Animal Ecology

Marburg an der Lahn, Germany

Animal Ecology

Marburg an der Lahn, Germany
SEARCH FILTERS
Time filter
Source Type

News Article | April 17, 2017
Site: www.newscientist.com

AS MORE than 40,000 runners prowl the start line of the London marathon this weekend, many of them will be wondering what they have got themselves into. Even without a heavy novelty costume, and no matter how well they have stuck to their training regime, running non-stop for 26.2 miles (42 kilometres) is going to hurt. Now consider the barnacle goose. Before setting off on a 3000-kilometre migration, it undertakes the training equivalent of sitting on the sofa guzzling fish and chips. What about the months of gradually building up fitness, followed by a steady taper before the big day? That’s not really the barnacle goose’s style. Instead, says Lewis Halsey, an environmental physiologist at the University of Roehampton, London, “they just basically sit on the water and eat a lot”. Scientists are only now beginning to investigate how this can be. Until recently, nobody had really asked whether exercise is as tightly connected to fitness in the rest of the animal kingdom as it is for us. In the past year or two, though, a handful of researchers have been inspired to do so by seemingly lazy creatures that manage feats of endurance that make marathons pale by comparison. The question is tied up in a broader assumption: that, because of the exercise they get finding food and escaping predators, wild animals live at the peak of physical fitness. Halsey, who recently wrote an article for the Journal of Animal Ecology with the provocative title “Do animals exercise to keep fit?”, points out that this may not necessarily be the case. Take, for a moment, a domestic equivalent, the house cat. Most cats spend much of the day lounging around, apparently doing nothing. But over short distances, even the laziest could put Usain Bolt to shame. And all that time spent napping seems to have no effect on their natural agility should a dog suddenly appear in the garden. Similarly, black and brown bears manage to come out of several months of hibernation with their muscle mass intact – without having to lift so much as a paw. “Over short distances, even the laziest cat could put Usain Bolt to shame” Barnacle geese go one better. In the process of sitting around, they don’t just maintain their fitness. They also develop stronger hearts, bigger flight muscles and – somehow – get fit enough to fly for thousands of miles in a migration lasting just two days. So, if exercise isn’t necessarily the key to physical prowess, then what is? One clue comes from a broader view of the meaning of physical fitness. Biologically speaking, all it means is that the body has undergone changes that make it stronger and more efficient. In humans, these changes are induced by exercise. In animals such as bears and migratory birds, they appear to be triggered by seasonal changes that alert their bodies to a coming challenge. For bears, that cue might be falling temperatures or a lack of available food. Whatever the exact tip-off, it seems to prompt the release of muscle-protecting compounds in their blood. In experiments in which rat muscle was bathed in the blood of hibernating bears, muscle loss was reduced by 40 per cent compared with muscle put in blood from bears that were not hibernating. Barnacle geese, Halsey suggests, may be responding to an environmental change such as temperature, which helps their bodies somehow “know” that a big physical challenge is looming and to beef up accordingly. In other bird species, that cue is a seasonal change in the amount of daylight. Chris Guglielmo, a physiological ecologist at the University of Western Ontario in Canada, has found that subjecting migratory yellow-rumped warblers to changing hours of daylight stimulates hundreds of changes in the genes that are activated in their muscles. “We don’t need to take little songbirds and train them up to do a 6 or 10-hour flight,” he says. If they are subjected to the right daylight cycle, “we can take them out of the cage and put them in the wind tunnel, and they fly for 10 hours“. Unlike migratory birds, however, humans have no biological shortcut to getting fit every April, however much the modern marathoner might wish we did. And we have no muscle-protecting substances in our blood that we can switch on to prevent losing our hard-earned strength while lounging on the sofa. Instead, pressures in our evolutionary history made our bodies tie fitness to exercise. Our ancestors’ lives were unpredictable. They had to do a lot of running to catch food and escape danger, but they also needed to keep muscle mass to a minimum because food was limited. Seen through this lens, losing condition is an adaptation in itself. Muscle is biologically expensive. Each kilogram contributes about 10 to 15 kilocalories a day to our resting metabolism – which doesn’t sound like much until you realise that muscles account for about 40 per cent of the average person’s body mass. “Most of us are spending 20 per cent of our basic energy budget taking care of muscle mass,” says Daniel Lieberman, an evolutionary biologist and marathon runner from Harvard University. So our physiology evolved to let our weight and fitness fluctuate depending on how much food was available. This makes us evolutionarily different from most other animals, says Lieberman. In general, animals merely need to be capable of short bouts of intense activity, whether it’s the cheetah chasing prey or the gazelle escaping. Cats are fast, but they don’t need to run very far. Perhaps a few mad dashes around the house are all it takes to keep a domestic one fit enough for feline purposes. Humans, on the other hand, needed to adapt to run slower, but for longer, says Lieberman. He argues that long ago on the African savannah, natural selection made us into “supremely adapted” endurance athletes, capable of running prey into the ground and ranging over long distances with unusual efficiency. But only, it appears, if we train. Otherwise we quickly degenerate into couch potatoes. As for speed, even those animals that do cover impressive distances don’t have to be the fastest they can possibly be. Barnacle geese needn’t set world records when crossing the North Atlantic; they just need to be able to do it. And, says exercise physiologist Ross Tucker at the University of the Free State in Bloemfontein, South Africa, humans may be the only animal that actually cares about reaching peak performance. Other than racehorses and greyhounds, both of which we have bred to race, animals aren’t directly competing against one another. “I don’t know that all animals are all the same, performance-wise… and we don’t know whether training would enhance their ability,” he says. So, what can the human fitness fanatic learn from nature’s lazy fit animals? It is tempting to hope that science will come up with a marathon preparation pill that might make our bodies transform like a goose’s, but, the health and ethical aspects of doping aside, that seems unlikely in the near future. In the meantime, perhaps we should look to a humbler kind of creature for motivation. As anyone who has ever had a pet hamster knows, rodents love to run. In fact, brain chemistry experiments show that they appear to derive pleasure from it, says Vincent Careau, an evolutionary biologist at the University of Ottawa, Canada. “Mice are wired to like it through the dopamine system,” he says. “It gives them a runner’s high.” In fact, a 2014 Dutch experiment found that it isn’t just domesticated rodents that react this way. If you put an exercise wheel outdoors, the study found, even wild mice will exercise on it, once they figure it out. This summer, Careau plans to follow up on this by putting training wheels out in the wild, tagging as many mice as possible and clocking their running miles to see if there is any effect on their survival rates. It makes sense that there might be, because mice spend their entire lives trying to avoid predators, whether they are hawks, foxes, snakes or weasels. It may turn out that, just like us, the exercise they get in the course of normal life isn’t enough for the running they may have to do, so they need to work out in their spare time. For humans, being fit is an evolutionary luxury. But for mice, being fit is the difference between survival and being cat food. So, if you are a marathoner looking for a good result, forget the geese, cats and bears. Instead, think like a mouse, and ride the dopamine high. This article appeared in print under the headline “All gain, no pain”


News Article | April 27, 2017
Site: phys.org

The phenomenon exists even when you adjust for male risky behavior which leads to more early male deaths than female (car accidents, wars, homocides, etc). Scientists don't know why. Females are not better at withstanding certain viruses or bacteria for instance—there seems to be no obvious physiological reasons. A new study in Journal of Ecology has looked at sex differences and mortality in the Eurasian sparrowhawk. It turns out that heterogeneity is what drives longer lives in female sparrowhawks. Heterogeneity in this context means that female sparrowhawk physiology is more diverse and less average than the males. There are more frail females than frail males, but there are also more robust females than robust males. With more frail females, there will of course be more early female deaths than male. But this is more than weighed up by the larger number of robust females than males. According to the study, the life expectancy for the most robust adult females reach up to 4.23 years, while for the most robust adult males it was 2.68 years. The results are a surprise to the researchers. Possible in other species. It is possible that this phenomenon can be found in other animal species, but it is still uncertain. I suggest that when studying sex differences in mortality, researchers should consider accounting for heterogeneity. Explore further: Sexual harassment in the fish world—male guppies suffer most More information: Fernando Colchero et al, Individual heterogeneity determines sex differences in mortality in a monogamous bird with reversed sexual dimorphism, Journal of Animal Ecology (2017). DOI: 10.1111/1365-2656.12677


News Article | April 27, 2017
Site: www.eurekalert.org

Females often live longer than men -- this is true for humans and for many other animal species. The phenomenon exists even when you adjust for male risky behavior which leads to more early male deaths than female (car accidents, wars, homocides, etc). Scientists don't know why. Females are not better at withstanding certain viruses or bacteria for instance -- there seems to be no obvious physiological reasons. A new study in Journal of Ecology has looked at sex differences and mortality in the Eurasian sparrowhawk. It turns out that heterogeneity is what drives longer lives in female sparrowhawks. Heterogeneity in this context means that female sparrowhawk physiology is more diverse and less average than the males. There are more frail females than frail males, but there are also more robust females than robust males. With more frail females, there will of course be more early female deaths than male. But this is more than weighed up by the larger number of robust females than males. According to the study, the life expectancy for the most robust adult females reach up to 4.23 years, while for the most robust adult males it was 2.68 years. The results are a surprise to the researchers. Possible in other species. It is possible that this phenomenon can be found in other animal species, but it is still uncertain. I suggest that when studying sex differences in mortality, researchers should consider accounting for heterogeneity. Journal of Animal Ecology: Individual heterogeneity determines sex differences in mortality in a monogamous bird with reversed sexual dimorphism. Authors: Fernando Colchero, Alix Eva Aliaga, Owen Jones, Dalia Amor Conde. Contact: Fernando Colchero, Associate Professor, PhD. Department of Mathematics and Computer Science and Max-Planck Odense Center. Email: olchero@imada.sdu.dk. Tel: +45 65502324. http://www.


News Article | December 29, 2016
Site: www.techtimes.com

Migrating birds arrive at their breeding grounds earlier because of increasing global temperatures, findings of a new study have revealed. Researchers from the Edinburgh University looked at a total of 413 species of birds across five continents and found how climate change is affecting the migration of birds. Birds arrive at their summer breeding ground about one day earlier per degree of rising global temperatures. In the study published in the Journal of Animal Ecology, researchers looked at how various species that take flight in response to cues such as food availability and changing seasonal temperatures experience changes in their behavior over time with rising global temperatures. By looking at the records of migrating bird species as far back as nearly 300 years ago, the researchers found that birds now reach their summer grounds at the wrong time. The data were taken from records made by amateur enthusiasts and scientists including 19th century American naturalist Henry David Thoreau. Reaching their breeding grounds even just a few days earlier could pose problems to birds. They may miss out on the best availability of crucial resources for their survival such as nesting places and food. The timing can affect the hatching of their offspring and the chances of their survival. Birds that travel long distances and are known to be less responsive to increasing temperatures may suffer the most since other species of birds gain advantage when they arrive at the breeding grounds earlier than the others. "We confirm earlier findings that on average birds have significantly advanced their spring migration time by 2·1 days per decade and 1·2 days °C-1. We find that over time and in response to warmer spring conditions, short-distance migrants have advanced spring migratory phenology by more than long-distance migrants," the researchers wrote in their study, which was published on Dec. 28. Study researcher Takuji Usui noted how many animal and plant species have changed the timing of their activities, which are linked with the start of spring such as breeding and flowering. In an earlier study, researchers found that more than 600 plant species are flowering at the wrong time because of warmer winter conditions. Usui said that their study offers detailed insight into the changes in migration timing and how this varies across species. "These insights may help us predict how well migratory birds keep up with changing conditions on their breeding grounds," Usui said. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.


News Article | November 14, 2016
Site: www.eurekalert.org

Showy ornaments used by the male of the species in competition for mates, such as the long tail of a peacock or shaggy mane of a lion, could indicate a species' risk of decline in a changing climate, according to a new study from Queen Mary University of London (QMUL). Males of many animal species compete for mates, either by producing showy ornaments to attract females, such as the plumes and bright colours of male Birds of Paradise, or, like stags and elephant seals, by fighting with other males for access to mates. Scientists have shown over the last few years that in many of these cases the winning males are fitter because they carry genes that make them better adapted to the environment - the so called 'good genes' effect. The researchers from QMUL's School of Biological and Chemical Sciences investigated whether these 'sexually selected' animals might be better able to cope with changes in the environment such as increasing temperatures or acidity. Using a sophisticated mathematical simulation model that integrates both ecological and evolutionary processes, the researchers found that sexually selected species can adapt faster to new environments, and are less likely to go extinct. There is a twist in this peacock's tail though - this effect only happens when the animal populations are large. When the populations are small, the presence of competitive males can actually make a population more likely to become extinct. This is because males pay a high price for engaging in their competitions. Either they have to invest lots of energy in expensive displays, which then make them more vulnerable to predators, or they get injured and even killed in fights with other males. When there are more than about 100 animals in a population this has little overall effect and the evolutionary benefits of sexual selection outweigh the costs - but when the population is below about 50 individuals the costs come to dominate and extinction becomes more likely. Co-author Dr Rob Knell said: "Although these results are currently largely theoretical, they are relevant to the conservation of a huge variety of animals. "Sexual selection is extremely common and is responsible for many of the most spectacular features that we see in modern animals, and as the environment changes this result will help conservationists assess the vulnerability of some of our favourite animals to global warming, ocean acidification and a multitude of other threats." The results are published in the Journal of Animal Ecology.


News Article | November 14, 2016
Site: www.sciencedaily.com

Showy ornaments used by the male of the species in competition for mates, such as the long tail of a peacock or shaggy mane of a lion, could indicate a species' risk of decline in a changing climate, according to a new study from Queen Mary University of London (QMUL). Males of many animal species compete for mates, either by producing showy ornaments to attract females, such as the plumes and bright colours of male Birds of Paradise, or, like stags and elephant seals, by fighting with other males for access to mates. Scientists have shown over the last few years that in many of these cases the winning males are fitter because they carry genes that make them better adapted to the environment -- the so called 'good genes' effect. The researchers from QMUL's School of Biological and Chemical Sciences investigated whether these 'sexually selected' animals might be better able to cope with changes in the environment such as increasing temperatures or acidity. Using a sophisticated mathematical simulation model that integrates both ecological and evolutionary processes, the researchers found that sexually selected species can adapt faster to new environments, and are less likely to go extinct. There is a twist in this peacock's tail though -- this effect only happens when the animal populations are large. When the populations are small, the presence of competitive males can actually make a population more likely to become extinct. This is because males pay a high price for engaging in their competitions. Either they have to invest lots of energy in expensive displays, which then make them more vulnerable to predators, or they get injured and even killed in fights with other males. When there are more than about 100 animals in a population this has little overall effect and the evolutionary benefits of sexual selection outweigh the costs -- but when the population is below about 50 individuals the costs come to dominate and extinction becomes more likely. Co-author Dr Rob Knell said: "Although these results are currently largely theoretical, they are relevant to the conservation of a huge variety of animals. "Sexual selection is extremely common and is responsible for many of the most spectacular features that we see in modern animals, and as the environment changes this result will help conservationists assess the vulnerability of some of our favourite animals to global warming, ocean acidification and a multitude of other threats." The results are published in the Journal of Animal Ecology.


News Article | November 14, 2016
Site: www.chromatographytechniques.com

Showy ornaments used by males of the species in competition for mates, such as the long tail of a peacock or shaggy mane of a lion, could indicate a species' risk of decline in a changing climate, according to a new study from Queen Mary University of London (QMUL). Males of many animal species compete for mates, either by producing showy ornaments to attract females, such as the plumes and bright colors of male Birds of Paradise, or, like stags and elephant seals, by fighting with other males for access to mates. Scientists have shown over the last few years that in many of these cases the winning males are fitter because they carry genes that make them better adapted to the environment - the so called 'good genes' effect. The researchers from QMUL's School of Biological and Chemical Sciences investigated whether these 'sexually selected' animals might be better able to cope with changes in the environment such as increasing temperatures or acidity. Using a sophisticated mathematical simulation model that integrates both ecological and evolutionary processes, the researchers found that sexually selected species can adapt faster to new environments, and are less likely to go extinct. There is a twist in this peacock's tail though - this effect only happens when the animal populations are large. When the populations are small, the presence of competitive males can actually make a population more likely to become extinct. This is because males pay a high price for engaging in their competitions. Either they have to invest lots of energy in expensive displays, which then make them more vulnerable to predators, or they get injured and even killed in fights with other males. When there are more than about 100 animals in a population this has little overall effect and the evolutionary benefits of sexual selection outweigh the costs - but when the population is below about 50 individuals the costs come to dominate and extinction becomes more likely. "Although these results are currently largely theoretical, they are relevant to the conservation of a huge variety of animals," said Rob Knell, co-author. "Sexual selection is extremely common and is responsible for many of the most spectacular features that we see in modern animals, and as the environment changes this result will help conservationists assess the vulnerability of some of our favorite animals to global warming, ocean acidification and a multitude of other threats." The results are published in the Journal of Animal Ecology.


News Article | February 22, 2017
Site: phys.org

A study of seabirds' foraging habits has found that they have strong long term preferences for the habitat in which they forage, and that those that can repeatedly go to the same place to find food have a better chance of fledging a chick than those who have to visit many locations. Researchers from the University of Liverpool and Centre d'Etudes Biologique de Chizé, CNRS analysed tracking data for black-browed albatrosses collected over 11 years on the Kerguelen Archipelago, in the Southern Indian Ocean. Following the same birds across multiple foraging trips with and between years, they identified the habitat and locations individuals preferred. They found that most of the birds had highly individual and specialised habitat choices, which may indicate individual prey preferences, persisting between breeding seasons. However, a subsection of birds were able to find their chosen habitat by repeatedly visiting the same areas and these had a better chance of fledging a chick. This result suggests that foraging site fidelity drives differences in reproductive success. This may be because individuals which can repeatedly go to the same place save energy by reducing searching and travelling costs, or that they are more successful foragers and so do not have to visit as many prey patches. Dr Samantha Patrick, Lecturer in Marine Biology in the University's School of Environmental Sciences, said: "Seabirds have the ability to locate food across a seemingly featureless ocean and this study helps us understand what birds are seeking when they go to sea to forage". "Black-browed albatrosses are very long lived birds and this evidence that they maintain foraging preferences across long time periods suggests that habitat preference may be relatively fixed". "If individuals always seek the same environmental conditions, changes to the ocean in response to changing climate may remove the habitat which some birds need to forage and survive, and we lack and through understanding of how able these birds are to adapt to this". The research is published in the Journal of Animal Ecology.


News Article | August 31, 2016
Site: phys.org

As conservationists work to recover endangered species populations, taking individuals that are maintained and protected under human care and reintroducing them into the wild, it becomes apparent that there is a great deal to learn about the science of species recovery. In a paper published in the recent edition of the Journal of Applied Ecology, a team of wildlife experts from San Diego Zoo Global, the U.S. Geological Survey, the U.S. Fish and Wildlife Service and the University of Nevada analyzed the effect of habitat quality on the survival and dispersal of released desert tortoises. Juvenile tortoises used in this study originated from eggs produced by females housed at the Desert Tortoise Conservation Center in Las Vegas. Ages ranged from 6 months to 4 years. The tortoises were translocated and monitored for one year, using radio tracking systems. "The goals of the study were to help re-establish populations of this threatened and declining species, and to understand better what critical resources on the landscape are associated with the ability of young tortoises to survive and thrive," said Ron Swaisgood, Ph.D., director of Applied Animal Ecology at San Diego Zoo Global. Tortoises released in habitat that included appropriate vegetation, rocks and the presence of animal burrows had lower mortality rates than those released in areas where land features offered fewer options for predator avoidance. "Burrows created by small mammals represent critical components of desert tortoise ecology," said Melia Nafus, Ph.D., a researcher for San Diego Zoo Global and lead author of the study. "Supporting healthy rodent populations through habitat management may improve juvenile desert tortoise survival and recruitment." Another interesting finding of the study was that tortoises released on rocky ground were less likely to disperse away from the release site. "This finding probably relates to the tortoise's dependence on rocky substrate, as camouflage to hide from predators," said tortoise expert and co-author Todd Esque, Ph.D., from the U.S. Geological Survey. "The U.S. Fish and Wildlife Service encourages research such as this because it provides vital knowledge that informs our policy and management decisions," stated study co-author Roy Averill-Murray, who heads the service's Desert Tortoise Recovery Office. "Now, we have better information when deciding which habitats to protect for desert tortoises, and where to attempt re-establishment of desert tortoise populations with future releases." Translocation of individuals back to the wild is one of many important tools that conservation biologists use to recover endangered and threatened species. "We view these translocations as a way to learn more about animals' habitat requirements, while also assisting directly with species recovery goals," said Ron Swaisgood.


News Article | March 31, 2016
Site: www.scientificamerican.com

One of the rarest bird species in the United Kingdom has a very big problem: they’re going blind. And it’s killing them. According to research published this month in the Journal of Animal Ecology, about 3 percent of the red-billed choughs (Pyrrhocorax pyrrhocorax pyrrhocorax) born in Scotland each year are blind or visually impaired. The chicks appear otherwise healthy, but the blindness carries an inevitable cost: “We’ve never seen a blind nestling survive post-fledging,” says Amanda Trask, a PhD student at the University of Aberdeen and the lead author of the study. Scotland only has about 60 breeding pairs of red-billed choughs left, a number that shrinks every year, so this “lethal blindness” (as the paper puts it) creates serious questions about the viability of the species in the country. Chick blindness first turned up in 1998 but until now the cause remained a mystery. One theory suggested it could have involved an environmental factor, but the new paper proves that it has actually the result of a recessive gene that is spreading through the small, inbred population. It still only affects a small number of chicks, but Trask and her fellow researchers found that parents who carry the mutation actually have more offspring per year than unaffected birds, so it could become even more of a problem in coming years. Importing additional choughs to Scotland from other areas could help inject healthier genes into the population, but options for that are extremely limited. The red-billed chough is an extremely widespread species, ranging all the way across Asia, but the subspecies in the UK exists in just a few fragmented pockets like the ones in Scotland. Trask says there are only 394 breeding pairs throughout the UK and the Isle of Man. Most of those other populations are stable at least, according to the recent State of the UK’s Birds report, but that doesn’t necessarily mean they could withstand the removal of any birds to supplement Scotland’s population. Right now blindness levels are still fairly low, so Trask says the main priority for conserving the birds should be preserving their habitats on the Islands of Islay and Colonsay. Still, the risk remains. Managing the blindness and recessive genes in the future, she says, will be a necessary part of conservation strategies moving forward.

Loading Animal Ecology collaborators
Loading Animal Ecology collaborators