Sunday, 25 November 2018

Drop your weapons! Autotomy, the shedding of a body part, reveals the hidden cost of conflict


Animal weapons such as antlers, tusks and limbs specialized for fighting require a large energy expenditure to produce and may cost even more to maintain. Because the leaf-footed bug sheds its large hind limbs, used as weapons in male-male battles, scientists working at the Smithsonian Tropical Research Institute (STRI) in Panama could measure energy use of live bugs with and without hind legs to calculate the hidden energetic cost of weapons' maintenance.
Wild animals can spend up to 30 and 40 percent of their total energy budget while at rest. "Human athletes often burn more calories during their relatively long rest periods than during physical exercise itself," said Ummat Somjee, who did this study as part of his doctoral dissertation at the University of Florida in co-author Christine Miller's lab group and is currently a Tupper post-doctoral fellow at STRI.
"We calculated the metabolic cost of maintaining large hind legs in a leaf-footed bug and found that males invest more in weapons than females do," Somjee said. "Large males expend relatively less energy on their super-sized weapons than smaller males." The results are published online in Proceedings of the Royal Society B.
Male leaf-footed bugs, Leptoscelis tricolor, hang out on bright orange or red heliconia inflorescences, feeding on nectar and developing heliconia fruit. Their hind legs, covered with thorny structures, are larger than females' legs and serve as weapons in male-male duels.

Eyeing echidnas: Study models echidna forelimbs to help shed new light on mammal evolution



November 17, 2018, Harvard University
These days, mammals can use their forelimbs to swim, jump, fly, climb, dig and just about everything in between, but the question of how all that diversity evolved has remained a vexing one for scientists.
To help answer it, Harvard researchers are turning to one of the most unusual mammals around—echidnas. These sprawling, egg-laying mammals have many anatomical features in common with earlier mammal ancestors, and so can help bridge the gap between extinct and other modern-day mammals.
Using a highly-detailed musculoskeletal model of an echidna forelimb, Sophie Regnault, a Post-Doctoral Fellow and Stephanie Pierce, Associate Professor of Organismic and Evolutionary Biology, were able to not only shed more light on how the little-studied echidna's forelimb works, but also open a window into understanding how extinct mammals might have used their forelimbs. The model is described in a November 14 paper published in Royal Society Open Science.
"Echidnas are not very well-studied, and little is known about their biomechanics." Regnault says. "There are few related species, and echidnas themselves can be difficult to study because they have very large spines hiding underlying movements. We made this virtual model using CT scans that allow us to look in closer detail at how the skeleton and muscles interact with one another."
The researchers discovered that the bony anatomy and muscles work together to optimize limb leverage and mobility for certain kinds of movements. In particular, the configuration of muscles support limb rotation important for the echidna's sprawling gait.
"This model gives us unique insight into not only the echidna but can also guide reconstructions of extinct mammals," Pierce says. "The similarities between the echidna forelimb skeleton and transitional animals can help us to understand the evolution of forelimb diversity in modern mammals."

Frogs breed young to beat virus


November 20, 2018, University of Exeter
Frogs from groups exposed to a deadly virus are breeding at younger ages, new research suggests.
Scientists studying European common frogs in the UK compared groups ("populations") exposed to ranavirus and those free from the disease.
While the youngest breeding frogs in disease-free populations are four years old, frogs in virus-exposed groups breed as young as two.
The reasons for this are not yet clear, but the team—led by researchers from the University of Exeter and the Zoological Society of London—warn that this decrease in breeding age means disease-exposed populations are at greater risk of local extinction sparked by environmental changes.
Frogs gather at breeding spots such as ponds and then disperse, but most return to the same ponds year after year.
"Our research shows that the ages of the frogs that return to breed varies between populations which are known to have ranavirus and those which don't," said Dr. Lewis Campbell, who conducted the research during his Ph.D. at the University of Exeter's Penryn Campus in Cornwall.
"We found significantly fewer old frogs and significantly more young frogs at populations which have ranavirus.
"It's possible that the more times an older frog returns to the same infected breeding pond, the more likely they are to become diseased and die.

Encourage reptiles and amphibians to take up residence, Berks environmental consultants urge - via Herp Digest



WRITTEN BY SUSAN SHELLY - READING EAGLE 11/12/18
Courtesy of Quillyn Bickley | Mike Torocco photographs an Eastern Kingsnake.

The message from Quillyn Bickley and Mike Torocco is clear: amphibians and reptiles should not be discouraged from taking up residence in our yards and gardens.

In fact, the environmental consultants urged, Pennsylvanians should do more to encourage snakes, toads, frogs, salamanders, turtles and other reptiles and amphibians onto their properties.

Bickley and Torocco of Spring Township are herpetologists, zoologists who study reptiles and amphibians. They are employed by Herpetological Consultants Inc., an environmental consulting firm that serves clients throughout the United States and abroad.
Courtesy of Mike Torocco | Quillyn Bickley holds a box turtle she found in a wooded area.
Courtesy of Quillyn Bickley | Mike Torocco handles a snapping turtle.

The New Jersey-based firm specializes in planning for wildlife conservation and protecting the environments of endangered and threatened plants and animals.

Bickley and Torocco recently presented a program on “Amphibians and Reptiles of Pennsylvania” during a gathering at the Reading Public Museum.

Pennsylvania is home to a great variety of common and rare amphibians and reptiles, collectively known as herps.

A number of them, including the bog turtle, redbelly turtle, southern leopard frog, New Jersey chorus frog and rough green snake, are endangered or threatened.

Considering the population, industry and environmental factors present in the state, the number and variety of herps here is surprising, Torocco said.

“This area has been settled and his habitat beat up for a long time,” he said. “It's amazing that we have the diversity that we do.”

Manmade factors such as gas and oil exploration, pipeline construction and automobile traffic are disruptive to amphibians and reptiles, as are natural predators such as raccoons, which dig up nests in order to get the eggs they contain.

“Raccoons are very good at finding nests,” Torocco said.

Eastern Pennsylvania is home to 22 varieties of salamanders, 16 kinds of turtles, 4 varieties of lizards and 21 types of snakes. Of the snakes, three types are poisonous.

“We have both rare species and then a great variety of common species,” Torocco said.

While many people are afraid of snakes, lizards and other amphibians and reptiles, they play an important role in the environmental landscape, Bickley explained.

Lizards, snakes, frogs and toads eat a variety of pests, including slugs, snails, roaches and rodents. Having herps on your property increases the diversity of animal life, which is an indicator of a healthy environment.

To that end, Bickley advised, try to be intentional when thinking about your yard and garden, and work to provide food, water, breeding habitat and places for reptiles and amphibians to survive over the winter.

Brush piles, wood piles, logs, rocks and ponds will all encourage herps to take up residence.

“Consider your surroundings, and then consider what you're willing to take on,” Bickley said. “Something as simple as a toad house can encourage herps on your property.”

Layered, flat rocks will encourage snakes, who love to bask in sunlight. Fallen logs in a moist, shady are will attract salamanders, and ponds are home to different varieties of turtles and frogs.

“If you build it, they will come,” Bickley said.

A variety of plants, shrubs and flowers also is important.

Learning to live with and appreciate reptiles and amphibians may require a change in mindset, Bickley said, but all living things are important in maintaining a healthy environment.

She warned that herps should not be relocated, but allowed to move from place to place on their own. Never release non-native species of amphibians or reptiles, and watch for hitchhikers when purchasing plants or other items.

“It's really important, ecologically, to leave what's wild in the wild, and where it belongs,” Bickley said.

About Quillyn Bickley and Mike Torocco

 Quillyn Bickley and Mike Torocco are herpetologists, or zoologists who specialize in the study of amphibians and reptiles.

 They are employed as regional managers of the Pennsylvania Field Office by Herpetological Consultants Inc., a New Jersey-based consulting firm with offices in New Jersey, Florida and Pennsylvania.

 Bickley and Torocco conduct environmental surveys for clients to determine the presence or absence of amphibians and reptiles on a property and other factors that may affect housing, utility or other construction projects.

Courtesy of Steve Edmonds | Quillyn Bickley and Mike Torocco exhibit a hellbender salamander found in a creek.
Courtesy of Quillyn Bickley | Mike Torocco and Quillyn Bickley use radio tracking to locate amphibians and reptiles
Winter habitat management will help Blanding’s Turtles in spring
by David Brooks /Nov 16, 2018/Granite Geek/Concord Monitor 

Winter habitat management will help Blanding’s Turtles in spring
by David Brooks | Nov 16, 2018
Blandings Turtle

From NH Fish and Game: Late summer and early fall is the time when eggs laid by New Hampshire turtles in the spring begin to hatch and future generations emerge from their upland nest chambers. With luck and excellent camouflage, these tiny hatchlings will make it to the safety of a pond, stream, or wetland. In an effort to move ahead with conservation actions while turtle populations overwinter, Fish and Game biologists have been working with local, state and federal partners, landowners, and land trusts to identify areas within high-priority turtle populations where nesting habitat can be created to decrease the likelihood of females crossing roads or entering residential developments.

“The location of a suitable nesting area is crucial for successful nesting and hatchling survival,” said New Hampshire Fish and Game Department Wildlife Biologist Josh Megyesy. “For some sites, creating nesting areas requires cutting trees to expose the ground to full sunlight and then bringing in sand, while others just need some vegetation cut back and soils scarified with heavy equipment.”

This kind of habitat management in sensitive turtle areas is done during the winter months when turtles are hibernating in the water and the ground is frozen. Some of this work has already been initiated in key areas in the Granite State, but more will continue this coming winter and beyond. The Fish and Game Department’s Nongame and Endangered Wildlife Program has been monitoring populations of several rare species of turtles throughout New Hampshire, including state-endangered Blanding’s turtles. Through mark-recapture methods and the use of radio telemetry to track individual turtles, biologists have been able to better understand how these turtles use their diverse wetland and upland habitats.

“For two years we followed this one particular female Blanding’s turtle,” explained Megyesy. “The first year we tracked her from wetland to wetland, and eventually after crossing a road she then nested in a residential environment. The second year it was amazing to watch her follow almost the exact path she had taken the previous year, and nest again on the same property. It became clear that good nesting habitat was lacking within the core of their territory and something needed to be done.”

Other females from other populations followed a similar pattern, each time increasing the chances of road mortality. These turtles require sandy, well-drained areas with full sun for nesting and successful incubation. Female turtles dig a nest chamber, deposit eggs, cover the eggs with soil and then depart, leaving the embryos and future young turtles to fend for themselves.

“For rare turtle populations to persist in New Hampshire, it is essential that adult female survival rates are high and that new young individuals are added to the populations,” Megyesy continued. “Turtles have coped with various threats by being able to live for a very long time, with some local species of turtles possibly exceeding 70 years! But low survival of young isn’t the only reason why turtles must live a long time − female turtles of some species may not be capable of reproducing until they are at least 15 years old.”

Many of the monitoring and conservation actions for rare turtles in New Hampshire are made possible by federal programs, such as State Wildlife Grants administered by the U.S. Fish and Wildlife Service and funds from the U.S. Fish and Wildlife Service New England Field Office, along with matching state funding from the NH Conservation License Plate funds and individual donations to the Nongame and Endangered Wildlife Program. Biologists are also working with the US Department of Agriculture’s Natural Resources Conservation Service to protect turtles and their habitats occurring on private working lands in the state.

To learn more about the Department’s involvement in the regional Blanding’s turtle conservation efforts, visit http://www.blandingsturtle.org. Learn more about New Hampshire’s turtles at https://wildlife.state.nh.us/nongame/turtles.html and the New Hampshire Fish and Game Department’s Nongame and Endangered Wildlife Program, supported by federal and state grants and individual donations, at http://www.wildnh.com/nongame.

Friday, 23 November 2018

How female hyaenas came to dominate males



In most animal societies, members of one sex dominate those of the other. Is this, as widely believed, an inevitable consequence of a disparity in strength and ferocity between males and females? Not necessarily. A new study on wild spotted hyaenas shows that in this social carnivore, females dominate males because they can rely on greater social support than males, not because they are stronger or more competitive in any other individual attribute. The main reason for females having, on average, more social support than males is that males are more likely to disperse and that dispersal disrupts social bonds. The study by scientists of the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW, Germany) and the Institut des Sciences de l'Evolution de Montpellier (ISEM, France) was published in the journal Nature Ecology & Evolution.
Spotted hyaena females are often portrayed as archetypes of powerful and ferocious females. They are on average heavier than the males, have highly masculinised outer genitalia (a 'pseudo-penis' and a 'pseudo-scrotum'), and usually occupy the highest position in the society. But according to the new study, it is not their manliness that allows them to dominate males. "When two hyaenas squabble, the one that can rely on greater social support wins, irrespective of sex, body mass or aggressiveness," explains Oliver Hoener, head of the Ngorongoro Hyena Project of the Leibniz-IZW. Differences in social support between two individuals correctly predicted who will be the dominant in almost all encounters and in all contexts—between natives and immigrants, members of the same and different clans, residents and intruders, and individuals of the same and opposite sex. Female dominance thus emerges from females being more likely to receive greater social support than males. "What is so fascinating is that it all works without any direct involvement of other hyaenas," says Colin Vullioud, Hoener's colleague at Leibniz-IZW and first author of the study. "In the end, it's all about assertiveness and how confident a hyaena is of receiving support if needed."
For their study, the scientists analysed the outcome of 4133 agonistic interactions between 748 hyaenas from eight different clans monitored for 21 years in the Ngorongoro Crater in Tanzania. To estimate potential social support, they developed an algorithm that predicted for each clan member, which of two interacting hyaenas it would support; this algorithm was derived from behavioural observations of social support and relatedness estimates based on one of the most comprehensive pedigrees of a free-ranging mammal. "To tease apart the effects of social support and intrinsic attributes such as body mass, one needs to evaluate each effect while controlling for the presence of the other" explains Francois Rousset (ISEM), who has developed statistical methods for such purposes. "When this is done, the effects of sex and body mass appear negligible."


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