Oregon's gray whales are known, spend the summer months feeding in coastal waters of Oregon, as well as northern California, Washington and southern Canada.Torres and her team conduct "health check-ups" on the whales using drones to capture images and nets to capture fecal samples -- two methods that provide researchers a lot of information in a noninvasive way, reducing stress on the whales.Lemos used images captured by the drones to calculate the whales' Body Area Index. The BAI is similar to the Body Mass Index, or BMI, in humans, because both allow for comparisons among individuals despite differences in length and height.The Body Area Index is a measurement that allows researchers to compare changes in individual whales as well as the population as a whole during the course of the feeding season and from year to year. The fecal samples help researchers determine a whale's hormones, sex and diet.Gray whales typically arrive on the foraging grounds on the skinny side, then in ideal conditions will bulk up over the course of the summer in preparation for migration and breeding."With this research, we're trying to understand more about the health of the whales and how it varies throughout the foraging season and from year to year," Torres said. "Once we establish a baseline for whale body condition, we can start to see what is healthy and what is not and why."The researchers often encounter the same whales multiple times in a season, or from one year to another, and have gotten to know their markings and features well enough to spot the whales by the names they've been assigned, such as Spray, Knife and Clouds."The first year the whales looked really fat and healthy. But after 2016, the whales were really skinny. You could see their skeletons," Lemos said. "For these whales, body condition is strongly related to food availability. It is also related to when they invest in reproduction."The researchers noted nine pairs of mothers and calves in 2016, but only one pair each in the two following years. Calves had the highest Body Area Index numbers, followed by pregnant females. Lactating females had the lowest BAI and the most depleted body condition.Overall, the whales' body condition deteriorated after poor upwelling conditions between 2016 and mid-2018. In 2016, the whales' mean BAI was 40.82, while in 2017 it was 38.67; 2018 was similar to 2017, at 38.62.The poor upwelling may have caused a shift in the availability or quality of zooplankton, the whales' primary prey. But the impact of the changing food supply really became noticeable a year after the poor upwelling condition began."There was a one-year lag, or carry-over, between the lack of prey in 2016 and the whales' body condition the next year," Torres said.One of the whales that died during the 2019 event had been observed and catalogued in previous years by Oregon State researchers.The study highlights the value of monitoring whale health over time, Torres said. The researchers now have four years of data on Oregon's resident whales and hope to continue monitoring them to better understand health patterns in the population and how they connect to changing ocean conditions.
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Animals
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April 27, 2020
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https://www.sciencedaily.com/releases/2020/04/200427125113.htm
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Disappearance of animal species takes mental, cultural and material toll on humans
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For thousands of years, indigenous hunting societies have subsisted on specific animals for their survival. How have these hunter-gatherers been affected when these animals migrate or go extinct?
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To answer this and other questions, Tel Aviv University (TAU) researchers conducted a broad survey of several hunter-gatherer societies across history in a retrospective study published on January 30 in "There has been much discussion of the impact of people on the disappearance of animal species, mostly through hunting," explains Halfon. "But we flipped the issue to discover how the disappearance of animals -- either through extinction or migration -- has affected people."The research reveals that these societies expressed a deep emotional and psychological connection with the animal species they hunted, especially after their disappearance. The study will help anthropologists and others understand the profound environmental changes taking place in our own lifetimes.Halfon and Prof. Barkai conducted a survey of different historical periods and geographical locations, focusing on hunter-gatherer societies that hunted animals as the basis for their subsistence. They also investigated situations in which these animals became extinct or moved to more hospitable regions as a result of climate change."We found that humans reacted to the loss of the animal they hunted -- a significant partner in deep, varied and fundamental ways," Halfon says.The new research explores hunter-gatherer societies throughout human history, from those dating back hundreds of thousands of years to modern-day societies that still function much the way prehistoric groups did. Ten case studies illustrate the deep connection -- existential, physical, spiritual and emotional -- between humans and animals they hunted."Many hunter-gatherer populations were based on one type of animal that provided many necessities such as food, clothing, tools and fuel," Prof. Barkai says. "For example, until 400,000 years ago prehistoric humans in Israel hunted elephants. Up to 40,000 years ago, residents of Northern Siberia hunted the woolly mammoth. When these animals disappeared from those areas, this had major ramifications for humans, who needed to respond and adapt to a new situation. Some had to completely change their way of life to survive."According to the study, human groups adapted in different ways. Siberian residents seeking sustenance after the disappearance of mammoths migrated east and became the first settlers of Alaska and northern Canada. Cave dwellers in central Israel's Qesem Cave (excavated by Prof. Barkai) hunted fallow deer, far smaller than elephants, which required agility and social connections instead of robust physical strength. This necessitated far-reaching changes in their material and social culture and, subsequently, physical structure.Halfon stresses the emotional reaction to an animal group's disappearance. "Humans felt deeply connected to the animals they hunted, considering them partners in nature, and appreciating them for the livelihood and sustenance they provided," he says. "We believe they never forgot these animals -- even long after they disappeared from the landscape."An intriguing example of this kind of memory can be found in engravings from the Late Paleolithic period in Europe, which feature animals like mammoths and seals. Studies show that most of these depictions were created long after these two animals disappeared from the vicinity."These depictions reflect a simple human emotion we all know very well: longing," says Halfon. "Early humans remembered the animals that disappeared and perpetuated them, just like a poet who writes a song about his beloved who left him."According to Prof. Barkai, another emotional response was a sense of responsibility -- even guilt. "Indigenous hunter-gatherer societies have been very careful to maintain clear rules about hunting. As a result, when an animal disappears, they ask: 'Did we behave properly? Is it angry and punishing us? What can we do to convince it to come back?'" he concludes. "Such a reaction has been exhibited by modern-day hunter-gatherer societies as well."
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Animals
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April 27, 2020
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https://www.sciencedaily.com/releases/2020/04/200427100459.htm
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Stress in parents of children with autism: Pets may help
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While current events have increased stress for all families, parents of children with autism report higher levels of stress on average than parents of typically developing kids. Feeling overwhelmed and overburdened by various responsibilities, some parents turn to pets as a source of comfort and support.
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Now, research from the University of Missouri has found that pets lead to strong bonds and reduced stress for both children with autism and their parents.Gretchen Carlisle, a research scientist with the Research Center for Human-Animal Interaction in the MU College of Veterinary Medicine, surveyed more than 700 families from the Interactive Autism Network on the benefits and burdens of having a dog or cat in the family. She found that despite the responsibility of pet care, both children with autism and their parents reported strong bonds with their pets. Pet ownership was not related to parent stress, and parents with multiple pets reported more benefits."Given that the characteristics of autism spectrum disorder are so broad, it can be difficult to identify interventions that are widely beneficial," Carlisle said. "Some of the core challenges that children with autism face include anxiety and difficulty communicating. As pets can help increase social interaction and decrease anxiety, we found that they are not only helpful in providing comfort and support to children with autism, but to their parents as well."For parents considering adding a pet into their family, Carlisle recommends including the child in the decision and making sure the pet's activity level is a good match with the child's."Some kids with autism have specific sensitivities, so a big, loud dog that is highly active might cause sensory overload for a particular child, while a quiet cat may be a better fit," Carlisle said. "My goal is to provide parents with evidence-based information so they can make informed choices for their families."
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Animals
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April 24, 2020
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https://www.sciencedaily.com/releases/2020/04/200424132617.htm
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Palaeontologists reveal 'the most dangerous place in the history of planet Earth'
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100 million years ago, ferocious predators, including flying reptiles and crocodile-like hunters, made the Sahara the most dangerous place on Earth.
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This is according to an international team of scientists, who have published the biggest review in almost 100 years of fossil vertebrates from an area of Cretaceous rock formations in south-eastern Morocco, known as the Kem Kem Group.The review, published in the journal ZooKeys, "provides a window into Africa's Age of Dinosaurs" according to lead author Dr Nizar Ibrahim, an Assistant Professor of Biology at the University of Detroit Mercy and Visiting Researcher from the University of Portsmouth.About 100 million years ago, the area was home to a vast river system, filled with many different species of aquatic and terrestrial animals. Fossils from the Kem Kem Group include three of the largest predatory dinosaurs ever known, including the sabre-toothed Carcharodontosaurus (over 8m in length with enormous jaws and long, serrated teeth up to eight inches long) and Deltadromeus (around 8m in length, a member of the raptor family with long, unusually slender hind limbs for its size), as well as several predatory flying reptiles (pterosaurs) and crocodile-like hunters. Dr Ibrahim said: "This was arguably the most dangerous place in the history of planet Earth, a place where a human time-traveller would not last very long."Many of the predators were relying on an abundant supply of fish, according to co-author Professor David Martill from the University of Portsmouth. He said: "This place was filled with absolutely enormous fish, including giant coelacanths and lungfish. The coelacanth, for example, is probably four or even five times large than today's coelacanth. There is an enormous freshwater saw shark called Onchopristis with the most fearsome of rostral teeth, they are like barbed daggers, but beautifully shiny."Researchers from the Universities of Detroit, Chicago, Montana, Portsmouth (UK), Leicester (UK, David Unwin), Casablanca (Morocco), and McGill (Canada), as well as the Paris Museum of Natural History, have produced the first detailed and fully illustrated account of the fossil-rich escarpment, previously known as the "Kem Kem beds." The researchers now define this sedimentary package as the Kem Kem Group, which consists of two distinct formations, the Gara Sbaa Formation and the Douira Formation.To assemble the huge datasets and fossil images, which were originally included in his PhD thesis, Dr Ibrahim visited Kem Kem collections on several continents.Shedding light on Africa's ancient past is important says Professor Martill, "This is the most comprehensive piece of work on fossil vertebrates from the Sahara in almost a century, since the famous German palaeontologist Ernst Freiherr Stromer von Reichenbach published his last major work in 1936."
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Animals
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April 23, 2020
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https://www.sciencedaily.com/releases/2020/04/200423174038.htm
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Hummingbirds show up when tropical trees fall down
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When the tree fell that October in 2015, the tropical giant didn't go down alone. Hundreds of neighboring trees went with it, opening a massive 2.5-acre gap in the Panamanian rainforest.
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Treefalls happen all the time, but this one just happened to occur in the exact spot where a decades-long ecological study was in progress, giving University of Illinois researchers a rare look into tropical forest dynamics."I've been walking around that tree for 30 years now. It was just humongous," says Jeff Brawn, Professor and Stuart L. and Nancy J. Levenick Chair in Sustainability in the Department of Natural Resources and Environmental Sciences at Illinois. "Here we are, running around on this plot for years and all of a sudden I couldn't even find my way around. We just lucked into it."What's lucky is that Brawn and his colleagues had amassed decades of data on the bird community in that exact spot, meaning they had a clear before-and-after view of what a treefall could mean for tropical birds.This particular gap meant hummingbirds. Lots and lots of hummingbirds."After the treefall, we saw a very large spike in the total number of hummingbird species," says Henry Pollock, a postdoctoral scholar working with Brawn and lead author on a study published in the The gap also attracted fruit-eating birds. The researchers documented a doubling of this group compared to pre-treefall numbers, with certain species being more than three times as abundant. Other species, including the thick-billed seed-finch, which typically inhabits grasslands, appeared as if out of thin air."They just swooped in," Brawn says. "It's analogous to a backyard bird feeder. As soon as you put one in, you'll see species you've never seen before."And then, almost as quickly, the birds disappeared.Within one to four years, depending on the species, the birds returned to pre-treefall numbers or were not detected again."What that suggests is these birds are incredibly mobile and opportunistic," Pollock says. "They are probably just cruising around the landscape prospecting for their preferred food sources and habitats. Given the sheer size of this gap, it acted as a sort of magnet, pulling in species from potentially kilometers away. I mean, 16 snowy-bellied hummingbirds and we've never caught one before? It's pretty astounding."Treefalls are a common and necessary occurrence in forests all over the world. As sunshine streams in from above, trees hunkered down in the understory finally get their chance to rise. Basking in the suddenly resource-rich environment, tropical trees and other plants produce nectar-filled flowers and fruit, important food sources for birds and other animals.Previous research has hinted at how important these food sources are for tropical birds, but no one had documented before-and-after differences until now. Instead, researchers typically compared treefall gaps with intact forest areas at a single time point. That approach has its uses, but it can't capture what Brawn and Pollock found: just how quickly the birds arrived on the scene, and how quickly they left."I was just really just astonished at how quickly and how efficiently these birds seem to be able to find and exploit a new source of food," Brawn says.Gaps don't stay open long in the tropics. Understory trees shoot up, elbowing each other out of the way to take the top spot. Soon, there's no evidence a gap -- or its riotous array of feathered occupants -- was there at all.As short-lived as they may be, treefall gaps represent critical opportunities for species turnover, especially in the tropics where forest fires are comparatively rare."This kind of periodic disturbance is probably necessary for these birds to persist in the landscape matrix," Pollock says. "That's true for many organisms and ecosystems; our study provides evidence to back that up in these birds."
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Animals
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April 23, 2020
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https://www.sciencedaily.com/releases/2020/04/200423130436.htm
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Conservation research on lynx
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Another piece of the puzzle about the longevity of the corpus luteum in lynxes has been uncovered. Scientists at the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) and the Leibniz Institute for Molecular Pharmacology (Leibniz-FMP) discovered that selected anti-oxidative enzymes, especially the enzyme superoxide dismutase (SOD2), may play an important role to maintain the unusual longevity of the corpus luteum in lynxes. It is highly likely that SOD2 not only detoxifies the reactive oxygen radicals in the cells, but also inhibits programmed cell death. The results were recently published in the scientific journal
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In contrast to other felids, Eurasian lynx, Canada lynx and Iberian lynx can only become pregnant once a year within a short period of conception. This restriction in terms of reproductive period is particularly observed in animals that live in strongly seasonal habitats, e.g. in the north with long winters or in southern Europe with hot and dry summers. The restriction ensures that the young are born at the optimal time of year, increasing their chances of survival. For endangered species such as the Iberian lynx this restriction of the reproductive season is a challenge for breeding in human care. In 2004, the Iberian lynx conservation breeding programme was established on the Iberian Peninsula to support the survival of the Iberian lynx. If a female Iberian lynx does not become pregnant or lose their young in the breeding programme, she can only contribute to the breeding programme one year later. It is therefore remarkable that husbandry and breeding success has been improved to such an extent that currently about 40 animals from the breeding programme are being released into the wild every year to support the decimated wild population of only a few hundred animals.In order to understand why lynxes can only become pregnant once a year and how a new cycle is induced, it is necessary to study the mechanism of female reproduction. After the ovulation of egg cells, corpora lutea -- hormone glands -- are formed on the ovaries. They produce the hormone progesterone which prevents a new ovulation, an effect also used in the contraceptive pill. If a corpus luteum regresses at the end of the cycle or after birth, a new cycle can start. As the Leibniz-IZW reproduction team found out in previous studies, the lynx corpora lutea remain present and active for several years, they persist. "We suspect that the longevity of the corpus luteum and their release of progesterone are responsible for the strong seasonality of lynx reproduction," explains Beate Braun, scientist of the Department of Reproduction Biology at Leibniz-IZW.Until now it was unclear how the longevity of the corpus luteum comes about. The scientists have now succeeded in solving part of this mystery. "We could show that anti-oxidative enzymes, especially superoxide dismutase (SOD2), is likely to contribute in a significant way to the regulation of corpus luteum longevity," says Beate Braun. The research team investigated ten anti-oxidative enzymes in fresh and older, at least one year old, corpora lutea of Iberian lynxes (Lynx pardinus) and Eurasian lynxes (Lynx lynx). The scientists recorded for different stages of the corpus luteum which enzyme was being produced, present and active. "The expression profiles of SOD2 showed remarkable differences between older corpora lutea of lynxes, fresh lynx corpora lutea and the corpora lutea of the domestic cat," explains Braun. SOD2 was conspicuous in the older lynx corpus luteum with very high expression and enzyme activity, whereas it played a subordinate role in the domestic cat in all corpus luteum stages. "We suspect that SOD2 in the older, long-lived/persistent, lynx corpora lutea has a classic anti-oxidative effect by transforming poisonous reactive oxygen radicals," says Katarina Jewgenow, head of the Department of Reproductive Biology. "During that process, SOD2 produces hydrogen peroxide, which is then broken down and converted into water by other enzymes. In addition, the hydrogen peroxide can function as a signaling molecule that protects the corpus luteum from programmed cell death and thus ensures its survival for several years," adds Jewgenow.These new findings contribute to a better understanding of lynx reproduction and provide an important basis for further investigations into the regulation of corpus luteum development and longevity. The aim is to elucidate the complex mechanisms of female reproduction in lynxes step by step and provide lasting support for the conservation breeding of lynxes in human care through the use of assisted reproduction techniques such as ovulation induction and artificial insemination.
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Animals
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April 23, 2020
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https://www.sciencedaily.com/releases/2020/04/200423130432.htm
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Following the insect meltdown, numbers of orb web spiders have drastically declined
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The abundance of large orb web spiders in the Swiss midland has declined drastically over the last 40 years. The main reason for this is the shrinking food supply available to these insectivorous animals. This is demonstrated in a study conducted by researchers from the University of Basel and Ghent University (Belgium), as reported in the scientific journal
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The approximately 48,400 known spider species around the world are among the most important insectivorous animals on earth. One group of these, the orb web spiders, spin conspicuous wheel-shaped webs. The perhaps best known and so far very common orb web spider species in Europe is the European garden spider Araneus diadematus. Apart from house gardens, their preferred habitats include parks, graveyards, hedgerows, forest edges and clearings.The European garden spider is easily recognizable by the bright, cross-shaped mark on the upper side of its abdomen. The females of this spider species which measures 10 to 18 mm as adults, legs not included, spins webs with a diameter of about 30 cm. In late summer 2019, the entomologists determined the population density of the European garden spider in the Swiss midland in 20 representative habitats: they counted the spider webs in test plots ranging from 200 to 1,000 square meters and converted these values to the number of webs per square meter.The results: in comparison with data from the 1970s and 1980s, the abundance of this spider has decreased alarmingly. The average population density in Switzerland, for example, is 140 times lower than the previous European average value. In two thirds of the sample plots inspected, no spider webs were found at all. The webs contained significantly fewer insects than in previous studies. Furthermore, the web threads were found to be considerably thinner, as is the case when spiders are malnourished.Most species of orb web spiders feed almost exclusively on small flying insects, such as flies, midges, and aphids, which are most affected by insect declines. That the population density of the European garden spider dropped to a very low level in more recent times, has also been shown in a study conducted in Northern Belgium. Not only the European garden spider -- which still exists almost everywhere in the Swiss midland -- but also other web-spinning spider species are now found less frequently than in the last century. "The results of our study are a strong indication for an insect meltdown in large parts of Europe," says lead author Dr. Martin Nyffeler from the University of Basel. The study furthermore suggests that those animals that feed on insects are affected by it, too: "If the abundance of insects and their natural enemies is decreasing drastically, ecosystems become impoverished and may eventually collapse."
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Animals
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April 23, 2020
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https://www.sciencedaily.com/releases/2020/04/200423130402.htm
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North Atlantic right whales are in much poorer condition than Southern right whales
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New research by an international team of scientists reveals that endangered North Atlantic right whales are in much poorer body condition than their counterparts in the southern hemisphere.
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This alarming research, led by Dr. Fredrik Christiansen from Aarhus University in Denmark, was published this week in the journal The analyses revealed that individual North Atlantic right whales -- juveniles, adults and mothers -- were all in poorer body condition than individual whales from the three populations of Southern right whales. This is alarming, since poor body condition for North Atlantic right whales helps explain why too many of them are dying and why they are not giving birth to enough calves. It could also be affecting their growth and delaying juveniles reaching sexual maturity. These combined impacts on individuals help explain why the species is in decline.Since the cessation of large-scale commercial whaling in the last century, most populations of southern right whales have recovered well. Now there are about 10,000-15,000 southern right whales. Unfortunately, the same cannot be said for the North Atlantic right whales, found today mostly off the east coast of North America. There are now around 410 individuals left, and the species is heading to extinction. Lethal vessel strikes and entanglement in fishing gear continue to kill these whales. Individual North Atlantic right whales also have to cope with the energetic expense and other costs that are caused by frequent entanglements in fishing gear, in particular lobster and crab pots. These burdens, along with a change in the abundance and distribution of the rice-sized plankton that they eat, have left these whales thin and unhealthy, which makes them less likely to have a calf. This, in turn, contributes to the current overall decline of the species. To quantify "thin and unhealthy," Dr. Christiansen and his colleagues investigated the body condition of individual North Atlantic right whales and compared their condition with individuals from three increasing populations of Southern right whales: off Argentina, Australia and New Zealand."Good body condition and abundant fat reserves are crucial for the reproduction of large whales, including right whales, as the animals rely on these energy stores during the breeding season when they are mostly fasting," said Dr. Christiansen. Stored fat reserves are particularly important for mothers, who need the extra energy to support the growth of their newly born calf while they are nursing.The study is the largest assessment of the body condition of baleen whales in the world. The international research team used drones and a method called aerial photogrammetry to measure the body length and width of individual right whales in these four regions around the world. From aerial photographs, the researchers estimated the body volume of individual whales, which they then used to derive an index of body condition or relative fatness."This started out as a conversation between a few of us over dinner at a conference in 2015. Now that the results are out, they're quite shocking," said Peter Corkeron of the Anderson Cabot Center for Ocean Life at the New England Aquarium. "We know that North Atlantic right whales as a species are doing poorly, but this work brings home that as individuals, they're also doing poorly. Their decline has been so rapid that we know it's not simply because not enough calves are being born -- too many whales are also dying from human-caused injuries. But this study also shows that their decline isn't solely due to these deaths. Their problems are more insidious, and we need to find a way to ensure that the health of all individual whales improves.""For North Atlantic right whales as individuals, and as a species, things are going terribly wrong. This comparison with their southern hemisphere relatives shows that most individual North Atlantic right whales are in much worse condition than they should be," said Michael Moore from the Woods Hole Oceanographic Institution. "As a veterinarian, I've long been concerned about how entanglements affect the welfare of these whales. Now we are starting to draw the linkages from welfare to this species' decline. Sub-lethal entanglement trauma, along with changing food supplies is making them too skinny to reproduce well, and lethal entanglement and vessel trauma are killing them. To reverse these changes, we must: redirect vessels away from, and reduce their speed in, right whale habitat; retrieve crab and lobster traps without rope in the water column using available technologies; and minimize ocean noise from its many sources."This work was supported by funding from NOAA, US Office of Naval Research Marine Mammals Program, World Wildlife Fund for Nature Australia, Murdoch University School of Veterinary and Life Sciences, New Zealand Antarctic Research institute, Otago University and New Zealand Whale and Dolphin Trust and Argentina National Geographic Society.For 40 years, the New England Aquarium's right whale team has extensively researched and tracked individual right whales and curates the North Atlantic Right Whale Catalog. The scientific team monitors the whales' arrival at breeding and feeding grounds, registering new calves, death rates, and also measuring changes in stress and reproductive hormones.The Woods Hole Oceanographic Institution is dedicated to advancing knowledge of the ocean and its connection with the Earth system through a sustained commitment to excellence in science, engineering and education, and to the application of this knowledge to problems facing society.
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Animals
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April 23, 2020
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https://www.sciencedaily.com/releases/2020/04/200423082231.htm
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Coronaviruses and bats have been evolving together for millions of years
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Bats do a lot of good for the world -- they pollinate plants, they eat disease-carrying insects, and they help disperse seeds that help with the regeneration of tropical forest trees. Bats and a range of other mammal groups are also natural carriers of coronaviruses. To better understand this very diverse family of viruses, which includes the specific coronavirus behind COVID-19, scientists compared the different kinds of coronaviruses living in 36 bat species from the western Indian Ocean and nearby areas of Africa. They found that different groups of bats at the genus and in some cases family level had their own unique strains of coronavirus, revealing that bats and coronaviruses have been evolving together for millions of years.
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"We found that there's a deep evolutionary history between bats and coronaviruses," says Steve Goodman, MacArthur Field Biologist at Chicago's Field Museum and an author of a paper just released in A lot of people use "coronavirus" as a synonym for "COVID-19," the kind of coronavirus causing the current pandemic. However, there are a vast number of types of different coronaviruses, potentially as many as bat species, and most of them are unknown to be transferred to humans and pose no known threat. The coronaviruses carried by the bats studied in this paper are different from the one behind COVID-19, but by learning about coronaviruses in bats in general, we can better understand the virus affecting us today.All animals have viruses that live inside them, and bats, as well as a range of other mammal groups, happen to be natural carriers of coronaviruses. These coronaviruses don't appear to be harmful to the bats, but there's potential for them to be dangerous to other animals if the viruses have opportunities to jump between species. This study examines the genetic relationships between different strains of coronaviruses and the animals they live in, which sets the stage for a better understanding of the transfer of viruses from animals to humans.Goodman, who has been based on Madagascar for several decades, and his colleagues took swab and some cases blood samples from more than a thousand bats representing 36 species found on islands in the western Indian Ocean and coastal areas of the African nation of Mozambique. Eight percent of the bats they sampled were carrying a coronavirus."This is a very rough estimate of the proportion of infected bats. There is increasing evidence for seasonal variation in the circulation of these viruses in bats, suggesting that this number may significantly vary according to the time of the year," says Camille Lebarbenchon, Disease Ecologist at the Université de La Réunion.The researchers ran genetic analyses of the coronaviruses present in these bats. By comparing the coronaviruses isolated and sequenced in the context of this study with ones from other animals including dolphins, alpacas, and humans, they were able to build a giant coronavirus family tree. This family tree shows how the different kinds of coronavirus are related to each other."We found that for the most part, each of the different genera of families of bats for which coronavirus sequences were available had their own strains," says Goodman. "Moreover, based on the evolutionary history of the different bat groups, it is clear that there is a deep coexistence between bats (at the level of genus and family) and their associated coronaviruses." For example, fruit bats of the family Pteropodidae from different continents and islands formed a cluster in their tree and were genetically different than the coronavirus strains of other groups of bats found in the same geographical zones.The team found that in rare cases, bats of different families, genera, and species that live in the same caves and have closely spaced day roost sites shared the same strain of coronavirus. But in this study, the transmission between species is the exception, not the rule. "It is quite reassuring that the transmission of coronavirus in the region between two bat species seems to be very rare given the high diversity of bat coronaviruses. Next, we need to understand environmental, biological, and molecular factors leading to these rare shifts" says Léa Joffrin, a disease ecologist who worked on bat coronavirus during her PhD at the Université de La Réunion.Learning how different strains of coronavirus evolved could be key for preventing future coronavirus outbreaks. "Before you can actually figure out programs for public health and try to deal with the possible shift of certain diseases to humans, or from humans to animals, you have to know what's out there. This is kind of the blueprint," says Goodman.Co-author Patrick Mavingui, microbial ecologist and head of the PIMIT Laboratory adds, "The development of serological methods targeting coronavirus strains circulating in the Indian Ocean will help show whether there have already been discrete passages in human populations, and their interaction with the hosts will allow a better understanding of the emergence risk."The study also highlights the importance of museum collections, says Goodman. The researchers used, in part, bat specimens housed in the Field Museum, to confirm the identities of the animals employed in this study. These voucher specimens helped them confidently say which bats and from which geographical regions hosted the different strains of coronaviruses. The research also drew from genetic databases like GenBank. "This information is important for public health, and the point of departure is closely linked to museum specimens," says Goodman. "We're able to use museum material to study the evolution of a group of viruses and its potential applications across wildlife in the world."Goodman also notes that despite the fact that bats carry coronaviruses, we shouldn't respond by harming or culling of bats in the name of public health. "There's abundant evidence that bats are important for ecosystem functioning, whether it be for the pollination of flowers, dispersal of fruits, or the consumption of insects, particularly insects that are responsible for transmission of different diseases to humans," he says. "The good they do for us outweighs any potential negatives."This study was contributed to by researchers from the PIMIT laboratory (Université de La Réunion/INSERM/CNRS/IRD), Association Vahatra, the Field Museum, Eduardo Mondlane University, University of Kwa-Zulu Natal, the National Parks and Conservation Service of Mauritius, the Seychelles Ministry of Health, and Instituto Nacional de Saúde.
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Animals
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April 22, 2020
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https://www.sciencedaily.com/releases/2020/04/200422151118.htm
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More protections needed to safeguard biodiversity in the Southern Ocean
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Current marine protected areas in the Southern Ocean need to be at least doubled to adequately safeguard the biodiversity of the Antarctic, according to a new CU Boulder study published today, Earth Day, in the journal
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Proposals under consideration by an international council this year would significantly improve the variety of habitats protected, sustain fish populations and enhance the region's resilience to the effects of climate change, the authors say."Compared to the rest of the world's oceans, we have some of the healthiest marine systems left in the world in Antarctica," said Cassandra Brooks, author of the new paper and assistant professor in the Environmental Studies Program. "But there are vast areas of the Southern Ocean that are left completely unprotected."Many international targets suggest that 10 to 30 percent of the world's combined oceans should be protected. The Southern Ocean, which surrounds Antarctica, comprises about 10 percent of the world's oceans, and its protection can play a large role in accomplishing this goal.At present, almost 12 percent of the Southern Ocean is designated as part of marine protected areas, or MPAs. MPAs -- especially "no-take" MPAs, or marine reserves which do not allow any fishing -- have been shown to support the abundance and diversity of species."But percentages aren't enough," said Brooks. "You want protected areas to be representative of all the different life that's in the Southern Ocean."The Antarctic region is home to as many as 10,000 species -- including whales, seals, penguins, fish, corals and giant Antarctic sea spiders -- many of which are found nowhere else in the world. And as far as scientists know, none of them have yet gone extinct from climate change or other human actions.If additional marine protected areas currently under negotiation by the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) are implemented, they would encompass almost 22 percent of the Southern Ocean and achieve at least 10 percent representation of its over 40 unique habitats."As marine scientists, it's important we have places left that we can actually study as healthy systems that are undergoing climate stress," said Brooks.But the Southern Ocean supports international commercial fisheries for Patagonian and Antarctic toothfish, sold as Chilean sea bass, as well as krill, which is farmed for fish meal and omega-3 fatty acid pills. Less than 5 percent of the Southern Ocean's protection bans fishing.Pressure on these fisheries has increased in recent years and is likely to continue, due to the popularity of omega-3 pills and demand for fish meal -- which is fed to pigs, chickens, and other farmed fish. At the same time, climate change pressures on Southern Ocean ecosystems are also increasing.To help boost the resilience of these ecosystems, "we really need large areas that are off limits to extraction," said Brooks. "Antarctica is a global commons that belongs to all of us."The importance of the Antarctic cannot be understated. The Southern Ocean stores 90 percent of the world's freshwater, drives global ocean circulation and regulates our entire climate."At its most basic level, all Earth's systems depend on the Southern Ocean," said Brooks. "And Antarctica is one of the fastest changing places in the whole world due to climate change. It is impacting the entire ecosystem in ways that we really don't understand yet."Populations of phytoplankton communities and krill -- at the bottom of the food chain -- to penguins and toothfish -- at the very top -- are changing. The whole system is in flux.Most of these animals cannot migrate or relocate. They're already as far south as they can go.Building on work from previous studies, Brooks and her co-authors wanted to know: Are we protecting the right areas that actually will conserve biodiversity?So they looked at the variety of Antarctic ocean habitats, from the seafloor to the open water, and examined what percentage of them rest within existing and proposed protected areas and which ones do not.They found that for protections to be fully representative of the biodiversity in the Southern Ocean, and better protect many ocean birds and mammals, they would need to be increased even more than protections currently proposed by CCAMLR. This international treaty group of 26 member states is next scheduled to meet in October of 2020.Adopting these protections would be an important milestone in the right direction, said Brooks.
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Animals
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April 22, 2020
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https://www.sciencedaily.com/releases/2020/04/200422112305.htm
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Spider combs tame unruly nanofibers
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Cribellate spiders spin thousands of tiny nanofibers into sticky threads. To keep from getting caught in their own webs, these spiders use a nonstick comb on their back legs. Now, researchers reporting in
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Unlike most spiders, which produce silk coated in a sticky glue, cribellate spiders' threads resemble a bristly wool that embeds into the bodies of their prey. During web-making, the spider's comb, or calamistrum, grabs onto the nanofibers emerging from its abdomen and assembles them into threads. Anna-Christin Joel and colleagues wondered why the sticky nanofibers don't cling to the spider's comb. They figured that the answer could reveal new strategies for handling synthetic nanomaterials and nanofibers, which can be tacky.The researchers began by shaving off the calamistrum from a group of "lace weaver" spiders. In contrast to normal spiders, those lacking combs showed a buildup of nanofibers where the comb should have been. The team also observed that in normal spiders, the surface of the comb was covered with fingerprint-like nanoripples. They found that this structure prevents nanofibers from closely contacting the surface of the spider's leg in the region of the comb, reducing adhesive van der Waals forces. To make an artificial nonstick surface inspired by the spiders' combs, the researchers used lasers to pattern similar nanostructures onto poly(ethylene terephthalate) (PET) foils and then coated the foils with gold. When tested for antiadhesive properties against spider silk, the artificial comb performed almost as well as the natural version.
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Animals
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