Tadpoles break the tension with bubble-sucking - via Herp Digest

Date: February 26, 2020

Source: University of Connecticut

When it comes to the smallest of creatures, the hydrogen bonds that hold water molecules together to form "surface tension" lend enough strength to support their mass: think of insects that skip across the surface of water. But what happens to small creatures that dwell below the surface of the water?

UConn researchers have taken a close look, and in research published recently in The Proceedings of the Royal Society B, have documented how tiny tadpoles are able to access air above the water's surface, breathing without having to break through the surface tension.

Tadpoles often live in water with low oxygen levels where fewer predators lurk, but this also means the tadpoles need a way to get to air to breathe. Tadpoles have gills, but they don't usually provide enough oxygen for them to survive, so most tadpoles also have lungs and breathe air as a back-up. But during the earliest period of their lives, tadpoles are too small to break through the water's surface to breathe. Luckily for the tadpoles, they have a way to work around this problem, says ecology and evolutionary biology professor Kurt Schwenk.

Tadpoles will often charge upward toward the surface of the water, yet due to their small size and the surface tension of the water, they bounce back down. While watching this during an unrelated study on aquatic salamanders feeding on tadpoles, Schwenk noticed a bubble left behind after one tadpole's visit to the underside of the water's surface.

"Many researchers have observed tadpoles breathing at the surface before, but unless you look very closely and slow the action down, you can't see what is actually happening," says Schwenk.

Using high-speed macro-videography, Schwenk and graduate researcher Jackson Phillips captured hundreds of breathing events on film shooting at the super slow motion rate of 500-1000 frames per second. The tadpoles were seen to use a never-before-described breathing mechanism they call "bubble-sucking," a novel breathing mechanism for vertebrates captured with novel technology.

"This research would have been much more difficult to do before high-speed video cameras were developed, and that is probably why the behavior has not been described before," says Schwenk.

The researchers studied tadpoles from five species of frogs -- four of which can be found in Connecticut. What they found was that tadpoles of all species were able to inflate their lungs within a few days of hatching, despite being too small to access air.

Instead of breaching the water's surface, the tadpoles were seen to bubble-suck. To bubble-suck, the tadpoles first attach their mouths to the undersurface of the water. They then open their jaws wide and draw a bubble of air into the mouth. What happens next was visible through the skin of some of the tadpoles. The tadpoles empty their lungs into their mouths, where the air mixes with the fresh air of the newly sucked bubble. After the mouth closes, the air bubble is forced down into the lungs, but since the bubble is larger than their lung capacity, a portion of the air remains in the mouth, which is then expelled as a small bubble that floats to the surface. The entire process takes about three tenths of a second.

Bubble-sucking appears to be an adaptation the tadpoles use while they are still small. When they grow large enough and charge the water's surface, they are able to break the surface tension and "breach-breathe." The researchers observed bubble-sucking in other species, as well -- larval salamanders and even snails. They note that it is likely limited to organisms that can create the suction necessary, therefore arthropods, like insects, cannot bubble-suck.

"As a result of an accidental observation, my research has taken a turn -- I never expected to work on these organisms," Schwenk says. "Before, I thought that tadpoles were uninteresting. But now I find them deeply fascinating.”

Schwenk says this accidental discovery conveys an important point about research in general.

"These frog species are incredibly well-studied and very common," he says. "Yet, one can learn new things even about the most common animals, which is a good lesson for students, because when getting into research, one can be left with the sense that it has all been done. The fact is, it hasn't been -- we just have to be observant and keep asking questions."

Story Source:

Materials provided by University of Connecticut. Note: Content may be edited for style and length.

Journal Reference:

1. Kurt Schwenk, Jackson R. Phillips. Circumventing surface tension: tadpoles suck bubbles to breathe air. Proceedings of the Royal Society B: Biological Sciences, 2020; 287 (1921): 20192704 DOI: 10.1098/rspb.2019.2704

Life in the fast flow: Tadpoles of new species rely on 'suction cups' to keep up

The frogs living in the rainforest of Sumatra also represent a new genus

Date:  March 12, 2018

Source:  Pensoft Publishers

Summary:

The young of two new species and a genus of frog found to inhabit Sumatra's rainforests have developed a unique ability to latch onto rocks in the fast-flowing rivers, using bellies crafted by evolution into 'suction cups'. Herpetologists use their remarkable discovery to highlight the unique biodiversity of the island, which is under imminent threat due to rampant habitat modification and deforestation.

Continued  

Japanese tadpoles relax in hot springs

One type of juvenile frog can survive in hot onsen water

Date: July 26, 2016

Source: Hiroshima University

Japanese tadpoles can live and grow in natural hots springs, or onsen, with water temperatures as high as 46.1oC (115oF). Living in onsen may benefit the tadpoles' immune systems, speed their growth, and allow the tadpoles to survive on small volcanic islands where there are few other natural sources of fresh water.

Tadpoles of the same frogs were previously found living in hot springs in Taiwan and other Japanese islands, but this field study found tadpoles living in the hottest ever recorded temperatures for any amphibian tadpole. The research was completed by scientists at Hiroshima University with collaborators at SOKENDAI, The Graduate University for Advanced Studies.

Japan's onsen attract locals and visitors to relax in the hot water year round in bathhouses built to contain the water in public tubs. The onsen where researchers found the tadpoles were shallow mud pools in the forests of the small, subtropical island of Kuchinoshima, approximately 310 kilometers (192 miles) due South of Nagasaki in the East China Sea.

"Scientists have studied the distributions of organisms and their environmental adaptations since the era of Darwin and Wallace. Our report is one of the best examples of a direct connection between an animal's physical ability to tolerate diverse environmental conditions and the animal's success at colonizing diverse geographic areas," said Takeshi Igawa, Ph.D., Assistant Professor at Hiroshima University and last author of the current study.

The tadpoles are Japanese stream tree frogs, known to scientists as Buergeria japonica. Japanese stream tree frogs are the only native species of amphibian on the Tokara Archipelago, a chain of volcanic islands off the Southwest coast of Japan. The adaptation to survive in water too warm for other amphibians may have allowed these frogs to exploit new habitats and avoid competition from other species. Future research will focus on the details of the tadpoles' behavior in their habitat.

Read on … 

Tadpoles hatch in seconds to escape predator

Date: June 16, 2016

Source: Smithsonian Tropical Research Institute

Although red-eyed tree frog embryos appear helpless within their jelly-coated eggs, they can hatch up to two days ahead of schedule, reacting within seconds to attacks by egg thieves. At the Smithsonian Tropical Research Institute (STRI) in Panama, scientists used high-speed video to uncover their rapid-hatching secret.

"Most people think of embryos as fairly passive," said Karen Warkentin, STRI research associate and professor at Boston University. "But evidence keeps accumulating that embryos of many species are actively engaged with their world, not only receiving information but also using it to do things that help them survive."

This is particularly true of the embryos of red-eyed tree frogs (Agalychnis callidryas). Native to Neotropical rainforests, adult frogs live in trees and lay clusters of 40 or so eggs on leaves, branches or other structures that overhang ponds or streams. Left undisturbed, tadpoles hatch after a week's development inside the gooey egg mass and drop into the water below. But the eggs are often attacked by hungry snakes or wasps and are also vulnerable to sudden environmental events like floods or heavy downpours. Developing embryos are able to assess the level of threat and have evolved a quick-release mechanism to escape the egg prematurely.

Continued … 

Tails full of metal: Tadpoles picking up toxics from Queensland coal mines – via Herp Digest

Queensland coal mine waste affects tadpole behavior and survival and leaves them full of toxic metals 

February 20, 2016, By Brian Bienkowski , Environmental Health News

Tadpoles exposed to coal mine wastewater in Queensland, Australia, had delayed development, hyperactivity and ended up full of toxic metals in their tails and livers, according to a new study.

The study, published in the Aquatic Toxicology journal last month, is concerning as Queensland is a major coal mining region. It comes amid increasing concern about amphibian population declines throughout the world and adds to evidence that pollution may play a key role.

“Amphibians are currently some of the most threatened organisms on the planet,” said Central Queensland University researchers and co-authors Chantal Lanctôt and Steven Melvin in a joint emailed response.

Camouflaged in earthy colors, striped marsh frogs live along the western half of Australia. Their call is an abrupt pop, like a racquetball return. Frogs and other aquatic animals hang out in wetlands near the holding dams where, during extreme rain or flooding, discharges of the mine waste can escape into the environment.

For four weeks the researchers exposed striped marsh frogs to 25, 50 or 100 percent coal mine wastewater from two dams in Central Queensland, Australia—an area known for heavy coal mining. All exposed tadpoles had hyperactivity, and elevated levels of selenium, cobalt and arsenic in tails and liver tissue. Those exposed to 100 percent wastewater were smaller as well.

None of the unexposed tadpoles died. But in the groups exposed to 50 percent and 100 percent wastewater, 40 percent and 55 percent of the tadpoles died, respectively.

Coal mining wastewater contains metals, hydrocarbons and salts that can impact the amphibians’ oxidative stress and mess with their hormones, Lanctôt and Melvin said. “These can, in turn, result in delayed development, altered swimming behavior, and even reduced survival.”

Striped marsh frog populations appear to be stable. But the findings don’t bode well for amphibians.

Two main things are influenced by altered swimming and activity—“foraging and predator avoidance,” said Christopher Salice, an assistant professor and researcher at Towson University who studies environmental impacts on amphibians.

“Acquiring resources and preventing them from being a resource,” added Salice, who was not involved in the study.

The study had some limits—for example, they only used one mass of eggs, which limits the genetic variability. The ones used “could have been more sensitive or more resistant” to pollutants, Salice said.

But there is a complex interplay of factors affecting developing baby frogs, including species competition, habitat loss and climate change. The recent striped marsh frog findings add to a growing body of science that suggests coal waste might tip the balance, leading to declines in certain areas.

For instance, researchers reported in 2014 that Blacksmith tree frogs from coal mining areas in Brazil had elevated levels of sulfur, chlorine, iron, zinc and bromine, and their antioxidant systems were sensitive to the pollution. 

And Southern leopard frogs and Southern toads that emerged from areas contaminated with coal waste had concentrations of arsenic, selenium and strontium up to 35 times higher than those from unpolluted wetlands, according to a 2005 University of Georgia study.

The current research carries extra weight because of where it was done—Queensland, which sits on the northeast coast of Australia and is a major coal mining region. The Australian government estimates there are two deposits of coal in the area that are more than five billion tons, five deposits between three and five billion tons and dozens more smaller deposits dotting the region.

The Bowen Basin in central Queensland has more than 50 active mines in a 29,000 square mile area, according to the Queensland Government’s Department of Natural Resources and Mines.

Queensland has been under fire for its widespread coal mines and associated pollution. According to Australia’s National Pollutant Inventory, central Queensland coal mines are nine of the top 10 emitters in the region for PM10, toxic air particulates greater than 10 micrometers or less in diameter. Coal mines in Australia account for almost half of such emissions, and PM10 emissions have doubled in the past five years, according to Environmental Justice Australia.

A survey released in December by 350.org of 1,500 people in Australia found 68 percent of respondents agreed Australia "needs to restrict coal mining because of the impact that it is having on our natural environment and biodiversity." 

The Minerals Council of Australia, which oversees the country’s coal mines, did not respond to numerous requests for comment.

Lanctôt and Melvin said “under normal circumstances, wastewater releases will be carefully controlled and limited to periods of high rainfall, as a means of reducing risks to wildlife” but added that accidental releases can happen.

And the pollution can stay with the creatures a lifetime, Salice said.

“Even if the initial effects of pollution don’t last [in tadpoles], it still might be a signature of something else,” he said. “Once they turn into terrestrial frogs everything that has happened to them is carried with them.”

Newly identified tadpole disease found across the globe

Highly infectious tadpole disease found in diverse range of frog populations across the world

Date: August 10, 2015

Source: University of Exeter

Summary: Scientists have found that a newly identified and highly infectious tadpole disease is found in a diverse range of frog populations across the world. The discovery sheds new light on some of the threats facing fragile frog populations, which are in decline worldwide.

The study, published in the Proceedings of the National Academy of Sciences journal, led by the University of Exeter and the Natural History Museum, describes the molecular methods used to test frog tadpoles for a newly identified infectious agent.

Tadpoles from six countries across three continents were tested for 'protists' -- single celled microbes with complex cells which store their DNA in a nucleus, like human cells. The previously unidentified parasite was present in tadpole livers in both tropical and temperate sites, and across all continents tested. The infectious agent was identified as a distant relative of Perkinsea sp., a marine parasites found in animals and algae.

Continued ...

Maternally derived chemical defences are an effective deterrent against some predators of poison frog tadpoles (Oophaga pumilio) – via Herp Digest

Biology Letters, 5/21/14

1. Jennifer L. Stynoski1⇑,
2. Georgia Shelton2 and
3. Peter Stynoski3

- Author Affiliations

1. ¹Organization for Tropical Studies, Apartado Postal 676-2050, San Pedro, Costa Rica 
2. ²Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA 
3. ³Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL 61801, USA 
4. e-mail: stynoski@gmail.com

Abstract

Parents defend their young in many ways, including provisioning chemical defences. Recent work in a poison frog system offers the first example of an animal that provisions its young with alkaloids after hatching or birth rather than before. But it is not yet known whether maternally derived alkaloids are an effective defence against offspring predators. We identified the predators of Oophaga pumilio tadpoles and conducted laboratory and field choice tests to determine whether predators are deterred by alkaloids in tadpoles. We found that snakes, spiders and beetle larvae are common predators of O. pumilio tadpoles. Snakes were not deterred by alkaloids in tadpoles. However, spiders were less likely to consume mother-fed O. pumilio tadpoles than either alkaloid-free tadpoles of the red-eyed treefrog, Agalychnis callidryas, or alkaloid-free O. pumilio tadpoles that had been hand-fed with A. callidryas eggs. Thus, maternally derived alkaloids reduce the risk of predation for tadpoles, but only against some predators.

Tadpoles Turn to Cannibalism Only When Desperate

By Laura Poppick, Staff Writer | February 20, 2014 05:49pm ET

Though seemingly docile creatures, tadpoles can get snippy when hungry, and sometimes end up eating each other when the stakes are high. Now, new research suggests that the tiny creatures are not ruthless cannibals, but rather only eat their pond-mates when resources are scarce. Otherwise, they avoid this actually nutritious option.

Many species of frogs, salamanders and other amphibians demonstrate some degree of cannibalism, particularly when resources are scarce. Still, whether the animals prefer this dietary option or rely on it only as a last resort remains unclear in some cases.

Researchers based at the University of Saskatchewan in Canada wondered whether cannibalism was the most nutritious dietary option for tadpoles — common throughout northern North America. This would make sense because, theoretically, the meat of one's own species should contain vitamins and nutrients in quantities well suited for an individual's physiology.

Continued

Poison Frogs Make Their Babies Toxic, Too – via Herp Digest

Posted by Guest Blogger in Weird & Wild on November 21, 2013

By Karl Gruber

Strawberry poison frogs (Oophaga pumilio) of Costa Rica give their newborn tadpoles a built-in weapon against predators: alkaloids.

Various animals and plants use alkaloids—naturally occurring, bitter-tasting chemical compounds—as a first line of defense.

For instance, adult strawberry poison frogs get the chemicals from their diets of ants and mites, “which essentially makes the frogs unpalatable to many potential predators,” said Ralph Saporito of John Carroll University in Ohio and leader of a new study on the species. (See more pictures of rain forest animals.)

But “prior to this study, most of what we knew about alkaloids in these frogs came from adults. So, we decided to fill this void by looking at alkaloids in all life stages of the strawberry poison frog,” Saporito said.

The team already knew that strawberry poison frog mothers feed their babies unfertilized eggs. But their new research revealed the eggs are also spiked with alkaloids—the first time an animal has been found to pass on such chemical defenses to its offspring.

Bitter Beginnings 

For their study, the researchers measured alkaloid content in strawberry poison frogs during different stages of development. (See more pictures of poison dart frogs.)

In one group, tadpoles were reared and fed by their mothers, and a second group was reared by the researchers and fed with eggs from another species of frog not known to harbor alkaloids.

As the tadpoles from both groups developed, the team analyzed their alkaloid contents. The results were clear-cut: Tadpoles reared by mom contained alkaloids in most stages, whereas tadpoles from the second group showed no sign of these chemicals, according to the study, published November 12 in the journal Ecology.

Ant Attacks

Researchers also tested whether the presence of these chemicals helped the tadpole defend itself.

The team set up an experiment with bullet ants, a predatory ant species found in the same habitat as the tadpoles. (See your frog pictures.)

Bullet ants were given the choice of attacking two groups of tadpoles: one consisting of strawberry poison frogs and another from a frog species without alkaloids. The bullet ants were nine times more likely to attack the non-toxic species—showing that the alkaloids protected the tadpoles.

Still, some key questions remain.

“At this point, we do not know how females are able to provision their eggs with alkaloids, nor how tadpoles store these alkaloids in their bodies,” Saporito noted.

He also hopes to explore whether other frog species supply their babies with alkaloids, beginning with other members of the egg-eating genus Oophaga.

Cannibal Tadpoles Could Reveal Gut Secrets

by LiveScience Staff 

Date: 09 May 2013 Time: 05:12 PM ET 

They may look fairly innocuous, perhaps just a little bloated, but Budgett's frogs are aggressive creatures with cannibalistic tendencies from the time they're just tadpoles. 

Tadpoles are frogs in their young larval stages, and in most species, they're stuck with simple diets because their digestive tracts cannot process insects or proteins until they mature. 

Budgett's frogs, meanwhile, have short complex guts that can break down protein from a remarkably early age. They swallow other animals whole, sometimes even eating their own siblings. 

Researchers at North Carolina State University recently studied how this meat-eating ability evolved. The team looked at the algae-eating tadpoles of African clawed frogs (Xenopus laevis), which, 110 million years ago, had a common ancestor with Budgett's frogs. 

By exposing embryos of African clawed frogs to certain gene-deactivating molecules, the researchers created tadpoles with guts that looked more like those of Budgett's frogs, fit to digest protein. Turning the technique on the embryos of a South American species of Budgett's frogs, Lepidobatrachus laevis, the researchers said they created tadpoles with stomachs more suited for a vegetarian diet. 

Continued: http://www.livescience.com/29490-cannibal-tadpoles-budgetts-frogs.html

Stressed-Out Tadpoles Grow Larger Tails to Escape Predators

Mar. 5, 2013 — When people or animals are thrust into threatening situations such as combat or attack by a predator, stress hormones are released to help prepare the organism to defend itself or to rapidly escape from danger -- the so-called fight-or-flight response.

Now University of Michigan researchers have demonstrated for the first time that stress hormones are also responsible for altering the body shape of developing animals, in this case the humble tadpole, so they are better equipped to survive predator attacks.

Through a series of experiments conducted at field sites and in the laboratory, U-M researchers demonstrated that prolonged exposure to a stress hormone enabled tadpoles to increase the size of their tails, which improved their ability to avoid lethal predator attacks.

"This is the first clear demonstration that a stress hormone produced by the animal can actually cause a morphological change, a change in body shape, that improves their survival in the presence of lethal predators. It's a survival response," said Robert Denver, a professor of molecular, cellular and developmental biology and of ecology and evolutionary biology.

Continued:  http://www.sciencedaily.com/releases/2013/03/130305200204.htm

Australia's native frogs beat invasive toads

By Ella Davies, Reporter, BBC Nature

The tadpoles of Australia's native frogs can outcompete invasive toads, scientists say.

The toads are considered a threat to Australian wildlife, leading researchers to investigate methods to control their population.

A study into competition between wild amphibian young revealed that the presence of green tree frogs reduced cane toad survival.

Experts now suggest reintroducing the familiar frogs to suburban areas.

The results are published in the journal Austral Ecology.

Cane toads are native to South America but were introduced to Australia in 1935 to control sugar cane pests.

Non-native nightmares

They are now one of the International Union for the Conservation of Nature's (IUCN) top 100 invasive species and considered feral pests across north-eastern Australia.

Their large clutches of eggs, ability to migrate 40km per year and poisonous defence are outlined as some of the primary reasons for their population explosion.

However, research by Professor Richard Shine and colleagues from the University of Sydney has highlighted the weaknesses of the animals in early stages of development.

Continued:  http://www.bbc.co.uk/nature/21629255

Whoa! Mutant Tadpoles Sprout Eyeballs on Their Tails

Charles Choi, LiveScience Contributor

Date: 27 February 2013 

Eyes hooked up to the tail can help blinded tadpoles see, researchers say.

These findings could help guide therapies involving natural or artificial implants, scientists added.

CREDIT: Douglas Blackiston 

A major roadblock when it comes to treating blindness and other sensory disorders is how much remains unknown about the nervous system and its ability to adapt to change. To learn more about the relationship between the body and the brain, researchers wanted to see how capable the brain was of interpreting sensory data from abnormal "ectopic" locations from which it normally does not receive  signals.

Researchers grafted the tails of blind tadpoles of the African frog with eye tissue, which gave the tadpoles sight.

More:  http://www.livescience.com/27518-tadpoles-sprout-eyeballs-on-tails.html

Deadly ranavirus hits box turtles, tadpoles in Montgomery County, Maryland (via Herp Digest)

By Katherine Shaver, 2/12/12, Washington Post

Maryland biologists study­ing box turtles rescued from the bulldozers on the Intercounty Connector construction site have made a grisly find: An alarming number of the tiny turtles later died, and biologists say their demise appears to be unrelated to the highway.

Worse yet, the cause of their death - an animal disease called ranavirus taking root across the United States - also is believed to have killed nearly every tadpole and young salamander in the study area in Montgomery County's North Branch Stream Valley Park since spring 2010.

The discoveries have alarmed state wildlife officials and biologists, who worry about how far ranavirus has spread, how widely it has affected the ecosystem, and how it apparently jumped between turtles - which are reptiles - and amphibians. If the virus spreads or goes unchecked for long, wildlife experts say, it could devastate some local populations of box turtles, frogs and salamanders. That loss, biologists say, would ripple along the food chain to other animals.

In all, 31 adult turtles were found dead near the ICC construction site between 2008 and 2011. Three had been hit by cars or construction equipment. The rest, apparently dead from illness, amounted to about one-quarter of the turtles monitored by Towson University researchers via radio transponders glued atop the tiny shells. Twenty-six of the deaths resulted from suspected or confirmed cases of ranavirus, which left some turtles gasping for breath as they gradually suffocated in their own mucus, researchers said.

"Finding even one dead turtle is unusual," said Richard Seigel, the Towson biology professor who led the ICC study. "Finding over 27 dead turtles in a two-to-three-year period was bizarre."
Box turtles can live 50 years or more in the wild. The ability of their hard shells to withstand predators usually affords them a 98 percent survival rate from one year to the next before they die of old age, usually alone and undetected beneath brush, Seigel said.

"This is a major concern to see these emerging pathogens," he said.

Ecological implications

Experts on animal diseases say ranavirus, whose origin is unknown, has never been detected in humans, livestock or common household pets because it cannot survive in mammals' relatively warm bodies.

Its long-term effects on local turtles, frogs and salamanders are not yet known and will depend on how long the virus lingers, how far it spreads and how quickly surviving animals build up immunity, biologists said. But several wildlife experts said the disease's short-term effects are probably affecting the food chain in the ICC study area between Muncaster Mill Road and Emory Lane, just west of Georgia Avenue in northern Silver Spring.

The birds, snakes and raccoons that dine on salamanders and tadpoles have less food at their disposal, experts say.

Meanwhile, the loss of hundreds, perhaps thousands, of tadpoles and salamander larvae wiped out in two consecutive breeding seasons has probably left far more of the insects that young salamanders and frogs eat.

"What is the ecological significance of a virus that can kill every one of an animal's offspring? The implications of that baffle me," said David Green, a veterinary pathologist at the U.S. Geological Survey's National Wildlife Health Center in Madison, Wis.

Wildlife experts say they're also concerned that the sudden appearance of ranavirus, a disease that some believe has been lurking in the United States for a century, might signal that local ponds and wetlands are becoming more susceptible to disease under the stresses of climate change, pollution and development.

"Amphibians are very good indicators of the health of our ecosystem," said Scott Smith, a wildlife ecologist for Maryland's Department of Natural Resources. "When we see things happen to them, it means our environment is unhealthy."

Green, the veterinary pathologist, said ranavirus causes measles-like or severe herpes-like symptoms. Often, turtles discharge mucus from their eyes and noses. He said the virus damages their skin, palate, esophagus, stomach, liver, spleen and blood vessels. ICC researchers said they found some turtles dead within four days of their first symptoms.

The ICC tadpoles and young salamanders became sluggish and were seen swimming off-kilter before bleeding into the skin of their bellies, thighs and feet.

"It's a really, really, really horrible disease," Seigel said.

Confirmed cases
Ranavirus, first identified in the United States in 1968, has been suspected or confirmed in turtle and amphibian deaths in 29 states 71 times since 1997, according to the USGS, which tracks animal diseases at its National Wildlife Health Center.

Maryland's first confirmed case came in 2005, when it and the Chytrid fungus killed more than 2,000 young wood frogs and spotted salamanders near Montgomery's portion of the C&O Canal, Smith said. Since 2000, ranavirus has been confirmed in Anne Arundel, Prince George's and Baltimore counties.
Virginia's only confirmed outbreak hit in 2003, when ranavirus killed 20 Southern leopard frogs in the Virginia Beach area, according to the USGS. No cases have been reported in the District.

Ken Ferebee, a National Park Service wildlife specialist in the city's Rock Creek Park, said he's seen no signs of the disease in the box turtles and pond life that he monitors about 12 miles south of the Montgomery outbreak area. He said he hopes box turtles' slow pace and propensity to stick close to home will keep the disease contained near the ICC.

"I don't think it's something we can stop," Ferebee said. "If we find it in the park, it will probably be way too late."

'Devastating impacts'
The Towson University findings, which are just beginning to circulate among biologists in the Northeast, stemmed from a $300,000 state-funded study of how to best save the turtles that, unlike deer and foxes, needed help to escape 18 miles of woods and wetlands ahead of the bulldozers. A team of Towson students attached radio transmitters to 123 of the more than 900 turtles rescued, allowing them to track the animals' every move.

The idea was to study whether the turtles fared better by being relocated about six miles away or to an adjacent area separated from the construction site by a fence. The study was considered potentially important to highway agencies and developers across the country, who are under pressure to reduce the environmental effects of road and building construction.

Rob Shreeve, the Maryland State Highway Administration's ICC environmental manager, said the study was helpful in concluding that the turtles' survival rates - even with ranavirus - were about the same even when they were moved to different locations with similar living conditions.

Seigel, the Towson researcher, said he has no data to show that turtles that were moved from the ICC's path started the outbreak or were more susceptible to illness. He said his team checked the turtles' mouths, eyes, noses and weight to make sure they were healthy before moving them.

The ranavirus death rate in turtles that were moved from the ICC site was roughly the same as the mortality rate in a control group of turtles that already lived in the area and never relocated, Seigel said. The apparently fast-acting virus didn't begin affecting any of the turtles until about 18 months after the ICC animals were moved, making it less likely that the relocation was at the source, he said.

Smith of the Natural Resources Department said state wildlife officials are so concerned that they have applied for research funding from the Association of Reptile and Amphibian Veterinarians. State budgets are too strapped to fund the necessary research, he said.

Scott Farnsworth, Seigel's graduate research assistant on the ICC study, said he's less worried about the local amphibian population's ability to recover because frogs and salamanders begin breeding when they're a few years old and each lay hundreds of eggs. If the virus dies off soon, he said, the overall population could bounce back relatively quickly.

But the population of tiny box turtles, most so small that they fit in the palm of a hand, isn't as resilient, he said. Box turtles don't breed until they reach 10 to 15 years old and females typically lay only eight to 10 eggs per year, he said. That means it wouldn't take as long for a virus killing off reproductive adults to send the species into a steep decline.

"If it's chronic, it could have devastating impacts on the turtle population," Farnsworth said. "It could take decades for them to recover from it, if they do recover."

First record of tadpoles hatching and feeding on tree bark (Via HerpDigest)

First record of tadpoles hatching and feeding on tree bark 3/29/11 Wildlife Extra.com -Unusual frog behaviour discovered in India's Western Ghats

Written by Ben Tapley

April 2011. In July of last year we were working on an amphibian ecology study at the Agumbe Rainforest Research Station (ARRS) in Karnataka, India (http://www.agumberainforest.com/)

We found several egg clutches and tadpoles of the brown leaping frog (Indirana semipalmata). The 11 species of the genus Indirana are all endemic to the Western Ghats of India. It has been documented by several authors that the tadpoles of Indirana frogs breed on rock faces surrounding splashing water and that tadpoles are semi terrestrial. We were surprised one night when we heard a frog vocalisation we had not heard before.

After a short search we located a single Indirana semipalmata sitting by a clutch of eggs laid on the bark of a tree. These eggs later hatched and we found tadpoles from a previous clutch feeding on the bark of the same tree. In total we found three Indirana semipalmata egg clutches all of which were at least 3m away from any standing water. To our knowledge this is the first recorded case of tadpoles feeding on a bark substrate and subsequently metamorphosing on the bark of a tree. This may be a localised phenomenon as Agumbe has the second highest annual rainfall in India and therefore these semi terrestrial tadpoles do not desiccate. Living in Agumbe during the monsoon was literally like living in a cloud.

This work was funded by the Gerry Martin project (http://www.gerrymartin.in/).

Tadpoles Croak Like Adults

MSNBC (New York, New York) 12/14/10

When frogs are just teensy tadpoles, they're already croaking like adults, researchers have observed for the first time.

They not only croak when attacked, but when they cannibalistically attack members of their own species as well, scientists find.

Tadpoles, or pollywogs, are frogs in their young larval stages. They dwell entirely in the water and look somewhat like fish.

Frogs are well known for croaking, with each species having its own unique call. Now researchers are discovering that tadpoles can speak up as well (albeit much more softly).

Evolutionary biologist Miguel Vences at the Technical University of Braunschweig in Germany investigated the tadpoles of a frog species from western Madagascar, Gephyromantis azzurrae, which prefers living in cool, shallow, fast streams. These pollywogs are carnivores, preying not just on insect larvae and shrimp, but also on tadpoles of the same and other species.

Vences and his colleagues found these predator tadpoles called out while attacking prey by making rapid clicks, perhaps by snapping the hard sheaths over their jaws together. They called out significantly more often when they were hungry or when attacking tadpoles of the same species.

Most animal sounds, such as in birds, frogs and crickets, "are produced in the context of reproduction and therefore by adult animals, usually males," Vences said. "It is very rare that young animals and especially larvae are producing sounds, except maybe in birds, where of course the young are known to chirp as loud as the adults."

Traveling tadpoles

The researchers actually initially discovered these tadpoles could make clicks in 1994.

"Almost 20 years ago, [taxonomist] Frank Glaw and I found them for the first time and suddenly realized that faint sounds were coming out of the bucket were we were keeping them," Vences told LiveScience.

Vences and Glaw, of the Bavarian State Collection of Zoology in Germany, found the tadpoles in the Isalo region and were struck by their unusual color and massive jaw sheaths. The pair decided to bring them back to Madagascar's capital Antananarivo where they could observe them.

"At the time, we had no money to rent [our] own car and had to travel with public transport, which in Madagascar is a real challenge, and in that year, there was a really bad hurricane striking the island," Vences said.

"So, there we were, traveling for more than three days in extremely overcrowded minibuses and cars, over roads partly destroyed by landslides, and all the time with a large bucket full of water and with some of these tadpoles on our knees," he added.

On more than one occasion, the pair contemplated throwing the tadpoles into a ditch to make their ride more comfortable - but they didn't.

"Then we had to wait over 15 years until we found some students interested in tadpoles and who would invest the effort to sit for many, many hours in front of a little aquarium with a video camera and special microphones to record these sounds and monitor the tadpole behavior," Vences said. "A very painstaking job, and [biologist] Erik Reeve really was exceptional in getting this system to work. Consider that these tadpoles are tiny and the sounds very faint - without a special microphone and amplifier, you can just barely hear them if your ear is very close to the aquarium."

What are the tadpoles saying?

The experiments showed that smaller tadpoles made fewer calls and were less likely than the big guys to use a combination of different call types, suggesting the sound of the clicks might yield clues about the size of the tadpoles making them. They might be used to chase away other members of their own species, the scientists speculated. Their findings will be detailed in an upcoming issue of the journal Naturwissenschaften. [Read about tadpoles with three eyes.]

Tadpoles of another frog species were also revealed earlier this year as capable of calling out - the South American horned frog Ceratophrys ornata. However, they mostly sounded off when attacked, emitting brief, clear metallic notes by pushing air out their lungs when tadpoles of their own species attacked them. These distress calls might prevent the tadpoles from cannibalizing each other.

"I find communication a marvelous thing, in nature, modern society, art expressions, technological development, and its evolution towards complex adaptive systems," said herpetologist Guillermo Natale at the National University of La Plata at Buenos Aires. He and his colleagues detailed their findings regarding South American horned frog tadpoles online Feb. 26 in the journal Acta Zoologica.

When it comes to future research into tadpole calls, "we need additional experiments showing that the tadpoles actually hear these sounds and alter their behavior accordingly - that is, they escape when they hear the sounds even if there is no one attacking them, or they become themselves more aggressive when hearing such sounds around them," Vences said.

Vences suggested that additional research on tadpoles could help better understand amphibian ecology and evolution.

"In Madagascar, we are realizing only now how diverse in morphology and feeding modes these larvae are, with extremely different oral structures and some of them now apparently even with, albeit simple, systems of acoustic communication," Vences said. The true depth of specialization and competition in frogs, which is "important to explain their extraordinary diversity in the tropics, may well take place at this level rather [than] at the level of adults."

From: Herp Digest,
Volume # 10 Issue # 55