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July 31, 2020
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https://www.sciencedaily.com/releases/2020/07/200731152732.htm
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To distinguish contexts, animals think probabilistically, study suggests
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Among the many things rodents have taught neuroscientists is that in a region called the hippocampus, the brain creates a new map for every unique spatial context -- for instance, a different room or maze. But scientists have so far struggled to learn how animals decides when a context is novel enough to merit creating, or at least revising, these mental maps. In a study in
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The approach offers scientists a new way to interpret many experiments that depend on measuring remapping to investigate learning and memory. Remapping is integral to that pursuit, because animals (and people) associate learning closely with context, and hippocampal maps indicate which context an animal believes itself to be in."People have previously asked 'What changes in the environment cause the hippocampus to create a new map?' but there haven't been any clear answers," said lead author Honi Sanders. "It depends on all sorts of factors, which means that how the animals define context has been shrouded in mystery."Sanders is a postdoc in the lab of co-author Matthew Wilson, Sherman Fairchild Professor in The Picower Institute for Learning and Memory and the departments of Biology and Brain and Cognitive Sciences at MIT. He is also a member of the Center for Brains, Minds and Machines. The pair collaborated with Samuel Gershman, a professor of psychology at Harvard on the study.Fundamentally a problem with remapping that has frequently led labs to report conflicting, confusing, or surprising results, is that scientists cannot simply assure their rats that they have moved from experimental Context A to Context B, or that they are still in Context A, even if some ambient condition, like temperature or odor, has inadvertently changed. It is up to the rat to explore and infer that conditions like the maze shape, or smell, or lighting, or the position of obstacles, and rewards, or the task they must perform, have or have not changed enough to trigger a full or partial remapping.So rather than trying to understand remapping measurements based on what the experimental design is supposed to induce, Sanders, Wilson and Gershman argue that scientists should predict remapping by mathematically accounting for the rat's reasoning using Bayesian statistics, which quantify the process of starting with an uncertain assumption and then updating it as new information emerges."You never experience exactly the same situation twice. The second time is always slightly different," Sanders said. "You need to answer the question: 'Is this difference just the result of normal variation in this context or is this difference actually a different context?' The first time you experience the difference you can't be sure, but after you've experienced the context many times and get a sense of what variation is normal and what variation is not, you can pick up immediately when something is out of line."The trio call their approach "hidden state inference" because to the animal, the possible change of context is a hidden state that must be inferred.In the study the authors describe several cases in which hidden state inference can help explain the remapping, or the lack of it, observed in prior studies.For instance, in many studies it's been difficult to predict how changing some of cues that a rodent navigates by in a maze (e.g. a light or a buzzer) will influence whether it makes a completely new map or partially remaps the current one and by how much. Mostly the data has showed there isn't an obvious "one-to-one" relationship of cue change and remapping. But the new model predicts how as more cues change, a rodent can transition from becoming uncertain about whether an environment is novel (and therefore partially remapping) to becoming sure enough of that to fully remap.In another, the model offers a new prediction to resolve a remapping ambiguity that has arisen when scientists have incrementally "morphed" the shape of rodent enclosures. Multiple labs, for instance, found different results when they familiarized rats with square and round environments and then tried to measure how and whether they remap when placed in intermediate shapes, such as an octagon. Some labs saw complete remapping while others observed only partial remapping. The new model predicts how that could be true: rats exposed to the intermediate environment after longer training would be more likely to fully remap than those exposed to the intermediate shape earlier in training, because with more experience they would be more sure of their original environments and therefore more certain that the intermediate one was a real change.The math of the model even includes a variable that can account for differences between individual animals. Sanders is looking at whether rethinking old results in this way could allow researchers to understand why different rodents respond so variably to similar experiments.Ultimately, Sanders said, he hopes the study will help fellow remapping researchers adopt a new way of thinking about surprising results -- by considering the challenge their experiments pose to their subjects."Animals are not given direct access to context identities, but have to infer them," he said. "Probabilistic approaches capture the way that uncertainty plays a role when inference occurs. If we correctly characterize the problem the animal is facing, we can make sense of differing results in different situations because the differences should stem from a common cause: the way that hidden state inference works."The National Science Foundation funded the research.
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July 30, 2020
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https://www.sciencedaily.com/releases/2020/07/200730110124.htm
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Remote islands: Stepping stones to understanding evolution
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For millions of years, remote islands have been hotbeds of biodiversity, where unique species have flourished. Scientists have proposed different theories to explain how animals and plants colonize and evolve on islands but testing ideas for processes happening over long time scales has always been a challenge.
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Recently, cutting-edge techniques in DNA sequencing, 3D imaging, and computation have opened up opportunities for investigating historical processes. In a new study published in Evolution, researchers from the Okinawa Institute of Science and Technology Graduate University (OIST) and collaborators from the University of the Ryukyus investigated evolutionary and ecological changes in ants in the South Pacific archipelago of Fiji to examine a controversial theory for how evolution occurs on islands."Islands like Fiji, which are small and remote, act as perfect natural laboratories to study the interplay between ecological and evolutionary processes," said Dr. Cong Liu, first author and former PhD student from the OIST Biodiversity and Biocomplexity Unit. "But until recently, there haven't been many studies on ants."The team focused on The researchers set out to examine how well the changes in appearance and distribution observed in trap-jaw ants over time fit with a theory called the taxon cycle hypothesis, which describes how species colonize and evolve on islands. According to this theory, species pass through a predictable "life cycle" of colonization, geographic range expansion, decline, and (sometimes) extinction, with this cycle then restarted by a new colonizer.The scientists extracted and sequenced DNA from "We discovered that all 14 of the trap-jaw ant species endemic to Fiji were descended from a single original colonizer, rather than from multiple colonizers," Dr. Liu explained.These results contradict what would be expected by the taxon cycle hypothesis, which predicts that later colonizers arrive and kickstart new taxon cycles of radiation and decline."There are a few reasons why repeated colonizations may not have occurred," said Dr. Liu. He explained that the first trap-jaw colonizers could have diversified and occupied all the niches, closing the door to any newcomers. Or perhaps, he added, the Fijian archipelago is so remote that additional colonizers never arrived.According to the taxon cycle hypothesis, a species first colonizes an island, and then undergoes a huge expansion in range, specializing to the available niches in each habitat.When the scientists looked at the distribution of the 14 trap-jaw species endemic to Fiji, they found that soon after colonization, the initial lineage split in two, with one giving rise to species living in lowland habitats, and one giving rise to species in upland habitats.The scientists then measured key morphological features of the ants to determine whether they established their niches through adaptive radiation. "Adaptive radiation often occurs on islands, with the most iconic example being Darwin's finches," said Dr. Liu. "This sudden explosion in abundance, diversity and appearance is often due to a greater number of empty niches that the ants can adapt to, due to a lack of competitors or predators."The scientists used micro-CT scanners to create 3D models of each Fijian ant species. They also measured the size of the ants' bodies, jaws (mandibles) and eyes."We saw a clear diversification of form that is associated with the niches they are occupying, which was clearly a result of adaptive radiation," said Dr. Liu. In general, the ants in the upland lineage evolved larger bodies, allowing them to catch larger prey. These ants also developed shorter mandibles, defining how they hunt.The taxon cycle hypothesis predicts that over time, as species adapt to increasingly specialized niches, their population size and the range of their habitat declines. These predictions only held true for the Fijian trap-jaw ants in the upland habitats.The team found that the populations of upland species of ants had shrunk in numbers over time and had greater genetic differences between populations, suggesting that they were less able to disperse and breed across the Fijian archipelago.This loss of competitive ability increases the vulnerability of these older, more specialized ants, which are currently threatened by deforestation -- a major environmental issue in Fiji. "Because these endemic species only occupy a small geographical area and only have a limited ability to disperse, deforestation can quickly lead to extinction of these species," said Dr. Liu.The team now plans to apply their approach, which combines population genomics, phylogenetics and morphological studies, to all ant species on Fiji.It's still not clear how closely data from the trap jaw ants aligns with the taxon cycle hypothesis, said Dr. Liu. This study, as well as one published last year that examined the
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Animals
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July 30, 2020
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https://www.sciencedaily.com/releases/2020/07/200730110128.htm
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Whale airway mucus reveals likely poor health during migration
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Whale-watching season is delighting the viewing public along the east Australian coast but while it's a boon for the tourism industry, for the majestic humpback whale it's potentially a time of less optimal health.
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UNSW Sydney researchers collected and analysed samples of whale blow -- similar to mucus from a human nose -- and found "significantly less" microbial diversity and richness on the return leg of the whales' migration, indicating the whales were likely in poorer health than when their journey began.Microbial diversity accounts for the wide array of microorganisms -- the smallest forms of life.Lead author Dr Catharina Vendl, UNSW Science researcher, said the study, published in East Australian humpback whales complete, on average, an arduous 8000-kilometre round trip between Antarctica and Queensland from May to November each year, fasting for most of their journey."The physical strains of the humpback's migration likely affected the microbial communities in the whales' airways -- so, our findings are key to further developing the analysis of airway microbiota as a non-invasive method for monitoring the immune function and overall health of whales and dolphins," Dr Vendl said."People enjoy whale-watching season, but with it comes reports of whales becoming stranded. Although humpback whale stranding events occur naturally and regularly to injured and young whales, it is crucial to monitor the population health of this iconic species to ensure its long-term survival."Humpback whales do not only play an essential role in their marine ecosystem but also represent an important economic resource, because whale watching is a booming industry in many Australian cities and around the world."Humpback whales were almost hunted to extinction. The last whaling station in NSW, at Byron Bay, closed in 1962 because so few whales could be found.Humpback whales are now protected throughout Australia, and in NSW are listed as a vulnerable species under the Dr Vendl, who has a background in veterinary science, said it was amazing the east and west Australian humpback whale populations had recovered well in the years since whaling stopped."So, these whale populations are not endangered, but that doesn't necessarily mean things will stay that way," she said.Dr Vendl said it was important to find a non-invasive method to study whale health, because many whale populations around the world were endangered -- yet scientists still knew fairly little about whales' physiology."Many whale species are at or near the top of their food chain -- so, a whale's general health can be a good indicator of the health of their marine ecosystem," she said."Humpback whales mostly live on tiny creatures called krill, but because there is less of this preferred food along the east Australian coast and it's such a huge effort for them to open their mouths to feed, they rely on energy stored in their blubber."Fasting is therefore a major physiological strain during the whales' migration."Dr Vendl collected airway mucus from 20 whales in Hervey Bay, Queensland, during the humpback's return leg to Antarctica when the whales were several months into their migration in August 2017.The researchers then analysed and compared the whales' blow microbiota to samples Macquarie University scientists collected near Sydney in May and June 2017, for a separate study, when the whales were at the start of their migration.UNSW Science Professor Tracey Rogers pioneered the technique the UNSW researchers used to examine the whales' airway microbial communities, more than a decade ago.Dr Vendl said researchers wanted to determine if there was a significant difference between the microbial communities of the whales at the start of and later on in their migration."I used two methods to collect the whales' blow while working from a boat. For one method, I flew a waterproof drone over the whales which carried a petri dish," she said."It was pure luck waiting for the whales to exhale at the same time the drone was within range for droplets from their blow to settle on the petri dish."My second technique was a 4.6-metre long telescopic pole with petri dishes attached to the end. In Hervey Bay, the whales are curious and approach boats."So, I held the pole out and waited until the whales exhaled and then collected their samples that way."The study found the whales' respiratory microbiota was severely depleted in diversity and richness the longer they fasted during their migration.Dr Vendl said such changes often reflected a compromised state of health in the airways of humans."We concluded the physical strains of the migration, likely in addition to the exposure to marine pollutants, compromise the whales' immune systems and consequently cause a shift in the whales' airway microbiota."Our findings are the first to provide good evidence of a connection between the whales' airway bacterial communities, their physiology and immune function -- something that has been established in humans."Dr Vendl said a high level of bacterial variety and richness in respiratory microbiota was a sign of healthy airways in humans."I researched literature in human medicine: when you have a respiratory disease in a person, it also means the bacterial communities in their airways have changed and are usually depleted," she said."We had no idea if we would find a similar pattern in whales, but we at least showed the initial evidence for that occurring."Dr Vendl said she hoped her research would lead to further study in non-invasive techniques to monitor whale health in populations around the world."Our findings showed the first evidence of a link between whales' respiratory microbiota and their overall health, but more research needs to be done," she said."Analysing whale blow to assess and monitor whale health opens up more possibilities for the use of non-invasive techniques, such as photogrammetry -- where you fly a drone to film and measure whales to determine how much blubber they have and things like that."Other methods were outside the scope of my PhD, but it's important for researchers to experiment with and refine new techniques to assess their effectiveness in helping whale conservation."
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Animals
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July 29, 2020
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https://www.sciencedaily.com/releases/2020/07/200729210509.htm
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Underwater robots reveal daily habits of endangered whales
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Not all humans are morning people. Neither, according to a new study, are all sperm whales -- at least when it comes to foraging for food.
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The research, led by the University of East Anglia (UEA), has revealed the daily habits of the endangered Mediterranean sperm whale. Unmanned underwater gliders equipped with acoustic monitors recorded the sperm whale sounds, or 'clicks', over several months and 1000s of kilometres of ocean.Sperm whales are highly vocal, producing distinct types of clicks for both echolocation and social interaction purposes. The study, published today in the The recordings confirmed the whales' widespread presence in the north-western Mediterranean Sea and identified a possible hotspot for sperm whale habitat in the Gulf of Lion, where a higher rate of clicks was found. This could indicate a higher number of whales, but could also be for behavioural reasons.In addition, continuous day and night monitoring during winter months suggests different foraging strategies between different areas. In the Ligurian Sea, mobile and scattered individual whales forage at all times of day. In the Sea of Sardinia usual clicks were also detected at all times of the day.However, in the Gulf of Lion larger groups target intense oceanographic features in the open ocean, such as fronts and mixing events, with acoustic activity showing a clear 24-hour pattern and decreased foraging effort at dawn. This could suggest they may have modified their usual foraging pattern of eating at any time to adapt to local prey availability. It provides a clue regarding sperm whale diet in this area and may be what makes it attractive to them.There are fewer than 2500 mature individual Mediterranean sperm whales and threats to them include being caught as bycatch in fishing nets and, as recently the case off the Italian coast, entanglement in illegal fishing gear. Other dangers are ship strike and ingestion of marine debris, to disturbance by human-made noise and whale watching activities.The study involved researchers from UEA and the Centre for Environment, Fisheries & Aquaculture Science (CEFAS), the Scottish Association for Marine Science (SAMS), University of Gothenburg and Sorbonne University.Lead author Pierre Cauchy, a postgraduate researcher at UEA's Centre for Ocean and Atmospheric Sciences (COAS) and CEFAS, said their findings would help conservation efforts: "Information on the ecology of the Mediterranean sperm whale subpopulation remains sparse and does not meet the needs of conservation managers and policy makers."Increasing observation efforts, particularly in winter months, will help us better understand habitat use, and identify key seasonal habitats to allow appropriate management of shipping and fishing activities."He added: "The clear daily pattern identified in our results appear to suggest that the sperm whales are adapting their foraging strategy to local prey behaviour. The findings also indicate a geographical pattern to their daily behaviour in the winter season."The whales spend a substantial amount of their time foraging -- when in a foraging cycle, they produce usual clicks 60 per cent of the time. As such, they provide a reliable indicator of sperm whale presence and foraging activity, and their specific features allow them to be identified and detected up to a distance of four to 20 km.The study involved analysing sounds recorded by passive acoustic monitoring (PAM) sensors, previously successfully used for weather observation, on gliders deployed by the team to collect oceanographic data during winter 2012-2013 and June 2014, covering 3200 km.Prof Karen Heywood, also of COAS, said the study demonstrated the possibilities of using existing glider missions to monitor the Mediterranean sperm whale over the winter months, for which there is a lack of crucial data for conservation."Our ability to successfully observe sperm whale distribution in different geographic areas of the north-western Mediterranean Sea, across the slopes and the open ocean, highlighted the complexity of sperm whale behaviour, foraging strategy and habitat use," she said."This study shows that the addition of PAM sensors to existing oceanographic glider missions offers the opportunity for sustained long-term observation, which would significantly improve sperm whale population monitoring and behaviour description, as well as identification of key habitat and potentially harmful interaction with human activities."Co-author Dr Denise Risch, a marine mammal ecologist at SAMS, added: "We need to understand the Mediterranean sperm whale population better in order to work towards their conservation by eliminating threats."This is also true for other marine mammal species globally, and gliders allow us to go into new areas, which we wouldn't have any observations from otherwise, and also at times of year when we are not usually monitoring."'Sperm whale presence observed using passive acoustic monitoring from gliders of opportunity', Pierre Cauchy, Karen J Heywood, Denise Risch, Nathan D Merchant, Bastien Y Queste, Pierre Testor, is published in
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Animals
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July 29, 2020
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https://www.sciencedaily.com/releases/2020/07/200729141410.htm
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Study sheds light on the evolution of the earliest dinosaurs
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The classic dinosaur family tree has two subdivisions of early dinosaurs at its base: the Ornithischians, or bird-hipped dinosaurs, which include the later Triceratops and Stegosaurus; and the Saurischians, or lizard-hipped dinosaurs, such as Brontosaurus and Tyrannosaurus.
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In 2017, however, this classical view of dinosaur evolution was thrown into question with evidence that perhaps the lizard-hipped dinosaurs evolved first -- a finding that dramatically rearranged the first major branches of the dinosaur family tree.Now an MIT geochronologist, along with paleontologists from Argentina and Brazil, has found evidence to support the classical view of dinosaur evolution. The team's findings are published today in the journal The team reanalyzed fossils of Pisanosaurus, a small bipedal dinosaur that is thought to be the earliest preserved Ornithiscian in the fossil record. The researchers determined that the bird-hipped herbivore dates back to 229 million years ago, which is also around the time that the earliest lizard-hipped Saurischians are thought to have appeared.The new timing suggests that Ornithiscians and Saurischians first appeared and diverged from a common ancestor at roughly the same time, giving support to the classical view of dinosaur evolution.The researchers also dated rocks from the Ischigualasto Formation, a layered sedimentary rock unit in Argentina that is known for having preserved an abundance of fossils of the very earliest dinosaurs. Based on these fossils and others across South America, scientists believe that dinosaurs first appeared in the southern continent, which at the time was fused together with the supercontinent of Pangaea. The early dinosaurs are then thought to have diverged and fanned out across the world.However, in the new study, the researchers determined that the period over which the Ischigualasto Formation was deposited overlaps with the timing of another important geological deposit in North America, known as the Chinle Formation.The middle layers of the Chinle Formation in the southwestern U.S. contain fossils of various fauna, including dinosaurs that appear to be more evolved than the earliest dinosaurs. The bottom layers of this formation, however, lack animal fossil evidence of any kind, let alone early dinosaurs. This suggests that conditions within this geological window prevented the preservation of any form of life, including early dinosaurs, if they walked this particular region of the world."If the Chinle and Ischigualasto formations overlap in time, then early dinosaurs may not have first evolved in South America, but may have also been roaming North America around the same time," says Jahandar Ramezani, a research scientist in MIT's Department of Earth, Atmospheric, and Planetary Sciences, who co-authored the study. "Those northern cousins just may not have been preserved."The other researchers on the study are first author Julia Desojo from the National University of La Plata Museum, and a team of paleontologists from institutions across Argentina and Brazil.The earliest dinosaur fossils found in the Ischigualasto Formation are concentrated within what is now a protected provincial park known as "Valley of the Moon" in the San Juan Province. The geological formation also extends beyond the park, albeit with fewer fossils of early dinosaurs. Ramezani and his colleagues instead looked to study one of the accessible outcrops of the same rocks, outside of the park.They focused on Hoyada del Cerro Las Lajas, a less-studied outcrop of the Ischigualasto Formation, in La Rioja Province, which another team of paleontologists explored in the 1960s."Our group got our hands on some of the field notes and excavated fossils from those early paleontologists, and thought we should follow their footsteps to see what we could learn," Desojo says.Over four expeditions between 2013 to 2019, the team collected fossils and rocks from various layers of the Las Lajas outcrop, including more than 100 new fossil specimens, though none of these fossils were of dinosaurs. Nevertheless, they analyzed the fossils and found they were comparable, in both species and relative age, to nondinosaur fossils found in the park region of the same Ischigualasto Formation. They also found out that the Ischigualasto Formation in Las Lajas was significantly thicker and much more complete than the outcrops in the park. This gave them confidence that the geological layers in both locations were deposited during the same critical time interval.Ramezani then analyzed samples of volcanic ash collected from several layers of the Las Lajas outcrops. Volcanic ash contains zircon, a mineral that he separated from the rest of the sediment, and measured for isotopes of uranium and lead, the ratios of which yield the mineral's age.With this high-precision technique, Ramezani dated samples from the top and bottom of the outcrop, and found that the sedimentary layers, and any fossils preserved within them, were deposited between 230 million and 221 million years ago. Since the team determined that the layered rocks in Las Lajas and the park match in both species and relative timing, they could also now determine the exact age of the park's more fossil-rich outcrops.Moreover, this window overlaps significantly with the time interval over which sediments were deposited, thousands of kilometers northward, in the Chinle Formation."For many years, people thought Chinle and Ischigualasto formations didn't overlap, and based on that assumption, they developed a model of diachronous evolution, meaning the earliest dinosaurs appeared in South America first, then spread out to other parts of the world including North America," Ramezani says. "We've now studied both formations extensively, and shown that diachronous evolution isn't really based on sound geology."Decades before Ramezani and his colleagues set out for Las Lajas, other paleontologists had explored the region and unearthed numerous fossils, including remains of Pisanosaurus mertii, a small, light-framed, ground-dwelling herbivore. The fossils are now preserved in an Argentinian museum, and scientists have gone back and forth on whether it is a true dinosaur belonging to the Ornithiscian group, or a " basal dinosauromorph" -- a kind of pre-dinosaur, with features that are almost, but not quite fully, dinosaurian."The dinosaurs we see in the Jurassic and Cretaceous are highly evolved, and ones we can nicely identify, but in the late Triassic, they all looked very much alike, so it's very hard to distinguish them from each other, and from basal dinosauromorphs," Ramezani explains.His collaborator Max Langer from the University of São Paulo in Brazil painstakingly reanalyzed the museum-preserved fossil of Pisanosaurus, and concluded, based on certain key anatomical features, that it is indeed a dinosaur -- and what's more, that it is the earliest preserved Ornithiscian specimen. Based on Ramezani's dating of the outcrop and the interpretation of Pisanosaurus, the researchers concluded that the earliest bird-hipped dinosaurs appeared around 229 million years ago -- around the same time as their lizard-hipped counterparts."We can now say the earliest Ornithiscians first showed up in the fossil record roughly around the same time as the Saurischians, so we shouldn't throw away the conventional family tree," Ramezani says. "There are all these debates about where dinosaurs appeared, how they diversified, what the family tree looked like. A lot of those questions are tied to geochronology, so we need really good, robust age constraints to help answer these questions."This research was mainly funded by the National Council for Scientific and Technical Research (Argentina) and the São Paulo State Research Support Foundation (Brazil). Geochronologic research at the MIT Isotope Lab has been supported in part by the U.S. National Science Foundation.
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July 29, 2020
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https://www.sciencedaily.com/releases/2020/07/200729114822.htm
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Smaller habitats worse than expected for biodiversity
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Biodiversity's ongoing global decline has prompted policies to protect and restore habitats to minimize animal and plant extinctions. However, biodiversity forecasts used to inform these policies are usually based on assumptions of a simple theoretical model describing how the number of species changes with the amount of habitat. A new study published in the journal
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One of the most fundamental theories in biodiversity science describes how the number of species increases as the area of habitat increases; conversely, as habitat is destroyed, species are lost. This theory allows ecologists to predict how many species will go extinct as humans destroy natural habitats, and how many species will be protected when habitats are protected. There is a potential flaw, however, in how the theory is applied to biodiversity forecasts.'Ecosystem decay' refers to the case when some species are more likely to go extinct when habitat is lost than predicted by theory. Pioneering conservation biologist, Thomas Lovejoy, coined the term to describe results from studies in small forest islands left behind after clearcutting in the Brazilian Amazon. High levels of sunlight encroached into the normally dark forest understory, harming plants adapted to lowlight conditions. Larger animals, like monkeys and big cats, left or went locally extinct.Using rigorous statistical tools and a database of 123 studies of habitat islands from across the world, Prof Dr Jonathan Chase, head of the Biodiversity Synthesis research group at iDiv and professor at MLU, and colleagues provide conclusive evidence that ecosystem decay is pervasive and point to a way to develop more realistic biodiversity forecasting models. Specifically, the scientists found fewer individuals, fewer species, and less even communities in samples taken from a small habitat compared to samples of the same size and effort taken from a larger habitat.Jonathan Chase said: "Mathematical models that are used for biodiversity forecasts typically ignore the effects of ecosystem decay. This is because we have not, until now, had systematic evidence for just how strong its effects are across ecosystems and species groups." He added: "This means that most forecasts underestimate how much biodiversity is being lost as habitats are lost."The scientists spent years compiling data from published habitat loss studies from across the world. These included data from tropical forest islands left within agricultural matrices of oil palm, coffee, chocolate and banana trees. From islands in lakes that were created during the construction of dams for hydroelectricity. And from nature reserves isolated within expanding agriculture and urbanization across the world. They included data from studies on plants and a wide variety of animals, including birds, bats, frogs and insects. In many cases, the data Chase and colleagues needed weren't available in the published paper. "We often went back to the authors of the studies. Many of them went above and beyond, digging up old field notebooks and cracking long-expired versions of software and hardware to get us what we needed for our analyses," said Chase.While the overall effect of ecosystem decay was clear, the scientists found some interesting variation in their dataset. "The quality of the land between the habitat islands, which we call the matrix, influenced just how strong the effect of ecosystem decay was," said Dr Felix May, formerly from iDiv and now a senior scientist at Freie Universität Berlin. May added: "When the matrix was very distinct from the habitat islands, like in landscapes with intense agriculture or urbanization, ecosystem decay in the habitat islands was quite intense. However, when the matrix was less hostile, like in bird- and bee-friendly agriculture, we found fewer extinctions in the habitat islands."Another co-author, Prof Dr Tiffany Knight, from MLU, UFZ and iDiv, added: "One surprise was that we found weaker ecosystem decay in studies from Europe, where habitat loss often occurred many hundreds of years ago, compared to studies from other places where losses occurred more recently." Knight continued: "We expected the opposite, because ecosystem decay is thought to emerge slowly as species go extinct. But what we found is that different species replaced those that were lost."The results of this new study could be seen as dire because it concludes that many biodiversity loss forecasts are too optimistic. But the authors prefer to see the brighter side. "What we have found is that it is possible to make more realistic projections for how biodiversity will be lost as habitats are lost," Chase said. He added: "This will allow us to make more informed policies regarding habitat protection and provides added incentives for restoring habitats to restore the biodiversity within."
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Animals
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July 27, 2020
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https://www.sciencedaily.com/releases/2020/07/200727194703.htm
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How day- and night-biting mosquitoes respond differently to colors of light and time of day
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In a new study, researchers found that night- versus day-biting species of mosquitoes are behaviorally attracted and repelled by different colors of light at different times of day. Mosquitoes are among major disease vectors impacting humans and animals around the world and the findings have important implications for using light to control them.
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The University of California, Irvine School of Medicine-led team studied mosquito species that bite in the daytime (Aedes aegypti, aka the Yellow Fever mosquito) and those that bite at night (Anopheles coluzzi, a member of the Anopheles gambiae family, the major vector for malaria). They found distinct responses to ultraviolet light and other colors of light between the two species. Researchers also found light preference is dependent on the mosquito's sex and species, the time of day and the color of the light."Conventional wisdom has been that insects are non-specifically attracted to ultraviolet light, hence the widespread use of ultraviolet light "bug zappers" for insect control. We find that day-biting mosquitoes are attracted to a wide range of light spectra during the daytime, whereas night-biting mosquitoes are strongly photophobic to short-wavelength light during the daytime," said principal investigator Todd C. Holmes, PhD, a professor in the Department of Physiology and Biophysics at the UCI School of Medicine. "Our results show that timing and light spectra are critical for species-specific light control of harmful mosquitoes."The new study titled, "Circadian Regulation of Light-Evoked Attraction and Avoidance Behaviors in Daytime- versus Nighttime-Biting Mosquitoes," is published in Mosquitoes pose widespread threats to humans and other animals as disease vectors. It is estimated historically that diseases spread by mosquitoes have contributed to the deaths of half of all humans ever to have lived. The new work shows that day-biting mosquitoes, particularly females that require blood meals for their fertilized eggs, are attracted to light during the day regardless of spectra. In contrast, night-biting mosquitoes specifically avoid ultraviolet (UV) and blue light during the day. Previous work in the Holmes lab using fruit flies (which are related to mosquitoes) has determined the light sensors and circadian molecular mechanisms for light mediated attraction/avoidance behaviors. Accordingly, molecular disruption of the circadian clock severely interferes with light-evoked attraction and avoidance behaviors in mosquitoes. At present, light-based insect controls do not take into consideration the day versus night behavioral profiles that change with daily light and dark cycles."Light is the primary regulator of circadian rhythms and evokes a wide range of time-of-day specific behaviors," said Holmes. "By gaining an understanding of how insects respond to short wavelength light in a species-specific manner, we can develop new, environmentally friendly alternatives to controlling harmful insects more effectively and reduce the need for environmentally damaging toxic pesticides."
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Animals
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July 27, 2020
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https://www.sciencedaily.com/releases/2020/07/200727114745.htm
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Artificial Intelligence to identify individual birds of same species
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Humans have a hard time identifying individual birds just by looking at the patterns on their plumage. An international study involving scientists form the CNRS, Université de Montpellier and the University of Porto in Portugal, among others, has shown how computers can learn to differentiate individual birds of a same species. The results are published on 27 July 2020 in
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Differentiating between individuals of a same species is essential in the study of wild animals, their processes of adaptation and behaviour. Scientists from the CEFE research centre in Ecology and Evolutionary Ecology (CNRS/ Université de Montpellier/ Université Paul-Valéry-Montpellier/ IRD/ EPHE) and the Research Centre in Biodiversity and Genetic Resources (CIBIO) at Porto University have for the very first time identified individual birds with the help of artificial intelligence technology.They have developed a technique that enables them to gather a large number of photographs, taken from various angles, of individual birds wearing electronic tags. These images were fed into computers which used deep learning technology to recognise the birds by analysing the photographs. The computers were able to distinguish individual birds according to the patterns on their plumage, something humans can't do. The technology was able to identify specimens from populations of three different species: sociable weavers, great tits and zebra finches.This new technique could not only result in a less invasive method of identification but also lead to new insights in ecology, for example, by opening ways of using AI to study animal behaviour in the wild.
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Animals
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July 27, 2020
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https://www.sciencedaily.com/releases/2020/07/200727114644.htm
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How the zebrafish got its stripes
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Animal patterns -- the stripes, spots and rosettes seen in the wild -- are a source of endless fascination, and now researchers at the University Bath have developed a robust mathematical model to explain how one important species, the zebrafish, develops its stripes.
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In the animal kingdom, the arrangement of skin pigment cells starts during the embryonic stage of development, making pattern formation an area of keen interest not only for a lay audience but also for scientists -- in particular, developmental biologists and mathematicians.Zebrafish are invaluable for studying human disease. These humble freshwater minnows may seem to have little in common with mammals but in fact they show many genetic similarities to our species and boast a similar list of physical characteristics (including most major organs).Zebrafish also provide fundamental insights into the complex, and often wondrous, processes that underpin biology. Studying their striking appearance may, in time, be relevant to medicine, since pattern formation is an important general feature of organ development. therefore, a better understanding of pigment pattern formation might give us insights into diseases caused by disruption to cell arrangements within organs.The new mathematical model devised in Bath paves the way for further explorations into pigment patterning systems, and their similarity across different species. Pigmentation in zebrafish is an example of an emergent phenomenon -- one in which individuals (cells in this case), all acting according to their own local rules, can self-organise to form an ordered pattern at a scale much larger than one might expect. Other examples of emergent phenomena in biology include the flocking of starlings and the synchronised swimming seen in schools of fish.Dr Kit Yates, the mathematician from Bath who led the study, said: "It's fascinating to think that these different pigment cells, all acting without coordinated centralised control, can reliably produce the striped patterns we see in zebrafish. Our modelling highlights the local rules that these cells use to interact with each other in order to generate these patterns robustly.""Why is it important for us to find a correct mathematical model to explain the stripes on zebrafish?" asks Professor Robert Kelsh, co-author of the study. "Partly, because pigment patterns are interesting and beautiful in their own right. But also because these stripes are an example of a key developmental process. If we can understand what's going on in the pattern development of a fish embryo, we may be able to gain deeper insight into the complex choreography of cells within embryos more generally."The stripes of an adult 'wild type' zebrafish are formed from pigment-containing cells called chromatophores. There are three different types of chromatophore in the fish, and as the animal develops, these pigment cells shift around on the animal's surface, interacting with one other and self-organising into the stripy pattern for which the fish are named. Occasionally, mutations appear, changing how the cells interact with each other during pattern development resulting in spotty, leopard-skin or maze-like labyrinthine markings.Scientists know a lot about the biological interactions needed for the self-organisation of a zebrafish's pigment cells, but there has been some uncertainty over whether these interactions offer a comprehensive explanation for how these patterns form. To test the biological theories, the Bath team developed a mathematical model that incorporated the three cell types and all their known interactions. The model has proven successful, predicting the pattern development of both wild type and mutant fish.Mathematicians have been trying to explain how zebrafish stripes form for many years, however many previous modelling attempts have been unable to account for the broad range of observed fish mutant patterns. Jennifer Owen, the scientist responsible for building and running the model, said "One of the benefits of our model is that, due to its complexity, it can help to predict the developmental defects of some less understood mutants. For example, our model can help to predict the cell-cell interactions that are defective in mutants such as leopard, which displays spots."
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July 24, 2020
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https://www.sciencedaily.com/releases/2020/07/200724191444.htm
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Fossil tracks: Wrong number of fingers leads down wrong track
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Have you ever wondered why our hands have five fingers? And what about amphibians? They usually only have four. Until now it was assumed that this was already the case with the early ancestors of today's frogs and salamanders, the Temnospondyli. However, a new find of the crocodile-like Temnospondyl Metoposaurus krasiejowensis from the late Triassic (about 225 million years old) in Poland shows five metacarpal bones and thus five fingers. As the researchers from the Universities of Bonn and Opole (Poland) note, this finding is very important, because until now, fossil animal tracks may have been wrongly assigned. The results have now been published in the
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Modern amphibians usually have four fingers on the forelimb (and never more), which is called a "four-rayed hand," as opposed to our five-rayed hand. Of all groups of terrestrial vertebrates, amphibians show the greatest variation in the number of frontfingers Reptiles are the most conservative and usually have five. In birds, the finger bones in the wing have been lost completely. In mammals, the number of toes in the forelimb also varies greatly: Primates and raccoons have five, in horses only the third has survived, while in cattle and other even-toed ungulates fingers three and four remain. What they all have in common, however, is that this loss of toes or fingers originates from a five-ray pattern, which is why amphibians cannot be the ancestors of all these terrestrial vertebrate groups.It has been known for some time that the earliest quadrupeds had significantly more fingers than five, such as Acanthostega, which had eight in the forelimb, or Ichthyostega with seven in the hind foot. As early as 300 million years ago, all but the five-fingered forms became extinct. The five-ray pattern was then retained in the real land animals, but was reduced again and again (see horses). The ancestors of today's amphibians, the Temnospondyli, presented contradictory evidence of skeletons with four fingers, but also tracks that had five.Temnospondyli is an important group of the early, very diverse quadrupeds. Some temnospondyls became as big as crocodiles, others were rather small. However, like all amphibians, they were dependent on water during their larval stage. Their most famous representatives include Eryops or Mastodonsaurus. "It's also important to understand the evolution of modern amphibians, as this group probably evolved from the Temnospondyli," says Dr. Dorota Konietzko-Meier from the Institute for Geosciences at the University of Bonn, who discovered and prepared the left forelimb of a Metoposaurus krasiejowensis in Krasiejów (southwest Poland).However, despite the long history of research, the exact number of fingers in Metoposaurus and other temnospondyls is still controversial. "It's remarkable that even in the case of the very well-researched Eryops, the skeletal reconstruction exhibited at the Muséum National d'Histoire Naturelle in Paris has five fingers, while only four fingers can be seen at the National Museum of Natural History in Washington," says Ella Teschner, a doctoral student from Bonn and Opole. Lately, science has assumed that, similar to most modern amphibians, all Temnospondyli have only four toes in their forelimbs. This resulted in the five-toed footprints common in the Permian and Triassic periods being almost automatically assumed to not belong to Temnospondyli."The find from the famous Upper Triassic site Krasiejów in Poland therefore offers a new opportunity to study the architecture and development of the hand of the early quadrupeds," says paleontologist Prof. Dr. Martin Sander from the University of Bonn. A considerably broader view of the entire group of Temnospondyli did not show a clear trend with regard to the five-ray pattern and suggested that the number of digits was not as limited in the phylogenetic context as was assumed. "Evidently, the temnospondyls were already experimenting with the four-ray pattern, and the five-ray pattern died out before the emergence of modern amphibians," adds Sander."Even if the ossification of five metacarpal bones described here was only a pathology, it still shows that a five-ray pattern was possible in Temnospondyli," says Konietzko-Meier. However, it could not be assumed with certainty that the reduction in the number of fingers/digits from five to four always affected the fifth place on the hand in these fossil taxa. The possibility that some of the four-fingered taxa were caused by the loss of the first ray cannot be excluded. Sander: "The new finding of a five-fingered hand is particularly important for the interpretation of tracks, as it shows that a five-fingered forefoot print could also belong to the Temnospondyli and thus indicate a considerably wider distribution area of these animals."These results are also of general importance, since limb development plays an important role in evolutionary biology and medicine, and fossils may therefore provide important information for the evaluation of theories of hand development.
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July 23, 2020
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https://www.sciencedaily.com/releases/2020/07/200723152332.htm
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New native Hawaiian land snail species discovered, first in 60 years
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Scientists have described a new native Hawaiian land snail species, sounding a rare, hopeful note in a story rife with extinction.
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Pacific island land snails are among the world's most imperiled wildlife, with more recorded extinctions since 1600 than any other group of animals. Hawaii's once-teeming land snail scene of more than 750 species has shrunk by more than half, ravaged by habitat loss and invasive species such as rats, Jackson's chameleons and the carnivorous rosy wolf snail.A team of researchers found "This is a happy story where we discovered a snail that is still around," Yeung said. "There are so many things in our collection that we can no longer find in the wild. But in this snail's case, we can finally put a name to it and describe it, which is huge for the conservation of this species."The tree-dwelling snail shows pronounced variation in coloring, from burnished tiger's-eye patterning to dramatic sable and white stripes. At less than two-tenths of an inch long, "you might be able to fit a dozen on your fingernail," said study co-author John Slapcinsky, collection manager of invertebrate zoology at the Florida Museum of Natural History.Land snails play a crucial role as decomposers and fungivores in Hawaii's ecosystems, essentially "our first recyclers," Yeung said.The researchers deposited a selection of The team's survey also produced new records of three snail species last documented in the 1950s and others feared extinct, as well as nearly 30 new species. The researchers failed to find two species, A. auricula and A. minuta, whose populations may have died out.But while the status of Hawaii's land snails is dire, it's too early to despair, said Slapcinsky, who gamely struggled through skin-ripping raspberry thickets and nearly slid off a cliff while sieving for snails."People used to think it wasn't even worth studying Hawaiian land snails because they were all extinct. Now we know they're not," he said. "If we work at it, there's still a chance to do something about it. That's why it's important to be out there surveying, finding the remaining populations of these species."Yeung said previous reports estimated that 90% of Hawaii's land snails were extinct, but the team's survey shows that about 300 species still survive in remote, isolated parts of the Hawaiian Islands."The challenge now is trying to identify all of these because we have lost a lot of experts, and a lot of these snails are super tiny," she said. "If you're not a trained malacologist, the small brown snails might all look the same to you. But when you take a closer look at their shells, bodies and genetics, these little things are all different and can be tied to different valleys and ridges. When one species turns out to be three, we can run into problems with conservation."The researchers used a combination of physical characteristics and DNA to describe the new species. While its shell size and shape mimic A. perpusilla snails from the Koolau Range on east Oahu, molecular evidence shows "We're not bemoaning that Achatinellinae are getting attention. They do need help," he said. "What we're concerned about is that these other things are getting ignored."Meanwhile, the team pushes forward in its analysis of a decade's worth of data and many new species descriptions. Afterwards, the researchers can turn their attention to the evolution and ecology of Hawaii's land snails, traditionally considered by native Hawaiians as important symbols and good omens that represent change, romance and song."The diversity is amazing, the species are amazing, and there are so many evolutionary stories you could tell," Yeung said, describing malacology as a "wide-open frontier.""But first we have to identify these snails. If you ask about their habitat and life history, it's like, I wish I could tell you. Right now, I can just tell you this is a different species and put a name on it. It's hard work, but it's so gratifying."The researchers published their findings in
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Animals
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July 23, 2020
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https://www.sciencedaily.com/releases/2020/07/200723143731.htm
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Genome-mapping reveals 'supermutation' resulting in cryptic coloration in stick insects
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Traits that form an organism's appearance, including color, are determined by many different genes and the creature's environment.
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"Humans and domestic animals, for example, have varied skin, fur and hair, as well as a range of heights -- an example of continuous variation," says Utah State University genetic ecologist Zach Gompert. "In the wild, however, types of genetic mutations affecting adaptation and thus, appearance, are only beginning to be understood. Some traits show more discontinuous or discrete variation."In a paper published July 23, 2020 in "Most research on the genetic basis of traits and adaptation has focused on individual genes and small mutations," says Gompert, associate professor in USU's Department of Biology and the USU Ecology Center "But in this paper, we uncover a greater role for large mutations and structural rearrangements of the genome that effectively 'lock up' suites of genes in groups."The stick insects used in the study are flightless and plant-feeding. Most Timema species have green and brown-color "morphs," a local variety of a species, which are cryptic, meaning they visually blend into their surroundings. Cryptic coloration enables the insects to avoid predation by birds, as they blend in on the leaves and stems or bark of the plants they eat. However, one species, "Using genome-mapping methods, we show that a large, million base pair, adaptive deletion -- a supermutation -- converts a continuum of color variation seen in
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Animals
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July 23, 2020
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https://www.sciencedaily.com/releases/2020/07/200723143710.htm
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Research breakthrough in fight against chytrid fungus
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For frogs dying of the invasive chytridiomycosis disease, the leading cause of amphibian deaths worldwide, the genes responsible for protecting them may actually be leading to their demise, according to a new study published today in the journal
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The lowland leopard frog, found in river drainages in Arizona, is one of a few amphibian species in which some individuals survive infection by Batrachochytrium dendrobatidis chytrid fungus (Bd) while other individuals do not -- even when they live in the same local population.In a study of lowland leopard frogs infected with Bd, the fungus that causes the disease chytridiomycosis or chytrid, researchers found that frogs that died from the disease had higher expression of major histocompatibility complex and other immune system genes than frogs that survived it.Those genes help organisms fight off infections and foreign substances."This result was totally counterintuitive and the opposite of the pattern we expected to recover," said Anna Savage, the study's lead author, an associate professor in UCF's Department of Biology and former postdoctoral fellow at SCBI's Center for Conservation Genomics (CCG)."My previous research on these immune genes showed that some variants were associated with higher survival to Batrachochytrium dendrobatidis, so I hypothesized that those genes were enabling the frogs to have a stronger immune response that would kill the fungus," she said."Instead, it seems like those stronger responses are linked to susceptibility, and the genes associating with survival are linked to reduced immune function."Savage said acquired immune responses can be very potent, require a lot of energy from the body and can sometimes produce toxic byproducts that harm the host and the pathogen."Immune responses are much more complex than just an on-off switch," she said. "A big part of the immune system is regulating the type, timing and dosage of a particular response, and if any of those components get dysregulated, it can have extremely negative consequences."She said, for instance, Batrachochytrium dendrobatidis suppresses the host immune system by killing B and T lymphocytes. "Because those are the same cells that proliferate during acquired immune responses, producing lots of those cells might just be wasting energy on something that chytrid can easily destroy," she said.Amphibian populations are in decline around the world, with two-thirds of the world's 8,000 species considered to be threatened and nearly 200 species that have already gone extinct in the last two decades.In the U.S., amphibian populations overall are declining at a rate of nearly 4 percent a year, with some areas, such as the Rocky Mountains and the West Coast, facing a higher rate of decline, according to the U.S. Geological Survey.Although the researchers studied immune gene expression in lowland leopard frogs with chytridiomycosis, the findings may be useful for studying the disease in other frog species due to genetic similarities they share, Savage said.Lowland leopard frogs were chosen for the study because their responses to chytridiomycosis vary from one individual to the next, unlike many other frog species that are completely susceptible to the disease or are completely resistant or tolerant.This allowed the researchers to rule out genetic variation between species and pinpoint specific differences in lowland leopard frogs' immune genes that predicted different responses to infection.The frogs were collected in Arizona and shipped overnight to the Smithsonian's National Zoo in Washington, D.C., where the infection experiments were conducted.Subsequent analyses of gene expression occurred at the Smithsonian Conservation Biology Institute's Center for Conservation Genomics. Statistical analyses of the data were performed at UCF.Robert Fleischer, senior scientist and head of the SCBI's CCG, co-authored the study and was Savage's main advisor for the research when she was a postdoctoral fellow at the Smithsonian.Fleischer said the results help in understanding why some frogs survive the disease and others do not."If we can solve this mystery, and we have taken a big step in that direction with this study, our hope and plan is to use this information to develop resources and strategies to mitigate the disease in the more susceptible species, and to counter the worldwide tide of extinction and endangerment caused by chytrid," he said.The researcher said the findings also show that acquired immune responses, such as those generated by vaccination, may not always be useful in combating invasive diseases of conservation concern.
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Animals
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July 23, 2020
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https://www.sciencedaily.com/releases/2020/07/200723143700.htm
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Hot or cold, venomous vipers still quick to strike
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Most reptiles move slower when temperatures drop, but venomous rattlesnakes appear to be an exception. The cold affects them, but not as much as scientists expected.
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"Many reptiles and other animals that rely on external sources of heat have muscles that don't contract as well when temperature drops. We wanted to know if that was the case with rattlesnakes," explained UC Riverside biologist Tim Higham.To answer their question, Higham and a team from San Diego State University examined the speed at which rattlers struck out at perceived threats in temperature-controlled containers. The team's work is detailed in a new paper published this week in the The team investigated how quickly the snakes struck out to defend themselves when faced with predators, as this speed can make the difference between life and death in nature."Although humans often fear snakes, it is important to realize that snakes are vulnerable to predation by animals such as birds, mammals, and other snakes," Higham said. "Defensive strikes are important for protecting them against predation."When placed in the experimental containers, the research team found that rattlers continued to strike quickly at a balloon filled with warm water that played the role of an intruder."By far, the hardest part of the study was working with snakes in the 35 C treatment," said San Diego State University doctoral student Malachi Whitford, first author of the new study. "The snakes were extremely fast, making them very difficult to corral."The strike speed was affected when the temperature dropped, but not as much as the team thought it would be."We expected their strike to be about half as fast for every 10-degree drop in temperature, but they're still able to uncoil and strike fairly rapidly, even at our lowest test temperatures," said SDSU ecologist and research team member Rulon Clark.At most, the snakes were about 25 percent slower at the lowest temperature. The finding means that pit vipers, the type of rattlesnake studied, are slightly more vulnerable to real or perceived threats in colder temperatures but not by a lot.This might help explain how rattlesnakes can thrive even in cooler climates like southern Canada. It also suggests that the snakes are using a mechanism other than just muscles in order to strike, as muscle movement becomes more difficult in the cold.Kangaroos use tendons like elastic bands to bounce and hop without using much energy, the way that humans use a bow and arrow. The findings suggest that snakes may also be storing elastic energy somehow."Striking in any way is important to do quickly," Higham said. "As global temperatures increase, it's possible that snakes will become even more effective predators."
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Animals
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July 23, 2020
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https://www.sciencedaily.com/releases/2020/07/200723115921.htm
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How mosquitoes got their taste for human blood and what it means for the future
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Of about 3,500 mosquito species around the world, only a few have taken to specifically targeting people for biting, making them important spreaders of infectious diseases. To predict and help control the spread of those mosquito-borne illnesses, it's important to know where and why, evolutionarily speaking, certain mosquitoes got their taste for biting humans in the first place. Now, researchers reporting in the journal
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"Aedes aegypti mosquitoes are invasive across the global tropics, where a strong preference for human hosts and habitats makes them important disease vectors," says Carolyn McBride of Princeton University. "We found that in their native range of sub-Saharan Africa, they show extremely variable attraction to human hosts, ranging from strong preference for humans to strong preference for non-human animals.""Mosquitoes living near dense human populations in cities such as Kumasi, Ghana, or Ouagadougou, Burkina Faso, showed increased willingness to bite human hosts," adds Noah Rose, also of Princeton. "But they only evolve a strong preference for human hosts in places with intense dry seasons -- in particular, in the Sahel region, where rainfall is concentrated in just a couple months out of the year. We think this is because mosquitoes in these climates are especially dependent on humans and human water storage for their life cycle."People tend to think of all mosquitoes as major pests to people. But, in fact, the researchers explain, mosquitoes are quite diverse. Some of them won't bite humans at all. Only a few species specialize in biting people. In the new study, the researchers focused their attention on Aedes aegypti, the primary spreader of dengue, Zika, yellow fever, and Chikungunya virus."Many people have speculated about why this species evolved to selectively bite humans, but our study is the first to address this question directly with systematic empirical data," McBride says.To do this, the researchers took advantage of the fact that this species came from Africa and that many populations in Africa still don't like to bite humans. They asked a simple question: where specifically do the mosquitoes like humans? And, where do they prefer to bite other animals instead?The researchers used special traps to collect Ae. aegypti eggs from multiple outdoor sites in each of 27 locations across sub-Saharan Africa. Back in the lab, they tested the preferences of each of those mosquito populations for the scent of people versus other animals, including guinea pigs and quail.Their studies led to two main findings. First, they show that mosquitoes living in dense urban cities were attracted to people more than those from more rural or wild places. However, the researchers note that this only applied to especially dense modern cities and therefore isn't likely to be the original reason that certain population of Ae. aegypti mosquitoes evolved to specialize in biting humans.Their second discovery was that mosquitoes living in places with longer and hotter dry seasons showed a strong preference for a human versus animal scent."I was surprised that immediate habitat didn't have much of an effect -- mosquitoes in forests and nearby towns had similar behavior," Rose says. "We thought that maybe moving into human landscapes would be a key driver of attraction to human hosts. But it seems like mosquitoes fly back and forth too readily between these habitats for their behavior to diverge in many cases."When we took a more regional view of things, we saw that regions with dense human populations had mosquitoes with a greater attraction to human hosts, but this wasn't dependent on the precise habitat we collected them from within each region," Rose continues. "I was also surprised that climate was more important than urbanization in explaining present day behavioral variation. Many mosquitoes living in fairly dense cities don't particularly prefer to bite human hosts.""I think it will be surprising to people that in many cities in Africa, this species actively discriminates against humans," McBride says. "It is only when the cities become extremely dense or are located in places with more intense dry seasons that they become more interested in biting humans."The researchers show that many genes concentrated in a few key parts of the genome drove this evolutionary shift in mosquitoes' biting preferences. Based on their findings, the researchers asked how near-term climate change and urban growth are expected to shape mosquito behavior in the near future. And, it's not good news.The researchers say that climate change in the next few decades isn't expected to drive major changes to the dry season dynamics they found were important to mosquitoes. But, they say, rapid urbanization could push more mosquitoes to bite humans in many cities across sub-Saharan Africa over the next 30 years.The researchers will continue to study the interplay between mosquitoes' biting preferences, climate, and urban life. They'd also like to understand why mosquitoes specialize on certain hosts to begin with and which specific genes and genetic changes are most important.
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July 23, 2020
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https://www.sciencedaily.com/releases/2020/07/200723115835.htm
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Lone Star ticks in Illinois can carry, transmit Heartland virus
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Researchers have confirmed that Heartland virus, an emerging pathogen with potentially dire consequences for those infected, is present in Lone Star ticks in two Illinois counties hundreds of miles apart. Lone Star ticks were first detected in Illinois in 1999, but had not been found to be infected with Heartland virus in the state.
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The findings are reported in the journal In July 2018, a resident of Kankakee County was hospitalized after suffering several tick bites while camping on private property. Two months later and more than 250 miles to the south, a resident of Williamson County was hospitalized with many of the same symptoms: fever, diarrhea, headache, fatigue, decreased appetite and nausea. This patient also noticed tick bites after camping. The Centers for Diseases Control and Prevention confirmed that clinical samples from both patients tested positive for Heartland virus, which is spread by ticks. Both patients eventually recovered.Tick-borne illnesses share symptoms with many other diseases and misdiagnoses sometimes occur, said Holly Tuten, a vector ecologist with the Illinois Natural History Survey who led the new research. INHS is a division of the Prairie Research Institute at the University of Illinois at Urbana-Champaign."Heartland virus won't show up on a standard diagnostic panel for tick-borne bacterial diseases," she said. "And with COVID-19 on the collective mind, a tick-borne viral infection could be overlooked, especially in cases where a tick bite was missed."According to the CDC, there are no vaccines to prevent infection with the Heartland virus or medications to treat it. Most people infected with the virus end up hospitalized and a few have died.To determine the source of the viral infections, health department officials in each county interviewed the patients to learn where they were when they were bit. This information allowed Tuten and her team to determine whether ticks in those areas carried the virus.Previous research showed that the Lone Star tick, Amblyomma americanum, can carry and transmit the Heartland virus, so the researchers focused their efforts on collecting this species."Lone Star ticks are very aggressive ambush predators and many people don't realize this," Tuten said. "I've seen Lone Star ticks run across a forest floor to me."The site in Kankakee County was a rural homestead with barnyard animals and a small amount of forest surrounded by cropland, Tuten said. The patient in Williamson County may have been exposed in a heavily wooded wildlife refuge or outside a suburban home with a few trees.The researchers collected ticks in all three locales. They shipped their tick samples to the CDC Arboviral Diseases Branch in Fort Collins, Colorado, where the ticks were combined in batches of 10-30 for testing."A single batch of male Lone Star ticks from each county was found to be positive for the Heartland virus," Tuten said. "Infected Lone Star ticks had been found as far north as Missouri, so we expected to find the infections in ticks from Williamson County in the southern part of Illinois. But finding so many Lone Star ticks in Kankakee County, including some with the virus, really surprised us."The detection of Heartland virus in adult Lone Star ticks a year after human infection suggests that the infected ticks may have overwintered in the area, Tuten said."We want to alert physicians and public health officials throughout Illinois that there is a fairly new pathogen out there that is a danger to public health," she said. "I don't want people to avoid the woods and parks. I just want them to be aware, so they can take concrete steps to reduce tick encounters and bites."This investigation was a collaboration between the INHS Medical Entomology Laboratory, the Illinois Department of Public Health, the CDC, conservation officials and Illinois residents.
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July 22, 2020
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https://www.sciencedaily.com/releases/2020/07/200722163236.htm
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Giant, fruit-gulping pigeon eaten into extinction on Pacific islands
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A large fruit-eating bird from Tonga joins the dodo in the lineup of giant island pigeons hunted to extinction.
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Fossils show that Unlike the dodo and the extinct Viti Levu giant pigeon of Fiji, however, "Some of these trees have big, fleshy fruit, clearly adapted for a big pigeon to gulp whole and pass the seeds," Steadman said. "Of the fruit-eating pigeons, this bird is the largest and could have gulped bigger canopy fruit than any others. It takes co-evolution to the extreme."The absence of "When Steadman first found "I said, 'Oh my God, I've never seen a pigeon that big,'" Steadman said. "It was clearly something different."Once he and archaeologist David Burley of Simon Fraser University -- who is also the species's namesake -- began excavating charred and broken remains of Columbids, the family that includes pigeons and doves, had few predators or competitors before people reached the Pacific islands, he said. The region was devoid of primates and carnivores such as cats, dogs and weasels, and hawks and owls were absent from many islands. The birds flourished in this nurturing environment, diversifying over the past 30-40 million years.Today, the Pacific islands are the global epicenter of pigeon and dove diversity, with more than 90 species, ranging from fruit doves as light as a handful of raisins to the turkey-sized, ground-dwelling crowned pigeon of New Guinea. But the number and distribution of birds in the region is a shadow of what it once was, Steadman said. Tonga's four remaining species of pigeons and doves represent less than half of the islands' historic diversity."This is another example of how looking at the modern fauna doesn't yield a complete picture of a region's diversity," he said.Steadman and Takano analyzed the features of columbid hindlimbs, dividing them into three groups: tree-dwelling species, ground-dwellers and those that live both on the ground and in trees. Pigeons and doves that spend most of their time in the canopy tend to have shorter legs, more suitable for perching and gripping in high winds. Those that forage for seeds on the ground have longer legs adapted for walking and running. Birds that flit between the understory and the forest floor have legs that are a blend of the characteristics of the other two groups.The researchers found surprising agreement between the groupings based on leg characteristics and molecular data: In other words, canopy-dwelling pigeons tend to be more closely related to one another than to birds in the other two groups."Given that there are 350 species of pigeons and doves, people might suspect these big changes in lifestyle evolved independently many times," Steadman said. "But right now, we don't have evidence that it happened more than once -- at least in the tropical Pacific."The relatively short hindlimbs of The researchers dedicated the study to the memory of W. Arthur "Art" Whistler, whose expertise in West Polynesian botany was unsurpassed, Steadman said. Whistler died from COVID-19 in April."There wasn't a plant on Fiji or Tonga that Art didn't know, including all of the pigeon-dispersed fruits," Steadman said. "He was a true plant nerd and complete salt of the earth. He always made time for people."
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July 22, 2020
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https://www.sciencedaily.com/releases/2020/07/200722142210.htm
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Foxes have been eating humans' leftovers for 42,000 years
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The diets of ancient foxes were influenced by humans, and these small carnivores might be tracers of human activity over time, according to a study published July 22, 2020 in the open-access journal
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Foxes love leftovers. In the wild, foxes regularly feed on scraps left behind by larger predators like bears and wolves, but the closer foxes live to human civilization, the more of their diet is made up of foods that humans leave behind. In this study, Baumann and colleagues hypothesized that if this commensal relationship goes back to ancient times, then foxes might be useful indicators of human impact in the past.The authors compared ratios of Carbon and Nitrogen isotopes between the remains of various herbivores, large carnivores, and red and Arctic foxes from several archaeological sites in southwest Germany dating to the Middle and Upper Palaeolithic. At sites older than 42,000 years, when Neanderthals sparsely occupied the region, fox diets were similar to their local large carnivores. But in the younger sites, as Homo sapiens became common in the area, foxes developed a more unique diet consisting largely of reindeer, which are too big for foxes to hunt but which are known to have been important game for ancient humans of the time.These results suggest that during the Upper Palaeolithic, these foxes made a shift from feeding on scraps left by local large predators to eating food left behind by humans. This indicates that foxes' reliance on human food goes back a good 42,000 years. The authors propose that, with further studies investigating this fox-human relationship, ancient fox diets may be useful indicators of human impact on ecosystems over time.The authors add: "Dietary reconstructions of ice-age foxes have shown that early modern humans had an influence on the local ecosystem as early as 40,000 years ago. The more humans populated a particular region, the more the foxes adapted to them."
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July 22, 2020
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https://www.sciencedaily.com/releases/2020/07/200722134929.htm
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Antibiotics disrupt development of the 'social brain' in mice
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Antibiotic treatment in early life impedes brain signalling pathways that function in social behaviour and pain regulation in mice, a new study by Dr Katerina Johnson and Dr Philip Burnet has found. It was published today in
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Katerina Johnson, from the University's Departments of Psychiatry and Experimental Psychology, was researching the effects of disrupting the microbiome on the brain in mice. 'We know from previous research that animals missing microbes, such as germ-free animals (which are devoid of microbes) or antibiotic-treated animals (whose microbes are severely depleted), have impaired social behaviour,' she explains. 'I was therefore particularly interested in the effects of the microbiome on endorphin, oxytocin and vasopressin signalling since these neuropeptides play an important role in social and emotional behaviour.'The most striking finding was in young animals treated with antibiotics. This resulted in reduced expression of the receptors which mediate endorphin, oxytocin and vasopressin signalling in the frontal cortex. Dr Johnson commented, 'If these signalling pathways are less active, this may help explain the behavioural deficits seen in antibiotic-treated animals. Whilst this study was in animals given a potent antibiotic cocktail, this finding highlights the potential detrimental effects that antibiotic exposure may have on the brain when it's still developing.'Dr Burnet added, 'Our research underlines the growing consensus that disturbing the microbiome during development can have significant impacts on physiology, including the brain.'The study was conducted using a relatively small number of animals with high doses of antibiotics and further research should follow up this finding given society's reliance on antibiotics, though of course they still play a vital role in medicine to fight bacterial infections.This was also the first study to investigate whether the microbiome affects the brain's endorphin system (where endorphin activates opioid receptors) and so these findings may have clinical relevance. Dr Johnson said, 'The adverse effect of antibiotics on the endorphin system may have implications not only for social behaviour but also for pain regulation. In fact we know that the gut microbiome affects the pain response so this might be one of the ways in which it does so.''A somewhat surprising observation from our research was the contrast in results for germ-free and antibiotic-treated mice, since the neurogenetic changes were generally in the opposite direction. This is a pertinent finding as the use of antibiotics to deplete the microbiome is often seen as a more accessible alternative to germ-free animals. However, we highlight the need to consider these two treatments as distinct models of microbiome manipulation when investigating the effects of microbes on the brain and behaviour.'
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July 22, 2020
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https://www.sciencedaily.com/releases/2020/07/200722112652.htm
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Genomic basis of bat superpowers revealed: Like how they survive deadly viruses
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The genetic material that codes for bat adaptations and superpowers -- such as the ability to fly, to use sound to move effortlessly in complete darkness, to tolerate and survive potentially deadly viruses, and to resist aging and cancer -- has been revealed and published in
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Although other bat genomes have been published before, the Bat1K genomes are 10 times more complete than any bat genome published to date.One aspect of the paper findings shows evolution through gene expansion and loss in a family of genes, APOBEC3, which is known to play an important role in immunity to viruses in other mammals. The details in the paper that explain this evolution set the groundwork for investigating how these genetic changes, found in bats but not in other mammals, could help prevent the worst outcomes of viral diseases in other mammals, including humans."More and more, we find gene duplications and losses as important processes in the evolution of new features and functions across the Tree of Life. But, determining when genes have duplicated is difficult if the genome is incomplete, and it is even harder to figure out if genes have been lost. At extremely high quality, the new bat genomes leave no doubts about changes in important gene families that could not be discovered otherwise with lower-quality genomes," said Dávalos, a Professor in Department of Ecology and Evolution in the College of Arts and Sciences at Stony Brook University.To generate the bat genomes, the team used the newest technologies of the DRESDEN-concept Genome Center, a shared technology resource in Dresden, Germany to sequence the bat's DNA, and generated new methods to assemble these pieces into the correct order and to identify the genes present. While previous efforts had identified genes with the potential to influence the unique biology of bats, uncovering how gene duplications contributed to this unique biology was complicated by incomplete genomes.The team compared these bat genomes against 42 other mammals to address the unresolved question of where bats are located within the mammalian tree of life. Using novel phylogenetic methods and comprehensive molecular data sets, the team found the strongest support for bats being most closely related to a group called Fereuungulata that consists of carnivorans (which includes dogs, cats and seals, among other species), pangolins, whales and ungulates (hooved mammals).To uncover genomic changes that contribute to the unique adaptations found in bats, the team systematically searched for gene differences between bats and other mammals, identifying regions of the genome that have evolved differently in bats and the loss and gain of genes that may drive bats' unique traits."It is thanks to a series of sophisticated statistical analyses that we have started to uncover the genetics behind bats' 'superpowers,' including their strong apparent abilities to tolerate and overcome RNA viruses," said Dávalos.The researchers found evidence the exquisite genomes revealed "fossilized viruses," evidence of surviving past viral infections, and showed that bat genomes contained a higher diversity of these viral remnants than other species providing a genomic record of ancient historical interaction with viral infections. The genomes also revealed the signatures of many other genetic elements besides ancient viral insertions, including 'jumping genes' or transposable elements.The study was funded in part by the Max Planck Society, the European Research Council, the Irish Research Council, the Human Frontiers of Science Program, and the National Science Foundation (Grant number 1838273).
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July 21, 2020
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https://www.sciencedaily.com/releases/2020/07/200721160725.htm
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Spider monkey groups as collective computers
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The wild spider monkeys living in a protected area near Punta Laguna, Mexico, collectively figure out good ways to divide up and conquer the forest. These monkeys live in a special type of society called a "fission-fusion" society. The group breaks up into little teams to find food -- called, "foraging" in the world of ecology -- but there is no "gym teacher" or "popular kid" picking teams. Rather, the monkeys each make decisions about how long to stay on foraging teams and when to switch to another. It turns out the collective effect of these individual decisions is to produce a range of foraging team sizes. And this range works well given how many trees in the forest have tasty fruit ready to eat. The monkeys are collectively computing good team sizes given the availability of food in the forest.
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The findings are published this week in the journal "By forming these subgroups -- constantly coming together and splitting -- the spider monkeys develop a more thorough knowledge of their environment," says the study's lead author, Gabriel Ramos-Fernandez at UNAM, who studies animal communication, social complexity and networks. "They seem to be pooling information about resources, so that as a group they know their environment better than any individual does on its own."Ramos-Fernandez and his group recorded the interactions of 47 monkeys for five hours per day over two years. He says the monkeys, which are accustomed to being observed by people, typically formed subgroups of 2 to 17 animals, but those subgroups typically stayed together only for 1-2 hours. "We noted who was where, and with whom, at any given time," he says.To understand how the monkeys to collectively compute team sizes, Ramos-Fernandez's team collaborated with SFI Professor Jessica Flack and SFI President David Krakauer. Flack leads SFI's Collective Computation Group, and Krakauer is co-developer of the collective computation ideas with Flack.The researchers used an approach called inductive game theory, developed by Flack and Krakauer in collaboration with another SFI researcher, Simon DeDeo, to figure out what decision rules the spider monkeys use in deciding to stay on or leave a foraging team. In traditional game theory, researchers make assumptions about the strategies in play. Inductive game theory, in contrast, asks what strategies are the animals (or cells or neurons) actually using -- what do we see in the data? Inductive Game Theory starts by specifying in advance a space of decision rules the study subjects -- here spider monkeys -- could be using given their cognitive and behavioral sophistication and, ideally, for which there is already some empirical support. The researchers search the data for evidence of these strategies and then ask how the strategies the individuals are found to use, combine to produce social structure."This kind of methodology is useful for studying optimal foraging because it requires no a priori assumptions about benefits and costs," says Ramos-Fernandez. The researchers found individual monkeys' decisions to stay or leave a foraging team were influenced by the stay and leave decisions of other individuals on the team. This result suggests spider monkeys take into account the opinions of their group mates about what a good team size is and use those opinions to inform their own decision-making. The collective effects of these decisions produced a range of team sizes that worked well given the availability of fruiting trees in the monkeys' forest. But the researchers also found that the spider monkeys' "collective intelligence" had room for improvement! The team sizes the monkeys collectively computed were not a perfect match to the availability of fruiting trees.A similar approach might help researchers understand other collective systems, including flocks of birds, groups of fish, or financial markets. Insights from this study also reinforce an idea in the collective intelligence literature that in decentralized systems when individual parts or agents have imperfect knowledge or only partial windows on the world, collective pooling of knowledge can be beneficial. Questions for future work include studying how individuals optimally combine the knowledge of group mates, depending on how diverse the group is, and how costly it is to make mistakes.
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July 21, 2020
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https://www.sciencedaily.com/releases/2020/07/200721102147.htm
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Researchers boost koala spotting system
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QUT researchers have published an improved and innovative method for estimating the number of koalas in an area detected by using drones and an artificial intelligent algorithm as they continue the quest of identifying surviving koala populations in bushfire areas.
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In an article published in the journal Their previous research, published in the Professor Hamilton, who co-authored the latest study with PhD student Evangeline Corcoran and Dr Simon Denman, said all methods for spotting koalas in heavy bushland faced challenges, whether spotters used traditional methods such as people looking up at the trees, dogs brought in to sniff out the koalas or high-tech tools such as infrared drones."All abundance estimation methods are at least a bit wrong -- that's why they're called estimates," Professor Hamilton said.The lead author on the article, Evangeline Corcoran, said that finding wildlife in a complex environment could be very challenging."We never have perfect knowledge, so we never know exactly how many koalas were there when we do a count," Ms Corcoran said."No matter how accurate the drone cameras, a koala could be hiding behind a branch when the drone flies over the area or perhaps one koala is counted twice in an aerial survey."That's why we generally have a margin of error. We use different terminology, but for example in general terms our current count might have an error margin of plus or minus ten per cent. That means we're confident that the true number of koalas is somewhere within the margin of error"By accounting for different factors about the site that can impact on how many koalas we detect, we're making the margin of error smaller and so making our estimates more accurate."In this way, we are deriving a count figure that accounts for more factors such as temperature, which is an important consideration because our thermal cameras give a more accurate estimate when its colder, and the density of the forest canopy."Professor Hamilton is currently involved in a project in which he is using his artificial intelligence (AI) system that uses drones and infrared imaging in a collaborative project to count Kangaroo Island's surviving koala population after the recent devastating bushfires.Professor Hamilton's system for detecting koalas in bushland begins with drones fitted infrared cameras covering an area in a "lawnmower" pattern at early morning and during the colder months so that the heat of the koalas better stands out.
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Animals
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July 21, 2020
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https://www.sciencedaily.com/releases/2020/07/200721094438.htm
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Eating habits of baby predator starfish revealed
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The varied diet of juvenile crown-of-thorns starfish complicates scientists' ability to age them. This makes plans for the management of this invasive species more difficult, as outbreaks of adults on the reef are unpredictable.
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Adult crown-of-thorns starfish pose one of the greatest threats to the Great Barrier Reef due to their coral diet. Marine life, including fish, crabs, seahorses, and turtles, depend on coral as a food source, as well as for shelter. No coral means no smaller creatures. This has a domino effect, ultimately decimating the food chain and ecosystem. Learning more about this starfish is crucial for efforts to save the Reef.New research from Dione Deaker, a PhD student at the University of Sydney, and her adviser Professor Maria Byrne, along with colleagues at the National Marine Science Centre, Coffs Harbour, adds another piece to the crown-of-thorns puzzle. The research team has already shown that baby starfish can survive on algae for up to six and a half years instead of switching to a coral diet at four months of age, per their typical growth pattern. Now, they have discovered that juveniles can eat a range of algae, not just the algae they are thought to prefer; crustose coralline algae. They can even subsist on biofilm -- microorganisms that cover the sea floor, including bacteria and protists -- to avoid starvation."The diet flexibility of juvenile crown-of-thorns starfish complicates our ability to age this species and, therefore, our ability to predict devastating outbreaks of adults on reefs," Ms Deaker said."There is potential for reserves of juveniles to accumulate on the reef and produce outbreaks when favourable feeding conditions arise."There is no doubt that these starfish are extremely opportunistic and resilient when their preferred food source is limited. We now demonstrate that this resilience also applies to the youngest juveniles."The researchers came to their conclusions, published in influential journal Small juvenile crown-of-thorns starfish are just millimetres in diameter. Once they switch to a coral diet, they can grow to up to a metre wide.
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July 20, 2020
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https://www.sciencedaily.com/releases/2020/07/200720112216.htm
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MRI scans of the brains of 130 mammals, including humans, indicate equal connectivity
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Researchers at Tel Aviv University, led by Prof. Yaniv Assaf of the School of Neurobiology, Biochemistry and Biophysics and the Sagol School of Neuroscience and Prof. Yossi Yovel of the School of Zoology, the Sagol School of Neuroscience, and the Steinhardt Museum of Natural History, conducted a first-of-its-kind study designed to investigate brain connectivity in 130 mammalian species. The intriguing results, contradicting widespread conjectures, revealed that brain connectivity levels are equal in all mammals, including humans.
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"We discovered that brain connectivity -- namely the efficiency of information transfer through the neural network -- does not depend on either the size or structure of any specific brain," says Prof. Assaf. "In other words, the brains of all mammals, from tiny mice through humans to large bulls and dolphins, exhibit equal connectivity, and information travels with the same efficiency within them. We also found that the brain preserves this balance via a special compensation mechanism: when connectivity between the hemispheres is high, connectivity within each hemisphere is relatively low, and vice versa."Participants included researchers from the Kimron Veterinary Institute in Beit Dagan, the School of Computer Science at TAU and the Technion's Faculty of Medicine. The paper was published in "Brain connectivity is a central feature, critical to the functioning of the brain," Prof. Assaf explains. "Many scientists have assumed that connectivity in the human brain is significantly higher compared to other animals, as a possible explanation for the superior functioning of the 'human animal.'" On the other hand, according to Prof. Yovel, "We know that key features are conserved throughout the evolutionary process. Thus, for example, all mammals have four limbs. In this project we wished to explore the possibility that brain connectivity may be a key feature of this kind -- maintained in all mammals regardless of their size or brain structure. To this end we used advanced research tools."The project began with advanced diffusion MRI scans of the brains of about 130 mammals, each representing a different species. (All of the brains were removed from dead animals, and no animals were euthanized for the purposes of this study.) The brains, obtained from the Kimron Veterinary Institute, represented a very wide range of mammals -- from tiny bats weighing 10 grams to dolphins whose weight can reach hundreds of kilograms. Since the brains of about 100 of these mammals had never been MRI-scanned before, the project generated a novel and globally unique database. The brains of 32 living humans were also scanned in the same way. The unique technology, which detects the white matter in the brain, enabled the researchers to reconstruct the neural network: the neurons and their axons (nerve fibers) through which information is transferred, and the synapses (junctions) where they meet.The next challenge was comparing the scans of different types of animals, whose brains vary greatly in size and/or structure. For this purpose the researchers employed tools from Network Theory, a branch of mathematics that enabled them to create and apply a uniform gauge of brain conductivity: the number of synopses a message must cross to get from one location to another in the neural network."A mammal's brain consists of two hemispheres connected to each other by a set of neural fibers (axons) that transfer information," Prof. Assaf explains. "For every brain we scanned, we measured four connectivity gages: connectivity in each hemisphere (intrahemispheric connections), connectivity between the two hemispheres (interhemispheric), and overall connectivity. We discovered that overall brain connectivity remains the same for all mammals, large or small, including humans. In other words, information travels from one location to another through the same number of synapses. It must be said, however, that different brains use different strategies to preserve this equal measure of overall connectivity: some exhibit strong interhemispheric connectivity and weaker connectivity within the hemispheres, while others display the opposite."Prof. Yovel describes another interesting discovery. "We found that variations in connectivity compensation characterize not only different species but also different individuals within the same species," he says. "In other words, the brains of some rats, bats, or humans exhibit higher interhemispheric connectivity at the expense of connectivity within the hemispheres, and the other way around -- compared to others of the same species. It would be fascinating to hypothesize how different types of brain connectivity may affect various cognitive functions or human capabilities such as sports, music or math. Such questions will be addressed in our future research.""Our study revealed a universal law: Conservation of Brain Connectivity," Prof. Assaf concludes. "This law denotes that the efficiency of information transfer in the brain's neural network is equal in all mammals, including humans. We also discovered a compensation mechanism which balances the connectivity in every mammalian brain. This mechanism ensures that high connectivity in a specific area of the brain, possibly manifested through some special talent (e.g. sports or music) is always countered by relatively low connectivity in another part of the brain. In future projects we will investigate how the brain compensates for the enhanced connectivity associated with specific capabilities and learning processes."
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July 20, 2020
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https://www.sciencedaily.com/releases/2020/07/200720093305.htm
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Michigan coyotes: What's for dinner depends on what the neighbors are having
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Michigan coyotes in most of the Lower Peninsula are the "top dogs" in the local food chain and can dine on a wide variety of small animals, including rabbits and rodents, along with berries and other plant foods, insects, human garbage and even outdoor pet food.
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But in the Upper Peninsula, coyotes coexist with gray wolves and play a subordinate role in the food web. As a result, the diets of U.P. coyotes contain less meat than Lower Peninsula coyotes.That's one of the findings of a University of Michigan study of the diets and gut microbiomes of three Michigan coyote populations, published in the The food-web study involved the genetic analysis of more than 350 carnivore scat samples -- 58 of which were confirmed as coyote scat -- collected at three Michigan locations, one in the Upper Peninsula and two in the Lower Peninsula: the Huron Mountain Club in the U.P.; the University of Michigan Biological Station, at the northern tip of the Lower Peninsula near Pellston; and the Shiawassee National Wildlife Refuge near Saginaw.The study also used photos from hundreds of motion-triggered wildlife cameras at the three sites to document local mammal populations, which include various coyote prey species. The camera network was established over the last several years by U-M wildlife ecologist Nyeema Harris, director of the Applied Wildlife Ecology Laboratory in the Department of Ecology and Evolutionary Biology and senior author of the new study.In the scat analysis, Harris and her graduate students used the ratios of stable carbon and nitrogen isotopes to examine variations in coyote diet at the three sites and to determine the animal's position in the local food web. They also sequenced RNA from the scat to investigate interactions between diet and gut microbiomes.Higher levels of the heavy nitrogen isotope N-15 in coyote scat indicates a higher position in the local food chain and generally corresponds to a diet richer in meat. In the U-M study, N-15 levels were highest at the southernmost site, the Shiawassee National Wildlife Refuge near Saginaw, where coyotes are the top predators. As so-called apex predators, they have their pick of what's for dinner, as well as where and when they roam the landscape.N-15 levels and dietary breadth were both lowest at the Huron Mountain Club in the Upper Peninsula, where coyotes live alongside gray wolves. There, coyotes most likely play a subordinate role in the local food web and have a more limited diet."The co-occurrence of gray wolves and coyotes at the Huron Mountain Club may cause the suppression of subordinate coyotes, forcing individuals to alter their consumption patterns and switch to alternate food sources," said Harris, an assistant professor in the U-M Department of Ecology and Evolutionary Biology.The study's findings are in accord with a phenomenon called mesopredator release, which occurs when populations of medium-sized predators are freed from top-down competition after the removal of traditional apex carnivores.For thousands of years, North American coyotes were outcompeted by gray wolves and other apex predators. But the vast majority of gray wolves in the contiguous United States were exterminated by the mid-20th century, allowing coyotes to assume the mantle of top predator in many places.Gray wolf populations have rebounded in recent years in parts of the West and the Upper Midwest, including Michigan's Upper Peninsula, where the gray wolf population has grown to more than 600.But at Lower Peninsula locations such as the Shiawassee National Wildlife Refuge, coyotes remain the top predator, with no observed pressure from gray wolves. These peninsular differences are reflected in the nitrogen-isotope ratios observed in the U-M scat study, said Shawn Colborn, the first author of the "As coyotes shifted from being a mid-level predator to being an apex predator at places like Shiawassee, they found themselves at the top of the food chain with no pressure from wolves," said Colborn, who conducted the scat analysis for his master's thesis in the U-M Department of Ecology and Evolutionary Biology, along with former EEB master's student Corbin Kuntze."So, they could change what they ate, where they roamed across the land, and when they were active. Those changes are reflected in their increased nitrogen level. Alternatively, N-15 values are lower in coyotes at the Huron Mountain Club in the Upper Peninsula, where they are most likely experiencing top-down pressure from gray wolves."The researchers also found that coyotes at the three locations harbored distinct gut microbial communities. About 500 types of bacteria were identified from the coyote scat samples collected at the three Michigan sites. As expected, the diversity of gut microbes was lowest at the northernmost site, the Huron Mountain Club.
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Animals
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July 20, 2020
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https://www.sciencedaily.com/releases/2020/07/200717150036.htm
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Scientists find faster way to count animal sperm using DNA
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Researchers at the University of New Hampshire have identified a quicker and less expensive way to count sperm in lobsters that could help scientists looking at any animal better understand mating, a key aspect of species survival.
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"Scientists used to have to do this using a very tedious or expensive method so it was rarely attempted," said Win Watson, professor emeritus of marine biology. "Now that DNA technology has become so accessible and affordable, we decided to try it and it worked great."The technique is described in their study which was recently featured in the "Imagine if it took a week to produce a complete lobster spermatophore. That would mean that male lobsters might only be able to mate once a week," said Watson. "That, in turn, might mean that some female lobsters that might be ready to mate, would not get the chance. Females only mate after they molt, which they do only once per year, and they all tend to do it around the same time. So, limited availability of male sperm could significantly impact the population."The absence of cost-effective ways to measure lobster sperm meant that testing the sperm limitation hypothesis were rarely attempted, despite concerns about the sustainability of the American lobster population."Beforehand, if we wanted to look at questions of reproductive output in lobsters, it took labor-intensive methods and an incredible amount of time," says Ben Gutzler, a recent PhD graduate from UNH in Marine Biology and lead author. "This new DNA method will hopefully make it possible for a broader group of scientists to ask more relevant questions about more animals."Although the researchers did not find evidence of sperm limitation among male lobsters, they did uncover inconsistent sperm production among the individual lobsters studied. For example, they found that lobsters with severe shell disease, which is very common in southern New England, packaged fewer sperm cells in each spermatophore. This could have implications for population sustainability and prompt further study.
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Animals
| 2,020 |
July 15, 2020
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https://www.sciencedaily.com/releases/2020/07/200715160008.htm
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When should you neuter your dog to avoid health risks?
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Some dog breeds have higher risk of developing certain cancers and joint disorders if neutered or spayed within their first year of life. Until now, studies had only assessed that risk in a few breeds. A new, 10-year study by researchers at the University of California, Davis, examined 35 dog breeds and found vulnerability from neutering varies greatly depending on the breed. The study was published in the journal
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"There is a huge disparity among different breeds," said lead author Benjamin Hart, distinguished professor emeritus at the UC Davis School of Veterinary Medicine. Hart said there is no "one size fits all" when it comes to health risks and the age at which a dog is neutered. "Some breeds developed problems, others didn't. Some may have developed joint disorders but not cancer or the other way around."Researchers analyzed 15 years of data from thousands of dogs examined each year at the UC Davis Veterinary Medical Teaching Hospital to try to understand whether neutering, the age of neutering, or differences in sex when neutered affect certain cancers and joint disorders across breeds. The joint disorders examined include hip dysplasia, cranial cruciate ligament tears and elbow dysplasia. Cancers examined include lymphoma; hemangiosarcoma, or cancer of the blood vessel walls; mast cell tumors; and osteosarcoma, or bone cancer.In most breeds examined, the risk of developing problems was not affected by age of neutering.Researchers found that vulnerability to joint disorders was related to body size."The smaller breeds don't have these problems, while a majority of the larger breeds tend to have joint disorders," said co-author Lynette Hart, professor at the UC Davis School of Veterinary Medicine.One of the surprising exceptions to this was among the two giant breeds -- great Danes and Irish wolfhounds -- which showed no increased risk to joint disorders when neutered at any age.Researchers also found the occurrence of cancers in smaller dogs was low, whether neutered or kept intact. In two breeds of smaller dogs, the Boston terrier and the shih tzu, there was a significant increase in cancers with neutering.Another important finding was that the sex of the dog sometimes made a difference in health risks when neutered. Female Boston terriers neutered at the standard six months of age, for example, had no increased risk of joint disorders or cancers compared with intact dogs, but male Boston terriers neutered before a year of age had significantly increased risks.Previous studies have found that neutering or spaying female golden retrievers at any age increases the risk of one or more of the cancers from 5 percent to up to 15 percent.Dog owners in the United States are overwhelmingly choosing to neuter their dogs, in large part to prevent pet overpopulation, euthanasia or reduce shelter intake. In the U.S., surgical neutering is usually carried out by six months of age.This study suggests that dog owners should carefully consider when and if they should have their dog neutered."We think it's the decision of the pet owner, in consultation with their veterinarian, not society's expectations that should dictate when to neuter," said Benjamin Hart. "This is a paradigm shift for the most commonly performed operation in veterinary practice."The study lays out guidelines for pet owners and veterinarians for each of 35 breeds to assist in making a neutering decision. See details in journal publication below.
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Animals
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July 15, 2020
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https://www.sciencedaily.com/releases/2020/07/200715131224.htm
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Invasive hedgehogs and ferrets habituate to and categorize smells
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To catch a thief, the saying goes, you have to think like a thief. The same is true for invasive predators: to foil their depredations on native wildlife, scientists have to understand how they think.
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A new study published in the Ecological Society of America's journal Previous research has established that "chemical camouflage" could be an effective way to deter invasive species from harming vulnerable bird populations: scientists can distribute appealing bird odors near nests before eggs appear, so that the predator eventually starts ignoring the smell -- even after tasty eggs become available.This study goes a step further, showing that invasive predators not only learn to pinpoint (or ignore) certain smells that are associated with food -- they can also classify similar smells into groups."We are trying to understand how these predators have been so effective at destroying the native fauna," says Catherine Price, a postdoctoral research associate at the University of Sydney and the study's lead author. "We are researching new ways to exploit behavioral patterns and traits to understand why native species are so vulnerable and how to protect them."In New Zealand, invasive mammalian predators have devastated local bird populations, especially of the wrybill, double-banded plover, kak?, and black-fronted tern, whose populations nest at the same time and in similar locations. Such nesting colonies are the proverbial sitting duck: with no defenses, small numbers of predators like ferrets and hedgehogs can essentially wipe out nearly a generation with very little effort.Hedgehogs and ferrets are generalists. Ferrets mainly hunt rabbits but will not turn down an easy meal of eggs or chicks. Hedgehogs eat mostly invertebrates and berries but also love eggs, especially right out of hibernation when they are especially hungry.Price wanted to understand how the predators seek out bird colonies. While humans are primarily visual, many other animals -- including ferrets and hedgehogs -- draw more information from other senses, including their sense of smell."Because humans aren't olfactory species, we don't often think about odor," Price said. "But these predators are very sensitive to odor, and to the costs of odor. They respond very quickly if a hunting tactic -- like following a certain odor -- isn't working."Price and her team captured local ferrets and hedgehogs and ran them through a series of controlled treatments in outdoor enclosures resembling their natural habitat to examine how these predators categorize smells -- whether they group smells of similar types of birds together -- and how and whether they habituate to smells. This is the first time this kind of research has been done on these predators in a controlled outdoor setting.The question of categorization reveals a substantial amount about the hunting strategies and priorities of the predator. Separating smells into individual species requires an investment that might not always be merited. In some cases, it is sufficient for ferrets or hedgehogs to simply sniff out a broad category of prey, such as "ground-nesting bird with eggs this time of year," but knowing exactly what kind of bird they are smelling is irrelevant."The idea that animals are grouping prey together by smell is exciting," Price said. "We never assumed wild animals did that before, and now we've shown that they can do this using smell."The team discovered that ferrets generalized the avian smells (in this case gulls and quail) but the hedgehogs did not. In many ways, this makes sense: ferrets consume lots of prey besides bird species, so distinguishing between bird smells may not be worth a ferret's time or energy. Seasonality may also have played a role. In the experiment, hedgehogs were getting ready to go into hibernation, making them especially motivated to find high-quality meals easily.This finding indicates it might be possible to protect bird colonies by distributing bird smell around the area. If an entire area were saturated with the smell of a nesting ground species, it could protect a nesting colony. Predators would become accustomed to the smell and ignore it, seeking out other prey."Understanding how predators group smell is important because if they generalize, we don't have to actually put out the smell of the bird we're protecting; we can put out chicken or quail odors that we can easily get in abundance," Price said.Understanding how invasive predators hunt and think gives scientists and conservationists an edge in protecting native prey. Further studies may reveal more ways to protect native populations by exploiting predators' behaviors.
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July 15, 2020
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https://www.sciencedaily.com/releases/2020/07/200715123141.htm
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How flies flip around on take-off from an upside- down position
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Flies are able to right themselves very quickly when taking off from an upside-down position. Scientists from the CNRS and from The Institute of Movement Science (ISM) at Aix-Marseille Université studying this phenomenon discovered the surprising way these insects begin by turning their bodies before their heads on take-off. The research will be published on 15 July 2020 in the
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With its legs pointing up and its wings down towards the floor, a fly can casually rest upside-down on a ceiling, but on take-off, it will right itself very quickly. Researchers from the CNRS and Aix-Marseille Université looked at how the insect flips itself around when taking off. With the aid of a high-speed camera, the scientists discovered that, contrary to cats which land on their feet by first turning their heads, flies begin by turning their bodies. The insect reorients itself within six wing beats at a speed of 10,000°/s, or approximately 30 revolutions per second. The whole movement takes approximately 0.05 s with the head turning 0.016 s later than the body.According to the scientists, during take-off flies flip their bodies before their heads due to an inherent stabilisation reflex. Small stabilisers near the wings function as a type of gyroscope. Humans have a similar reflex which kicks in when they continue to stare at something despite turning their bodies around. In the study, the team included modelling which suggested that, during reorientation, the insect stabilises its visual system before resuming normal flight. The research aims to elucidate how flies orient themselves relative to a vertical axis. The scientists will now further their research to investigate the effect of light on a fly's orientation.
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July 15, 2020
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https://www.sciencedaily.com/releases/2020/07/200715111427.htm
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Mystery about history of genetic disease in horses
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Warmblood fragile foal syndrome is a severe, usually fatal, genetic disease that manifests itself after birth in affected horses. Due to the defect, the connective tissue is unstable. Under force, for instance, the skin tears from the tissue underneath and the joints can suffer dislocation. A research team from the Universities of Göttingen and Halle has now been able to prove that the disease did not stem from the English thoroughbred stallion Dark Ronald XX, which had been the assumption until now. The results have been published in the journal
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The mystery of the genetic defect could have been solved in 2012: this is when gene responsible was identified. It is called PLOD1 and normally ensures that collagen molecules in the skin and connective tissue can bind to form a stable network. The mutation in the PLOD1 gene prevents "cross-linking" which is needed for stable collagen. The exact origin of the mutation was previously unclear. Since the spread of the genetic defect is also a problem in horse-breeding in Germany, the Vereinigte Informationssysteme Tierhaltung (IT-Solutions for Animal Production) in Verden 2019 determined the possible origin of the genetic defect from the test results of around 2,000 horses and their pedigree records. The investigation concluded that the genetic defect was probably due to the English thoroughbred stallion Dark Ronald XX (1905-1928) or his father, Bay Ronald XX, and the defect was then spread through their offspring. The current research, led by the University of Göttingen, calls this theory into question. "We have now succeeded in proving that Dark Ronald XX was not a carrier of the PLOD1 mutation and can therefore be excluded as the original source of this genetic defect," says Professor Bertram Brenig, Director of the Institute of Veterinary Medicine at the University of Göttingen and lead author of the study. Doubts about whether the mutation descended from Dark Ronald XX were already expressed in 2019, and further investigation reveals a Hanoverian stallion born in 1861.Dark Ronald XX was an important thoroughbred stallion who had a great influence on German horse-breeding. He was sold to Germany in 1913 and was used as a stud -- a stallion with highly prized heritable characteristics -- first in Graditz and later in Altefeld. In 1928, he was brought to the veterinary clinic of the University of Halle for treatment due to intestinal colic and this is where he died. Since then his remains -- such as skeleton, heart and skin -- have been kept in one of the natural science collections of the Martin Luther University Halle-Wittenberg. "This is most fortunate, as it has allowed us to examine Dark Ronald XX directly for the presence of the PLOD1 mutation," says Brenig. The scientists were thus able to examine small pieces of Dark Ronald XX's skin. "Examining the DNA from the nearly 100-year-old skin of Dark Ronald XX was not easy," says co-author Dr Renate Schafberg from the University of Halle, "because we knew nothing about the tanning or other preservation treatments of the skin."The disease itself is not new and probably originated in the middle of the 18th century. Since then, all breeding animals have been consistently tested for the genetic defect. There is a comparable genetic disease in humans, known as Ehlers-Danlos syndrome, which shows similar symptoms.
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July 14, 2020
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https://www.sciencedaily.com/releases/2020/07/200714182154.htm
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For chimpanzees, salt and pepper hair not a marker of old age
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Silver strands and graying hair is a sign of aging in humans, but things aren't so simple for our closest ape relatives -- the chimpanzee. A new study published today in the journal
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This research calls into question the significance of the graying phenotype in wild non-human species. While graying is among the most salient traits a chimpanzee has -- the world's most famous chimpanzee was named David Greybeard -- there is significant pigmentation variation among individuals. Graying occurs until a chimpanzee reaches midlife and then plateaus as they continue to age, according to Elizabeth Tapanes, a Ph.D. candidate in the GW Department of Anthropology and lead author of the study."With humans, the pattern is pretty linear, and it's progressive. You gray more as you age. With chimps that's really not the pattern we found at all," Tapanes said. "Chimps reach this point where they're just a little salt and peppery, but they're never fully gray so you can't use it as a marker to age them."The researchers gathered photos of two subspecies of wild and captive chimpanzees from their collaborators in the field to test this observation. They visually examined photos of the primates, evaluated how much visible gray hair they had and rated them accordingly. The researchers then analyzed that data, comparing it to the age of the individual chimpanzees at the time the photos were taken.The researchers hypothesize there could be several reasons why chimpanzees did not evolve graying hair patterns similar to humans. Their signature dark pigmentation might be critical for thermoregulation or helping individuals identify one another.Dr. Brenda Bradley, an associate professor of anthropology, is the senior author on the paper. This research dates back to an observation Dr. Bradley made while visiting a field site in Uganda five years ago. As she was learning the names of various wild chimpanzees, she found herself making assumptions about how old they were based on their pigmentation. On-site researchers told her that chimps did not go gray the same way humans do. Dr. Bradley was curious to learn if that observation could be quantified.There has been little previous research on pigmentation loss in chimpanzees or any wild mammals, Dr. Bradley said. Most existing research on human graying is oriented around the cosmetic industry and clinical dermatology."There's a lot of work done on trying to understand physiology and maybe how to override it," Dr. Bradley said. "But very little work done on an evolutionary framework for why is this something that seems to be so prevalent in humans."The researchers plan to build on their findings by looking at the pattern of gene expression in individual chimpanzee hairs. This will help determine whether changes are taking place at the genetic level that match changes the eye can see.This study comes ahead of World Chimpanzee Day on July 14. GW's faculty and student researchers make contributions to our global understanding of chimpanzees and primates as part of the GW Center for the Advanced Study of Human Paleobiology. Through various labs, investigators study the evolution of social behavior in the chimpanzees and bonobos, the evolution of primate brain structure, and lead on-the-ground projects at the Gombe Stream Research Center in Tanzania. Dr. Bradley's lab is also currently working on research about color vision and hair variation in lemurs.
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July 14, 2020
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https://www.sciencedaily.com/releases/2020/07/200714143044.htm
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A Raspberry Pi-based virtual reality system for small animals
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The Raspberry Pi Virtual Reality system (PiVR) is a versatile tool for presenting virtual reality environments to small, freely moving animals (such as flies and fish larvae), according to a study published July 14, 2020 in the open-access journal
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PiVR consists of a behavioral arena, a camera, a Raspberry Pi microcomputer, an LED controller, and a touchscreen. This system can implement a feedback loop between real-time behavioral tracking and delivery of a stimulus. PiVR is a versatile, customizable system that costs less than $500, takes less than six hours to build (using a 3D printer), and was designed to be accessible to a wide range of neuroscience researchers.In the new study, Tadres and Louis used their PiVR system to present virtual realities to small, freely moving animals during optogenetic experiments. Optogenetics is a technique that enables researchers to use light to control the activity of neurons in living animals, allowing them to examine causal relationships between the activity of genetically-labeled neurons and specific behaviors.As a proof-of-concept, Tadres and Louis used PiVR to study sensory navigation in response to gradients of chemicals and light in a range of animals. They showed how fruit fly larvae change their movements in response to real and virtual odor gradients. They then demonstrated how adult flies adapt their speed of movement to avoid locations associated with bitter tastes evoked by optogenetic activation of their bitter-sensing neurons. In addition, they showed that zebrafish larvae modify their turning maneuvers in response to changes in the intensity of light mimicking spatial gradients. According to the authors, PiVR represents a low-barrier technology that should empower many labs to characterize animal behavior and study the functions of neural circuits."More than ever," the authors note, "neuroscience is technology-driven. In recent years, we have witnessed a boom in the use of closed-loop tracking and optogenetics to create virtual sensory realities. Integrating new interdisciplinary methodology in the lab can be daunting. With PiVR, our goal has been to make virtual reality paradigms accessible to everyone, from professional scientists to high-school students. PiVR should help democratize cutting-edge technology to study behavior and brain functions."
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July 14, 2020
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https://www.sciencedaily.com/releases/2020/07/200714143040.htm
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What determines a warbler's colors?
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A new study has narrowed down the region of the genome that drives the black color in throat and face of warblers by studying the hybrid offspring produced when two species mate. The hybrids of golden-winged and blue-winged warblers have a mix of coloration from the parent species, which allows researchers to identify which regions of the genome are associated with which color patterns. The study, led by researchers at Penn State, also reveals a more complex basis for the amount of yellow in warbler bellies and raises concerns about how hybrids of these species are classified.
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Their results appear online in the journal "The distinct plumage of these otherwise very similar birds has perplexed ornithologists for more than a hundred years," said Marcella Baiz, postdoctoral researcher at Penn State and first author of the paper. "Our research team previously compared the genomes of golden-winged and blue-winged warblers and identified 6 regions that differed between them, some of which may control color. In this study, we used hybrid birds of these species, which mix and match the features of their parent species, to help identify which regions of the genome are associated with which color patterns."Color is an important cue for warblers and is prominently displayed during mating and other behaviors. Blue-winged warblers have yellow throats and bellies, while golden-winged warblers have white bellies and a black throat patch and face mask. Hybrids of these species vary in amounts of yellow and whether they have a black face mask and throat, and these characteristics are commonly used to categorize birds into different classes of hybrids.The research team rated hybrid birds based on their plumage color and genetic likeness to the two parental species. They found that the amount of yellow in hybrids, which is produced by pigments called carotenoids, is not directly related to a bird's genetic likeness to the parent species -- for example, hybrids with more yellow were not genetically closer to blue-winged warblers. Additionally, the extent of yellow in hybrids re-captured in subsequent years appeared to decline over time."Some researchers have hoped that the extent of yellow could indicate how many generations a hybrid is removed from the parent species," said David Toews, assistant professor of biology at Penn State and leader of the research team. "Our results indicate that it isn't quite so straightforward, and that classifying hybrids into groups based on the amount of yellow can be misleading."The inheritance of a black throat patch and face mask, however, appears to be much more straightforward. The research team previously identified a genetic region related to black coloration in warblers. In the current study, the team used a rarer type of hybrid to narrow that to a region about five times smaller."This one type of very rare hybrid looks almost entirely like a blue-winged warbler, with a yellow body but with a black throat patch and face mask, like a golden-winged warbler," said Baiz. "By comparing its genome to that of blue-wing warblers, we were able to identify a much smaller genetic region where the birds differed, which we believe drives the black coloration."The genetic region is located near the Agouti-signaling protein (ASIP) gene, which is thought to regulate production of the pigment melanin in some birds. Next, the research team would like to confirm that this section of the genome affects expression of the ASIP protein in warblers and underlies differences in their black plumage patches."We plan to continue to study the evolution of color across the 110 species of warblers, which have incredibly diverse plumage," said Toews. "Now that we have identified a starting point, this narrowed down genetic region, we won't be stabbing in the dark."In addition to Baiz and Toews, the research team includes Gunnar Kramer and Henry Streby from the University of Toledo, Scott Taylor from the University of Colorado, Boulder, and Irby Lovette from the Cornell Lab of Ornithology. This research was supported by the Cornell Lab of Ornithology, the U.S. Geological Survey, and the National Science Foundation.
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Animals
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July 14, 2020
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https://www.sciencedaily.com/releases/2020/07/200714143036.htm
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Researchers cast doubt on earlier COVID-19 origins study citing dogs as possible hosts
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A study published earlier this year claiming the coronavirus may have jumped from dogs to humans is scientifically flawed, offering no direct evidence to support its conclusions, according to a collaborative group of international researchers, including scientists at the University of Colorado Anschutz Medical Campus.
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"During this time of Covid-19 we are seeing people publish things that make wild leaps to conclusions that are not justified by the evidence," said David Pollock, PhD, professor of biochemistry and molecular genetics at the University of Colorado School of Medicine. "And this seems to be one of them."Pollock and CU Anschutz alumnus Todd Castoe, an associate professor of biology at the University of Texas Arlington, are lead authors of an academic letter published this week in Pollock and his co-authors, including PhD student Kristen Wade and colleague Elizabeth Carlton, PhD, MPH, an assistant professor at the Colorado School of Public Health at CU Anschutz, took issue with the April 2020 study by biology Professor Xuhua Xia of the University of Ottawa in Canada.Many scientists are interested in the origins of the novel coronavirus. The want to know which host the SARS-CoV-2 virus, responsible for Covid-19, came from before making the leap from animal to human.The classic way to address this is by finding viruses with similar genome sequences in a particular animal host. Xia, however, focused on a feature of the coronavirus genome known as CpG content, and found that a distantly-related dog coronavirus had similar CpG content as SARS-CoV-2. Because this distant virus replicated well in the dog's digestive tract, he concluded that a dog's intestines were the ideal place to have affected the ancestral SARS-CoV-2's CpG content."However, there is no evidence for the logical premise of Xia's argument, considering that all mammals have digestive tracts," the researchers wrote.They showed that dogs aren't special in their content of ZAP and ABOBEC3G proteins, which help safeguard humans from viruses and can interact with viral CpG content."Additionally, a recent inoculation study found that while other domesticated mammalian hosts are highly susceptible to SARS-CoV-2, canines exhibited low susceptibility, and no traces of viral RNA were detectable in any dog organs," the scientists wrote.Pollock and his colleagues said that although the recent origin of SARS-CoV-2 is uncertain, the best current evidence makes it likely that it was passed to humans by horseshoe bats or possibly pangolins, a kind of spiny anteater in China. There is strong evidence that the virus has recently jumped between humans and these animals or other intermediate hosts.Bat and pangolin viruses also have CpG content similar to human SARS-CoV-2, so the environment that affected viral CpGs must have happened long ago and possibly in one of these two mammals. They noted that there are signs of prior recombination events among divergent viruses. That suggests that over the years relatives of coronaviruses found in bats and pangolins mixed and mutated to give rise to SARS-CoV-2.The proposition that dogs were likely recent ancestors of SARS-CoV-2 is not justified by the available evidence, the researchers concluded."Xia did not demonstrate that the low CpG frequency in the SARS- CoV-2 genome was driven by a unique selective environment in dog digestive tracts," the authors wrote. "Dogs are not more plausible than most other potential host species, and based on current data, far less plausible than bats or pangolins."Pollock said determining how the virus jumped from animals to humans is critical in preparing for the next pandemic.Even so, he said, in the midst of a pandemic scientific results can be over-interpreted and misused, leading to misappropriation of resources and effort. Rather than promote the speculations of a study based on weak evidence, he noted, it is better to admit uncertainty. If not, the scientific community has an obligation to respond."Considering the ramifications, scientists need to be particularly careful in interpreting findings, and avoid rushing to conclusions that are not well supported by solid evidence" co-lead author Castoe said. "We need to get this right."
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Animals
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July 14, 2020
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https://www.sciencedaily.com/releases/2020/07/200714101224.htm
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More than one cognition: A call for change in the field of comparative psychology
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What makes a species "smart" and how do strategies for processing information evolve? What goes on in the minds of non-human animals and which cognitive skills can we claim as hallmarks of our species? These are some of the questions addressed by the field of comparative psychology, but a recent review in the
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Based on 40 years of scientific literature and case studies of three non-human animals, the current paper identifies two main problems hindering research in comparative psychology.First of which is the assumption that human cognition is the standard by which animal cognition should be measured. Human cognition is generally believed to be the most flexible, adaptable form of intelligence, with the abilities of other species evaluated in accordance to the extent they match human cognitive skills. Such an approach tends to overrate human-like cognitive skills and may overlook cognitive skills that play only a small part, or no part at all, in human psychology."This approach, whether implicit or explicit, can only produce a restrictive, anthropocentric view of cognitive evolution that ignores the incredible diversity of cognitive skills present in the world," says Juliane Bräuer, leader of the DogLab at the Max Planck Institute for the Science of Human History. Instead, research into the evolution of cognition should take a biocentric approach, considering each species investigated in its own right."Applying Darwinian thinking to comparative psychology and removing the 'benchmark' of human intelligence allows us to reveal the evolutionary, developmental and environmental conditions that foster the growth of certain unique abilities and the convergence of skills shared among a species," adds Natalie Uomini, the main co-author of the paper.To further address this anthropocentric view, the authors also argue for increased focus on cognitive abilities in which animals outperform humans and discuss cases in which various species demonstrate better-than-human abilities in delayed gratification, navigation, communication, pattern recognition and statistical reasoning.The second problem addressed is the assumption that cognition evolves as a package of skills similar to those apparent in humans, skills which taken together constitute "one cognition." The authors survey various major hypotheses from psychology, including Social Intelligence Hypothesis, Domestication Hypothesis and Cooperative Breeding Hypothesis, and argue that while each has evidence to support its claims, none account for the whole picture of cognition.Instead of a cluster of linked skills originating from a single evolutionary pressure, the paper provides a framework for understanding cognitive arrays as the result of species-typical adaptations to the entire ecological and social environment."If we want to account for the fascinating variety of animal minds, comparative scientists should focus on skills that are ecologically relevant for a given species," say Bräuer and Uomini.The paper discusses three distantly related species -- chimpanzees, dogs and New Caledonian crows -- that are highly sophisticated in one cognitive domain yet perform poorly in others generally believed to be linked.The paper also lays out recommendations to make future experiments in comparative psychology ecologically relevant to the target species, including differentiating tasks for each species and accounting for diverse senses of perception, such as smell in the case of dogs.In Germany, where the authors of the paper are based, comparative psychology is a relatively unknown field. The authors hope to stimulate interest and growth in the subject with future research dedicated to the study of each species' cognitive skills for their own sake, leading to a more relevant and holistic perspective on animals' cognitive skills and the recognition that there is not only "one cognition."
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Animals
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July 13, 2020
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https://www.sciencedaily.com/releases/2020/07/200713133456.htm
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When calling loudly, echolocation is costly for small bats
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Calling in the ultrasonic range enables small bats to orient themselves in the dark and track down tiny insects. Louder calls travel farther, improving a bat's ability to detect their prey. It was long assumed that echolocation does not contribute much to energy expenditure in flight because individuals simply couple their calls with the beat of their wings. Scientists at the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in Berlin have now shown that high intensity echolocation calls are by no means free and substantially contribute to energy expenditure. Bats must therefore find a balance between energy expenditure and effective echolocation and use the latter economically.
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For many animals, vocalisations are essential for survival. With their calls, roars, croaks, chirps or songs, animals attract potential mating partners, repulse competitors or locate prey. These sounds can be deafening. A bison, for instance, roars at up to 127 decibels (dB), some birds reach 132 dB and sea lions even manage 137 dB! For comparison: a sound pressure level of 110dB is equivalent to the sound of jet engine 100m away. Despite their small size, bats can reach a sound pressure level of 137 dB, amongst the loudest animals in the world. But because of their high frequency, these sounds are inaudible to the human ear.In principle, generating a higher sound pressure level is associated with higher energy costs. If a bat in search of prey wants to increase the distance over which its echolocation travel, it has to call louder, which should cost more energy. Until now, the prevailing opinion amongst scientists was that, at least in flight, bats can boost the sound pressure level of their calls without additional energy expenditure. This is because they synchronize the contraction of the abdominal wall, necessary for sound production, with the contractions of the large, active flight muscles to generate echolocation calls. According to conventional wisdom, the pressure generated by the wing beat is sufficient to support the production of very loud echolocation. The energy expenditure of flying bats should therefore remain more or less the same, regardless of whether they call softly or loudly.A team of scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in Germany and Tel Aviv University in Israel has now shown that this is not the case. In their experiments, they allowed Nathusius' pipistrelle bats (Pipistrellus nathusii) to fly freely in a wind tunnel under controlled conditions. Using loudspeakers, the researchers generated a loud background noise inside the tunnel. This encouraged the bats to drown out the noise with more intense echolocation calls. Before flying in the wind tunnel, the animals had received an isotonic solution of 13C-labelled sodium bicarbonate, which is exhaled as carbon dioxide during breathing, a proxy for metabolic rate. From the isotopic composition of the breathing air before and after the flight, the scientists determined the animals' energy expenditure when flying in the tunnel."When bats were flying with only the noise from the wind tunnel, echolocation intensity was 113 dB on average" says Leibniz-IZW scientist Shannon Currie, joint first author of the study. "But when flying in background noise of 109dB, the bats increased their echolocation intensity to an average of 128 dB." Since the sound pressure level follows a logarithmic scale, the bat calls were actually 30 times (!) louder when there was a high background noise in the wind tunnel.This had significant effects on energy expenditure. Metabolic power rose by 0.12 watts when bats were calling 15 dB louder. If a bat were to maintain this high sound pressure level throughout a typical night-time foraging flight, it would have to catch about 0.5 grams of additional insect prey to compensate for the added energy expenditure, or one fourteenth of their own body mass. This is an enormous amount for an animal that itself weighs only seven grams."Our study illustrates that in bats the coupling of the abdominal wall movement with the flight muscle contractions alone is not sufficient to produce very loud calls," explains Christian Voigt, head of the Department of Evolutionary Ecology at the Leibniz-IZW. "We therefore assume that with more intense echolocation, additional muscles must become active to support the production of sound. This clearly costs a great deal of energy -- especially above 130 dB. A bat in search of prey cannot increase at will the intensity and thus the distance over which its calls range. Instead, it must use loud calls economically and find a good compromise between the associated energy expenditure and the efficiency of echolocation."
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Animals
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July 13, 2020
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https://www.sciencedaily.com/releases/2020/07/200713133452.htm
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Bird droppings carry risk of antibiotic resistance
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Bird droppings may pose more health risks than people realize, according to Rice University environmental engineers who study antibiotic resistance.
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Their study found high levels of genes that encode antibiotic resistance harbored by opportunistic pathogens in the droppings of common urban ducks, crows and gulls.The study led by postdoctoral research associate Pingfeng Yu of Rice's Brown School of Engineering appears in the Elsevier journal Previous studies determined bird-carried antibiotic resistant genes (ARGs) and bacteria (ARBs) can be transferred to humans through swimming, contact with feces or impacted soil or inhalation of aerosolized fecal particles. Studies have also analyzed bird feces found near ARG hotspots like wastewater treatment plants and drainage from poultry farms.But the Rice study digs deeper to quantify the abundance, diversity and seasonal persistence of ARGs."We still do not fully understand what factors exert selective pressure for the occurrence of ARGs in the gastrointestinal system of wild urban birds," Alvarez said. "Residual antibiotics that are incidentally assimilated during foraging is likely one of these factors, but further research is needed to discern the importance of other potential etiological factors, such as bird diet, age, gut microbiome structure and other stressors."The team that included lead authors Huiru Zhao, a student at Nankai University in China, and Rice graduate student Ruonan Sun compared "freshly deposited" samples from each species found around Houston during the winter and summer months to samples from poultry and livestock known to carry some of the same mutations.They found that ARGs in all of the species, regardless of season, encoded significant resistance to tetracycline, beta-lactam and sulfonamide antibiotics. The researchers were surprised to see the relatively high abundance of ARGs were comparable to those found in the fresh feces of poultry occasionally fed with antibiotics.They also found intI1, an integron that facilitates rapid bacterial acquisition of antibiotic resistance, was five times more abundant in the birds than in farm animals."Our results indicate that urban wild birds are an overlooked but potentially important reservoir of antimicrobial resistance genes, although their significance as vectors for direct transmission of resistant infections is possible but improbable due to low frequency of human contact," Alvarez said.The team also looked for ARGs in soil up to 1 inch deep around bird deposits and discovered they are "moderately persistent" in the environment, with half-lives of up to 11.1 days.Of the three species, crows showed a significantly lower level of ARGs during the summer compared to ducks and gulls, they reported."That's probably due to differences in their ecological niches, foraging patterns and gut microbiome," Sun said. "Crows are omnivores and feed on abundant natural food with less anthropogenic contaminations in the summer. In addition, the composition of their gut microbiome impacts ARG dissemination and enrichment in vivo, and therefore influences ARG levels in the excreted bird feces."The researchers found that opportunistic pathogens including bacteria that cause urinary tract infections, sepsis and respiratory infections were common in the feces of all of the birds, and another associated with food poisoning was detected in samples collected during the winter.Winter feces, they wrote, contained more of the bad bacteria that may also harbor ARGs, possibly due to lower sunlight inactivation and differences in moisture levels and temperature."Our study raises awareness to avoid direct contact with bird droppings in urban public areas, especially for vulnerable or sensitive populations," Yu said. "Meanwhile, regular cleaning should also help to mitigate associated health risks."
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Animals
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July 13, 2020
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https://www.sciencedaily.com/releases/2020/07/200713104354.htm
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Bat research critical to preventing next pandemic
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The current SARS-CoV-2 pandemic has a likely connection to bats, and the next viral outbreak probably will too, unless scientists can quickly learn more about the thousands of viruses carried by one of the most diverse mammals on the planet.
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Evidence already links different bat species to human outbreaks of SARS, MERS, some Ebola viruses as well as the Marbug, Hendra, Sosuga and Nipah viruses. Beyond these connections, there is very little known, and a recent article in "The more researchers have looked, the more we've found that a lot of these emerging pathogens, at one point or another, originated in bats," said Michael Letko, the lead author and an assistant professor of molecular virology at Washing State University's Paul G. Allen School of Global Animal Health. "Over time, we have accumulated a lot of information about some of the species of bats and some of the viruses they carry, but there are still these huge glaring holes in our knowledge."With more than 1,400 species, bats represent an extremely diverse mammalian order, second only to rodents, which are also known viral hosts. However, unlike rats and mice, bats are not great lab animals. Simply keeping flying animals in labs is difficult. Also, most of the mammalian cell lines developed for research came from other animals and cannot be used to study viruses found in bats.This knowledge gap is dangerous as the current pandemic shows. Bats are found almost everywhere scientists have looked, and with expanding human encroachment on their habitat, viral infection is almost inevitable, Letko said."We are coming into more contact with animal species around us in general, and then we find out these species are loaded with viruses," he said. "The COVID-19 pandemic is unfortunate, but it's not surprising. We roll the dice for 20 years not doing anything to reduce contact with these animals. It was more or less a matter of time before something like this was going to happen."In the paper, Letko, and his co-authors including WSU assistant professor Stephanie Seifert and Vincent Munster from Rocky Mountain Laboratories, outline ways to decrease the odds of the next pandemic by increasing research into bats on the smallest, molecular level and on the broader macro-level of the environment.While many pathogens have been identified, the authors point out the need to move beyond discovery and use the latest genetic technologies to better understand how viruses can be transmitted. This knowledge can increase the ability to develop medicines quickly after a pathogen has been found -- or even better, create vaccines to protect against whole virus groups before they emerge.Letko has already taken a step in this direction. Before the current crisis, he built a platform using synthetic coronavirus particles to test which were most likely to infect human cells. When the current pandemic began, Letko tested the SARS-Cov-2 genome as soon as the sequence was available and quickly identified the likely receptor on human cells. That study, published in Nature Microbiology on Feb. 24, was one of the first to provide functional laboratory data on the new virus, providing researchers with necessary information and tools to help determine which existing drugs might work against SARS-Cov-2 and start development on new ones as well as test various aspects of SARS-CoV-2 vaccine efficacy.Letko is setting up his lab at WSU to continue this work, providing initial screening of bat-borne viruses to help identify those that are most likely to be transmitted to humans.Beyond the lab, Letko and his colleagues point to the need for better understanding of bat ecology which can lead to solutions that are relatively simple to implement. The researchers cite examples such as the effort to vaccinate horses in Australia to stop the Hendra virus which was spreading from fruit bats to horses and then potentially on to humans. Another intervention in Bangladesh involved simply putting lids on palm sap containers to keep bats out and prevent human outbreaks of Nipah virus."Sometimes, you don't need vaccines or drugs. It's just a behavioral change that helps mitigate and reduce the contact between people and the animals," Letko said. "These are some of the kinds of interventions that we can take once we begin to understand what these viruses actually do."
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July 13, 2020
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https://www.sciencedaily.com/releases/2020/07/200713120028.htm
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Biosignatures may reveal a wealth of new data locked inside old fossils
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Step aside, skeletons -- a new world of biochemical "signatures" found in all kinds of ancient fossils is revealing itself to paleontologists, providing a new avenue for insights into major evolutionary questions.
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In a new study published in the journal "What we're discovering is that molecular, carbonaceous residues almost always preserve a microscopic clue within fossils," said Jasmina Wiemann, a graduate student in the Department of Earth & Planetary Sciences at Yale and first author of the study. "Fossil organic matter is a wild mix of things, based on the chemical degradation products of original biomolecules."Working with Yale paleontologist Derek Briggs and Yale chemist Jason Crawford -- both co-authors of the study -- Wiemann analyzed the molecular composition of 113 animal fossils dating back 541 million years. It is the largest fossil data set to be analyzed by chemical means.What they found was an abundance of soft tissues that fossilize into polymers. Recognizing these polymers and the soft tissues they represent may help researchers determine how various animals relate to each other in evolutionary history."We show that proteins, lipids, and sugars in all types of animal tissues converge in composition during fossilization through processes such as lipoxidation and glycoxidation to form polymers," said Briggs, the G. Evelyn Hutchinson Professor of Geology & Geophysics in the Yale Faculty of Arts and Sciences.Wiemann used Raman spectral analysis -- a non-destructive chemical analysis technique -- to determine whether there are identifiable biochemical signatures that survive within these polymers.Thus far, she and her colleagues have found three main categories of signatures: biomineralization signals (which helped determine the soft nature of early dinosaur egg shells); tissue signals that differentiate between, for example, insect cuticle and vertebrate cartilage (used to identify the Tully Monster as a vertebrate); and phylogenetic signals that are based on fossilization products of amino acids, revealing how animals are related.The researchers said understanding biological signatures in fossils has the potential to fundamentally advance scientific knowledge about the evolution of life on Earth."With this approach, we can go in a number of different research directions, representing big questions for animal evolution with answers that we thought were beyond the reach of fossils," Wiemann said.Grants from the Yale Institute for Biospheric Studies and the Geological Society of America funded the research.
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Animals
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July 10, 2020
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https://www.sciencedaily.com/releases/2020/07/200710212233.htm
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Like humans, beluga whales form social networks beyond family ties
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A groundbreaking study using molecular genetic techniques and field studies brings together decades of research into the complex relationships among beluga whales (
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The study, led by Florida Atlantic University's Harbor Branch Oceanographic Institute, is the first to analyze the relationship between group behaviors, group type, group dynamics, and kinship in beluga whales. Findings, just published in Findings indicate that evolutionary explanations for group living and cooperation in beluga whales must expand beyond strict inclusive fitness arguments to include other evolutionary mechanisms. Belugas likely form multi-scale societies from mother-calf dyads to entire communities. From these perspectives, beluga communities have similarities to human societies where social networks, support structures, cooperation and cultures involve interactions between kin and non-kin. Given their long lifespan (approximately 70 years) and tendency to remain within their natal community, these findings reveal that beluga whales may form long-term affiliations with unrelated as well as related individuals."This research will improve our understanding of why some species are social, how individuals learn from group members and how animal cultures emerge," said Greg O'Corry-Crowe, Ph.D., lead author and a research professor at FAU's Harbor Branch. "It also has implications for traditional explanations based on matrilineal care for a very rare life-history trait in nature, menopause, which has only been documented in a handful of mammals, including beluga whales and humans."Researchers found that belugas formed a limited number of group types, from mother-calf dyads to adult male groups, and from mixed-age groups to large herds. These same group types were consistently observed across population and habitats. Furthermore, certain behaviors were associated with group type, and group membership was found to often be dynamic."Unlike killer and pilot whales, and like some human societies, beluga whales don't solely or even primarily interact and associate with close kin. Across a wide variety of habitats and among both migratory and resident populations, they form communities of individuals of all ages and both sexes that regularly number in the hundreds and possibly the thousands," said O'Corry-Crowe. "It may be that their highly developed vocal communication enables them to remain in regular acoustic contact with close relatives even when not associating together."Beluga whale groupings (beyond mother-calf dyads) were not usually organized around close maternal relatives. The smaller social groups, as well as the larger herds, routinely comprised multiple matrilines. Even where group members shared the same mtDNA lineage, microsatellite analysis often revealed that they were not closely related, and many genealogical links among group members involved paternal rather than maternal relatives. These results differ from earlier predictions that belugas have a matrilineal social system of closely associating female relatives. They also differ from the association behavior of the larger toothed whales that informed those predictions. In 'resident' killer whales, for example, both males and females form groups with close maternal kin where they remain for their entire lives."Beluga whales exhibit a wide range of grouping patterns from small groups of two to 10 individuals to large herds of 2,000 or more, from apparently single sex and age-class pods to mixed-age and sex groupings, and from brief associations to multi-year affiliations," said O'Corry-Crowe. "This variation suggests a fission-fusion society where group composition and size are context-specific, but it may also reflect a more rigid multi-level society comprised of stable social units that regularly coalesce and separate. The role kinship plays in these groupings has been largely unknown."For the study, researchers used field observations, mtDNA profiling, and multi-locus genotyping of beluga whales to address fundamental questions about beluga group structure, and patterns of kinship and behavior, which provide new insights into the evolution and ecology of social structure in this Arctic whale.The study was conducted at 10 locations, in different habitats, across the species' range, spanning from small, resident groups (Yakutat Bay) and populations (Cook Inlet) in subarctic Alaska to larger, migratory populations in the Alaskan (Kasegaluk Lagoon, Kotzebue Sound, Norton Sound), Canadian (Cunningham Inlet, Mackenzie Delta, Husky Lakes) and Russian (Gulf of Anadyr) Arctic to a small, insular population in the Norwegian High Arctic (Svalbard)."This new understanding of why individuals may form social groups, even with non-relatives, will hopefully promote new research on what constitutes species resilience and how species like the beluga whale can respond to emerging threats including climate change," said O'Corry-Crowe.
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July 10, 2020
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https://www.sciencedaily.com/releases/2020/07/200710140724.htm
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Extraordinary regeneration of neurons in zebrafish
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Biologists from the University of Bayreuth have discovered a uniquely rapid form of regeneration in injured neurons and their function in the central nervous system of zebrafish. They studies the Mauthner cells, which are solely responsible for the escape behaviour of the fish, and previously regarded as incapable of regeneration. However, their ability to regenerate crucially depends on the location of the injury. In central nervous systems of other animal species, such a comprehensive regeneration of neurons has not yet been proven beyond doubt. The scientists report their findings in the journal
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Mauthner cells are the largest cells found in animal brains. They are part of the central nervous system of most fish and amphibian species and trigger life-saving escape responses when predators approach. The transmission of signals in Mauthner cells to their motoneurons is only guaranteed if a certain part of these cells, the axon, is intact. The axon is an elongated structure that borders the cell body with its cell nucleus at one of its two ends. If the injury of the axon occurs close to the cell body, the Mauthner cell dies. If the axon is damaged at its opposite end, lost functions are either not restored at all or only slowly and to a limited extent. However, the Mauthner cell reacts to an injury in the middle of the axon with rapid and complete regeneration. Indeed, within a week after the injury, the axon and its function are fully restored, and the fish is able to escape approaching predators again."Such a rapid regeneration of a neuron was never observed anywhere in the central nervous system of other animal species until now. Here, regeneration processes usually extend over several weeks or months," says Dr. Alexander Hecker, first author of the new study and member of the Department of Animal Physiology. This finding clearly disproves the widely accepted view in the scientific community that Mauthner cells are unable to regenerate.However, the observation that the escape response of zebrafish were fully intact so soon after regeneration did not necessarily prove the functional regenerative capacity of the Mauthner cell. It might be possible that other neurons in zebrafish are able to induce this life-saving escape behaviour and thus take over the lost function of Mauthner cells. However, precisely this possibility was ruled out by findings published by the Bayreuth biologists led by Prof. Dr. Stefan Schuster in PNAS in January 2020. They were able to show for the first time that it is only the Mauthner cells that control the escape behaviour of zebrafish. If the axon is irreversibly destroyed, there are no other cells in the fish that are able to compensate for the loss."Mauthner cells now offer us the possibility to investigate the very different responses to injuries of individual cells within the same nervous system: an absence of or insufficient regeneration processes on the one hand, and robust and complete regeneration on the other. Surprisingly, the injuries to the axon, which led to such contradictory responses, were not very far apart. Elucidating the causes is an exciting field of research, which also includes the identification of the genes that are active in the regeneration of neurons. And if we find out the reasons why regeneration processes in Mauthner cells fail to occur, we might also be able to better understand the mechanisms that prevent the regeneration of neurons in humans," said Hecker.
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July 9, 2020
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https://www.sciencedaily.com/releases/2020/07/200709141600.htm
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Global wildlife surveillance could provide early warning for next pandemic
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The virus that causes COVID-19 probably originated in wild bats that live in caves around Wuhan, China, and may have been passed to a second animal species before infecting people, according to the World Health Organization. Many of the most devastating epidemics of recent decades -- including Ebola, avian influenza and HIV/AIDS -- were triggered by animal viruses that spilled over into people. Despite the ever-present danger of a new virus emerging and sparking a worldwide pandemic, there is no global system to screen for viruses in wild animals that eventually may jump to humans.
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In a perspective article published July 9 in "It's impossible to know how often animal viruses spill over into the human population, but coronaviruses alone have caused outbreaks in people three times in the last 20 years," said co-author Jennifer A. Philips, MD, PhD, referring to the SARS, MERS and COVID-19 epidemics. Philips is an associate professor of medicine and co-director of the Division of Infectious Diseases at Washington University School of Medicine in St. Louis. "Even a decade ago it would have been difficult to conduct worldwide surveillance at the human-wildlife interface. But because of technological advances, it is now feasible and affordable, and it has never been more obvious how necessary it is."Every animal has its own set of viruses, with some overlap across species. Often, an animal species and its viruses have lived together for so long that they've adapted to one another, and the viruses cause either no symptoms or only mild to moderate disease. But when different animal species that don't normally have much contact are brought together, viruses have the opportunity to jump from one species to another. Most viruses don't have the genetic tools to infect another species. But viruses with such tools can be lethal to a newly infected species with no natural immunity.Human activity is making such spillover events more and more likely. As the population of the world continues to grow, the demand for natural resources skyrockets. People push into wild areas to make space for new homes and businesses, and to access resources to fuel their economies and lifestyles. Wild animals are caught and sold for consumption, or as exotic pets at wildlife markets, where diverse species are jumbled together under crowded and unsanitary conditions. Wild-animal parts are shipped around the world as trinkets or ingredients for traditional or alternative medicines.And yet there is no international system set up to screen for disease-causing viruses associated with the movement of wildlife or wildlife products."In the lead up to this article, I spoke with friends and colleagues around the world who do wildlife research in Madagascar, Indonesia, Peru, Ecuador and asked them, 'Where do you take your samples for screening?'" said co-author Gideon Erkenswick, PhD, a postdoctoral research associate in Philips' lab. Erkenswick is also the director of Field Projects International, a nonprofit organization dedicated to the study and conservation of tropical ecosystems. "In almost every situation, the answer was 'Nowhere.' Locally, there is nobody with dedicated time and resources to do this work. To find new disease-causing viruses, we have to find willing foreign collaborators, then get samples out of the country, which is difficult and expensive."Philips, Erkenswick, and colleagues in the Wildlife Disease Surveillance Focus Group that authored the "There's now a genetic sequencer available that is literally the size of a USB stick," Erkenswick said. "You could bring that and a few other supplies into a rainforest and analyze a sample for sequences associated with disease-causing viruses on site in a matter of hours. I mean, if you do chance upon something like the virus that causes COVID-19, do you really want to be collecting it, storing it, transporting it, risking further exposure, sample degradation, and adding months or years of delay, before you figure out what you've got? There are people with the expertise and skills to do this kind of work safely pretty much everywhere in the world, they just haven't been given the tools."Once viral sequences are uploaded, researchers around the world could help analyze them to identify animal viruses that may be a threat to people and to develop a better understanding of the universe of viruses that thrive in different environments. By comparing genomic sequence data, researchers can identify what family an unknown virus belongs to and how closely it is related to any disease-causing viruses. They can also identify whether a virus carries genes associated with the ability to cause disease in people."By knowing the diversity out there, and tracking its evolution, we can ensure that we stay ahead of what's in wildlife populations and at the wildlife-human interface," Philips said. "In the past, before modern transportation, spillover events would have been local and spread slowly, giving people elsewhere time to respond. But now the world is so small that an event in one place puts the whole world at risk. This is not someone else's problem. It's everyone's problem."
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Animals
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July 9, 2020
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https://www.sciencedaily.com/releases/2020/07/200709135631.htm
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Bats offer clues to treating COVID-19
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Bats are often considered patient zero for many deadly viruses affecting humans, including Ebola, rabies, and, most recently, the SARS-CoV-2 strain of virus that causes coronavirus.
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Although humans experience adverse symptoms when afflicted with these pathogens, bats are remarkably able to tolerate viruses, and, additionally, live much longer than similar-sized land mammals.What are the secrets to their longevity and virus resistance?According to researchers at the University of Rochester, bats' longevity and capacity to tolerate viruses may stem from their ability to control inflammation, which is a hallmark of disease and aging. In a review article published in the journal The idea for the paper came about when Gorbunova and Seluanov, who are married, were in Singapore in March before COVID-19 travel bans began. When the virus started to spread and Singapore went into lockdown, they were quarantined at the home of their colleague Brian Kennedy, director of the Centre for Healthy Aging at the National University of Singapore and co-author of the paper.The three scientists, all experts on longevity in mammals, got to talking about bats. SARS-CoV-2 is believed to have originated in bats before the virus was transmitted to humans. Although bats were carriers, they seemed to be unaffected by the virus. Another perplexing factor: generally, a species' lifespan correlates with its body mass; the smaller a species, the shorter its lifespan, and vice versa. Many bat species, however, have lifespans of 30 to 40 years, which is impressive for their size."We've been interested in longevity and disease resistance in bats for a while, but we didn't have the time to sit and think about it," says Gorbunova, the Doris Johns Cherry Professor of Biology at Rochester. "Being in quarantine gave us time to discuss this, and we realized there may be a very strong connection between bats' resistance to infectious diseases and their longevity. We also realized that bats can provide clues to human therapies used to fight diseases."While there have been studies on the immune responses of bats and studies of bats' longevity, until their article, "no one has combined these two phenomena," Seluanov says.Gorbunova and Seluanov have studied longevity and disease resistance in other exceptionally long-lived animals, including naked mole rats. One common theme in their research is that inflammation is a hallmark of the aging process and age-related diseases, including cancer, Alzheimer's, and cardiovascular disease. Viruses, including COVID-19, are one factor that can trigger inflammation."With COVID-19, the inflammation goes haywire, and it may be the inflammatory response that is killing the patient, more so than the virus itself," Gorbunova says. "The human immune system works like that: once we get infected, our body sounds an alarm and we develop a fever and inflammation. The goal is to kill the virus and fight infection, but it can also be a detrimental response as our bodies overreact to the threat."Not so with bats. Unlike humans, bats have developed specific mechanisms that reduce viral replication and also dampen the immune response to a virus. The result is a beneficial balance: their immune systems control viruses but at the same time, do not mount a strong inflammatory response.According to the researchers, there are several factors that may contribute to bats having evolved to fight viruses and live long lives. One factor may be driven by flight. Bats are the only mammals with the ability to fly, which requires that they adapt to rapid increases in body temperature, sudden surges in metabolism, and molecular damage. These adaptations may also assist in disease resistance.Another factor may be their environment. Many species of bats live in large, dense colonies, and hang close together on cave ceilings or in trees. Those conditions are ideal for transmitting viruses and other pathogens."Bats are constantly exposed to viruses," Seluanov says. "They are always flying out and bringing back something new to the cave or nest, and they transfer the virus because they live in such close proximity to each other."Because bats are constantly exposed to viruses, their immune systems are in a perpetual arms race with pathogens: a pathogen will enter the organism, the immune system will evolve a mechanism to combat the pathogen, the pathogen will evolve again, and so on."Usually the strongest driver of new traits in evolution is an arms race with pathogens," Gorbunova says. "Dealing with all of these viruses may be shaping bats' immunity and longevity."That's not an invitation for humans to toss their masks and crowd together in restaurants and movie theaters. Evolution takes place over thousands of years, rather than a few months. It has only been in recent history that a majority of the human population has begun living in close proximity in cities. Or that technology has enabled rapid mobility and travel across continents and around the globe. While humans may be developing social habits that parallel those of bats, we have not yet evolved bats' sophisticated mechanisms to combat viruses as they emerge and swiftly spread."The consequences may be that our bodies experience more inflammation," Gorbunova says.The researchers also recognize that aging seems to play an adverse role in humans' reactions to COVID-19."COVID-19 has such a different pathogenesis in older people," Gorbunova says. "Age is one of the most critical factors between living and dying. We have to treat aging as a whole process instead of just treating individual symptoms."The researchers anticipate that studying bats' immune systems will provide new targets for human therapies to fight diseases and aging. For example, bats have mutated or completely eliminated several genes involved in inflammation; scientists can develop drugs to inhibit these genes in humans. Gorbunova and Seluanov hope to start a new research program at Rochester to work toward that goal."Humans have two possible strategies if we want to prevent inflammation, live longer, and avoid the deadly effects of diseases like COVID-19," Gorbunova says. "One would be to not be exposed to any viruses, but that's not practical. The second would be to regulate our immune system more like a bat."
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Animals
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July 9, 2020
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https://www.sciencedaily.com/releases/2020/07/200709113518.htm
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15-foot-long skeleton of extinct dolphin suggests parallel evolution among whales
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A report in the journal
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The researchers say that multiple lines of evidence -- from the skull anatomy and teeth, to the flipper and vertebral column -- show that this large dolphin (a toothed whale in the group Odontoceti) was a top predator in the community in which it lived. They say that many features of the dolphin's postcranial skeleton also imply that modern baleen whales and modern toothed whales must have evolved similar features independently, driven by parallel evolution in the very similar aquatic habitats in which they lived."The degree to which baleen whales and dolphins independently arrive at the same overall swimming adaptations, rather than these traits evolving once in the common ancestor of both groups, surprised us," says Robert Boessenecker of the College of Charleston in Charleston, South Carolina. "Some examples include the narrowing of the tail stock, increase in the number of tail vertebrae, and shortening of the humerus (upper arm bone) in the flipper."This is not apparent in different lineages of seals and sea lions, for example, which evolved into different modes of swimming and have very different looking postcranial skeletons," he adds. "It's as if the addition of extra finger bones in the flipper and the locking of the elbow joint has forced both major groups of cetaceans down a similar evolutionary pathway in terms of locomotion."Though first discovered in the 1880s from a fragmentary skull during phosphate dredging of the Wando River, the first skeleton of Ankylorhiza was discovered in the 1970s by then Charleston Museum Natural History curator Albert Sanders. The nearly complete skeleton described in the new study was found in the 1990s. A commercial paleontologist by the name of Mark Havenstein found it during construction of a housing subdivision in South Carolina. It was subsequently donated to the Mace Brown Museum of Natural History, to allow for its study.While there's much more to learn from this fossil specimen, the current findings reveal that Ankylorhiza was an ecological specialist. The researchers say the species was "very clearly preying upon large-bodied prey like a killer whale."Another intriguing aspect, according to the researchers, is that Ankylorhiza is the first echolocating whale to become an apex predator. When Ankylorhiza became extinct by about 23 million years ago, they explain, killer sperm whales and the shark-toothed dolphin Squalodon evolved and reoccupied the niche within 5 million years. After the last killer sperm whales died out about 5 million years ago, the niche was left open until the ice ages, with the evolution of killer whales about 1 or 2 million years ago."Whales and dolphins have a complicated and long evolutionary history, and at a glance, you may not get that impression from modern species," Boessenecker says. "The fossil record has really cracked open this long, winding evolutionary path, and fossils like Ankylorhiza help illuminate how this happened."Boessenecker notes that more fossils of Ankylorhiza are awaiting study, including a second species and fossils of Ankylorhiza juveniles that can offer insight into the dolphin's growth. He says that there's still much to learn from fossilized dolphins and baleen whales from South Carolina."There are many other unique and strange early dolphins and baleen whales from Oligocene aged rocks in Charleston, South Carolina," Boessenecker says. "Because the Oligocene epoch is the time when filter feeding and echolocation first evolved, and since marine mammal localities of that time are scarce worldwide, the fossils from Charleston offer the most complete window into the early evolution of these groups, offering unparalleled evolutionary insight."
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Animals
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July 9, 2020
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https://www.sciencedaily.com/releases/2020/07/200709105122.htm
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Structural analysis of COVID-19 spike protein provides insight into its evolution
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Researchers at the Francis Crick Institute have characterised the structure of the SARS-CoV-2 spike protein as well as its most similar relative in a bat coronavirus. The structures provide clues about how the spike evolved and could help inform vaccine design.
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A characterising feature of SARS-CoV-2, the virus that causes COVID-19, is the protein spikes which cover the surface, which the virus uses to bind with and enter human cells.Analysing the structure of these spikes could provide clues about the virus' evolution. It is not yet known how SARS-CoV-2 evolved to infect humans and whether this happened directly from coronaviruses in bats or via an intermediary species.In their study, published in While the spikes as a whole were over 97% similar, the researchers found a number of significant differences at the location where SARS-CoV-2 binds with a receptor on human cells, called ACE2, and at the surfaces that keep the subunits of the spike together.These differences mean the spike of SARS-CoV-2 is more stable and is able to bind around 1,000 times more tightly to a human cell than this bat virus.Based on their findings, the researchers suggest it is unlikely that a bat virus similar to RaTG13 could infect human cells. This supports the theory that SARS-CoV-2 is the result of different coronaviruses coming together and evolving over time, potentially also through several host species.Antoni Wrobel, co-lead author and postdoctoral training fellow in the Structural Biology of Disease Processes Laboratory at the Crick, says: "The spike is the entry key that allows SARS-CoV-2 into human cells. Changes in the virus' genome, which affect the spike's structure, therefore have potential to make the virus either more or less able to enter the host's cell.""At some point in the evolution of this virus, it seems to have picked up changes, like the differences we found, which made it able to infect humans."Donald Benton, co-lead author and postdoctoral training fellow in the Structural Biology of Disease Processes Laboratory at the Crick, says: "The exact process of how SARS-CoV-2 evolved remains unclear and is something many researchers are trying to piece together. Our work provides a piece of this puzzle, as it suggests that the virus did not come straight from the bat coronaviruses currently known."Steve Gamblin, group leader of the Structural Biology of Disease Processes Laboratory at the Crick says: "The world was caught off guard by SARS-CoV-2. Examining the structure of this virus, and its likely precursor, helps us understand where it came from, and how it interacts with human cells."The Crick researchers will continue to study the structure of the virus, with a view to finding further clues as to its evolutionary path.The spike protein structures are open-access, so other researchers can use these in their work and to aid with drug discovery and vaccine design.
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Animals
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July 9, 2020
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https://www.sciencedaily.com/releases/2020/07/200709105116.htm
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Skull of two million year-old giant dormouse reconstructed
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A PhD student has produced the first digital reconstruction of the skull of a gigantic dormouse, which roamed the island of Sicily around two million years ago.
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In a new study, the student from Hull York Medical School, has digitally pieced together fossilised fragments from five giant dormouse skulls to reconstruct the first known complete skull of the species.The researchers estimate that the enormous long-extinct rodent was roughly the size of a cat, making it the largest species of dormouse ever identified.The digitally reconstructed skull is 10 cm long -- the length of the entire body and tail of many types of modern dormouse.PhD student Jesse Hennekam said: "Having only a few fossilised pieces of broken skulls available made it difficult to study this fascinating animal accurately. This new reconstruction gives us a much better understanding of what the giant dormouse may have looked like and how it may have lived."The enormous prehistoric dormouse is an example of island gigantism -- a biological phenomenon in which the body size of an animal isolated on an island increases dramatically.The palaeontological record shows that many weird and wonderful creatures once roamed the Italian islands. Alongside the giant dormouse, Sicily was also home to giant swans, giant owls and dwarf elephants.Jesse's PhD supervisor, Dr Philip Cox from the Department of Archaeology at the University of York and Hull York Medical School, said: "While Island dwarfism is relatively well understood, as with limited resources on an island animals may need to shrink to survive, the causes of gigantism are less obvious."Perhaps, with fewer terrestrial predators, larger animals are able to survive as there is less need for hiding in small spaces, or it could be a case of co-evolution with predatory birds where rodents get bigger to make them less vulnerable to being scooped up in talons."Jesse spotted the fossilised fragments of skull during a research visit to the Palermo Museum in Italy, where a segment of rock from the floor of a small cave, discovered during the construction of a motorway in northwest Sicily in the 1970s, was on display."I noticed what I thought were fragments of skull from an extinct species embedded in one of the cave floor segments," Jesse said. "We arranged for the segment to be sent to Basel, Switzerland for microCT scanning and the resulting scans revealed five fragmented skulls of giant dormice present within the rock."The reconstruction is likely to play an important role in future research directed at improving understanding of why some small animals evolve larger body sizes on islands, the researchers say."The reconstructed skull gives us a better sense of whether the giant dormouse would have looked similar to its normal-sized counterparts or whether its physical appearance would have been influenced by adaptations to a specific environment," Jesse explains."For example, if we look at the largest living rodent -- the capybara -- we can see that it has expanded in size on a different trajectory to other species in the same family."Jesse is also using biomechanical modelling to understand the feeding habits of the giant dormouse."At that size, it is possible that it may have had a very different diet to its smaller relatives," he adds.
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Animals
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July 9, 2020
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https://www.sciencedaily.com/releases/2020/07/200709092459.htm
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Daytime aardvark sightings are a sign of troubled times
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Aardvarks occur across most of sub-Saharan Africa, but very few people have seen one, because they are solitary, mostly active at night, and live in burrows. They use their spade-like claws to build these burrows and to dig up ants and termites on which they feed. However, seeing aardvarks feeding in the day is becoming more common in the drier parts of southern Africa. While catching sight of an aardvark is a delight for many a wildlife enthusiast, researchers from the Wildlife Conservation Physiology laboratory at the University of the Witwatersrand (Wits) warn that seeing aardvarks in the daytime does not bode well for this secretive animal.
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New research by the team from Wits, with collaborators from the University of Cape Town and University of Pretoria, reveals what a shift from night-time to daytime activity means for the well-being of aardvarks in a warming and drying world. The researchers studied aardvarks living at Tswalu, a reserve in the Kalahari that lies at the edge of the aardvark's distribution and provides support and infrastructure for researchers through the Tswalu Foundation. The results are published in the journal Using biologgers, the researchers recorded body temperature and activity of aardvarks for three years, during which Dr Nora Weyer followed the aardvarks as part of her PhD research.Assisted by satellite imaging that showed her how droughts affected the vegetation, Weyer was able to connect changes in aardvark behaviour and body temperature to what was happening in the aardvarks' environment.Weyer's research confirmed earlier findings by the team that there are times when the aardvarks switched their feeding to the day, and showed, for the first time, that drought caused that switch. "We suspected that it was drought," says co-worker Dr Robyn Hetem, "but we needed a long-term, comprehensive data set to confirm that it really was drought causing this unusual behaviour."The Kalahari is arid at the best of times, but drought killed the vegetation that fed the ants and termites. Most of the ants and termites disappeared, leaving the aardvarks starving. "It was heart-breaking to watch our aardvarks waste away as they starved," says Weyer.By shifting their activity from the cold nights to the warm days during dry winter months, aardvarks can save some of the energy needed to keep their body temperatures up. But those energy savings were not enough to see the aardvarks through a particularly bad drought in which many aardvarks died."Aardvarks have coped with the Kalahari's harsh environment in the past, but it is getting hotter and drier, and the current and future changes to our climate might be too much for the aardvarks to bear," says Weyer. "Because the Kalahari is such a unique and potentially vulnerable ecosystem, we need to better understand whether its animals can cope with the increasingly dry conditions," says Professor Andrea Fuller, co-worker and project leader of the Kalahari Endangered Ecosystem Project (KEEP).Disappearance of aardvarks from the Kalahari would be devastating for many other animals in this ecosystem. The large burrows which aardvarks build provide important shelters for many other species that cannot dig their own burrows, earning the aardvark the title of ?ecosystem engineer'."Unfortunately, the future looks grim for Kalahari aardvarks and the animals that use their burrows. Tackling climate change is key, but there is no quick fix," says Weyer. What conservationists do know is that any solution will require a much better understanding of what capacities animals have to cope with drought. And that means many more long-term comprehensive studies of physiology and behaviour, like the study that Dr Weyer and her colleagues carried out at Tswalu.
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July 9, 2020
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https://www.sciencedaily.com/releases/2020/07/200709085318.htm
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Care for cats? So did people along the Silk Road more than 1,000 years ago
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Common domestic cats, as we know them today, might have accompanied Kazakh pastoralists as pets more than 1,000 years ago. This has been indicated by new analyses done on an almost complete cat skeleton found during an excavation along the former Silk Road in southern Kazakhstan. An international research team led by Martin Luther University Halle-Wittenberg (MLU), Korkyt-Ata Kyzylorda State University in Kazakhstan, the University of Tübingen and the Higher School of Economics in Russia has reconstructed the cat's life, revealing astonishing insights into the relationship between humans and pets at the time. The study will appear in the journal
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The tomcat -- which was examined by a team led by Dr Ashleigh Haruda from the Central Natural Science Collections at MLU -- did not have an easy life. "The cat suffered several broken bones during its lifetime," says Haruda. And yet, based on a very conservative estimate, the animal had most likely made it past its first year of life. For Haruda and her colleagues, this is a clear indication that people had taken care of this cat.During a research stay in Kazakhstan, the scientist examined the findings of an excavation in Dzhankent, an early medieval settlement in the south of the country which had been mainly populated by the Oghuz, a pastoralist Turkic tribe. There she discovered a very well-preserved skeleton of a cat. According to Haruda, this is quite rare because normally only individual bones of an animal are found during an excavation, which prevents any systematic conclusions from being drawn about the animal's life. The situation is different when it comes to humans since usually whole skeletons are found. "A human skeleton is like a biography of that person. The bones provide a great deal of information about how the person lived and what they experienced," says Haruda. In this case, however, the researchers got lucky: after its death, the tomcat was apparently buried and therefore the entire skull including its lower jaw, parts of its upper body, legs and four vertebrae had been preserved.Haruda worked together with an international team of archaeologists and ancient DNA specialists. An examination of the tomcat's skeleton revealed astonishing details about its life. First, the team took 3D images and X-rays of its bones. "This cat suffered a number of fractures, but survived," says Haruda. Isotope analyses of bone samples also provided the team with information about the cat's diet. Compared to the dogs found during the excavation and to other cats from that time period, this tomcat's diet was very high in protein. "It must have been fed by humans since the animal had lost almost all its teeth towards the end of its life."DNA analyses also proved that the animal was indeed likely to be a domestic cat of the Felis catus L. species and not a closely related wild steppe cat. According to Haruda, it is remarkable that cats were already being kept as pets in this region around the 8th century AD: "The Oghuz were people who only kept animals when they were essential to their lives. Dogs, for example, can watch over the herd. They had no obvious use for cats back then," explains the researcher. The fact that people at the time kept and cared for such "exotic" animals indicates a cultural change, which was thought to have occurred at a much later point in time in Central Asia. The region was thought to have been slow in making changes with respect to agriculture and animal husbandry.The Dhzankent settlement, where the remains of the cat were found, was located along the Silk Road, an ancient network of important caravan routes that connected Central and East Asia with the Mediterranean region by land. According to Haruda, the find is also an indication of cultural exchange between the regions located along the Silk Road.The study was funded by the Wenner-Gren Foundation, the German Research Foundation (DFG), the University of Leicester and the Max Planck Society.
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July 8, 2020
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https://www.sciencedaily.com/releases/2020/07/200708150611.htm
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Fossil jawbone from Alaska is a rare case of a juvenile Arctic dromaeosaurid dinosaur
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A small piece of fossil jawbone from Alaska represents a rare example of juvenile dromaeosaurid dinosaur remains from the Arctic, according to a study published July 8, 2020 in the open-access journal
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Dromaeosaurids are a group of predatory dinosaurs closely related to birds, whose members include well-known species such as Deinonychus and Velociraptor. These dinosaurs lived all over the world, but their bones are often small and delicate and rarely preserve well in the fossil record, complicating efforts to understand the paths they took as they dispersed between continents.The Prince Creek Formation of northern Alaska preserves the largest collection of polar dinosaur fossils in the world, dating to about 70 million years ago, but the only dromaeosaurid remains found so far have been isolated teeth. The jaw fossil described in this study is a mere 14mm long and preserves only the tip of the lower jaw, but it is the first known non-dental dromaeosaurid fossil from the Arctic. Statistical analysis indicates this bone belongs to a close relative of the North American Saurornitholestes.North American dromaeosaurids are thought to trace their origins to Asia, and Alaska would have been a key region for the dispersal of their ancestors. This new fossil is a tantalizing clue toward understanding what kinds of dromaeosaurs inhabited this crucial region. Furthermore, the early developmental stage of the bone suggests this individual was still young and was likely born nearby; in contrast to previous suggestions that this part of Alaska was exclusively a migratory pathway for many dinosaurs, this is strong evidence that some dinosaurs were nesting here. The authors suggest that future findings may allow a more complete understanding of these mysterious Arctic dromaeosaurids.Chiarenza summarizes: "There are places where dinosaur fossils are so common that a scrap of bone, in most cases, cannot really add anything scientifically informative anymore: this is not the case with this Alaskan specimen. Even with such an incomplete jaw fragment, our team was not only able to work out the evolutionary relationships of this dinosaur, but also to picture something more on the biology of these animals, ultimately gaining more information on this Ancient Arctic ecosystem." Fiorillo adds: "Years ago when dinosaurs were first found in the far north, the idea challenged what we think we know about dinosaurs. For some time afterwards, there was a great debate as to whether or not those Arctic dinosaurs migrated or lived in the north year round. All of those arguments were somewhat speculative in nature. This study of a predatory dinosaur jaw from a baby provides the first physical proof that at least some dinosaurs not only lived in the far north, but they thrived there. One might even say, our study shows that the ancient north was a great place to raise a family and now we have to figure out why."
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Animals
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July 8, 2020
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https://www.sciencedaily.com/releases/2020/07/200708110014.htm
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Where did the Asian longhorned ticks in the US come from?
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Asian longhorned ticks outside the U.S. can carry debilitating diseases. In the United States and elsewhere they can threaten livestock and pets. The new study, published in the journal
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"While additional samples from the tick's native range are needed to pinpoint more exactly the source of the U.S. introduction, our data suggest that they came from one or more locations in northeastern Asia -- either through a single introduction of at least three ticks or as multiple introductions from different populations," said lead author Andrea M. Egizi, a visiting professor in the Department of Entomology at Rutgers University-New Brunswick and a research scientist with the Monmouth County Tick-borne Diseases Laboratory hosted by the Rutgers Center for Vector Biology.In 2017, Rutgers Center for Vector Biology and other researchers detected an infestation of the Asian longhorned tick (Although this species transmits serious illnesses to people and animals in other countries, experts don't know whether the tick populations in the United States will make people sick, according to the U.S. Centers for Disease Control and Prevention.The species has two forms: one with males and females, and one with self-cloning females that lay eggs without needing to mate, a process called "parthenogenesis." The self-cloning form, free from the need to look for mates, are especially likely to thrive and spread. A single female can establish a fast-growing population. This type entered Australia and New Zealand in the early 1900s, and now causes significant losses in the cattle industry.Rutgers Center for Vector Biology researchers enlisted about 25 collaborators at 20 institutions to get samples of Asian longhorned ticks across the United States and internationally, and used gene sequencing to detect genetic similarities and differences between various populations.Their findings indicate that at least three individual ticks, from self-cloning populations, were brought to the United States, which explains why all adult Asian longhorned ticks found in the U.S. so far have been female. Overall, U.S. ticks are more likely to have come from an East Asian country (or countries) than from Australia and New Zealand.As part of the study, the U.S. Department of Agriculture Animal and Plant Health Inspection Service, Veterinary Services found evidence that these ticks traveled within the United States on wildlife as well as through the transport of pets or livestock."One thing we uncovered is the ease with which pets, especially dogs, can accidentally help ticks cross international borders and state lines," said senior author Dina M. Fonseca, a professor and director of the Center for Vector Biology in the Department of Entomology in the School of Environmental and Biological Sciences. "Many countries require dogs to be treated for ticks and other parasites before entering the country, but the United States does not. We urge greater awareness of this issue to prevent future exotic tick introductions."Rutgers-affiliated coauthors include Matthew Bickerton and James L. Occi, both entomology doctoral students.
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July 8, 2020
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https://www.sciencedaily.com/releases/2020/07/200708105948.htm
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Animals who try to sound 'bigger' are good at learning sounds
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Some animals fake their body size by sounding 'bigger' than they actually are. Researchers studied 164 different mammals and found that animals who lower their voice to sound bigger are often skilled vocalists. Both strategies -- sounding bigger and learning sounds -- are likely driven by sexual selection, and may play a role in explaining the origins of human speech evolution.
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"If you saw a Chihuahua barking as deep as a Rottweiler, you would definitely be surprised," says Andrea Ravignani, a researcher at the MPI and the Dutch Sealcentre Pieterburen. Body size influences the frequency of the sounds animals produce, but many animals found ways to sound 'smaller' or 'bigger' than expected. "Nature is full of animals like squeaky-Rottweilers and tenor-Chihuahuas," explains Ravignani. Some animals fake their size by developing larger vocal organs that lower their sound, which makes them sound larger than you would expect. Other animals are good at controlling the sounds they produce. Such strategies (called 'dishonest signalling' by biologists) could be driven by sexual selection, as males with larger body size or superior singing skills (hitting very high or low notes) attract more females (or vice versa).Garcia and Ravignani wondered whether some animals may have learned to make new sounds as a strategy to attract mates. Few animal species are capable of vocal learning, among them mammals such as seals, dolphins, bats and elephants. For instance, seals can imitate sounds, and some seals copy call types of successfully breeding individuals. Would animals who often 'fake' their body size also be the ones capable of learning new sounds?The researchers analysed the sounds and body size of 164 different mammals, ranging from mice and monkeys to water dwelling mammals such as the subantarctic fur seal and the Amazonian manatee. They combined methods from acoustics, anatomy, and evolutionary biology to compare the different sorts of animals in the dataset.The scientists found that animals who 'fake' their body size are often skilled sound learners. According to Garcia and Ravignani, their framework provides a new way of investigating the evolution of communication systems. "We want to expand our theory to take into account other evolutionary pressures, not just sexual selection," adds Ravignani. "We also want to replicate our preliminary findings with more mammals and test whether our ideas also apply to birds or other taxonomic groups."In their position paper, Garcia and Ravignani suggest that there may be a link to human speech evolution. "We believe that a 'dishonest signalling' strategy may be a first evolutionary step towards learning how to make new sounds of any sort," says Garcia. "Speculatively, it brings us closer to understanding human speech evolution: our ancestors may have learnt how to speak after learning how to sound bigger or how to hit high notes."
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Animals
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July 8, 2020
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https://www.sciencedaily.com/releases/2020/07/200708174303.htm
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New bird checklists from Coiba National Park, Panama
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The first published bird checklist from Jicarón and Jicarita, Panama's southernmost islands and part of Coiba National Park, underscores the importance of sending biologists to explore new territory. Both islands are accessible from the Smithsonian Tropical Research Institute's newest research station on Coibita Island.
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In 2015, photographer Christian Ziegler (with the International League of Conservation Photographers) and ecologist Omar Lopez (then at Panama's government research institute, INDICASAT, now at SENACYT) organized biologists from several institutions to join the first Coiba BioBlitz, an effort to document as many species as possible in the park."During the BioBlitz we only spent a couple of days on Jicarón Island, " said Claudio Monteza, former STRI fellow, now doctoral student at the Max Planck Institute for Animal Behavior. "While we were there, we also noticed capuchin monkeys spending more time on the ground.""Later, Pedro [Castillo] and I went back to study the monkeys. Pedro would go to a stream to wash the breakfast dishes and stay for a half an hour washing, watching birds and adding new species to our bird list for Jicaron. Once, he looked up at the sky and, soaring above the canopy, he observed a Zone-tailed Hawk (a new record for the park). We decided to do a proper checklist.""As an ornithologist, creating a checklist of birds for Coiba National Park is exciting and intimidating, because you know Alexander Wetmore [sixth Secretary of the Smithsonian Institution 1945-1952] visited many islands and islets in the park. In 1957, he published the first checklist of birds for Coiba National Park, registering 133 species. Nevertheless, he was not able to visit Jicarón, the second-largest island," explained Pedro Castillo, a University of Panama student.Between 2004 and 2019, a total of 115 species were recorded on Jicarón Island and 53 on Jicarita, including 23 bird species never before reported from the park. Ten species are endemic subspecies that are found nowhere else, and 29 are migratory birds -- including seven warblers -- that depend on the park as they travel through the area during their winter migration.The most common species recorded were the Gray-headed Dove (Brown-backed), the Rufous-tailed Hummingbird and the Bananaquit.Scarlet Macaws, probably flying in from Coiba Island, are now nearly extirpated on the mainland. It is relatively easy to see macaws on Jicarón. Coiba is probably the most important refuge for this species in Panama. Three-wattled Bellbirds, which usually live at higher elevations come down to 400 meters on Coiba Island.Monteza thinks that careful, environmentally conscious birdwatching may be a way to support the park and area residents in the future."There are no trails on Jicarón nor on Jicarita and the terrain is steep," Monteza explains, "but it would be a great place for boat tours.""Hundreds of Brown Boobies, Frigatebirds and other seabirds gather on the cliffs along Jicarita's southern shoreline at sunset, where the continental shelf ends and one can do birdwatching pelagic birds. It's really spectacular." Castillo said.There are roughly 1500 islands off the coast of Panama. Though fewer bird species live on islands than on the mainland, the fact that very few of these islands have been surveyed means that surprises await birdwatchers and other biologists who find the means visit them."Despite rough storms and wobbly landings, one of the motivations to join each field trip was the chance to observe a rare bird species on Jicarón Island. Sometimes we got lucky. There are a few rare species on our checklist, but one of the most unusual is the Western Kingbird, a rare migrant for Panama. Our record is the southernmost for this species," Castillo said.
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Animals
| 2,020 |
July 7, 2020
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https://www.sciencedaily.com/releases/2020/07/200707183920.htm
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Famous 'Jurassic Park' dinosaur is less lizard, more bird
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From movies to museum exhibits, the dinosaur Dilophosaurus is no stranger to pop culture. Many probably remember it best from the movie "Jurassic Park," where it's depicted as a venom-spitting beast with a rattling frill around its neck and two paddle-like crests on its head.
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The dinosaur in the movie is mostly imagination, but a new comprehensive analysis of Dilophosaurus fossils is helping to set the record straight. Far from the small lizard-like dinosaur in the movies, the actual Dilophosaurus was the largest land animal of its time, reaching up to 20 feet in length, and it had much in common with modern birds.The analysis was published open access in the Dilophosaurus lived 183 million years ago during the Early Jurassic. Despite big-screen fame, scientists knew surprisingly little about how the dinosaur looked or fit into the family tree, until now."It's pretty much the best, worst-known dinosaur," said lead author Adam Marsh. "Until this study, nobody knew what Dilophosaurus looked like or how it evolved."Seeking answers to these questions, Marsh conducted an analysis of the five most-complete Dilophosaurus specimens while earning his Ph.D. from The University of Texas at Austin's Jackson School of Geosciences. He is now the lead paleontologist at Petrified Forest National Park.The analysis is co-authored by Jackson School Professor Timothy Rowe, who discovered two of the five Dilophosaurus specimens that were studied.The study adds clarity to a muddled research record that reaches back to the first Dilophosaurus fossil to be discovered, the specimen that set the standard for all following Dilophosaurus discoveries. That fossil was rebuilt with plaster, but the 1954 paper describing the find isn't clear about what was reconstructed -- a fact that makes it difficult to determine how much of the early work was based on the actual fossil record, Marsh said.Early descriptions characterize the dinosaur as having a fragile crest and weak jaws, a description that influenced the depiction of Dilophosaurus in the "Jurassic Park" book and movie as a svelte dinosaur that subdued its prey with venom.But Marsh found the opposite. The jawbones show signs of serving as scaffolding for powerful muscles. He also found that some bones were mottled with air pockets, which would have helped reinforce the skeleton, including its dual crest."They're kind of like bubble wrap -- the bone is protected and strengthened," Marsh said.These air sacs are not unique to Dilophosaurus. Modern birds and the world's most massive dinosaurs also have bones filled with air. In both cases, the air sacs lighten the load, which helped big dinosaurs manage their bulky bodies and birds take to the skies.Many birds use the air sacs to perform other functions, from inflating stretchy areas of skin during mating rituals, to creating booming calls and dispersing heat. The intricate array of air pockets and ducts that extend from Dilophosaurus' sinus cavity into its crests means that the dinosaur may have been able to perform similar feats with its headgear.All the specimens Marsh examined came from the Kayenta Formation in Arizona and belong to the Navajo Nation. The University of California Museum of Paleontology holds in trust three of the specimens. The Jackson School Museum of Earth History holds the two discovered by Rowe."One of the most important responsibilities of our museum is curation," said Matthew Brown, director of the Vertebrate Paleontology Collections. "We are very excited to help share these iconic Navajo Nation fossils with the world through research and educational outreach, as well as preserve them for future generations."To learn more about how the fossils compared with one another, Marsh recorded hundreds of anatomical characteristics of each fossil. He then used an algorithm to see how the specimens compared with the first fossil -- which confirmed that they were indeed all Dilophosaurus.The algorithm also revealed that there's a significant evolutionary gap between Dilophosaurus and its closest dinosaur relatives, which indicates there are probably many other relatives yet to be discovered.The revised Dilophosaurus record will help paleontologists better identify specimens going forward. Marsh said that the research is already being put into action. In the midst of his analysis, he discovered that a small braincase in the Jackson School's collections belonged to a Dilophosaurus."We realized that it wasn't a new type of dinosaur, but a juvenile Dilophosaurus, which is really cool," Marsh said.
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Animals
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July 7, 2020
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https://www.sciencedaily.com/releases/2020/07/200707113227.htm
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Double take: New study analyzes global, multiple-tailed lizards
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Curtin research into abnormal regeneration events in lizards has led to the first published scientific review on the prevalence of lizards that have re-generated not just one, but two, or even up to six, tails.
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PhD Candidate Mr James Barr, from Curtin University's School of Molecular and Life Sciences, said while the phenomena of multiple-tailed lizards are widely known to occur, documented events were generally limited to opportunistic, single observations of one in its natural environment."This limited available research about multiple-tailed lizards has made it difficult for biologists to fully understand their ecological importance, and our study helps to highlight this knowledge gap," Mr Barr said.Many species of lizards have the ability to self-amputate a portion of their tail, an event known as caudal autotomy, as a defence mechanism when they are being attacked by a predator.Most commonly the tail grows back as a single rod of cartilage, but Mr Barr explained that sometimes an anomaly occurs, resulting in the regeneration of more than just one tail."Sometimes following an incomplete autotomy event, when the lizard's original tail does not fully separate from its body, a secondary tail regenerates, resulting in the lizard having two separate tails," Mr Barr said."There have even been records of lizards re-generating up to six tails."Our study indicates that this phenomenon may actually be occurring more frequently in lizards than previously thought."We analysed the available two-tailed lizard data from more than 175 species across 22 families, from 63 different countries. Contrasting this data with all comparable lizard population numbers, our findings suggest an average of 2.75 per cent of all lizards within populations could have two tails or more at any one time."This is quite a surprisingly high number, and it really begins to make us wonder what ecological impacts this could have, especially noting that to the lizard, an extra tail represents a considerable increase in body mass to drag around."Co-researcher Curtin University Associate Professor Bill Bateman explained that while there is a significant lack of studies to understand these potential ecological impacts, his team believes that having two tails might affect the overall fitness and life history for individual lizards, and their overall populations."Shedding a tail to escape a predator and then regenerating it seems like a good tactic; however, when this regeneration goes awry and results in multiple abnormal tails, this is likely to have an effect on the lizard."It could affect a range of things, such as their kinetic movements, restrictions they might have when trying to escape a predator, their anti-predation tactics, and socially speaking, how other lizards might react to them," Professor Bateman said."For example, could having two tails potentially affect their ability to find a mate, and therefore reduce opportunities for reproduction? Or on the contrary, could it potentially be of benefit?"Behaviourally testing out these hypotheses would be an interesting and important future research direction, so biologists can learn more about the lifestyles of these multiple-tailed lizards."
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Animals
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July 6, 2020
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https://www.sciencedaily.com/releases/2020/07/200706152659.htm
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A tiny ancient relative of dinosaurs and pterosaurs discovered
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Dinosaurs and flying pterosaurs may be known for their remarkable size, but a newly described species from Madagascar that lived around 237 million years ago suggests that they originated from extremely small ancestors. The fossil reptile, named
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"There's a general perception of dinosaurs as being giants," said Christian Kammerer, a research curator in paleontology at the North Carolina Museum of Natural Sciences and a former Gerstner Scholar at the American Museum of Natural History. "But this new animal is very close to the divergence of dinosaurs and pterosaurs, and it's shockingly small."Dinosaurs and pterosaurs both belong to the group Ornithodira. Their origins, however, are poorly known, as few specimens from near the root of this lineage have been found. The fossils of Kongonaphon were discovered in 1998 in Madagascar by a team of researchers led by American Museum of Natural History Frick Curator of Fossil Mammals John Flynn (who worked at The Field Museum at the time) in close collaboration with scientists and students at the University of Antananarivo, and project co-leader Andre Wyss, chair and professor of the University of California-Santa Barbara's Department of Earth Science and an American Museum of Natural History research associate."This fossil site in southwestern Madagascar from a poorly known time interval globally has produced some amazing fossils, and this tiny specimen was jumbled in among the hundreds we've collected from the site over the years," Flynn said. "It took some time before we could focus on these bones, but once we did, it was clear we had something unique and worth a closer look. This is a great case for why field discoveries -- combined with modern technology to analyze the fossils recovered -- is still so important.""Discovery of this tiny relative of dinosaurs and pterosaurs emphasizes the importance of Madagascar's fossil record for improving knowledge of vertebrate history during times that are poorly known in other places," said project co-leader Lovasoa Ranivoharimanana, professor and director of the vertebrate paleontology laboratory at the University of Antananarivo in Madagascar. "Over two decades, our collaborative Madagascar-U.S. teams have trained many Malagasy students in paleontological sciences, and discoveries like this helps people in Madagascar and around the world better appreciate the exceptional record of ancient life preserved in the rocks of our country."Kongonaphon isn't the first small animal known near the root of the ornithodiran family tree, but previously, such specimens were considered "isolated exceptions to the rule," Kammerer noted. In general, the scientific thought was that body size remained similar among the first archosaurs -- the larger reptile group that includes birds, crocodilians, non-avian dinosaurs, and pterosaurs -- and the earliest ornithodirans, before increasing to gigantic proportions in the dinosaur lineage."Recent discoveries like Kongonaphon have given us a much better understanding of the early evolution of ornithodirans. Analyzing changes in body size throughout archosaur evolution, we found compelling evidence that it decreased sharply early in the history of the dinosaur-pterosaur lineage," Kammerer said.This "miniaturization" event indicates that the dinosaur and pterosaur lineages originated from extremely small ancestors yielding important implications for their paleobiology. For instance, wear on the teeth of Kongonaphon suggests it ate insects. A shift to insectivory, which is associated with small body size, may have helped early ornithodirans survive by occupying a niche different from their mostly meat-eating contemporaneous relatives.The work also suggests that fuzzy skin coverings ranging from simple filaments to feathers, known on both the dinosaur and pterosaur sides of the ornithodiran tree, may have originated for thermoregulation in this small-bodied common ancestor. That's because heat retention in small bodies is difficult, and the mid-late Triassic was a time of climatic extremes, inferred to have sharp shifts in temperature between hot days and cold nights.Sterling Nesbitt, an assistant professor at Virginia Tech and a Museum research associate and expert in ornithodiran anatomy, phylogeny, and histological age analyses, is also an author on this study.This study was supported, in part, by the National Geographic Society, a Gerstner Scholars Fellowship from the Gerstner Family Foundation and the Richard Gilder Graduate School, the Division of Paleontology at the American Museum of Natural History, and a Meeker Family Fellowship from the Field Museum, with additional support from the Ministry of Energy and Mines of Madagascar, the World Wide Fund for Nature (Madagascar), University of Antananarivo, and MICET/ICTE (Madagascar).
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Animals
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July 6, 2020
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https://www.sciencedaily.com/releases/2020/07/200706113931.htm
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Why it's no last orders for the Tequila bat
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Native to the Americas, the tequila bat (
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While known that some tequila bat populations migrate in Mexico's spring months to the Sonoran Desert to give birth to their pups and pollinate a variety of plants iconic to the region, including the economically important Blue Agave plant. Other tequila bat populations inhabit Southern Mexico year-round, forming large breeding colonies in the winter months.This study aimed to help better inform conservationists of the species' breeding and migratory patterns by determining whether the bats inhabiting Southern Mexico year-round have a similar ancestral origin to those that migrate to the Sonoran Desert.DNA analysis was necessary to understand how historical events may have shaped current tequila bat populations. But first, an international team, comprising researchers from the University of Bristol, the Centro de Investigación Científica y de Educación Superior de Ensenada and the Universidad Nacional Autónoma de México, had to track down the elusive creatures by travelling to remote caves in Mexico to collect DNA skin samples.Bat expert, Angelica Menchaca (PhD) from Bristol's School of Biological Sciences who led the study, said: "Tequila bats are beautiful, especially after they arrive back from feeding as they return covered in pollen, completely yellow, a sign of how important they are to this ecosystem. They are easy to handle, not like other bat species that can be more aggressive."However, our expedition to the desert was not without hitches and dangers. We were often hiking in temperatures routinely exceeding 40°C and encountering desert wildlife such as rattle snakes, scorpions, hares, reptiles and ring-tailed cats along the way."Once we located the bat colony, our aim was to collect DNA skin samples from the bat's wing which heals quickly and doesn't harm them. We would wait until the bats went out to forage at around midnight and then enter the caves that were filled with thousands of baby bats, all packed together in nurseries, waiting for their mums to return."Bats are subject to many threats around the world. Their populations are threatened by habitat loss, their roosts are often disturbed, and people fear them both from myths and as potential disease carriers. Bat-phobia is only increasing in our current climate. However, despite their often-negative press, bats are very valuable to ecosystems and the benefits they bring to our societies including the popular beverage tequila.After analysing samples, the team were able to identify the bats' mitochondrial DNA and use this to trace the maternal line of the different populations to understand the ancestral descent of the species.Explaining the findings, Dr Menchaca added: "Contrary to current practice, our study demonstrates that the species must be managed as two conservation units (CUs) in Mexico. We have shown that tequila bat populations that establish maternity colonies in the Sonoran Desert in northern Mexico show a distinct migratory behaviour, breed during the summer, have specific habitat requirements and belong to a maternal line distinct to their southern counterparts."In the present context of an accelerated rate of habitat loss, increased fear of bats and decreased appreciation as ecosystem service providers, understanding how we can help support this important species survive these threats is even more relevant."We are studying other differences related to their behaviour and morphology that will also help us understand how these bats adapt to diverse habitats."Importantly, this research will be used to help inform conservation management strategies, as the tequila bat is considered "Near Threatened" by the IUCN Red List of Endangered Species.
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July 3, 2020
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https://www.sciencedaily.com/releases/2020/07/200703141213.htm
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First evidence of snake-like venom glands found in amphibians
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Caecilians are limbless amphibians that, to the untrained eye, can be easily mistaken for snakes. Though caecilians are only distantly related to their reptilian cousins, researchers in a study appearing July 3 in the journal
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Caecilians are peculiar creatures, being nearly blind and using a combination of facial tentacles and slime to navigate their underground tunnels. "These animals produce two types of secretions -- one is found mostly in the tail that is poisonous, while the head produces a mucus to help with crawling through the earth," says senior author Carlos Jared, a biologist and Director of the Structural Biology Lab at the Butantan Institute in São Paulo. "Because caecilians are one of the least-studied vertebrates, their biology is a black box full of surprises.""It is while examining the mucous glands of the ringed caecilian that I stumbled upon a never before described set of glands closer to the teeth," says first author Pedro Luiz Mailho-Fontana, a post-doctoral student in the Structural Biology Lab at the Butantan Institute.What Mailho-Fontana found were a series of small fluid-filled glands in the upper and lower jaw, with long ducts that opened at the base of each tooth. Using embryonic analysis, he found that these oral glands originated from a different tissue than the slime and poison glands found in the caecilian's skin. "The poisonous skin glands of the ringed caecilian form from the epidermis, but these oral glands develop from the dental tissue, and this is the same developmental origin we find in the venom glands of reptiles," says Mailho-Fontana. This marks the first time glands of this kind have been found in an amphibian.Researchers suspect that the ringed caecilian may use the secretions from these snake-like oral glands to incapacitate its prey. "Since caecilians have no arms or legs, the mouth is the only tool they have to hunt," says co-author Marta Maria Antoniazzi, an evolutionary biologist at the Butantan Institute. "We believe they activate their oral glands the moment they bite down, and specialized biomolecules are incorporated into their secretions.A preliminary chemical analysis of the oral gland secretions of the ringed caecilian found high activity of phospholipase A2, a common protein found in the toxins of venomous animals. "The phospholipase A2 protein is uncommon in non-venomous species, but we do find it in the venom of bees, wasps, and many kinds of reptiles," says Mailho-Fontana. In fact, the biological activity of phospholipase A2 found in the ringed caecilian was higher than what is found in some rattlesnakes. Still, more biochemical analysis is needed to confirm whether the glandular secretions are toxic.If future work can verify the secretions are toxic, caecilian oral glands could indicate an early evolutionary design of oral venom organs. "Unlike snakes which have few glands with a large bank of venom, the ringed caecilian has many small glands with minor amounts of fluid. Perhaps caecilians represent a more primitive form of venom gland evolution. Snakes appeared in the Cretaceous probably 100 million years ago, but caecilians are far older, being roughly 250 million years old," Jared says.Very few groups of land-dwelling vertebrates have serpent-like bodies, and this research suggests there might be a connection between a limbless body plan and the evolution of a venomous bite. "For snakes and caecilians, the head is the sole unit to explore the environment, to fight, to eat, and to kill," says Antoniazzi. "One theory is that perhaps these necessities encourage the evolution of venom in limbless animals."
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July 2, 2020
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https://www.sciencedaily.com/releases/2020/07/200702144106.htm
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Grassroots dog vaccinations can help stop rabies, but not alone
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In the US, dying from rabies is virtually unheard of. But around the world, rabies kills 59,000 people every year. Ninety-nine percent of those deaths are caused by dog bites; half of the people killed are children. There's a relatively simple way of preventing these deaths -- vaccinating dogs against the disease -- but systemic challenges make that easier said than done. In a new study in PLOS Neglected Tropical Diseases, an international team of researchers reported on a multi-year effort to vaccinate dogs in Kenya and highlighted some of the challenges scientists and public health officials face in eradicating the disease. They found that grassroots efforts helped lots of individuals -- but that to stop the disease once and for all, these smaller campaigns must be coupled with large-scale efforts.
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"It's important to focus on rabies because it's 100% preventable," says Adam Ferguson, a mammalogist at Chicago's Field Museum and one of the study's lead authors. "There's no reason why people should be dying from rabies. It's not like COVID in the sense that we don't have a vaccine for it or we don't know what to do with it."Rabies is a virus, and it spreads through saliva in animal bites. It causes brain inflammation, and once a person begins showing symptoms, it's nearly always fatal. Any mammal can carry rabies, but humans are most likely to pick it up from dogs, because we spend more time in close contact with them than with wild animals like raccoons and bats. And while a rabies vaccine was first discovered in 1885, large parts of the world remain vulnerable to the disease to this day. "It disproportionately impacts low-income, rural communities," says Ferguson, who began the project as a National Science Foundation postdoctoral fellow at Kenya's Karatina University. "In the US, we have the luxury that if one person dies of rabies a year, it makes the front page news. In Kenya, an estimated 2,000 people die of the disease every year."For the new study, Ferguson and his colleagues conducted grassroots dog vaccination campaigns in 2015, 2016, and 2017 in Kenya's Laikipia County. The Laikipia Rabies Vaccination Campaign expanded over the course of the three-year period, and 13,155 dogs were vaccinated. Across different communities, the team set up a central station for people to bring their dogs to get vaccines. "The excitement and commitments by the communities to bring their dogs in the centers was overwhelming. This for sure made the effort feel worth investing into. You could tell that rabies eradication was tending to be more communal than an individual effort," says Dedan Ngatia, a scientist at the University of Wyoming and one of the study's lead authors.For rural areas, team members used a combination of central stations and door-to-door vaccinations, asking people if they had dogs and offering free rabies vaccines. "We found that in the pastoral communities, you definitely need more door-to-door outreach than you do in the other communities," says Ferguson, partly because of how sparsely populated those areas are, and partly because many of the dogs there are working animals used to herd goats and sheep and wouldn't be used to walking on a leash to go to one of the central vaccination stations.As the project grew, more and more people were interested in getting their dogs vaccinated. But the project's popularity presented the researchers with a tough decision. They could focus on smaller areas where they could try to get 70% of the dogs vaccinated, the amount needed for risk of dogs spreading the disease to humans to be effectively eliminated. Alternatively, they could vaccinate as many dogs from as many places as possible, without reaching a critical mass of vaccinations necessary for herd immunity. They didn't have the resources to get to 70% immunity on the large scale."I think the question grassroots campaigns have to ask themselves is, is that their goal just to have local outreach and help a few individuals, or are they trying to eliminate it at the landscape-level scale, which is the bigger picture goal. I think, going forward, the answer should be, you should have both," says Ferguson. "We need massive, large-scale efforts, but the reality is that money and resources are limited. That's where these grassroots campaigns are helpful. We were able to expand from 5 to 17 communities because we partnered with the national and county government from the get-go.""Our target of vaccinating more than 70% of dogs in Laikipia County through sustained campaigns will interrupt transmission in the reservoir population so that the disease is eliminated. LRVC does more than just vaccinating dogs against rabies, we visit schools to raise awareness amongst children -- the most affected population by the disease -- about rabies prevention," says Dishon Muloi, a scientist at International Livestock Research Institute and one of the study's lead authors."The need to eradicate rabies is both for the protection of people as well as wildlife, which includes some of the most endangered carnivores like the African wild dogs. For many years, infectious diseases have remained the main cause of endangerment for these species, with rabies playing a leading role in the endangerment of the African wild dogs. With massive vaccinations, and achieving 70% coverage, we will be able to protect both people and wildlife," says Ngatia.This study was contributed to by scientists from the Field Museum, the Smithsonian Conservation Biology Institute, the University of Edinburgh, the International Livestock Research Institute, Karatina University, Maasai Mara University, the Kenya Agricultural and Livestock Research Organization, the Kenya Zoonotic Disease Unit, Washington State University, the Zoological Society of London, the Ministry of Agriculture, Livestock, and Fisheries, County Government of Laikipia, the University of Liverpool, and the Mpala Research Centre.
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July 2, 2020
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https://www.sciencedaily.com/releases/2020/07/200702144104.htm
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Anaplasmosis bacterium tinkers with tick's gene expression to spread to new hosts
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For the first time, scientists have shown that the bacterium that causes the tick-borne disease anaplasmosis interferes with tick gene expression for its survival inside cells and to spread to a new vertebrate host. Girish Neelakanta of Old Dominion University and colleagues report these findings in a study published July 2nd in
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In the United States, new cases of tick-borne diseases, such as anaplasmosis, Lyme disease and babesiosis, are on the rise. There are few ways to prevent ticks from spreading these pathogens to humans, so researchers decided to look instead at interactions between the pathogen and the tick to find new ways to control the spread of disease. By looking at how the bacterium that causes anaplasmosis affects gene expression in the black legged tick, they discovered that the bacterium dials down the level of a regulatory molecule that normally stops the production of a protein called the Organic Anion Transporting Polypeptide (OATP). Further experiments showed that the bacterium's actions cause an increase in OATP levels, which results in higher numbers of the bacterium that helps it to spread to a new vertebrate host, in this case, mice.Previous experiments have shown that both bacterial and viral pathogens depend on OATPs to colonize and survive inside ticks. Together, the findings suggest that OATPs may be ideal candidates for developing new vaccines to protect humans against tick-borne illnesses. The current study also represents an important advance in our understanding of the tick-pathogen relationship, as currently we know surprisingly little about the mechanisms that allow pathogens to use ticks as vectors. Understanding how pathogens manipulate gene expression in vectors for their benefit may lead to novel strategies for blocking their transmission from the vector to vertebrate hosts."Studies like these would provide important evidence that tick molecules, such as OATPs, play a significant role in tick-pathogen interactions," commented author Girish Neelakanta. "Current and future studies from my laboratory are addressing therapeutic potential of OATP as a candidate for the development of a strong anti-vector vaccine to block transmission of tick-borne pathogens."
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July 2, 2020
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https://www.sciencedaily.com/releases/2020/07/200702113649.htm
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How old is your dog in human years? New method better than 'multiply by 7'
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How old is your tail-wagging bundle of joy in human years? According to the well-known "rule of paw," one dog year is the equivalent of 7 years. Now, in a study published July 2, in the journal
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Dogs share the same environment as their owners and receive almost the same standard of health care as humans, providing a unique opportunity for scientists to understand aging across species. Like humans, dogs follow similar developmental trajectories that lead them to grey and become more susceptible to age-related diseases over time. However, how they age on a molecular level is more complicated -- aging rapidly at first and slowing down later in life."In terms of how physiologically mature a 1-year-old dog is, a 9-month-old dog can have puppies. Right away, you know that if you do the math, you don't just times seven," says senior author Trey Ideker (@TreyIdeker) of the University of California, San Diego. "What's surprising is exactly how old that one-year-old dog is -- it's like a 30-year old human."Human and dog DNA, which codes who we are, doesn't change much throughout the course of life, but chemical marks on the DNA, called methylation marks, do. Ideker considers these marks like wrinkles in the genome. "I tend to think of it very much like when you look at someone's face and guess their age based on their wrinkles, gray hair, and other features," he says. "These are just similar kinds of features on the molecular level."The researchers studied 104 Labrador retrievers spanning from few-week-old puppies to 16-year-old dogs with the help of two canine experts, Danika Bannasch of the University of California, Davis, and Elaine Ostrander of the National Institutes of Health. They compared the changes in the methylation pattern to humans.The comparison revealed a new formula that better matches the canine-human life stages: human age = 16 ln(dog age) + 31. Based on the new function, an 8-week-old dog is approximately the age of a 9-month-old baby, both being in the infant stage where puppies and babies develop teeth. The average 12-year lifespan of Labrador retrievers also corresponds to the worldwide life expectancy of humans, 70 years."I like to take my dogs on runs, and so I'm a little bit more sympathetic to the 6-year-old now," says Ideker, who realized that his dog is pushing 60 according to the new calculation.In both species, they found that the age-driven methylation largely happens in developmental genes that are hotly fired up to create body plans in utero and regulating childhood development. By the time one becomes an adult and stops growing, "you've largely shut off these genes, but they're still smoldering," says Ideker. "If you look at the methylation marks on those developmental genes, they're still changing."Focusing on the smoldering developmental genes, the team developed a clock that can measure age and physiological states across different species, while other methylation-quantifying age-predicting methods only do well in one species. Ideker also noted that future investigation in different dog breeds with various lifespans could provide more insight into the new clock. The clock may not only serve as a tool to understand cross-species aging but also apply as clinical practice for veterinarians to take proactive steps to treat animals.
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July 2, 2020
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https://www.sciencedaily.com/releases/2020/07/200702113715.htm
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A novel sperm selection technology to increase success rates of in vitro fertilization
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Motile sperm are difficult to collect with a conventional cell sorter because they are vulnerable to physical damage. A research collaboration between Kumamoto and Kyoto Universities in Japan has developed a technique that uses a cell sorter with microfluidic chip technology to reduce cell damage and improve in vitro fertilization (IVF) rates. This research is expected to increase IVF rates to improve production of experimental animals and livestock, and could be used as a fertility treatment in human reproductive medicine.
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It is important to select fertile sperm with good motility to obtain high IVF rates. Conventional cell sorters use flow cytometry to separate specific cells by type, and can be used to select sperm. However, since sperm cells are susceptible to physical damage, it is extremely difficult to separate them without effecting motility.To reduce sperm cell damage, Professor Toru Takeo's research team at Kumamoto University tried to develop a sperm selection technique using a cell sorter with microfluidic chip technology that reduces detrimental effects to cells. Microfluidic devices have minute channel structures with a width and depth between several to several-hundreds of micrometers and are widely used in chemical and biotechnology research.While investigating the optimum separation conditions of sperm from a culture medium with their device, the researchers successfully collected mouse sperm that maintained motility. Furthermore, IVF using sperm collected with this device produced fertilized eggs and the embryos developed into neonatal mice after being transplanted into female mice.This new technology can also be used to improve IVF. At the end stage of maturation, before egg penetration and fertilization, sperm undergo morphological and physiological changes called the acrosome reaction that makes them ready to fertilize an egg. To test whether they could increase fertility, researchers prepared a fluorescent substance that binds to fertile sperm and used the device to sort them from non-fertile sperm. Comparison IVF experiments revealed that the fertile sperm had a higher fertilization rate than the non-fertile sperm."We expect that our research can be used to increase the success rate of IVF in animals, and for fertility treatments in human reproductive medicine," said Prof. Takeo. "Combined with techniques for labeling sex chromosomes in sperm, we may even be able to selectively breed males or females in experimental animals and livestock."
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Animals
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July 1, 2020
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https://www.sciencedaily.com/releases/2020/07/200701151714.htm
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Study confirms ultra music festival likely stressful to fish
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A new study published in the Journal
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An interdisciplinary team of researchers findings show that the fish experienced a significant stress response on the first day of the Ultra Music Festival in March 2019 on Virginia Key, Florida when there was elevated noise."The stress response was similar to what toadfish would experience when hearing bottlenose dolphins, a toadfish predator," said the study's co-investigator Danielle McDonald, professor of marine biology and ecology at the UM Rosenstiel School.The researchers' findings showed that the toadfish experienced a 4-5 fold increase in blood cortisol, their main stress hormone, during the first night of the Ultra Music Festival compared to two baseline samples taken before Ultra began.In addition to testing cortisol levels, the research team placed recording devices to measure sound intensity in the air and underwater. Hydrophones were placed in the toadfish tanks and in the waters directly next to the Ultra stages in Bear Cut Inlet in the Historic Virginia Key Beach Park and in Lamar Lake, a shallow mangrove lagoon further north."Recordings revealed that the sound intensity increased by 7-9 decibels in the toadfish tanks and 2-3 decibels in the nearby waters of Bear Cut in the low frequency range where fish are the most sensitive to changes in sound pressure," said co-investigator Claire Paris, professor of ocean sciences at the UM Rosenstiel School. "Variations in the sonic activity of marine organisms and additional noise from boat traffic may have contributed to the signal detected in Bear Cut during Ultra. In situ measurements, including long term acoustic recording, are necessary to evaluate the effect of Ultra on wild fish populations."Prior studies have shown that "underwater noise pollution causes stress and various physiological and behavioral disruptions on communication, hearing, spawning behavior and reproduction in aquatic organisms," said Maria Cartolano, lead postdoctoral scientist on the study.Gulf toadfish (Opsanus beta) play an important ecological role in the local marine environment and rely heavily on sound and their hearing for reproduction, social interactions and avoiding prey. This study could not determine if the elevated cortisol levels will have any long-term effects on the fish."We conducted the study on the effects of the multi-day music concert due to the close proximity of the festival to our experimental hatchery and aquaculture facility," said co-investigator Martin Grosell, professor of marine biology and ecology and Maytag Chair of Ichthyology at the UM Rosenstiel School. "It provided us an opportunity to investigate the potential impacts a large music festival of this kind can have on fish."The electronic music festival, held at the Miami Marine Stadium and Virginia Key Beach Park, on March 29-31, 2019 attracted over 170,000 attendees during the three-day event, one of the largest electronic music festivals in the world.
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Animals
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July 1, 2020
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https://www.sciencedaily.com/releases/2020/07/200701100030.htm
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New species described in 2020
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It is estimated that 15 million different species live on our planet, but only 2 million of them are currently known to science. Discovering new species is important as it helps to protect them. Furthermore, new species can also produce compounds that could lead to the development of new medicine.
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"Biodiversity is declining at an accelerating rate and, according to estimates, even a million organisms are in danger of becoming extinct in the next few decades. If we want to protect nature's biodiversity as efficiently as possible, we have to discover as many species as we can," says Professor of Biodiversity Research Ilari E. Sääksjärvi from the University of Turku, Finland.Discovering new species enables, for example, studying their habits and defining their geographical distribution.So far this year, the researchers of the Biodiversity Unit at the University of Turku have described 17 new spider species, 23 insects, one bristly millipede, and one monitor lizard. The new species have been discovered from the Amazon, Europe, India, the Middle East, and the Pacific islands. In addition to the species, the researchers have also described four new genera previously unknown to science.In one of the most recent studies from the Biodiversity Unit, Doctoral Candidate Alireza Zamani described a new spider species Loureedia phoenixi from Iran."The discovery was amazing as the new species belongs to the genus of velvet spiders, of which only few species have been known so far. They are very shy in their habits so discovering a new species was a great and welcome surprise. The species in this genus are amazingly beautiful and colourful so I wish this new discovery can make people understand the beauty and importance of spiders. We discovered the species from an area that is about 1,500 kilometres outside the known geographical distribution of the Loureedia genus," describes Zamani.Zamani and Sääksjärvi say that the Loureedia phoenixi spider was named after actor Joaquin Phoenix. The colourful pattern on its back resembles the face paint of the movie character Joker.The researchers of the Biodiversity Unit have also described tropical parasitoid wasps belonging to the Acrotaphus and Hymenoepimecis genera. These wasps are parasitic on spiders and manipulate the host in complicated ways. The parasitoid wasp lays its egg on the spider and then manipulates it into spinning a special web instead of a normal web for catching prey. The wasp's pupa nests safely inside this special web while developing into adulthood.New discoveries increase our information about the history of species and can therefore affect their conservation in the future. A good example is the Varanus bennetti monitor lizard described this year, as the importance of the species' conservation was concluded only after close field and laboratory studies."The monitor lizard species that was first considered an invasive species to Micronesia turned out to be two separate species native to the islands. We described one of these as new to science," say researchers Valter Weijola and Varpu Vahtera who discovered the species.Discovering, classifying, and describing a new species is a long process. New discoveries often require challenging field studies in remote places. Before conducting the field study, the researcher has to make sure that the required permits for collecting specimens and taking them out of the country are in order. The studies are conducted together with local scientists as often as possible.After the field study, the other research work begins: the species is examined in a laboratory, described, named, and classified and then the research article is published in an international journal.In the last few years, the Biodiversity Unit of the University of Turku has profiled itself especially in describing the biodiversity of unknown ecosystems. Each year, the unit describes dozens of new species which is a great amount even by international standards."Our goal is to discover new species and tell their story to the world. At the moment, we are in the process of describing even more new species and genera. Many of these animals live in areas that might transform or even disappear in the next few years. Describing new species to science is a race against the clock. We hope that our research draws people's attention to the life of these unique species and thus promotes the conservation of biodiversity," conclude Sääksjärvi and Zamani.
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June 30, 2020
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https://www.sciencedaily.com/releases/2020/06/200630193202.htm
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Hints at jaw evolution found in marsupials and monotremes
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Infant marsupials and monotremes use a connection between their ear and jaw bones shortly after birth to enable them to drink their mothers' milk, new findings in
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This discovery by researchers at King's College London, UK, provides new insights about early development in mammals, and may help scientists better understand how the bones of the middle ear and jaw evolved in mammals and their predecessors.Marsupials such as opossums, and monotremes such as echidnas, are unusual types of mammals. Both types of animal are born at a very early stage in development, before many bones in the body have started to form. Opossums latch on to their mother's nipple and stay there while they finish developing. Monotremes, which hatch from eggs, lap milk collected near their mother's milk glands as they grow. But how they are able to drink the milk before their jaw joint is fully developed was previously unclear."Given the lack of a jaw joint in marsupials and monotremes at birth, scientists have previously suggested that the animals may use a connection between the middle ear bones and jaw bones to allow them to feed," explains lead author Neal Anthwal, Research Associate at the Centre for Craniofacial & Regenerative Biology, at King's College London's Faculty of Dentistry, Oral & Craniofacial Sciences in the UK.To find out if this is true, Anthwal and his colleagues compared the jaw bones in platypus, short-beaked echidnas, opossums and mice shortly after birth. Their work revealed that, soon after echidnas hatch, their middle ear bones and upper jaw fuse, eventually forming a joint that is similar to the jaws of mammal-like reptile fossils. The team found a similar connection in mouse embryos, but this disappears and the animals are born with functioning jaw joints.Opossums, by contrast, use connective tissue between their middle ear bones and the base of their skull to create a temporary jaw joint that enables them to nurse shortly after birth. "This all shows that marsupials and monotremes have different strategies for coping with early birth," Anthwal says.The findings suggest that the connection between the ear and jaw dates back to an early mammal ancestor and persisted when mammals split into subgroups. Marsupials and monotremes continue to use these connections temporarily in early life. In other mammals, such as mice, these connections occur briefly as they develop in the womb but are replaced by a working jaw joint before birth."Our work provides novel insight into the evolution of mammals," concludes senior author Abigail Tucker, Principal Investigator and Professor of Development & Evolution at the Centre for Craniofacial & Regenerative Biology, King's College London. "In particular we highlight how structures can change function over evolutionary time but also during development, with the ear bones moving from feeding to hearing. The recent availability of monotreme tissue for molecular analysis, as showcased here, provides an amazing future opportunity to understand the biology of these weird and wonderful mammals, which we are keen to explore."
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June 30, 2020
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https://www.sciencedaily.com/releases/2020/06/200630072051.htm
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Goodbye northwestern crow, hello Mexican duck
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The latest supplement to the American Ornithological Society's Checklist of North and Middle American Birds, published in
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The Northwestern Crow has long been considered a close cousin of the more familiar and widespread American Crow, with a range limited to the Pacific Northwest. However, a recent study on the genetics of the two species prompted AOS's North American Classification Committee to conclude that the two species are actually one and the same. "People have speculated that the Northwestern Crow and the American Crow should be lumped for a long time, so this won't be a surprise to a lot of people," says the U.S. Geological Survey's Terry Chesser, chair of the committee. "Northwestern Crows were originally described based on size, being smaller than the American Crow, and behavior, but over the years the people who've looked at specimens or observed birds in the field have mostly come to the conclusion that the differences are inconsistent. Now the genomic data have indicated that this is really variation within a species, rather than two distinct species."However, birdwatchers disappointed to lose the Northwestern Crow from their life lists can take solace in the addition of a new species to the official checklist: the Mexican Duck. "The checklist recognized Mexican Duck until 1973, when it was lumped with Mallard," says Chesser. "But the Mexican Duck is part of a whole complex of Mallard-like species, including Mottled Duck, American Black Duck, and Hawaiian Duck, and all of those are considered distinct species except for, until recently, the Mexican Duck. Now genomic data have been published on the complex and on the Mexican Duck and Mallard in particular, and they show that gene flow between them is limited, which was enough to convince the committee to vote for the split."Additional changes introduced in this year's checklist supplement include a massive reorganization of a group of Central American hummingbirds known as the emeralds -- adding nine genera, deleting six others, and transferring seven additional species between already-recognized genera -- as well as an update to the criteria for adding introduced, non-native species to the list that raises the bar for introduced species to officially be considered established.
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Animals
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June 29, 2020
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https://www.sciencedaily.com/releases/2020/06/200629164148.htm
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Researchers look for answers as to why western bumblebees are declining
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A University of Wyoming researcher and her Ph.D. student have spent the last three years studying the decline of the Western bumblebee. The two have been working with a group of bumblebee experts to fill in gaps of missing information from previous data collected in the western United States. Their goal is to provide information on the Western bumblebee to the U.S. Fish and Wildlife Service while it considers listing this species under the U.S. Endangered Species Act.
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"The decline of the Western bumblebee is likely not limited to one culprit but, instead, due to several factors that interact such as pesticides, pathogens, climate change and habitat loss," says Lusha Tronstad, lead invertebrate zoologist with the Wyoming Natural Diversity Database (WYNDD). "Western bumblebees were once the most abundant bumblebees on the West Coast of the U.S., but they are much less frequently observed there now. Pathogens (or parasites) are thought to be a major reason for their decline."Tronstad and Christy Bell, her Ph.D. student in the Department of Zoology and Physiology, from Laramie, are co-authors of a paper, titled "Western Bumble Bee: Declines in the United States and Range-Wide Information Gaps," that was published online June 26 in The two are co-authors because they are members of the Western Bumble Bee Working Group and serve as experts of the Western bumblebee in Wyoming, Tronstad says.Other contributors to the paper are from the U.S. Geological Survey; U.S. Fish and Wildlife Service; Canadian Wildlife Service; Xerces Society for Invertebrate Conservation in Portland, Ore.; British Columbia Ministry of Environment and Climate Change Strategy; University of Hawaii-Hilo; U.S. Department of Agriculture; The Institute for Bird Populations; University of Vermont; Utah State University; Ohio State University; Denali National Park and Preserve; and the Royal Saskatchewan Museum.This paper is the result of the Western Bumble Bee Working Group, which is a group of experts on this species who came together to assemble the state of knowledge on this species in the United States and Canada, Tronstad says. The paper shows both what is known and knowledge gaps, specifically in the lack of samples and lack of knowledge about the species. Some prime examples of where spatial gaps in limited sampling exist include most of Alaska, northwestern Canada and the southwestern United States."Some areas in the U.S. have less bumblebee sampling in the past and present," Tronstad explains. "This could be for a variety of reasons such as lack of funding for such inventories, lack of bee expertise in that state, etc."Using occupancy modeling, the probability of detecting the Western bumblebee decreased by 93 percent from 1998-2018, Tronstad says. Occupancy modeling is a complex model that estimates how often the Western bumblebee was detected from sampling events between 1998-2018 in the western United States."The data we assembled will be used by the U.S. Fish and Wildlife Service to inform its decision on whether or not to protect the Western bumblebee under the U.S. Endangered Species Act," Tronstad says. "At WYNDD, we collect data, and that data is used by managers. Our mission is to provide the most up-to-date data on which management decisions can be based."Tronstad says there are several things that homeowners or landowners can do to help this species of bumblebee survive and thrive. These include:Tronstad says Bell's research will continue this summer, as Bell will investigate pathogens in the Rocky Mountains of Wyoming that affect Western bumblebees there. Max Packebush, a UW sophomore majoring in microbiology and molecular biology, from Littleton, Colo.; and Matt Green, a 2018 UW graduate from Camdenton, Mo., will assist Bell in her research. NASA and the Wyoming Research Scholars Program will fund Packebush to conduct his work. The U.S. Geological Survey and the U.S. Fish and Wildlife Service funded the research for this paper.
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Animals
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June 29, 2020
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https://www.sciencedaily.com/releases/2020/06/200629120218.htm
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New extinct family of giant wombat relatives discovered in Australian desert
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The unique remains of a prehistoric, giant wombat-like marsupial --
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An analysis of UNSW Science's Professor Mike Archer, a co-author on the paper, was part of the original international team of palaeontologists along with Professor Dick Tedford, another co-author, that found the skeleton in 1973 in the clay floor of Lake Pinpa -- a remote, dry salt lake east of the Flinders Ranges in South Australia. He says their discovery of "It was an extremely serendipitous discovery because in most years the surface of this dry lake is covered by sands blown or washed in from the surrounding hills," he says."But because of rare environmental conditions prior to our arrival that year, the fossil-rich clay deposits were fully exposed to view. And this unexpected view was breathtaking."On the surface, and just below we found skulls, teeth, bones and in some cases, articulated skeletons of many new and exotic kinds of mammals. As well, there were the teeth of extinct lungfish, skeletons of bony fish and the bones of many kinds of water birds including flamingos and ducks."These animals ranged from tiny carnivorous marsupials about the size of a mouse right up to Professor Archer says when "We found it by probing the dry flat surface of the Lake with a thin metal pole, like acupuncturing the skin of Mother Earth. We only excavated downwards into the clay if the pole contacted something hard below the surface -- and in this case it turned out to be the articulated skeleton of a most mysterious new creature."The researchers' recent study of the partial skull and skeleton reveals that despite its bear-like size, Lead author on the paper Dr Robin Beck from the University of Salford says "Griffith University's Associate Professor Julien Louys, who co-authored the study, said "the description of this new family adds a huge new piece to the puzzle about the diversity of ancient, and often seriously strange marsupials that preceded those that rule the continent today."The scientists examined how body size has evolved in vombatiform marsupials -- the taxonomic group that includes "Koalas and wombats are amazing animals" says Dr Beck, "but animals like The original party that discovered Video:
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June 26, 2020
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https://www.sciencedaily.com/releases/2020/06/200626092739.htm
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Bizarre saber-tooth predator from South America was no saber-tooth cat
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A new study led by researchers from the University of Bristol has shown that not all saber-tooths were fearsome predators.
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Saber-tooth cats, such as the North American species Smilodon fatalis, are among the most iconic fossil animals with a reputation for being fierce predators. However, saber-tooths came in all shapes and sizes and nearly a hundred different saber-tooths are known to science so far.Thylacosmilus atrox (which means 'terrible pouched knife') is a well-known animal that lived around five million years ago in Argentina.A jaguar-sized marsupial, it is popularly known as the 'marsupial saber-tooth', compared with the sabertoothed cats elsewhere in the world, and it is often presented as a classic case of convergent evolution -- where animals appear similar in form despite having very different evolutionary relationships (such as marsupial flying possums and placental flying squirrels -- both of course being gliders rather than true fliers).Thylacosmilus had huge, ever-growing canines, leading people to speculate that it was an even more vicious predator than the placental carnivores it superficially resembled such as Smilodon.But was it really a fierce predator like the extinct placental saber-toothed cats, which seem to have been much like modern cats but with a different mode of killing their prey?An international team of researchers, led by Professor Christine Janis from Bristol's School of Earth Sciences, have performed a series of studies on the skull and teeth of this animal and have come to a different conclusion. Their findings are published in the journal Professor Janis said: "The title of this paper, 'An Eye for a Tooth', sums up how we think this animal has been perceived."It has impressive canines, for sure: but if you look at the whole picture of its anatomy, lots of things simply don't add up. For example, it just about lacks incisors, which big cats today use to get meat off the bone, and its lower jaws were not fused together."In addition, the canines of Thylacosmilus were different from the teeth of other saber-toothed mammals, being triangular in shape like a claw rather than flat like a blade."A statistical study, comparing aspects of the skull and teeth of Thylacosmilus with both present-day big cats and a diversity of extinct saber-toothed cats, confirmed suspicions about the differences from its placental supposed counterparts.Co-author Borja Figueirido of the University of Málaga (Spain) added: "The skull superficially looks rather like that of a saber-toothed placental."But if you actually quantify things, it becomes clear that Thylacosmilus' skull was different in many details from any known carnivorous mammal, past or present."Detailed biomechanical studies comparing the skulls of Thylacosmilus and Smilodon, simulating performance under different conditions, were also revealing.Stephan Lautenschlager from the University of Birmingham, the contributing author on the paper who performed these analyses, said: "Previous studies by other researchers have shown Thylacosmilus to have had a weaker bite than Smilodon."But what we can show is there was probably a difference in behaviour between the two species: Thylacosmilus' skull and canines are weaker in a stabbing action than those of Smilodon, but are stronger in a 'pull-back' type of action. This suggests that Thylacosmilus was not using its canines to kill with, but perhaps instead to open carcasses."Finally, the other teeth of Thylacosmilus also pose problems for the interpretation of this animal as a cat-like predator, whether saber-toothed or not. Besides the puzzling lack of incisors, the molars are small, and did not wear down along the sides as seen in an animal feeding on meat.Larisa DeSantis from Vanderbilt University (USA), who conducted a detailed dental study, added: "The molars tend to wear flat from the top, rather like you see in a bone crusher."But if you examine the detailed microwear on tooth surfaces, it's clear that it was eating soft food. Its wear is most similar to that of cheetahs which eat from fresh carcasses and suggests an even softer diet than fed to captive lions."Thylacosmilus was not a bone-crusher and may have instead specialised on internal organs."Professor Janis said: "It's a bit of a mystery as to what this animal was actually doing but it's clear that it wasn't just a marsupial version of a saber-toothed cat like Smilodon."In addition to the differences in the skull and the teeth, it was also short-legged and stiff-backed, and lacked retractile claws, so it would have had difficulties in pursuing its prey, pouncing on it and holding on to it. I suspect it was some sort of specialised scavenger."It may have employed those canines to open carcasses and perhaps also used a big tongue to help extract the innards: other mammals that have lost the incisors, like walruses and anteaters, also have big tongues that they use in feeding."When Thylacosmilus lived on the plains of Argentina five million years ago, it would have inhabited a very different type of ecosystem to any modern one. Then the big predators were huge flightless birds, the "terror birds" or phorusrachiformes, now all extinct. Life in the past may have been very different to the present day.Borja Figueirido added: "In Africa today it's the mammals who are the killers and the big birds, like vultures, are the scavengers. But perhaps five million years ago in Argentina it was the other way around, and it was the mammals who were the scavengers."
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Animals
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June 25, 2020
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https://www.sciencedaily.com/releases/2020/06/200625144816.htm
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Sled dogs are closely related to 9,500-year-old 'ancient dog'
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Sledge dogs are much older and have adapted to Arctic conditions much earlier than previously thought. In a new study from the QIMMEQ project, researchers from the University of Copenhagen show that ancestors of modern sledge dogs have worked and lived with humans for over 9,500 years.
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Dogs play an important role in human life all over the world -- whether as a family member or as a working animal. But where the dog comes from and how old various groups of dogs are is still a bit of a mystery.Now, light has been shed on the origin of the sledge dog. In a new study published in "We have extracted DNA from a 9,500-year-old dog from the Siberian island of Zhokhov, which the dog is named after. Based on that DNA we have sequenced the oldest complete dog genome to date, and the results show an extremely early diversification of dogs into types of sledge dogs," says one of the two first authors of the study, PhD student Mikkel Sinding, the Globe Institute.Until now, it has been the common belief that the 9,500-year-old Siberian dog, Zhokhov, was a kind of ancient dog -- one of the earliest domesticated dogs and a version of the common origin of all dogs. But according to the new study, modern sledge dogs such as the Siberian Husky, the Alaskan Malamute and the Greenland sledge dog share the major part of their genome with Zhokhov."This means that modern sledge dogs and Zhokhov had the same common origin in Siberia more than 9,500 years ago. Until now, we have thought that sledge dogs were only 2-3,000 years old," says the other first author, Associate Professor Shyam Gopalakrishnan, Globe Institute.To learn more about the origins of the sledge dog, researchers have further sequenced genomes of a 33,000-year-old Siberian wolf and ten modern Greenlandic sledge dogs. They have compared these genomes to genomes of dogs and wolves from around the world."We can see that the modern sledge dogs have most of their genomes in common with Zhokhov. So, they are more closely related to this ancient dog than to other dogs and wolves. But not just that -- we can see traces of crossbreeding with wolves such as the 33,000-year-old Siberian wolf -- but not with modern wolves. It further emphasises that the origin of the modern sledge dog goes back much further than we had thought," says Mikkel Sinding.The modern sledge dogs have more genetic overlap with other modern dog breeds than Zhokhov has, but the studies do not show us where or when this occurred. Nevertheless, among modern sledge dogs, the Greenland sledge dogs stands out and has the least overlap with other dogs, meaning that the Greenland sledge dog is probably the most original sledge dog in the world.In addition to advancing the common understanding of the origin of sledge dogs, the new study also teaches the researchers more about the differences between sledge dogs and other dogs. Sledge dogs do not have the same genetic adaptations to a sugar and starch rich diet that other dogs have. On the other hand, they have adaptations to high-fat diets, with mechanisms that are similar to those described for polar bears and Arctic people."This emphasises that sledge dogs and Arctic people have worked and adapted together for more than 9,500 years. We can also see that they have adaptations that are probably linked to improved oxygen uptake, which makes sense in relation to sledding and give the sledding tradition ancient roots," says Shyam Gopalakrishnan.
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Animals
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June 25, 2020
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https://www.sciencedaily.com/releases/2020/06/200625124939.htm
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Dangerous tick-borne bacterium extremely rare in New Jersey
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There's some good news in New Jersey about a potentially deadly tick-borne bacterium. Rutgers researchers examined more than 3,000 ticks in the Garden State and found only one carrying Rickettsia rickettsii, the bacterium that causes Rocky Mountain spotted fever.
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But cases of tick-borne spotted fevers have increased east of the Mississippi River, and more research is needed to understand why, according to a study in The Rocky Mountain spotted fever from infection with Rickettsia rickettsii can involve blood vessel damage, gangrene and organ failure. It was rare in the United States and limited to the Mountain states until the beginning of this century. Since then, the mid-Atlantic states have seen a steep increase in spotted fever cases that are associated with a lower risk of severe illness and death -- a puzzling and unexplained phenomenon.In the past decade, New Jersey has reported between 42 and 144 cases of spotted fever a year, but it is unclear which, if any, involved the dangerous Rickettsia rickettsii since current blood tests for spotted fever do not distinguish between different kinds of Rickettsia bacteria."CDC researchers recently found that the invasive Asian longhorned tick, like the American dog tick and lone star tick, is an efficient vector of Rickettsia rickettsii in the lab," said senior author Dina M. Fonseca, a professor and director of the Center for Vector Biology in the Department of Entomology in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick. "The Asian longhorned tick, which was first detected in the U.S. by Rutgers Center for Vector Biology researchers, is now very abundant in some New Jersey counties. And while this tick species has not been found infected with any human pathogens in the U.S. so far, this raised concerns. Our finding of the rarity of Rickettsia rickettsii in New Jersey is good news, but we can't let our guard down."Rutgers researchers looked for the pathogen in two separate studies. The latest one, published this week, included 805 ticks collected statewide during a 2018 Tick Blitz and 394 ticks collected from 2013 to 2018. It found no evidence of the pathogen. The other study, published this year, involved 1,858 ticks collected in Monmouth County in 2018 and found Rickettsia rickettsii in one."We do not rule out that cases of Rocky Mountain spotted fever may occur in New Jersey since the deadly bacteria have been detected in New Jersey ticks. However, our results indicate that most cases of spotted fevers in New Jersey are likely caused by other Rickettsia bacteria," said Jim Occi, a Rutgers doctoral student who was the lead author of the statewide study.The Monmouth County study was led by Andrea M. Egizi, a visiting professor in the Department of Entomology at Rutgers who earned a doctorate at Rutgers, and is a research scientist with the Monmouth County Tick-borne Diseases Laboratory hosted by the Rutgers Center for Vector Biology.Rutgers Center for Vector Biology researchers reviewed studies from neighboring states and, in New Jersey, developed statewide surveillance of Rickettsia pathogens in the American dog tick and the lone star tick, the two tick species thought to be the primary vectors. The surveillance confirmed the increased distribution and abundance of lone star ticks across the Garden State.
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Animals
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June 25, 2020
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https://www.sciencedaily.com/releases/2020/06/200625122730.htm
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Tiny brains, big surprise: Eavesdropping wasps gain insights about fighting abilities of potential rivals
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Paper wasps eavesdrop on fighting rivals to rapidly assess potential opponents without personal risk. This new finding adds to mounting evidence that even mini-brained insects have an impressive capacity to learn, remember and make social deductions about others.
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Many vertebrate animals -- including some birds and fish and numerous primates -- minimize the costs of conflict by using "social eavesdropping" to learn about the fighting ability of potential rivals before interacting with them personally.Keeping track of a network of individually differentiated social relationships is thought to be cognitively challenging and, until recently, was considered to be beyond the reach of lowly insects like paper wasps, which have brains a million times smaller than the human brain.But a growing body of evidence suggests that the miniature nervous systems of insects do not limit sophisticated behaviors. The capacity for complex insect behavior may be shaped more by social environment than brain size, according to University of Michigan biologist Elizabeth Tibbetts, senior author of a paper scheduled for publication June 25 in the journal "It is surprising that wasps can observe and remember a complex network of social interactions between individuals without directly interacting with them," said Tibbetts, a professor in the U-M Department of Ecology and Evolutionary Biology. "Complex social relationships are thought to favor the evolution of large brains and increased social intelligence, but paper wasp brains are relatively small."In the study, Tibbetts and her students collected female Polistes fuscatus paper wasps from sites around Ann Arbor, Michigan, in the early spring.Unlike a honeybee colony -- which has a single queen and multiple equally ranked female workers -- paper wasp colonies contain several reproductive females called foundresses. These females battle their rivals and form complex, linear dominance hierarchies based on the outcomes of those fights. A wasp's rank in the hierarchy determines its share of reproduction, work and food.In the laboratory, the researchers used enamel to mark all foundresses with unique color patterns on the thorax. Then, two at a time, "fighter" wasps were placed in a small container known as the fighting arena while two "bystander" wasps observed the pair through clear plastic partitions.All trials were videotaped, and a research assistant assigned scores to each fighter using an aggression index that awards points for behaviors like biting, mounting, grappling and stinging. Dominance rank was determined using the number of mounts -- a dominance behavior in which the dominant wasp drums her antennae on the subordinate while the subordinate crouches and lowers her antennae -- during a fight.Later, bystander wasps were paired in the fighting arena either with a wasp they had observed (experimental trial) or a fighter they had never seen before (control trial). Tibbetts and her students compared the behaviors in the experimental and control trials to determine the role of social eavesdropping.They found that bystander wasps were more aggressive when paired with an individual that was the victim of lots of aggression in a previous bout, as well as individuals who initiated very little aggression in the previous fight.By comparing experimental and control trials, the researchers were also able to reject non-eavesdropping explanations for the observations, including phenomena called priming and winner/loser effects."The results show that P. fuscatus wasps use social eavesdropping," Tibbetts said. "Bystanders observe other individuals fight, and they use information about the fight to modulate subsequent behavior."In previous studies over more than a decade, Tibbetts and her colleagues showed that paper wasps recognize individuals of their species by variations in their facial markings, and they behave more aggressively toward wasps with unfamiliar faces.They also demonstrated that paper wasps have surprisingly long memories and base their behavior on what they remember of previous social interactions.But the previous work focused on how wasps use individual recognition during direct interactions and did not test -- as this new study did -- whether wasps learn about other individuals via observation alone.In addition to Tibbetts, the authors of the
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Animals
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June 25, 2020
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https://www.sciencedaily.com/releases/2020/06/200625115929.htm
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Dolphins learn foraging skills from peers
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Dolphins can learn new skills from their fellow dolphins. That's the conclusion of a new study reported in the journal
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"Our study shows that the foraging behavior 'shelling' -- where dolphins trap fish inside empty seashells -- spreads through social learning among close associates," says Sonja Wild, who conducted this research for her doctorate at the University of Leeds. "This is surprising, as dolphins and other toothed whales tend to follow a 'do-as-mother-does' strategy for learning foraging behavior."Another aspect that makes the findings especially intriguing is that shelling represents only the second reported case of tool use in dolphins. The dolphins of Shark Bay, Western Australia, are also known to use marine sponges as foraging tools to help them catch prey, according to the researchers.Wild and her colleagues made the discovery during boat-based surveys in Shark Bay between 2007 and 2018. In almost 5,300 encounters with dolphin groups over that time, they identified more than 1,000 different Indo-Pacific bottlenose dolphins ("During shelling, dolphins chase their prey -- usually a fish -- into empty shells of giant gastropods, insert their beak into the shell, bring it to the water surface and then shake it about to drain the water out of the shell, so that the fish falls into their open mouth," Wild explains.The researchers saw 19 different individual dolphins perform this shelling behavior. They note that there are surely more 'shellers' in the population than they saw, since the whole event may only take a few seconds and could easily be missed. The question then was: how had this new way of foraging spread from one dolphin to the next?To find out, the researchers used social network analysis, taking into account the social network, genetic relationships, and environmental factors. Their analysis concluded that the shelling behavior spreads socially primarily within -- rather than between -- generations, providing the first evidence that dolphins are also capable of learning from their peers, not just their mothers."The fact that shelling is socially transmitted among associates, rather than between mother and offspring, highlights the similarities between cetaceans [the group including dolphins, whales, and porpoises] and great apes in the way cultural behaviors are passed on," says Michael Krützen, University of Zurich, who initiated the study."Indeed, despite having divergent evolutionary histories and occupying different environments, there are striking similarities between cetaceans and great apes: both are long-lived, large-brained mammals with high capacities for innovation and cultural transmission of behaviors," he adds.Wild noted that not all shelling dolphins seem to engage in the behavior at the same frequency. "Some dolphins use shells quite regularly during foraging, while others have only ever been seen with a shell once," she says. "So, while there may be other explanations, it's possible that some dolphins have mastered the skill more than others."Wild says that the findings have important implications for understanding how dolphins may be able to adapt behaviorally to changing environments. "Learning from others allows for a rapid spread of novel behaviors across populations, and it has been suggested that species with the capacity for learning from others in this way may be better able to survive," she says.
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Animals
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June 25, 2020
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https://www.sciencedaily.com/releases/2020/06/200625102519.htm
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Bugs resort to several colors to protect themselves from predators
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New research has revealed for the first time that shield bugs use a variety of colours throughout their lives to avoid predators.
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Shield bugs are often bright, colourful insects that use colours to warn off their distastefulness to predators. The paper, published in "We found that in most species, the same individual bug will use different colour combinations as nymphs -- young bugs -- and adults, going for example from red and green to yellow and green," said lead author and ecologist, Dr Iliana Medina, from the University of Melbourne's School of Biosciences."This is significant because many of these species use colour to warn predators that they are distasteful, and for years it has been thought that animals living in the same environment -- like nymphs and adults of the same species -- should use similar warning colours, not different ones."The joint research between scientists at the University of Melbourne and the Australian National University combined information on colour in young and adults for more than 100 species of shield bugs worldwide. They then used field work in Canberra, with white-winged choughs, to measure how likely these birds were to attack adult and nymphs of one Australian species of shield bug, the cotton harlequin bug.Experiments were also conducted in the aviary, training two-week-old chicks to see how fast they learned to avoid nymphs and adults, then testing whether their previous experience with adults could reduce attack rates on nymphs."Our experiments with the cotton harlequin bug showed that predators could quickly learn to avoid both types of colour signals from nymphs and adults, but nymphs get a larger benefit," Dr Medina said."Although young and adult cotton harlequin bugs have different colours, previous experience with adults make chicks less likely to attack the nymphs. Also, chicks and wild predators that have never seen the insects before do not show much interest in eating them. The colours in these insects are a great strategy against predators."Many animals such as frogs, insects and sea slugs use bright colourations to advertise toxicity or distastefulness. In theory, warning signals of prey that live in the same environment should be the same because predators can learn more effectively to avoid one type of pattern, instead of many different ones.While this idea has been used to explain the great examples of mimicry in nature, and why distantly related species end up having the same warning colours, such as black and red, or black and yellow, researchers say there are multiple examples of variation in local warning signals and an overlooked type of variation is that across life stages."If predators were able to learn to avoid only one type of warning colour, we would expect nymphs and adults to look similar in many species," Dr Medina said. "What our findings show, however, is that the wide colour variation in shield bugs is probably the result of predators being able to learn to avoid different types of colourful signals."
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Animals
| 2,020 |
June 24, 2020
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https://www.sciencedaily.com/releases/2020/06/200624172042.htm
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Habitat for Rattlesnakes: Sunnier but Riskier
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Conservation efforts that open up the canopy of overgrown habitat for threatened timber rattlesnakes -- whose venom is used in anticoagulants and other medical treatments -- are beneficial to snakes but could come at a cost, according to a new study by researchers at Penn State and the University of Scranton. The researchers confirmed that breeding areas with more open canopies do provide more opportunities for these snakes to reach required body temperatures, but also have riskier predators like hawks and bobcats. The study, which appears in the June issue of the
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Timber rattlesnakes are a species of conservation concern in Pennsylvania and are considered threatened or endangered in many of the northern states within their range. Like other ectothermic animals, snakes do not produce their own body heat and must move to warmer or cooler areas to regulate their temperature. Timber rattlesnakes typically use sunny, rocky forest clearings to breed, however many of these "gestation sites" are becoming overgrown with vegetation, blocking much-needed sunlight."Pregnant timber rattlesnakes typically maintain a temperature 6 to 8 degrees Celsius higher than normal so that their embryos can develop," said Christopher Howey, assistant professor of biology at the University of Scranton and former postdoctoral researcher at Penn State. "If a gestation site doesn't provide enough opportunities for snakes to reach that temperature, a snake might abort its litter, or babies might be born too small or later in the season, which reduces their chances of obtaining an essential first meal before hibernation. We wanted to understand if existing conservation efforts to open up the canopy in gestation sites actually do provide more thermal opportunities for snakes, as intended, and if these efforts impact predation risk."The research team first quantified thermal opportunities for rattlesnakes in known gestation sites that had open or closed canopies. They logged temperatures within thermal models -- essentially a copper tube painted to have similar reflectivity and heat absorbance to a snake -- placed in areas where the researchers had seen snakes basking."As expected, we found that gestation sites with more open canopies did indeed provide more opportunities for snakes to reach optimal temperatures," said Tracy Langkilde, professor and head of biology at Penn State. "This confirms that conservation efforts to open up the canopy do what they are intended to do. But we also found that this might come at a cost, in the form of more threatening predators."The research team also placed foam models painted like rattlesnakes at gestation sites and monitored for predators using trail game cameras -- remote cameras that are triggered by movement. While there was a similar overall number of predators at sites with open canopies and closed canopies, the more threatening species -- red-tailed hawks, fishers, and bobcats -- only appeared at open sites."Our results suggest that there are tradeoffs to any management strategy and that by opening up a gestation site, we may inadvertently put more predation risk on a species," said Julian Avery, assistant research professor of wildlife ecology and conservation at Penn State. "Our models were slightly less visible to potential predators than actual snakes, so our estimates of predation risk are probably conservative, and the tradeoff may be more pronounced than what we observed."Less threatening predators -- raccoons and black bears -- appeared at sites with both open and closed canopies."As far as we know, this is the first time that a black bear has been observed preying on a rattlesnake, or at least a model," said Howey. "Until now, we always thought that black bears avoided rattlesnakes, but we observed one bear attack two models and bite into a third."The team suggests that forest managers should balance canopy cover and predation risk during future conservation efforts, for example by selectively removing trees that block direct sunlight but that do not considerably open up the canopy.Improving conservation efforts at rattlesnake gestation sites is particularly important because, as far as the researchers know, snakes return to the same sites year after year to breed. If a gestation site decreases in quality, they might leave the site to find a new area, but it is unclear how successful these efforts are and the act of moving to new sites could increase contact with humans.The researchers are currently radio-tracking actual snakes and directly manipulating the canopy cover to better understand how snakes behave in response to predators at sites with open vs. closed canopies."Timber rattlesnakes are an important part of the ecosystem, and where you have more rattlesnakes, you tend to have lower occurrences of Lyme disease because the snakes are eating things like chipmunks and mice which are the main vectors for the disease," said Howey. "Rattlesnake venom is also used in anticoagulants, in blood pressure medicine, and to treat breast cancer. Our research will help us refine how we conserve these important animals."
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Animals
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June 24, 2020
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https://www.sciencedaily.com/releases/2020/06/200624151613.htm
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Protein in mitochondria appears to regulate health and longevity
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A new study led by researchers at the USC Leonard Davis School of Gerontology is the first to demonstrate that a tiny protein has a big impact on health and longevity in both animals and humans.
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The researchers examined humanin, a peptide encoded in the small genome of mitochondria -- the powerhouses of the cell. From experiments in laboratory animals to measurements in human patients, the multi-site collaboration demonstrates how higher levels of humanin in the body are connected to longer lifespans and better health. It is linked to a lower risk for diseases such as Alzheimer's."Humanin has long been known to help prevent many age-related diseases, and this is the first time that it has been shown that it can also increase lifespan," said senior author Pinchas Cohen, professor of gerontology, medicine and biological sciences and dean of the USC Leonard Davis School.Humanin has been found not only in human mitochondria but also throughout the animal kingdom, a sign that its related gene has been maintained, or conserved, throughout evolution. The study, which was published online in the journal The results highlight the potential for humanin and other mitochondrial proteins to become treatments for age-related ailments. They also indicate that humanin may be an ancient mitochondrial signaling mechanism that is key for regulating the body's health and lifespan, said first author and USC Leonard Davis Research Assistant Professor Kelvin Yen.Humanin levels have previously been observed to decrease with age in many species. In this new study, the scientists observed higher levels of humanin in organisms predisposed to long lives, including the famously age-resistant naked mole rat, which experiences only a very slow decline in levels of humanin circulating in the body throughout its 30-year lifespan.In contrast, mice experience a 40% drop in humanin over the first 18 months of life, and primates such as rhesus macaques appeared to have a similarly dramatic drop in humanin between the ages of 19 and 25.In humans, researchers observed this phenomenon of higher and more sustained levels of humanin in 18 children of centenarians, versus a control group of 19 children of non-centenarians. Individuals whose parents reach 100 years old are statistically more likely than other people to reach very old age.In some species, including worms and mice, modifying their genes to produce higher amounts of humanin within their bodies was enough to significantly increase lifespans. But these longer-lived animals had fewer offspring. Scientists have observed a similar pattern in long-lived humans."This tradeoff between longevity and reproduction is thought to be due to an evolutionarily conserved balance between using energy to produce more offspring or using the energy to maintain the organism for future reproductive efforts," Yen said. "Evolutionarily speaking, the goal of life is to reproduce and then you're done, but if you can't reproduce, you should try to hang around as long as possible, and a side effect of that is longevity."Higher humanin levels aren't just linked to increased lifespan; lower levels may increase the risk of disease and lower resistance to toxic exposures.The researchers analyzed samples of cerebral spinal fluid from a small number of Alzheimer's patients and control individuals without dementia and noticed that humanin levels were much lower in the Alzheimer's patients. And in newborn cord blood samples, high levels of humanin correlated with a high mitochondrial DNA (mtDNA) copy number, or the number of copies of the mitochondrial genome present within each cell."Humanin levels are inversely correlated with a decrease in mitochondrial DNA (mtDNA) copy number, which in itself has been associated with a number of different diseases such as cancer, kidney disease, and cardiovascular disease," Yen said.Cohen's laboratory was one of three groups that independently discovered humanin and has continued to unlock the secrets of the mitochondrial genome. Other promising mitochondrial peptides characterized by Cohen's team include MOTS-c, which plays a role in communication between the mitochondria and the nucleus in cells and appears to mimic the effects of exercise.This new wide-ranging study highlights the importance of humanin as a potentially powerful regulator of lifespan and health, and harnessing it for treatments could address a variety of age-related illnesses, Cohen said."This study, as well as many others, suggest that humanin administration would be an effective therapeutic treatment for a large number of diseases and further solidifies the importance of the mitochondria beyond its traditional role as the 'powerhouse of the cell,'" he said.
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June 24, 2020
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https://www.sciencedaily.com/releases/2020/06/200624151551.htm
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Effects from low-level concentrations of harmful chemicals preserved in three generations of fish
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Fish exposed to very low levels of chemicals commonly found in waterways can pass the impacts on to future generations that were never directly exposed to the chemicals, according to Oregon State University researchers.
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"What that gets at is something your grandparents may have come into contact with in their environment can still be affecting the overall structure of your DNA in your life today," said Kaley Major, a postdoctoral scholar at Oregon State and lead author of the paper published today in the journal The study focused on synthetic (human-made) endocrine disrupting chemicals, which mimic the body's hormones. They are found in many household and industrial products including flame retardants, food, toys, cosmetics and pesticides. Previous research has shown exposures to the chemicals can lead to altered sex ratios, lower fertility rates and deformities in fish.Endocrine disruptors can cause adverse biological effects in other animals, including humans, by altering natural hormones in the body that are responsible for development, behavior and fertility. Past research done elsewhere has shown that those adverse alterations in humans can be passed to future generations."It's really important to understand how animals can deal with stress in the environment, particularly when we are introducing new stressors on a daily basis," said Susanne Brander, an assistant professor and aquatic toxicologist in OSU's Department of Fisheries and Wildlife with whom Major worked."Our research helps show what animals do to respond to these changes and how quickly they can respond to them. That's going to help us understand our impact on the environment in the long run."The researchers conducted the study with inland silversides, a fish found in estuaries that averages about 4 inches in length and is native in eastern North America and the Gulf of Mexico. They have also been introduced in California. They primarily feed on zooplankton and are an important prey species for birds and commercially valuable fish.Previous research had shown negative impacts on fish exposed to high levels of endocrine disruptors, but little is known about fish exposed to low levels of the chemicals, Major said.In the experiment, the inland silversides were exposed to the equivalent of a few drops of each endocrine disruptor in an Olympic-size swimming pool. The researchers studied three generations of fish over 21 months to see if the effects of endocrine disruptor exposure only to the parents were passed from generation to generation.The experiment focused on methylation, a process by which a set of carbon and hydrogen atoms known as a methyl group is added to a DNA molecule. Methylation can be tracked and can be an important indicator of how an organism will develop.Previous research with mammals and other species of fish has found that endocrine disruptors impact methylation. That led Brander, Major and their collaborators to wonder whether endocrine disruptors, particularly low concentrations, would impact methylation in fish that live in estuaries, ecosystems which are important for biodiversity and often impacted by nearby urban areas.The results were surprising, the researchers said. They found consistent patterns of methylation across the three generations of fish they studied, even though only the first generation was exposed to endocrine disruptors for a few weeks in early life.The researchers believe the methylation patterns they observed across the three generations may influence expression of genes associated with the skewed sex ratios, reduced hatching and developmental defects observed by Ph.D. student Bethany DeCourten as part of the larger study. Future research will help the scientists understand more about what the methylation markers mean and what that says about how pollutants may affect evolution of inland silversides.The study was funded by the Environmental Protection Agency, California Department of Fish and Wildlife and the Delta Stewardship Council.
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Animals
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June 24, 2020
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https://www.sciencedaily.com/releases/2020/06/200624100033.htm
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Jellyfish contain no calories, so why do they still attract predators?
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They contain no carbohydrates. No fats. No proteins. Not much else but water. Still, the moon jelly (Aurelia aurita) are eaten by predators in the sea; fish, crustaceans, sea anemones and even corals and turtles.
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Now a new study may explain why these predators bother to eat the gelatinous creatures. The study is based on moon jelly samples from a German Fjord."The jellyfish in our study showed to contain some fatty acids that are very valuable for their predators. Fatty acids are vital components of cell membranes and play a crucial role in processes like growth and reproduction," says marine biologist and jellyfish expert, Jamileh Javidpour from University of Southern Denmark.She is Principle Investigator and co-author of the study, published in The researchers collected moon jellies from North German Kiel Fjord every two weeks for two years. Their content of fatty acids varied with seasons, and variations linked to developmental stages were also found: mature individuals with reproductive tissues had the highest content."Jelly fish are likely to be more than just an opportunistic prey to many organisms. It is true that a predator does not get much from eating a single jelly fish, but if it eats many, it will make a difference and provide the predator with valuable fatty acids," she says.In other words: Low food quality can be weighed up by high food quantity. As an example, researchers have observed a salmon eat a jelly fish 20 times faster than it took for it to eat a shrimp.So, if the predator doesn't have to spend much energy on eating loads of jelly fish, this preying strategy begins to make sense, she explains:"Jellyfish often come in shoals and they move slowly through the water. They can't really swim away when predators start eating them."On a global scale, marine environments are changing, and an increasing abundance of jelly fish is thought to replace other prey items in the oceans."As we see an increase in jelly fish, I suspect that we will also come to see a change in predator populations -- especially in areas where the abundances of usual prey items might be endangered by a changing environment," says Jamileh Javidpour.Several essential fatty acids were found in the German moon jellies. Among them are the polyunsaturated fatty acids arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid.
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Animals
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June 24, 2020
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https://www.sciencedaily.com/releases/2020/06/200624082713.htm
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Environmental DNA detection could cut pathogens in pet trade
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As the SARS-CoV-2 puts new focus on zoonotic pathogens, a Washington State University researcher has developed a method to use environmental DNA (eDNA) to detect disease in the vast international trade of aquatic animals.
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The problem with monitoring the pet trade is one of magnitude. In the Unites States alone, more than 225 million live animals are imported every year, the majority destined for the aquatic or pet industries. Creating a "clean trade" by detecting infections in these populations requires huge sample sizes, a labor-intensive and costly process.In a paper published in "The best way to prevent the emergence of these pathogens, and the diseases that come from them, is to keep them from getting here in the first place," said Brunner. "It's an important goal but a really hard one because of the scale of the problem. With the eDNA method you are theoretically sampling an entire population at once, so you are more likely to detect whatever is there, and you can do that much more efficiently than with traditional approaches."Environmental DNA is already used to look for the presence of invasive species in places like the Great Lakes. Brunner saw that it might also be useful to sample water from the tanks of captive species being transported in the pet trade since infected animals will shed pathogens into their water.As an example, Brunner used Bsal (Batrachochochytrium salamandrivorans) a chytrid fungus which threatens salamander populations. Bsal is a cousin of the devastating Bd (Batrachocytrium dendrobatidis) that was responsible for the decline of more than 500 amphibian species around the world, including 90 that likely went extinct.Now Bsal has jumped into wild salamander populations in Europe from imported pets from Southeastern Asia. While it has not yet been found in North America, the threat of Bsal prompted the U.S. Fish and Wildlife Service to enact a ban in 2016 on the import of 201 species of salamanders into the United States, which is home to tremendous salamander diversity.Brunner's paper outlines the statistical formulas needed to conduct surveillance of imported salamanders for Bsal using eDNA. It shows the volume of samples needed to be taken and tested to produce a good degree of confidence in a negative or positive result. If proven out, the method could reduce the amount of sampling and work required to effectively monitor for the pathogen. This paper provides the framework for the method, and Brunner and colleagues are currently testing it with real samples.As part of a Bsal Task Force, Brunner and his colleagues are in conversation with the pet industry which is naturally interested in creating a clean trade for salamanders, but finding better solutions to test for pathogens in salamanders also has broader implications."The problem that we're having with amphibians is also the same problem that we're having with all sorts of wildlife and with human disease," said Brunner. "I think if we can solve this problem, we'll be in much better shape to solve others."
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Animals
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June 22, 2020
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https://www.sciencedaily.com/releases/2020/06/200622133051.htm
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Are protected areas effective at maintaining large carnivore populations?
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A recent study, led by the University of Helsinki, used a novel combination of statistical methods and an exceptional data set collected by hunters to assess the role of protected areas for carnivore conservation in Finland.
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Overall, protected areas do not harbour higher densities of large carnivore species than unprotected lands. These areas even had declining wolverine densities within their limits while populations outside remained overall stable over a 30-year study period. The study was published in the journal The international group of authors, led by Dr Julien Terraube from the Faculty of Biological and Environmental Sciences at the University of Helsinki, proposes that the results do not indicate that protected areas are unimportant for carnivore conservation, as they may support seasonal habitats and prey for these highly mobile species. However, the outcomes highlight complex socio-ecological pressures on carnivore populations that vary in both time and space and affect the conservation outcomes of protected areas. For example, the largest Finnish protected areas are located in Lapland, and due to their sizes these areas are most suitable for large carnivores. However, the areas seem unable to maintain stable wolverine populations, which may be linked to increased conflicts with herders in the reindeer husbandry area."Wolverines are only found in three Nordic countries within the European Union, and therefore Finland plays an important role for the conservation of this species," explains Dr Terraube. He adds: "The negative trend of wolverine populations inside northern protected areas is alarming and highlights that further research is needed to understand the dynamics of wolverine populations in Lapland, how this species is affected by illegal killing and what protected areas could do to improve this situation."On a brighter note, the researchers also found lynx densities to be higher within protected areas located in eastern Finland than those located in the western part of the country. The ecological factors that may influence this, such as prey abundance or connectivity to healthy Russian populations, remain unexplored.The results show that counterfactual approaches applied to long-term and large-scale data are powerful analytical tools for evaluating the effectiveness of protected areas in maintaining wildlife populations. A counterfactual approach means comparing protected and unprotected sites that have similar environmental characteristics or human-caused threats. The method has been increasingly used to assess the effectiveness of protected areas in halting deforestation. This allows researchers to isolate the effect of protection on land cover from other confounding factors such as elevation. Until now, these types of approaches focused on matching analyses have been restricted to studies investigating the effects of protected areas on land-use changes. Finding wildlife time series with enough temporal and spatial coverage to conduct such robust effectiveness assessments is often difficult.Dr. Terraube explains: "We were able to use data collected through the Finnish Wildlife Scheme to conduct this study. Hunters throughout the country have collected this data set since 1989, offering a fantastic opportunity to apply matching analyses to wildlife data for the first time and to assess large-scale and long-term patterns of protected area effectiveness. We chose to focus on large carnivores, as this species group is particularly prone to rising conflicts with local communities. Carnivore-human conflicts have increased in Finland following the recent recovery of most carnivore species. This has resulted in increasingly negative attitudes towards certain species, such as the wolf, and to increased levels of illegal killing."The study highlights the need to design robust methodological tools to strengthen our understanding of conservation outcomes and opens new avenues for improving protected area impact assessments. This is of the utmost importance, as the international community is currently turning to the post-2020 targets drafted by the UN Convention on Biological Diversity aiming to upgrade protected areas in an attempt to halt global biodiversity loss."We argue that this study shows that, despite methodological challenges, robust assessments of protected area effectiveness for the conservation of wide-ranging species, such as large carnivores, are possible and greatly needed as a basis for further research. It also highlights the extraordinary value of long-term wildlife monitoring activities conducted by citizens across an entire country," concludes Dr Terraube.
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Animals
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June 22, 2020
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https://www.sciencedaily.com/releases/2020/06/200622133020.htm
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COVID-19 lockdown reveals human impact on wildlife
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In an article published in
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Many countries around the world went into lockdown to control the spread of Covid-19. Brought about by the most tragic circumstances, this period of unusually reduced human mobility, which the article's authors coined "anthropause," can provide invaluable insights into human-wildlife interactions.There have been countless posts on social media over the past few months reporting unusual wildlife encounters. Anecdotal observations, especially from metropolitan areas, suggest that nature has responded to lockdown. There not only seem to be more animals than usual, but there are also some surprising visitors: pumas have been spotted prowling the streets of downtown Santiago, Chile, and dolphins recently showed up in untypically calm waters in the harbour of Trieste, Italy.For other species, the pandemic may have created new challenges. For example, some urban-dwelling animals, like gulls, rats or monkeys, may struggle to make ends meet without access to human food. In more remote areas, reduced human presence may potentially put endangered species, such as rhinos or raptors, at increased risk of poaching or persecution.The authors emphasise that society's priority must be to tackle the immense human tragedy and hardship caused by Covid-19. But, they argue that we cannot afford to miss the opportunity to chart, for the first time on a truly global scale, the extent to which modern human mobility affects wildlife.To address this challenge, researchers recently formed the "COVID-19 Bio-Logging Initiative." This international consortium will investigate animals' movements, behaviour and stress levels, before, during and after Covid-19 lockdown, using data collected with nifty animal-attached electronic devices called "bio-loggers."The article's lead author, Professor Christian Rutz, a biologist at the University of St Andrews, UK, and President of the International Bio-Logging Society, explains: "All over the world, field biologists have fitted animals with miniature tracking devices. These bio-loggers provide a goldmine of information on animal movement and behaviour, which we can now tap to improve our understanding of human-wildlife interactions, with benefits for all."The team will integrate results from a wide variety of animals, including fish, birds and mammals, in an attempt to build a global picture of lockdown effects.Dr Francesca Cagnacci, Senior Researcher at the Edmund Mach Foundation in Trento, Italy, and Principal Investigator of the Euromammals research network, says: "The international research community responded quickly to our recent call for collaboration, offering over 200 datasets for analysis. We are very grateful for this support."So, what do the scientists hope to learn? Dr Matthias-Claudio Loretto, a Marie Skłodowska-Curie Fellow at the Max Planck Institute of Animal Behavior in Radolfzell, Germany, explains that it will be possible to address previously intractable questions: "We will be able to investigate if the movements of animals in modern landscapes are predominantly affected by built structures, or by the presence of humans. That is a big deal."These insights will in turn inspire innovative proposals for improving human-wildlife coexistence, according to Professor Martin Wikelski, Director of the Max Planck Institute of Animal Behavior in Radolfzell, Germany. "Nobody is asking for humans to stay in permanent lockdown. But we may discover that relatively minor changes to our lifestyles and transport networks can potentially have significant benefits for both ecosystems and humans."Coordinated global wildlife research during this period of crisis will provide unforeseen opportunities for humans to forge a mutually beneficial coexistence with other species, and to rediscover how important a healthy environment is for our own well-being.
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Animals
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June 19, 2020
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https://www.sciencedaily.com/releases/2020/06/200619143439.htm
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A new social role for echolocation in bats that hunt together
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Searching for food at night can be tricky. To find prey in the dark, bats use echolocation, their "sixth sense." But to find food faster, some species, like Molossus molossus, may search within hearing distance of their echolocating group members, sharing information about where food patches are located. Social information encoded in their echolocation calls may facilitate this foraging strategy, according to a recent study by Smithsonian Tropical Research Institute (STRI) scientists and collaborating institutions published online in
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Previous research has identified several ways in which echolocation can transfer social information in bats. For example, "feeding buzzes," the echolocation calls bats produce to home in on prey they've spotted, can serve as cues of prey presence to nearby eavesdropping bats. On the other hand, echolocation calls that bats produce while looking for food, called "search-phase" calls, were not known to transfer social information.However, for group-foraging bats, coordinating flight in the dark with several other fast-flying individuals may require an ability to identify group members on the wing. If search-phase calls contain individual signatures the bats can perceive, it could allow them to know which individuals are flying near them without requiring specialized signals for communication.Led by Jenna Kohles, STRI fellow and doctoral candidate at the Max Planck Institute of Animal Behavior in Germany, the research team tested whether search-phase echolocation calls contain information about a bat's identity, and whether M. molossus can use this information to discriminate among different group members. The team exposed bats to search-phase echolocation calls in a habituation-dishabituation paradigm, a method where an animal is exposed to a repeating stimulus until it no longer reacts to it. Then, it is exposed to a new but similar stimulus to see if it reacts, which would indicate that it perceives a difference between the two stimuli."We played echolocation calls from two different bats that were both group members of the subject bat," Kohles said. "By measuring the responses of the subject bats as we switched between calls from different individuals, we could learn about whether the bats perceived differences and similarities between the calls."They found that the bats indeed distinguish between different group members, likely by using individual signatures encoded in the calls. Their results could mean that search-phase calls serve a double function. They not only help bats detect prey, but also convey individual identities to nearby foraging group members. This coincides with the fact that the majority of M. molossus' auditory cortex is tuned in to these search-phase calls, indicating the importance of processing them.This finding offers insight into not only the social strategies these bats may use to meet their energetic needs, but also into the evolution of echolocation signals and social communication in bats."This study suggests that we may be underestimating the crucial ways social information influences bat foraging success and ultimately survival," Kohles said.
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Animals
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June 19, 2020
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https://www.sciencedaily.com/releases/2020/06/200619094203.htm
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An ant-inspired approach to mathematical sampling
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In a paper published by the Royal Society, a team of Bristol researchers observed the exploratory behaviour of ants to inform the development of a more efficient mathematical sampling technique.
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Animals like ants have the challenge of exploring their environment to look for food and potential places to live. With a large group of individuals, like an ant colony, a large amount of time would be wasted if the ants repeatedly explored the same empty areas.The interdisciplinary team from the University of Bristol's Faculties of Engineering and Life Sciences, predicted that the study species -- the 'rock ant' -- uses some form of chemical communication to avoid exploring the same space multiple times.Lead author, Dr Edmund Hunt, said:"This would be a reversal of the Hansel and Gretel story -- instead of following each other's trails, they would avoid them in order to explore collectively."To test this theory, we conducted an experiment where we let ants explore an empty arena one by one. In the first condition, we cleaned the arena between each ant so they could not leave behind any trace of their path. In the second condition, we did not clean between ants. The ants in the second condition (no cleaning) made a better exploration of the arena -- they covered more space."In mathematics, a probability distribution describes how likely are each of a set of different possible outcomes: for example, the chance that an ant will find food at a certain place. In many science and engineering problems, these distributions are highly complex, and they do not have a neat mathematical description. Instead, one must sample from it to obtain a good approximation: with a desire to avoid sampling too much from unimportant (low probability) parts of the distribution.The team wanted to find out if adopting an ant-inspired approach would hasten this sampling process."We predicted that we could simulate the approach adopted by the ants in the mathematical sampling problem, by leaving behind a 'negative trail' of where has already been sampled. We found that our ant-inspired sampling method was more efficient (faster) than a standard method which does not leave a memory of where has already been sampled," said Dr Hunt.These findings contribute toward an interesting parallel between the exploration problem confronted by the ants, and the mathematical sampling problem of acquiring information. This parallel can inform our fundamental understanding of what the ants have evolved to do: acquire information more efficiently."Our ant-inspired sampling method may be useful in many domains, such as computational biology, for speeding up the analysis of complex problems. By describing the ants' collective behaviour in informational terms, it also allows us to quantify how helpful are different aspects of their behaviour to their success. For example, how much better do they perform when their pheromones are not cleaned away. This could allow us to make predictions about which behavioural mechanisms are most likely to be favoured by natural selection."
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Animals
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June 18, 2020
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https://www.sciencedaily.com/releases/2020/06/200618150301.htm
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Human brain size gene triggers bigger brain in monkey fetus
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A human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.
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The expansion of the human brain during evolution, specifically of the neocortex, is linked to our cognitive abilities such as reasoning and language. A certain gene called ARHGAP11B that is only found in humans triggers brain stem cells to form more stem cells, a prerequisite for a bigger brain. Past studies have shown that ARHGAP11B, when expressed in mice and ferrets to unphysiologically high levels, causes an expanded neocortex, but its relevance for primate evolution has been unclear. Researchers at the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) in Dresden together with colleagues at the Central Institute for Experimental Animals (CIEA) in Kawasaki and the Keio University in Tokyo, both located in Japan, show now that this human-specific gene, when expressed to physiological levels, causes an enlarged neocortex in the common marmoset, a New World monkey. This suggests that the ARHGAP11B gene may have caused neocortex expansion during human evolution. The researchers published their findings in the journal The human neocortex, the evolutionarily youngest part of the cerebral cortex, is about three times bigger than that of our closest relatives, the chimpanzees, and its folding into wrinkles increased during evolution to fit inside the restricted space of the skull. A key question for scientists is how the human neocortex became so big. In a 2015 study, the research group of Wieland Huttner, a founding director of the MPI-CBG, found that under the influence of the human-specific gene ARHGAP11B, mouse embryos produced many more neural progenitor cells and could even undergo folding of their normally unfolded neocortex. The results suggested that the gene ARHGAP11B plays a key role in the evolutionary expansion of the human neocortex.The human-specific gene ARHGAP11B arose through a partial duplication of the ubiquitous gene ARHGAP11A approximately five million years ago along the evolutionary lineage leading to Neanderthals, Denisovans, and present-day humans, and after this lineage had segregated from that leading to the chimpanzee. In a follow-up study in 2016, the research group of Wieland Huttner uncovered a surprising reason why the ARHGAP11B protein contains a sequence of 47 amino acids that is human-specific, not found in the ARHGAP11A protein, and essential for ARHGAP11B's ability to increase brain stem cells. Specifically, a single C-to-G base substitution found in the ARHGAP11B gene leads to the loss of 55 nucleotides from the ARHGAP11B messenger RNA, which causes a shift in the reading frame resulting in the human-specific, functionally critical 47 amino acid sequence. This base substitution probably happened much later than when this gene arose about 5 million years ago, anytime between 1.5 million and 500,000 years ago. Such point mutations are not rare, but in the case of ARHGAP11B its advantages of forming a bigger brain seem to have immediately influenced human evolution.However, it has been unclear until now if the human-specific gene ARHGAP11B would also cause an enlarged neocortex in non-human primates. To investigate this, the researchers in the group of Wieland Huttner teamed up with Erika Sasaki at the Central Institute for Experimental Animals (CIEA) in Kawasaki and Hideyuki Okano at the Keio University in Tokyo, both located in Japan, who had pioneered the development of a technology to generate transgenic non-human primates. The first author of the study, postdoc Michael Heide, travelled to Japan to work with the colleagues directly on-site. They generated transgenic common marmosets, a New World monkey, that expressed the human-specific gene ARHGAP11B, which they normally do not have, in the developing neocortex. Japan has similarly high ethical standards and regulations regarding animal research and animal welfare as Germany does. The brains of 101-day-old common marmoset fetuses (50 days before the normal birth date) were obtained in Japan and exported to the MPI-CBG in Dresden for detailed analysis. Michael Heide explains: "We found indeed that the neocortex of the common marmoset brain was enlarged and the brain surface folded. Its cortical plate was also thicker than normal. Furthermore, we could see increased numbers of basal radial glia progenitors in the outer subventricular zone and increased numbers of upper-layer neurons, the neuron type that increases in primate evolution." The researchers had now functional evidence that ARHGAP11B causes an expansion of the primate neocortex.Wieland Huttner, who led the study, adds: "We confined our analyses to marmoset fetuses, because we anticipated that the expression of this human-specific gene would affect the neocortex development in the marmoset. In light of potential unforeseeable consequences with regard to postnatal brain function, we considered it a prerequisite -- and mandatory from an ethical point of view -- to first determine the effects of ARHGAP11B on the development of fetal marmoset neocortex."The researchers conclude that these results suggest that the human-specific ARHGAP11B gene may have caused neocortex expansion in the course of human evolution.
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Animals
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June 18, 2020
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https://www.sciencedaily.com/releases/2020/06/200618120155.htm
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High-tech CT reveals ancient evolutionary adaptation of extinct crocodylomorphs
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The tree of life is rich in examples of species that changed from living in water to a land-based existence. Occasionally, some species took the opposite direction. New insights into the anatomy of the inner ear of prehistoric reptiles, the thalattosuchians, revealed details about one of these evolutionary turning points. During the Mesozoic era, these now extinct crocodile relatives ventured into the ocean after a long semiaquatic phase. During this process, the skeleton of the thalattosuchians gradually adapted to the new pelagic habitat. In particular, the changes to the inner ear vestibular system of these reptiles enhanced their ability to swim. Compared to whales, which adapted quickly to life in water without a prolonged semiaquatic stage, this is a strikingly different evolutionary path for the same transition. These new findings of an international research team were made possible by the use of a Canon high-tech computed tomography (CT) scanner from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW). The results have been published in the
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Thalattosuchians lived during the Mesozoic about 182 to 125 million years ago and evolved from their land-living relatives to become fast-swimming marine predators. An international research team led by scientists from the School of Geosciences at the University of Edinburgh studied the evolutionary changes which these crocodylomorphs went through during their transition from land to the ocean. The team focused on one of the most important vertebrate sensory systems -- the inner ear. Using high-resolution computed tomography (CT), the skulls of 18 thalattosuchians from the late Triassic to the Early Cretaceous were scanned to span much of the evolutionary history of crocodylomorphs. The CT scans were compared with the scans of modern crocodiles. Some of the scans were performed at the Leibniz-IZW in Berlin. The x-ray scans reveal detailed changes in the vestibular system of the inner ear, particularly in the bony labyrinth, which plays a crucial role in sensing balance and spatial orientation. "As they transitioned from land to water, thalattosuchians developed a strikingly compact, reduced and thickened bony labyrinth reminiscent of the reduced labyrinths of other marine reptiles and whales," explains Guido Fritsch, scientist and CT expert at the Leibniz-IZW. "Extinct land crocodiles, on the other hand, had a taller and narrower bony labyrinth. The labyrinths of semiaquatic crocodiles, which also include modern crocodiles, are longer and more compact than those of their land-living relatives." These results illustrate that the inner ear morphology of an animal is strongly linked to its habitat.Interestingly, thalattosuchians developed the reduction of their inner ear labyrinth only after a long semiaquatic phase that lasted tens of millions of years. First, their skeleton changed during this phase -- limbs became flippers, the body became streamlined, which allowed them to move efficiently in the water and improved their ability to swim. Only then did the changes in the inner ear develop, possibly as a response to changing sensory requirements, when the thalattosuchians moved into deeper, more open waters. This adaptation process distinguishes them from whales, whose inner ear labyrinth was miniaturised soon after their transition from land to water, without a prolonged semiaquatic phase. Thus, thalattosuchians and whales took different evolutionary routes for the same type of transition.Future studies will examine the advantages of a reduced inner ear labyrinth for water-living animals, investigate how quickly thalattosuchians developed the adaptations in their inner ear as they entered the water, and how other sensory organs changed during this transition.
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June 18, 2020
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https://www.sciencedaily.com/releases/2020/06/200618073540.htm
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Catastrophic disease events in marine mammals mostly caused by viruses
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As the COVID-19 pandemic sweeps across the globe, people are beginning to understand, at a very personal level, the ways in which infectious diseases can devastate life. But disease outbreaks are not confined to just humans or to life on land.
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"We are perhaps more alert than ever to the catastrophic impacts of infectious disease in both humans and animals. Our task now is to begin to understand what drives these events, particularly in species like marine mammals, where our knowledge is even more limited," said Claire Sanderson, a research associate in the Department of Fish and Wildlife Conservation within the College of Natural Resources and Environment and the research coordinator of the Center for African Resources: Animals, Communities, and Land Use (CARACAL).In 2000, over 10,000 endangered Caspian seals died in less than a four-month span. Researchers later discovered that the culprit behind this devastating mass mortality event was canine distemper virus.Infectious disease-induced mass mortality events are known to afflict a variety of species, including invertebrates, birds, fish, and both land and aquatic mammals. However, these events in aquatic mammals are understudied compared to their land-dwelling counterparts.To help fill in the knowledge gaps, Sanderson worked with Kathleen Alexander, a professor in the Department of Fish and Wildlife Conservation and co-founder of CARACAL, to evaluate the factors influencing the occurrence of these events in marine mammals. They published their findings in Sanderson and Alexander defined a mass mortality event as a "devastating number of fatalities within the same species over a brief period of time," which is also dependent on the species' conservation status and population size. Beyond the deaths of individual animals, mass mortality events can initiate a cascade of events with severe ecological repercussions. Affected populations are often at a greater risk of local extinction, and changes in community structure can upset an ecosystem's balance.By conducting extensive literature searches, Sanderson and Alexander discovered that infectious disease-induced mass mortality events occurred in 14 percent of marine mammal species between 1955 and 2018. Viruses were responsible for 72 percent of these events and caused 20 times the number of deaths than bacterial outbreaks. Specifically, morbillivirus and influenza A outbreaks were the most commonly recorded. Due to their life cycles, both viruses can infect multiple hosts since they have the potential to be transmitted between various species.To determine which factors influenced the occurrence of infectious disease-induced mass mortality events in marine mammals, Sanderson and Alexander evaluated key life history traits and environmental variables.To evaluate the role of life history traits, they focused on sociality, trophic level (a species' position on the food chain), and habitat breadth. While sociality and trophic level did not appear to be associated with mass mortality events in marine mammals, habitat breadth did. More than half of the species experiencing mass mortality events were pinnipeds, an order of semi-aquatic species that includes seals, sea lions, and walruses."Pinnipeds bridge the terrestrial and aquatic interfaces and may have a greater exposure to pathogens that occur across these land types," Sanderson said. For instance, seals and sea lions are often observed on beaches, rocky shorelines, and docks, but they also spend a significant part of their lives in water.In contrast to life history traits, environmental variables -- such as season and sea surface temperature anomalies -- were significantly associated with disease outbreaks in marine mammals.One of the most indicative measures of climate change is fluctuating sea surface temperatures. Sanderson and Alexander found that 61 percent of mass mortality events in marine mammals occurred during periods in which regional sea surface temperature anomalies occurred. The study suggested that the incident rate of an infectious disease-induced mass mortality event increases by nearly 12 percent for "every unit increase in global sea surface temperature anomalies.""As climate change intensifies, this may set off a complex chain of events that dramatically alter these ecosystems, affecting marine populations living in these environments," said Alexander an affiliated faculty member of the Fralin Life Sciences Institute. Climate change effects on sea ice and ocean salinity also have implications for the spread of disease.In polar regions, sea ice is melting more quickly due to increasing air temperature, but various species of pinnipeds need sea ice to give birth, rest, mate, escape predators, and molt. As the ice melts away, pinnipeds are forced to congregate onto smaller, shrinking ice sheets. At higher densities, increased contact between individuals can allow pathogens to be transmitted more readily through a population and region.The chemical balance of the ocean is also changing. In polar regions, melting sea ice dilutes the salty ocean water in a process called freshening. This can result in decreased prey abundance, since species like fish, mollusks, and crustaceans are sensitive to small changes in the environment. With less food to feed on, marine mammals may suffer from nutritional stress, resulting in decreased immune function and a greater susceptibility to disease."Marine mammals represent important sentinels of aquatic health by providing information essential for managing threats to these vulnerable ecosystems," said Sanderson. "Addressing the root causes of climate change will be of critical importance as we chart a path forward in managing these species."Of all the marine mammal species that suffered an infectious disease-induced mass mortality event, the study found that 37 percent were listed as endangered or vulnerable to extinction."This work underscores the critical threat infectious disease can pose to marine species and the potential importance of climate change as a wide reaching driver of this process. Here, our role is complex as we contribute directly to our changing climate, increasing pathogen pollution, and habitat degradation. But we also have the power to change things, address climate change, protect species and environments through effort and innovation -- humanity at its best," Alexander said.The National Science Foundation funded this research through the multi-agency Ecology and Evolution of Infectious Diseases program.
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Animals
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June 18, 2020
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https://www.sciencedaily.com/releases/2020/06/200618111011.htm
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African lion counts miss the mark, but new method shows promise
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The current technique used for counting lion populations for research and conservation efforts doesn't add up, according to a University of Queensland researcher.
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But UQ PhD candidate Mr Alexander Braczkowski has been investigating new methods of photographing and reviewing data analytics to count lions."African lions receive immense publicity and conservation attention," Mr Braczkowski said."Yet their populations are thought to have experienced a 50 per cent decline since 1994 -- coincidentally the same year Disney's The Lion King was released."Current calculations suggest that between 20,000 and 30,000 lions remain in the wild -- scattered among 102 populations across approximately 2.5 million square kilometres of Africa."Our research shows that the majority of estimates on African lion population and density are based on track counts, audio lure surveys and expert solicitation -- which are simply not reliable enough to understand how lion populations are doing over time."According to Mr Braczkowski, a recently developed technique has shown promise in better counting big cats and understanding their movements."It involves driving extensively and searching actively for lions, and then taking high quality photographs to individually identify them and noting their locations," Mr Braczkowski said."We use an analytical method known as Spatially Explicit Capture-Recapture (SECR)."For African lions, it was first applied in the Maasai Mara by Dr Nicholas Elliot and Dr Arjun Gopalaswamy, and has now been adopted by the Kenya Wildlife Service and others to survey lions and other carnivores across the country."Mr Braczkowski and his colleagues have trialled the technique to better understand the status and density of lions in Uganda's Queen Elizabeth Conservation Area."This was the perfect place to use this novel approach since lions at Queen Elizabeth spend a lot of their time up in trees and it is relatively straightforward to get good pictures of them," Mr Braczkowski said."Due to this unique tree-climbing behaviour, managers and tourists at this park very frequently see lions."But, our study showed that these lions are now moving more and have larger home range sizes compared to a previous study conducted about a decade agoDr Arjun Gopalaswamy, a co-author and science advisor to the Wildlife Conservation Society's Global Programs said, since larger home range sizes in big cats are usually associated with reduced density due to poorer prey availability, this is a concerning trend."There's great value in using methods that keep track of lion populations directly and we urge conservation and research communities to cease using ad hoc, indirect methods and shift to more reliable and direct methods."
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Animals
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June 17, 2020
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https://www.sciencedaily.com/releases/2020/06/200617150038.htm
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'Cooperative' and 'independent' dog breeds may not react differently to unfair outcomes
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Cooperative worker dog breeds do not appear to respond more negatively to unfair outcomes than do independent worker breeds, according to a study published June 17 in the open-access journal
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Dogs and many other animals display inequity aversion -- negative responses to unfair outcomes -- which is thought to contribute to the maintenance of cooperation. But only limited evidence supports the hypothesis that cooperation and inequity aversion co-evolved. Dogs provide a suitable model species to test this hypothesis because breeds vary in the extent to which they were selected for cooperativeness. In the new study, McGetrick and colleagues examined the responses of 12 dogs from cooperative worker breeds (e.g.: Australian shepherds, border collies, Labrador retrievers, and rough collies), which work in continuous visual contact with humans, and 12 dogs from independent worker breeds (e.g.: akita inus, basenji, Siberian huskies, shiba inus). In the paw task, the experimenter alternately asked two dogs to give their paw, but only one dog was always rewarded.Dogs belonging to both breed groups displayed inequity aversion, and there was no significant difference between the groups in the extent of the negative response to inequity or in the impact of the inequity on subsequent social behaviors. But there were some differences between the breed groups. For example, dogs from independent breeds gave their paw fewer times than did dogs from cooperative breeds, especially in the unrewarded conditions. In addition, dogs from cooperative breeds spent more time close to their partners when allowed to freely interact than did dogs from independent breeds.According to the authors, the findings provide some evidence for basic breed group differences in the tendency to work without rewards, and possibly in general sociability, which could offer fruitful areas of investigation for future studies focused on understanding dog breed differences.The authors add: Cooperative worker breeds tended to work for longer than independent worker breeds in our task. This may indicate a history of selection, in cooperative worker breeds, for increased motivation to work with humans.
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Animals
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June 17, 2020
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https://www.sciencedaily.com/releases/2020/06/200617150021.htm
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First dinosaur eggs were soft like a turtle's
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New research suggests that the first dinosaurs laid soft-shelled eggs -- a finding that contradicts established thought. The study, led by the American Museum of Natural History and Yale University and published today in the journal
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"The assumption has always been that the ancestral dinosaur egg was hard-shelled," said lead author Mark Norell, chair and Macaulay Curator in the Museum's Division of Paleontology. "Over the last 20 years, we've found dinosaur eggs around the world. But for the most part, they only represent three groups -- theropod dinosaurs, which includes modern birds, advanced hadrosaurs like the duck-bill dinosaurs, and advanced sauropods, the long-necked dinosaurs. At the same time, we've found thousands of skeletal remains of ceratopsian dinosaurs, but almost none of their eggs. So why weren't their eggs preserved? My guess -- and what we ended up proving through this study -- is that they were soft-shelled."Amniotes -- the group that includes birds, mammals, and reptiles -- produce eggs with an inner membrane or "amnion" that helps to prevent the embryo from drying out. Some amniotes, such as many turtles, lizards, and snakes, lay soft-shelled eggs, whereas others, such as birds, lay eggs with hard, heavily calcified shells. The evolution of these calcified eggs, which offer increased protection against environmental stress, represents a milestone in the history of the amniotes, as it likely contributed to reproductive success and so the spread and diversification of this group. Soft-shelled eggs rarely preserve in the fossil record, which makes it difficult to study the transition from soft to hard shells. Because modern crocodilians and birds, which are living dinosaur, lay hard-shelled eggs, this eggshell type has been inferred for all non-avian dinosaurs.The researchers studied embryo-containing fossil eggs belonging to two species of dinosaur: Protoceratops, a sheep-sized plant-eating dinosaur that lived in what is now Mongolia between about 75 and 71 million years ago, and Mussaurus, a long-necked, plant-eating dinosaur that grew to 20 feet in length and lived between 227 and 208.5 million years ago in what is now Argentina. The exceptionally preserved Protoceratops specimen includes a clutch of at least 12 eggs and embryos, six of which preserve nearly complete skeletons. Associated with most of these embryos -- which have their backbones and limbs flexed -- consistent with the position the animals would assume while growing inside of the egg -- is a diffuse black-and-white egg-shaped halo that obscures some of the skeleton. In contrast, two potentially hatched Protoceratops newborns in the specimen are largely free of the mineral halos. When they took a closer look at these halos with a petrographic microscope and chemically characterized the egg samples with high-resolution in situ Raman microspectroscopy, the researchers found chemically altered residues of the proteinaceous eggshell membrane that makes up the innermost eggshell layer of all modern archosaur eggshells. The same was true for the Mussaurus specimen. And when they compared the molecular biomineralization signature of the dinosaur eggs with eggshell data from other animals, including lizards, crocodiles, birds, and turtles, they determined that the Protoceratops and Mussaurus eggs were indeed non-biomineralized -- and, therefore, leathery and soft."It's an exceptional claim, so we need exceptional data," said study author and Yale graduate student Jasmina Wiemann. "We had to come up with a brand-new proxy to be sure that what we were seeing was how the eggs were in life, and not just a result of some strange fossilization effect. We now have a new method that can be applied to all other sorts of questions, as well as unambiguous evidence that complements the morphological and histological case for soft-shelled eggs in these animals."With data on the chemical composition and mechanical properties of eggshells from 112 other extinct and living relatives, the researchers then constructed a "supertree" to track the evolution of the eggshell structure and properties through time, finding that hard-shelled, calcified eggs evolved independently at least three times in dinosaurs, and probably developed from an ancestrally soft-shelled type."From an evolutionary perspective, this makes much more sense than previous hypotheses, since we've known for a while that the ancestral egg of all amniotes was soft," said study author and Yale graduate student Matteo Fabbri. "From our study, we can also now say that the earliest archosaurs -- the group that includes dinosaurs, crocodiles, and pterosaurs -- had soft eggs. Up to this point, people just got stuck using the extant archosaurs -- crocodiles and birds -- to understand dinosaurs."Because soft eggshells are more sensitive to water loss and offer little protection against mechanical stressors, such as a brooding parent, the researchers propose that they were probably buried in moist soil or sand and then incubated with heat from decomposing plant matter, similar to some reptile eggs today.Other authors on this paper include Congyu Yu from the American Museum of Natural History; Claudia Marsicano from the University of Buenos Aires; Anita Moore-Nall and David Varricchio from Montana State University; Diego Pol from the Museum of Paleontology Egidio Feruglio, Argentina; and Darla K. Zelenitsky from the University of Calgary.
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Animals
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June 17, 2020
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https://www.sciencedaily.com/releases/2020/06/200617150011.htm
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First egg from Antarctica is big and might belong to an extinct sea lizard
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In 2011, Chilean scientists discovered a mysterious fossil in Antarctica that looked like a deflated football. For nearly a decade, the specimen sat unlabeled and unstudied in the collections of Chile's National Museum of Natural History, with scientists identifying it only by its sci-fi movie-inspired nickname -- "The Thing."
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An analysis led by researchers at The University of Texas at Austin has found that the fossil is a giant, soft-shell egg from about 66 million years ago. Measuring in at more than 11 by 7 inches, the egg is the largest soft-shell egg ever discovered and the second-largest egg of any known animal.The specimen is the first fossil egg found in Antarctica and pushes the limits of how big scientists thought soft-shell eggs could grow. Aside from its astounding size, the fossil is significant because scientists think it was laid by an extinct, giant marine reptile, such as a mosasaur -- a discovery that challenges the prevailing thought that such creatures did not lay eggs."It is from an animal the size of a large dinosaur, but it is completely unlike a dinosaur egg," said lead author Lucas Legendre, a postdoctoral researcher at UT Austin's Jackson School of Geosciences. "It is most similar to the eggs of lizards and snakes, but it is from a truly giant relative of these animals."A study describing the fossil egg was published in Co-author David Rubilar-Rogers of Chile's National Museum of Natural History was one of the scientists who discovered the fossil in 2011. He showed it to every geologist who came to the museum, hoping somebody had an idea, but he didn't find anyone until Julia Clarke, a professor in the Jackson School's Department of Geological Sciences, visited in 2018."I showed it to her and, after a few minutes, Julia told me it could be a deflated egg!" Rubilar-Rogers said.Using a suite of microscopes to study samples, Legendre found several layers of membrane that confirmed that the fossil was indeed an egg. The structure is very similar to transparent, quick-hatching eggs laid by some snakes and lizards today, he said. However, because the fossil egg is hatched and contains no skeleton, Legendre had to use other means to zero in on the type of reptile that laid it.He compiled a data set to compare the body size of 259 living reptiles to the size of their eggs, and he found that the reptile that laid the egg would have been more than 20 feet long from the tip of its snout to the end of its body, not counting a tail. In both size and living reptile relations, an ancient marine reptile fits the bill.Adding to that evidence, the rock formation where the egg was discovered also hosts skeletons from baby mosasaurs and plesiosaurs, along with adult specimens."Many authors have hypothesized that this was sort of a nursery site with shallow protected water, a cove environment where the young ones would have had a quiet setting to grow up," Legendre said.The paper does not discuss how the ancient reptile might have laid the eggs. But the researchers have two competing ideas.One involves the egg hatching in the open water, which is how some species of sea snakes give birth. The other involves the reptile depositing the eggs on a beach and hatchlings scuttling into the ocean like baby sea turtles. The researchers say that this approach would depend on some fancy maneuvering by the mother because giant marine reptiles were too heavy to support their body weight on land. Laying the eggs would require the reptile to wriggle its tail on shore while staying mostly submerged, and supported, by water."We can't exclude the idea that they shoved their tail end up on shore because nothing like this has ever been discovered," Clarke said.
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Animals
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June 17, 2020
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https://www.sciencedaily.com/releases/2020/06/200617150001.htm
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Wind farms on the Black Sea coast could endanger bat populations in Eastern Europe
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The Via Pontica, an important migration route for birds in Eastern Europe, runs along the Black Sea coast of Romania and Bulgaria. Bats also use this route. In this region, numerous wind farms have been installed in recent years because of good wind conditions, but there has been little implementation of the legally required measures for the protection of bats. A Romanian research team cooperated with the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in Berlin to demonstrate that this leads to high death rates of migrating bats and potentially large declines even in populations living far away in other countries. The scientists therefore recommend the widespread introduction of turn-off times during the migration months, which -- as the team was able to show in a local wind farm -- would massively decrease bat mortality yet produce only a marginal loss in the energy production of the turbines.
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Over the past ten years, the coastal region west of the Black Sea developed into a hotspot for wind energy production in Eastern Europe. Favourable wind conditions make the operation of wind farms particularly profitable in this area. Moreover, the region is relatively sparsely populated, so conflicts between operators and residents are rare.Because of the good wind conditions, there is also an important migration route for numerous bird and bat species -- the so-called Via Pontica, named after a historical Roman road connection. This area should therefore particularly benefit from conservation measures such as carefully chosen turbine turn-off times in order to keep bat mortality to a minimum. International agreements such as the EUROBATS agreement and the European Union's Fauna Flora Habitat Directive do already provide the legal framework for that. Currently, few protective measures have been implemented and monitoring of the populations is limited or absent in many regions in Eastern Europe. Accordingly, little is known about the impact of wind farms on bat populations.A Romanian research team in cooperation with the Leibniz-IZW investigated bat fatalities in a local wind farm over a period of four years. The wind farm, comprising twenty turbines, is located in the Romanian part of the Dobruja, a historical coastal region between the Danube and the Black Sea which forms the border between Romania and Bulgaria. Within the four years, the scientists collected a total of 166 dead bats of 10 different species in the wind farm. Carcasses of Nathusius' pipistrelle bats (Pipistrellus nathusii) and common noctule bats (Nyctalus noctula) were particularly common. Since many bats had open wounds and/or broken wing bones, they most likely died as a result of direct collisions with rotating rotor blades. About half as many animals died without direct collision from barotrauma, which are commonly deadly lung injuries caused by huge differences in air pressure close to the rotor blades.Since the scientists conducted selective, punctual searches, the scientists calculated the total loss of animals taking into account the search pattern, search times and other factors such as the likely removal of carcasses by foxes and stray dogs. According to this projection, 2,394 bats had died in this wind farm over the period of four years -- or in other words 30 bats per wind turbine and year or 14.2 bats per megawatt and year. "This fatality rate is extremely high," says Dr Christian Voigt, head of the Department of Evolutionary Ecology at the Leibniz-IZW. "For comparison: the highest fatality rates in Central Europe or the USA are 10 bats per megawatt and year." A stable isotope analysis of fur samples carried out at the Leibniz-IZW additionally revealed that 90 percent of bats came from distant regions in the north and northeast, including the Ukraine, Belarus and Russia."This has given us a clear picture of what happened," explains Christian Voigt. "The fatality rate is so high because the wind farm under investigation is located in the middle of an important migration route for bats. Thus, the wind farm does not only negatively affect local bats, but also distant populations. This makes it all the more important to take appropriate measures to keep the fatality rate as low as possible, especially on such migration routes."The scientists have already shown at this site that this is relatively easy to achieve. During the summer months, when there is a high level of bat migration, the operator -- in consultation with the scientists -- increased the threshold wind speed at which the turbines start up (the cut-in speed) to 6.5 metres per second. As a result, the fatality rate fell massively by 78 percent. "The energy production of the wind farm decreased by only 0.35 percent per year, which is a marginal loss for the operator," says Christian Voigt."This wind farm has a total capacity of 42 megawatts and is rather small," the Leibniz-IZW scientist continues. "The wind farms throughout the Dobruja region have a total capacity of at least 3,000 megawatts in operation. The total number of fatalities across this area could lead to a long-term decline in local bat populations as well as those from large parts of Eastern Europe. We therefore strongly recommend the widespread introduction of turn-off times and higher cut-in speeds. This will cost the operators almost nothing and could make the Via Pontica once again a largely safe flight path for bats."
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Animals
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June 17, 2020
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https://www.sciencedaily.com/releases/2020/06/200617100426.htm
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Tick surveillance and control lagging in US
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While the prevalence of Lyme disease and other illnesses spread by ticks has steadily increased in the United States over the past 20 years, a new study of the state of American tick surveillance and control reveals an inconsistent and often under-supported patchwork of programs across the country.
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Annually reported cases of tickborne disease more than doubled between 2004 and 2018, according to the U.S. Centers for Disease Control and Prevention (CDC), while seven new tickborne germs were discovered in that same timeframe. But a clear gap exists in our public health infrastructure, say researchers who have conducted the first-ever survey of the nation's tick management programs.The survey showed that less than half of public health and vector-control agencies engage in active tick surveillance, and only 12 percent directly conduct or otherwise support tick-control efforts. These and other findings from the survey, conducted by university researchers at the CDC's five Vector-Borne Disease Regional Centers of Excellence, are published today in the "Ticks are responsible for the majority of our vector-borne illnesses in the U.S., and our programming does not adequately meet the need in its current form, for both surveillance and control," says Emily M. Mader, MPH MPP, lead author on the study and program manager at the Northeast Regional Center for Excellence in Vector-Borne Diseases, housed at Cornell University.Mader and colleagues surveyed 140 vector-borne disease professionals working at state, county, and local agencies in the fall of 2018 to learn about their program objectives and capabilities for tick surveillance and control, testing ticks for disease-causing germs, and barriers to success. Reaching even that many respondents proved challenging, as no central database of tick-management programs or contacts was available.Highlights from the survey of tick-management programs include:"Pathogen testing is an essential component of surveillance and is needed in order to understand tickborne disease risk to communities," says Mader. "There appears to be a significant barrier for many tick-surveillance programs across the country to access pathogen-testing services."Mader says limited resources mean tick-management programs need reliable, proven control methods. "They are not going to invest in a strategy unless it has been investigated and shown to make a difference in reducing the burden of ticks and tickborne diseases," she says. "Right now, supporting this research is a major need. These kinds of evaluations often take at least three years to complete and require a significant investment.""The world of ticks reaches entomologists, veterinarians, medical doctors, public health, natural resource managers, farmers, pet owners, scientists, and anyone that enjoys the outdoors," says Nohra Mateus-Pinilla, Ph.D., co-author on the study and director of the Veterinary Epidemiology Laboratory at the University of Illinois's Illinois Natural History Survey. "The partnerships stand out because broad, collaborative networks are paramount to a positive and productive path for the advancement of this field."In December 2019, the Kay Hagan Tick Act was signed into federal law, authorizing $150 million to strengthen various aspects of the nation's efforts to vector-borne disease, including reauthorization of the CDC's Vector-Borne Disease Regional Centers of Excellence for an additional five years, through 2026. The CDC also issued guidance documents in late 2018 and early 2020 to provide tick-management programs with best practices for surveillance of blacklegged tick species (These steps address needs revealed in the survey of tick-management programs, and Mader and Mateus-Pinilla say the survey will serve as an important baseline from which to measure future progress and improvement."Overall, tick-work demands a long-term commitment. Ticks can take years to complete their life cycle, use different hosts to move around, and take advantage of weather and habitat changes," says Mateus-Pinilla. "As such, research on these vectors requires long-term and sustained commitment to research, surveillance, and partnerships across a broad range of disciplines, health professionals, and the public."
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Animals
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June 17, 2020
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https://www.sciencedaily.com/releases/2020/06/200616155948.htm
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Off-the-shelf tool for making mouse models of COVID-19
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Until there are effective treatments or vaccines, the COVID-19 pandemic will remain a significant threat to public health and economies around the world. A major hurdle to developing and testing new anti-viral therapies and vaccines for COVID-19 is the lack of good, widely available animal models of the disease.
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Researchers at the University of Iowa Carver College of Medicine and Medical University, Guangzhou, in China, have developed a simple tool to overcome that bottleneck. The researchers have created a gene therapy approach that can convert any lab mouse into one that can be infected with SARS-CoV-2 and develops COVID-like lung disease. The international team, led by Paul McCray, MD, and Stanley Perlman, PhD, at the UI, and Jincun Zhao, PhD, at Medical University, Guangzhou, have made their gene therapy vector freely available to any researchers who want to use it."There is a pressing need to understand this disease and to develop preventions and treatments," says McCray, UI professor of pediatrics, and microbiology and immunology. "We wanted to make it as easy as possible for other researchers to have access to this technology, which allows any lab to be able to immediately start working in this area by using this trick."The "trick" is the use of an adenovirus gene therapy vector that is inhaled by the mice to deliver the human ACE2 protein into mouse airway cells. This is the protein that SARS-CoV-2 uses to infect cells. Once the mouse airway cells express the hACE2 protein, the mice become susceptible to infection with SARS-CoV-2 and they develop COVID-19-like lung symptoms. Although the disease is not fatal in the mice, the animals do get sick, losing weight and developing lung damage. Importantly, the vector is readily adaptable to any strain of mice (and other lab animals), which means research teams can rapidly convert mice with specific genetic traits into animals that are susceptible to SARS-Cov-2, allowing them to test whether those traits influence the disease.Reporting in Mice are the most commonly used experimental animal for studying human disease in the lab because they are accessible, inexpensive, and easy to use. They are also one of the easier animal models to use in biosafety level three environments, which are needed for work on COVID-19. However, due to differences between the human and mouse ACE2 protein, wild-type mice are not susceptible to the SARS-Cov-2 virus.The gene therapy vector is essentially an off-the-shelf tool that allows labs to create their own COVID-19 mouse model within a few days. McCray, Zhao, and Perlman developed this approach in 2014, when Zhao was a postdoctoral researcher in Perlman's UI lab, to create mouse models of MERS."You can create these mice very quickly. You don't have to breed the strain, which is very time consuming and expensive," McCray explains. "We think this technology will be useful for investigating COVID-19 lung disease and rapidly testing interventions that people think are promising for treating or preventing COVID-19."McCray credits the UI's long-standing expertise in gene therapy vector development as a basis for this advance. The vector was made in the University of Iowa Vector Core, which is an outgrowth of the UI Center for Gene Therapy for Cystic Fibrosis funded by the National Institutes of Health. The vector is freely available through the BEI Resources Repository at the National Institute of Allergy and Infectious Diseases (NIAID).The research was supported by the grants from the NIH (AI060699 and AI129269 and DK-54759), and the Cystic Fibrosis Foundation. Zhao and his team also received funding from several Chinese governmental organizations. McCray also is supported by the Roy J. Carver Charitable Trust.
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Animals
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June 17, 2020
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https://www.sciencedaily.com/releases/2020/06/200617091018.htm
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Oocyte collection and embryo creation in southern white rhinos
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In order to prevent the extinction of species such as the northern white rhino, the BioRescue consortium is developing new methods and technologies for conservation. An important part of this work is basic research in cooperation with zoological institutions. This partnership has enabled the BioRescue team to continue working even during the Corona pandemic. On May 26, 2020, the team extracted oocytes from the southern white rhino female "Makena" in Serengeti Park in Hodenhagen, Germany, and then fertilized them in the Avantea laboratory in Italy to create four viable embryos. This was the team's most successful procedure of its kind and nourishes the hope that advanced assisted reproduction technologies (aART) are well established to ensure the survival of the northern white rhino in the near future.
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Problems with natural reproduction are often a major factor in the decline of wildlife populations, both in the wild and in human care. Therefore, techniques and methods of assisted reproduction are of crucial importance for science-based conservation. The northern white rhino is no longer able to survive on its own as a species since both remaining individuals are females. In order to perpetuate the species' existence, immature egg cells (oocytes) were collected from them in the past, which were then fertilised in the laboratory with thawed sperm collected from already deceased bulls and kept frozen. These embryos will be transferred at some stage to southern white rhino surrogate mothers and could ensure the birth of a northern white rhino calf.Southern white rhinos in European zoos also have reproduction problems. Basic research for complex assisted reproduction technologies can therefore be carried out as a win-win situation for southern and northern white rhinos. To achieve this, cooperation with zoological institutions is an essential component of the BioRescue Consortium. On 26 May 2020, Prof. Dr. Hildebrandt , the leader of this Consortium, and his team extracted 12 oocytes from the seven-year-old southern white rhino female "Makena" in the Serengeti Park in Hodenhagen, Germany. This was made possible because a suitable partner for Makena could not be transported to the zoo because of the corona pandemic. Subsequently, the extracted occytes were matured in the Avantea laboratory in Italy and seven of them were successfully fertilised with sperm from a southern rhino bull from Salzburg Zoo. Four embryos developed, which are now preserved in liquid nitrogen. This is BioRescue's most successful egg collection and embryo creation in white rhinos so far.Owing to restrictions on international travel, the BioRescue team had to postpone a procedure in Kenya planned for May. It will be rescheduled as soon as circumstances permit. BioRescue is an international consortium of research institutions, zoological gardens and conservation organisations. Its goal is to develop advanced assisted reproduction technologies (aART) and stem cell-associated techniques (SCAT), and to apply them as new science-based interventions for conservation. The consortium is led by Prof. Dr. Thomas Hildebrandt, head of the Department of Reproduction Management at Leibniz-IZW. Further consortium partners are the Max Delbrück Center for Molecular Medicine (MDC), the AVANTEA Laboratory of Reproductive Technologies, the Safari Park Dvur Králové, the Universita degli studi di Padua and Kyushu University. BioRescue is funded by the German Federal Ministry of Education and Research (BMBF).Statements Prof. Dr. Thomas Hildebrandt, head of the Department of Reproduction Management at Leibniz-IZW and the BioRescue consortium: "We are glad that we could restart with BioRescue project after the COVID-19 lockdown. We have found a very competent partner in the Serengeti Park Hodenhagen, so that we achieved our best result collection and embryo production ever. Based on this outcome our optimism regarding a successful rescue of the practically extinct northern white rhinoceros has improved significantly."Dr. Fabrizio Sepe, owner and managing director of Serengeti Park Hodenhagen: "Conservation is a central task for us. In 1996 our bull Kai in Namibia was the first European-born white rhino in the world to be released into the wild. Giving something back to nature was also a very moving moment for me personally. In this context I am even prouder today that we can make a valuable contribution to the BioRescue project with our Makena. I am confident that with our joint efforts we can secure a long-term future for many species on this planet!"Prof. Cesare Galli, Head of Avantea Laboratory: "We are pleased that international activities have resumed after the pandemic and we were able to store additional embryos that will be crucial to achieve our main milestone now i.e. the establishment of a pregnancy after the transfer of a frozen embryo. This will be crucial when we come to transfer the few and precious NWR embryos that we have produced so far and will be producing in the future. The laboratory procedures are now well established, reproducible. To achieve this milestone, we will need the support of the rhino community as we do not know how long it will take to master this final aspect of the technology."Jan Stejskal, Director of communication and international projects at Safari Park Dvur Králové and coordinator of the international efforts to save the northern white rhino: "All the methods and protocols that we now use in Kenya to save the northern white rhino were developed thanks to a collaboration between scientists and European zoos. The results from Hodenhagen are very promising and show that research that helps animals in human care can be beneficial even for saving species in their wild environment. We believe that experience and knowledge gained through work with southern white rhino females in European zoos will lead to a successful pregnancy with the pure northern white rhino embryo in Kenya in the foreseeable future."
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Animals
| 2,020 |
June 16, 2020
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https://www.sciencedaily.com/releases/2020/06/200616173227.htm
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Chemistry behind bombardier beetle's extraordinary firepower
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If you want to see one of the wonders of the natural world, just startle a bombardier beetle. But be careful: when the beetles are scared, they flood an internal chamber with a complex cocktail of aromatic chemicals, triggering a cascade of chemical reactions that detonates the fluid and sends it shooting out of the insect's spray nozzle in a machine-gun-like pulse of toxic, scalding-hot vapor. The explosive, high-pressure burst of noxious chemicals doesn't harm the beetle, but it stains and irritates human skin -- and can kill smaller enemies outright.
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The beetle's extraordinary arsenal has been held up by some as a proof of God's existence: how on earth, creationists argue, could such a complex, multistep defense mechanism evolve by chance? Now researchers at Stevens Institute of Technology in Hoboken, N.J. show how the bombardier beetle concocts its deadly explosives and in the process, learn how evolution gave rise to the beetle's remarkable firepower."We explain for the first time how these incredible beetles biosynthesize chemicals to create fuel for their explosions," said Athula Attygalle, a research professor of chemistry and lead author of the work, which appears today in the July 2020 issue of the To trace the workings of the beetle's internal chemistry set, Attygalle and colleagues at University of California, Berkeley used deuterium, a rare hydrogen isotope, to tag specially synthesized chemical blends. The team led by Kipling Will then either injected the deuterium-labeled chemicals into the beetles' internal fluids, or mixed them with dog food and fed them to the beetles over a period of several days.Attygalle's team sedated the bugs by popping them in the freezer, then gently tugged at their legs, annoying the sleepy insects until they launched their defensive sprays onto carefully placed filter papers. The team also dissected some beetles, using human hairs to tie closed the tiny ducts linking their chemical reservoirs and reaction chambers, and sampling the raw chemicals used to generate explosions.Using mass spectrometers, Attygalle checked the samples sent to Stevens for deuterium-labeled products, enabling him to figure out exactly which chemicals the beetles had incorporated into their bomb-making kits. "People have been speculating about this for at least 50 years, but at last we have a clear answer," Attygalle said. "It turns out that the beetles' biochemistry is even more intricate than we'd thought."Previously, researchers had assumed that two toxic, benzene-like chemicals called benzoquinones found in the beetles' spray were metabolized from hydroquinone, a toxic chemical that in humans can cause cancer or genetic damage. The team at Stevens showed that in fact just one of the beetle's benzoquinones derived from hydroquinone, with the other springing from a completely separate precursor: m-cresol, a toxin found in coal tar.It's fascinating that the beetles can safely metabolize such toxic chemicals, Attygalle said. In future studies, he hopes to follow the beetles' chemical supply chain further upstream, to learn how the precursors are biosynthesized from naturally available substances.The team's findings also show that the beetles' explosives rely on chemical pathways found in many other creepy-crawlies. Other animals such as millipedes also use benzoquinones to discourage predators, although they lack the bombardier's ability to detonate their chemical defenses. Evolutionarily distant creatures such as spiders and millipedes use similar strategies, too, suggesting that multiple organisms have independently evolved ways to biosynthesize the chemicals.That's a reminder that the bombardier beetle, though remarkable, is part of a rich and completely natural evolutionary tapestry, Attygalle said. "By studying the similarities and differences between beetles' chemistry, we can see more clearly how they and other species fit together into the evolutionary tree," he explained. "Beetles are incredibly diverse, and they all have amazing chemical stories to tell."
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Animals
| 2,020 |
June 16, 2020
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https://www.sciencedaily.com/releases/2020/06/200616135810.htm
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Shhhh, the whales are resting
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We need new guidelines to shield whales from human-made noise to ensure them some peace and quiet. It is no good keeping whale-watching boats out of whales' sight if the noise from the boats' engines disturb the whales most. And whales can hear the boats' engines from far away, according to a Danish-Australian research team.
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Whale-watching has become a multi-billion-dollar business, and companies want to give passengers the best possible experience by positioning their boats close to the whales.Public authorities around the globe have set restrictions on whale-watching boats in order to protect whales. For example, some countries require boats to keep a distance of at least 100 metres from the whales, or require them to stay behind or next to the whales at slow speed. However, scientific studies have shown that even when boats keep to these restrictions, the whales are still disturbed and change behaviour:They dive, change course, swim faster, breathe more often, disperse and may make different sounds compared to usual.Now, a team of researchers from Aarhus University in Denmark believe they have found an explanation: The engines in some of the boats are too loud. And authorities can now place noise emission standards on this noise."Unlike humans, the dominant sense in whales is not sight -- it is hearing. As such, a whale may not be able to see a whale-watch boat at 100 meter distance, but they are likely to hear it, so it makes sense to consider this when stipulating whale-watching guidelines," says Australian Kate R. Sprogis, biologist and Marie Skłowdowska-Curie Fellow at Aarhus University.Kate R. Sprogis is the lead of a team of researchers who, using underwater speakers and drone cameras, have experimented to find out how much noise from boats it takes for humpback whales to change their behaviour. The results have been published in the scientific journal The experiments were carried out in Exmouth Gulf on the west coast of Australia, which has the largest population of humpback whales in the world. Exmouth Gulf is a resting area where the whales rely on their fat deposits during winter as they are not feeding, and where their calves suckle to become strong enough for the migration to the feeding ground in colder waters during summer.Using a drone, the researchers would search for a mother and her calf, and drive their boat to a 100 metres distance from them in a whale-watching scenario whilst emitting boat-engine noises at different noise levels. They completed a total of 42 controlled exposure experiments of this type and recorded all behavioural movements of the whales from the aerial perspective with the drone's camera.At the highest boat-noise level of 172 decibels (a loud boat), at a 100 metres distance to the whales, they found that the resting time of whale mothers dropped by 30%, their breathing rate doubled and their swimming speed rose by 37%.However, they often returned to a state of resting when the boat noise moved further away. Despite this, other research shows that repeated disturbance from humans can have long-term consequences for the whales: When whale mothers spend a great deal of energy negatively responding to underwater noise, they have less energy to feed their offspring, avert predators and unwanted males, and to migrate to their polar feeding ground to fatten up."For the calves, multiple disturbances can also mean that they don't get enough milk: In a short time, they have to grow big and strong enough to be able to cope with the migration to colder regions and to minimise the risk of being predated upon by sharks and killer whales," explains Kate R. Sprogis.The researchers concluded that the noise level from a boat's engine should stay below 150 decibels (or, more specifically, 150 dB re 1 μPa RMS) to avoid impacting the humpback whales' behaviour.Now, the researchers recommend introducing this noise emission standard, to ensure that loud boats are not disturbing whales unnecessarily.They note that a number of whale-watching boats are already quiet and therefore comply with the recommendation.You can see a humpback mother and calf responding to different levels of noise in the video below.
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Animals
| 2,020 |
June 16, 2020
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https://www.sciencedaily.com/releases/2020/06/200616135741.htm
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Digitize your dog into a computer game
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Researchers from the University of Bath have developed motion capture technology that enables you to digitise your dog without a motion capture suit and using only one camera.
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The software could be used for a wide range of purposes, from helping vets diagnose lameness and monitoring recovery of their canine patients, to entertainment applications such as making it easier to put digital representations of dogs into movies and video games.Motion capture technology is widely used in the entertainment industry, where actors wear a suit dotted with white markers which are then precisely tracked in 3D space by multiple cameras taking images from different angles. Movement data can then be transferred onto a digital character for use in films or computer games.Similar technology is also used by biomechanics experts to track the movement of elite athletes during training, or to monitor patients' rehabilitation from injuries. However, these technologies -- particularly when applying them to animals -- require expensive equipment and dozens of markers to be attached.Computer scientists from CAMERA, the University of Bath's motion capture research centre digitised the movement of 14 different breeds of dog, from lanky lurchers to squat pugs, which were residents of the local Bath Cats' and Dogs' Home (BCDH).Wearing special doggie motion capture suits with markers, the dogs were filmed under the supervision of their BCDH handlers doing a range of movements as part of their enrichment activities.They used these data to create a computer model that can accurately predict and replicate the poses of dogs when they're filmed without wearing the motion capture suits. This model allows 3D digital information for new dogs -- their shape and movement -- to be captured without markers and expensive equipment, but instead using a single RGBD camera. Whereas normal digital cameras record the red, green and blue (RGB) colour in each pixel in the image, RGBD cameras also record the distance from the camera for each pixel.PhD researcher Sinéad Kearney said: "This is the first time RGBD images have been used to track the motion of dogs using a single camera, which is much more affordable than traditional motion capture systems that require multiple cameras."This technology allows us to study the movement of animals, which is useful for applications such as detecting lameness in a dog and measuring its recovery over time."For the entertainment industry, our research can help produce more authentic movement of virtual animals in films and video games. Dog owners could also use it to make a 3D digital representation of their pet on their computer, which is a lot of fun!"The team presented their research at one of the world's leading AI conferences, the CVPR (Computer Vision and Pattern Recognition) conference on 17 &18 June.The team has also started testing their method on computer-generated images of other four-legged animals including horses, cats, lions and gorillas, with some promising results. They aim in the future to extend their animal dataset to make the results more accurate; they will also be making the dataset available for non-commercial use by others.Professor Darren Cosker, Director of CAMERA, said: "While there is a great deal of research on automatic analysis of human motion without markers, the animal kingdom is often overlooked."Our research is a step towards building accurate 3D models of animal motion along with technologies that allow us to very easily measure their movement. This has many exciting applications across a range of areas -- from veterinary science to video games."
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Animals
| 2,020 |
June 16, 2020
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https://www.sciencedaily.com/releases/2020/06/200616083356.htm
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Shining like a diamond: A new species of diamond frog from northern Madagascar
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Despite the active ongoing taxonomic progress on Madagascar's frogs, the amphibian inventory of this hyper-diverse island is still very far from being complete. The known diversity of the diamond frog genus Rhombophryne in Madagascar has increased significantly (more than doubled!) over the last 10 years, but still there are several undescribed candidate species awaiting description. New species are constantly being discovered in Madagascar, often even within already well-studied areas. One such place is the Montagne d'Ambre National Park in northern Madagascar.
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Montagne d'Ambre National Park is widely known for its endemic flora and fauna, waterfalls and crater lakes, and considered to be a relatively well-studied area. Yet, only two studies have been published so far on the reptiles and amphibians of the Park.Serving the pursuit of knowledge of the herpetofauna in the region, Germany-based herpetologist Dr. Mark D. Scherz (Bavarian State Collection of Zoology, Technical University of Braunschweig, University of Konstanz) published a description of a new diamond frog species: Rhombophryne ellae, in the open-access journal "As soon as I saw this frog, I knew it was a new species," shares Dr. Scherz, "The orange flash-markings on the legs and the large black spots on the hip made it immediately obvious to me. During my Master's and PhD research, I studied this genus and described several species, and there are no described species with such orange legs, and only few species have these black markings on the hip. It's rare that we find a frog and are immediately able to recognise that it is a new species without having to wait for the DNA sequence results to come back, so this was elating."The new species is most closely related to a poorly-known and still undescribed species from Tsaratanana in northern Madagascar, but is otherwise quite different from all other diamond frogs. With the orange colouration on its legs, Rhombophryne ellae joins the growing list of frogs that have red to orange flash-markings. The function of this striking colouration remains unknown, despite having evolved repeatedly in frogs, including numerous times in Madagascar's narrow-mouthed frogs alone."The discovery of such a distinctive species within a comparatively well-studied park points towards the gaps in our knowledge of the amphibians of the tropics. It also highlights the role that bad weather, especially cyclones, can play in bringing otherwise hidden frogs out of hiding -- Rhombophryne ellae was caught just as Cyclone Ava was moving in on Madagascar, and several other species my colleagues and I have recently described were also caught under similar cyclonic conditions," says Dr. Scherz.The species is known so far only from a single specimen, making it difficult to estimate its conservation status. Yet, based on the status of other, related frogs from the same area, it will probably be Red-listed as Near Threatened due to its presumably small range and micro-endemicity.
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Animals
| 2,020 |
June 15, 2020
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https://www.sciencedaily.com/releases/2020/06/200615155114.htm
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Spectacular bird's-eye view? Hummingbirds see diverse colors humans can only imagine
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To find food, dazzle mates, escape predators and navigate diverse terrain, birds rely on their excellent color vision.
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"Humans are color-blind compared to birds and many other animals," said Mary Caswell Stoddard, an assistant professor in the Princeton University Department of Ecology and Evolutionary Biology. Humans have three types of color-sensitive cones in their eyes -- attuned to red, green and blue light -- but birds have a fourth type, sensitive to ultraviolet light. "Not only does having a fourth color cone type extend the range of bird-visible colors into the UV, it potentially allows birds to perceive combination colors like ultraviolet+green and ultraviolet+red -- but this has been hard to test," said Stoddard.To investigate how birds perceive their colorful world, Stoddard and her research team established a new field system for exploring bird color vision in a natural setting. Working at the Rocky Mountain Biological Laboratory (RMBL) in Gothic, Colorado, the researchers trained wild broad-tailed hummingbirds (Selasphorus platycercus) to participate in color vision experiments."Most detailed perceptual experiments on birds are performed in the lab, but we risk missing the bigger picture of how birds really use color vision in their daily lives," Stoddard said. "Hummingbirds are perfect for studying color vision in the wild. These sugar fiends have evolved to respond to flower colors that advertise a nectar reward, so they can learn color associations rapidly and with little training."Stoddard's team was particularly interested in "nonspectral" color combinations, which involve hues from widely separated parts of the color spectrum, as opposed to blends of neighboring colors like teal (blue-green) or yellow (green-red). For humans, purple is the clearest example of a nonspectral color. Technically, purple is not in the rainbow: it arises when our blue (short-wave) and red (long-wave) cones are stimulated, but not green (medium-wave) cones.While humans have just one nonspectral color -- purple, birds can theoretically see up to five: purple, ultraviolet+red, ultraviolet+green, ultraviolet+yellow and ultraviolet+purple.Stoddard and her colleagues designed a series of experiments to test whether hummingbirds can see these nonspectral colors. Their results appear June 15 in the The research team, which included scientists from Princeton, the University of British Columbia (UBC), Harvard University, University of Maryland and RMBL, performed outdoor experiments each summer for three years. First they built a pair of custom "bird vision" LED tubes programmed to display a broad range of colors, including nonspectral colors like ultraviolet+green. Next they performed experiments in an alpine meadow frequently visited by local broad-tailed hummingbirds, which breed at the high-altitude site.Each morning, the researchers rose before dawn and set up two feeders: one containing sugar water and the other plain water. Beside each feeder, they placed an LED tube. The tube beside the sugar water emitted one color, while the one next to the plain water emitted a different color. The researchers periodically swapped the positions of the rewarding and unrewarding tubes, so the birds could not simply use location to pinpoint a sweet treat. They also performed control experiments to ensure that the tiny birds were not using smell or another inadvertent cue to find the reward. Over the course of several hours, wild hummingbirds learned to visit the rewarding color. Using this setup, the researchers recorded over 6,000 feeder visits in a series of 19 experiments.The experiments revealed that hummingbirds can see a variety of nonspectral colors, including purple, ultraviolet+green, ultraviolet+red and ultraviolet+yellow. For example, hummingbirds readily distinguished ultraviolet+green from pure ultraviolet or pure green, and they discriminated between two different mixtures of ultraviolet+red light -- one redder, one less so."It was amazing to watch," said Harold Eyster, a UBC Ph.D. student and a co-author of the study. "The ultraviolet+green light and green light looked identical to us, but the hummingbirds kept correctly choosing the ultraviolet+green light associated with sugar water. Our experiments enabled us to get a sneak peek into what the world looks like to a hummingbird."Even though hummingbirds can perceive nonspectral colors, appreciating how these colors appear to birds can be difficult. "It is impossible to really know how the birds perceive these colors. Is ultraviolet+red a mix of those colors, or an entirely new color? We can only speculate," said Ben Hogan, a postdoctoral research associate at Princeton and a co-author of the study."To imagine an extra dimension of color vision -- that is the thrill and challenge of studying how avian perception works," said Stoddard. "Fortunately, the hummingbirds reveal that they can see things we cannot.""The colors that we see in the fields of wildflowers at our study site, the wildflower capital of Colorado, are stunning to us, but just imagine what those flowers look like to birds with that extra sensory dimension," said co-author David Inouye, who is affiliated with the University of Maryland and RMBL.Finally, the research team analyzed a data set of 3,315 feather and plant colors. They discovered that birds likely perceive many of these colors as nonspectral, while humans do not. That said, the researchers emphasize that nonspectral colors are probably not particularly special relative to other colors. The wide variety of nonspectral colors available to birds is the result of their ancient four color-cone visual system."Tetrachromacy -- having four color cone types -- evolved in early vertebrates," said Stoddard. "This color vision system is the norm for birds, many fish and reptiles, and it almost certainly existed in dinosaurs. We think the ability to perceive many nonspectral colors is not just a feat of hummingbirds but a widespread feature of animal color vision."
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Animals
| 2,020 |
June 12, 2020
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https://www.sciencedaily.com/releases/2020/06/200612172216.htm
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As rare animals disappear, scientist faces 'ecological grief'
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Five years before the novel coronavirus ran rampant around the world, saiga antelopes from the steppes of Eurasia experienced their own epidemic.
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Millions of these grazing animals -- easily recognizable by their oversized snouts -- once migrated across what is today Kazakhstan, Mongolia, Georgia and more.But then, over the span of three weeks in 2015, nearly 200,000, or two-thirds of their existing population, sickened and died from a bacterial infection. Today, the a little more than 100,000 saiga are hanging onto survival in a few pockets of Eurasia.The decline, and uncertain fate, of the saiga is a story that resonates with Joanna Lambert. She's a conservation biologist at the University of Colorado Boulder and a coauthor of a paper published this week in the journal Lambert, who has studied ecological communities in both North America and Equatorial Africa, explained that many of these creatures aren't well-known outside of their home regions. But when these animals disappear, entire ecosystems can reshuffle, occasionally beyond recognition."We're losing these animals without people ever knowing they were there in the first place," said Lambert, a professor in the Program of Environmental Studies at CU Boulder.For the researcher, the study's publication marks an opportunity to reflect on how she stays hopeful even amid tremendous losses -- and how to talk about the natural world during a period of unprecedented social upheaval."I tell my students, 'I have to give you the facts. This is the world you're growing up in, but don't let that paralyze you,'" Lambert said.The new research was led by Joel Berger of Colorado State University and also included scientists from Bhutan, Argentina and Chile.The team decided to look at ungulates because -- with a few exceptions like rhinos and elephants -- they don't usually pop up in brochures for conservation organizations. But, Lambart said, they're still in trouble: Huemel, for example, once roamed across the Patagonia region of South America. Today, a little more than 1,000 of these fluffy deer still live in the wild. The tamaraw, a pint-sized buffalo from the Philippines, is down to just a few hundred individuals."The whole world knows the stories of pandas and mountain gorillas, but there are untold numbers of unsung species that come and go without the world's attention," she said.Their cases also show just how complicated conservation can be.Lambert has spent years trekking the grasslands and forests of Yellowstone National Park to study wildlife. After federal officials killed all the park's wolves in the 1940s, elk herds there began to multiply -- big time. Head counts for these herbivores surged from a few thousand individuals to tens of thousands, and they devoured once-abundant plants like cottonwood and willow trees."When you pull one species out of its community, or if you add a new one in, the entire assembly changes," Lambert said. "That has been the history of what humans have done on the planet."When the park brought wolves back in the 1990s, and elk numbers dropped back down, something unexpected happened: beavers, which had also disappeared from Yellowstone, began reappearing, too. The furry swimmers, it turns out, depend on those same tree species to build their dams."In many cases, we don't know what rules these ecosystems followed in the past," she said. "Even when we do know, it doesn't matter because we now have this added element of human tinkering."Lambert has also struggled to keep going as a conservation biologist as the wilds around her field sites in Africa and North America dwindled, then vanished entirely."As I returned each year from the field, it was taking me longer and longer to recover from a sort of existential depression," she said. "I realized that I have been profoundly impacted by the losses I've seen."Many of Lambert's students feel similarly hopeless, a phenomenon that psychologists call "ecological grief." She tells them to focus on the success stories, however rare they are. Protected areas like Yellowstone have saved countless animals from extinction and have given others like wolves new chances at survival. Lambert is also providing scientific guidance around proposals to return wolves to Colorado.And there are still a lot of animals out there -- including the few remaining herds of big-nosed saiga."We need to fight like hell to keep all that," she said.
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Animals
| 2,020 |
June 11, 2020
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https://www.sciencedaily.com/releases/2020/06/200611152440.htm
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Simulations reveal interplay between scent marking and disease spread
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In a new mathematical model that bridges animal movement and disease spread, territorial behaviors decreased the severity of potential disease outbreaks -- but at the cost of increased disease persistence. Lauren White of the University of Maryland's National Socio-Environmental Synthesis Center, Annapolis, MD, and colleagues present these findings in
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Disease research often addresses direct social contact without considering individual animals' movement. Individual movement can be shaped by indirect social cues; for instance, a puma might mark its territory with a scent. While territorial behaviors could, in theory, inhibit diseases that require direct transmission, pathogens able to persist in the environment could still spread.To better understand the interplay between indirect communication and disease spread, White and colleagues developed a mathematical model in which infected animals can indirectly infect others by leaving behind pathogens whenever they deposit scent marks. The researchers used the model to simulate territorial movement of animals over a landscape, as well as the resulting disease spread.In simulated outbreak-prone conditions with high animal density and slow disease-recovery rates, territorial movement decreased the number of animals infected, but at the cost of longer disease persistence within the population. These results suggest that indirect communication could play a more important role in disease transmission than previously thought."It was exciting to be able to incorporate a movement-ecology perspective into a disease-modeling framework," White says. "Our findings support the possibility that pathogens could evolve to co-opt indirect communication systems to overcome social barriers in territorial species."This study demonstrates that accounting for movement behavior in disease models could improve understanding of how infectious diseases spread. Moving forward, the researchers hope to strengthen their model with additional dynamics, such as varying habitat quality and prey kill sites.
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Animals
| 2,020 |
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