STAR-TRIBUNE (Casper, Wyoming) 02 July 08 Scientists track toads with tiny transceivers
Pocatello, Idaho (AP): A researcher who attaches tiny transceivers to toads to find out why a fungus is killing them in some states but not others says elevation could be the key factor.
Peter Murphy, a visiting assistant professor of biology at Idaho State University, has been putting the miniature transceivers on toads around Grand Teton National Park in Wyoming and the Bears Ears Mountains in Colorado.
"It's easy to capture them -- these things are slow," Murphy told the Idaho State Journal. "Every day we try to locate an individual toad, and we test them for disease by essentially taking skin flaps. We swipe the skin of their belly with a sterile Q-tip every two weeks."
Murphy is trying to find out why the Bofu boreas -- more commonly called the Western toad -- is able to better resist the chytrid fungus in parts of Idaho, Wyoming and Montana than in Colorado.
About half of the Western toads in Wyoming carry the bacteria that can lead to the deadly fungal skin disease. Researchers say the ailment has led to massive die-offs of Western toads in Colorado and New Mexico.
Researchers also say chytrid fungus is responsible for declines in amphibian species throughout the rest of the world.
In the study, Murphy and Sophie St. Hilaire, an assistant researcher in biology, have been testing environmental and behavioral factors.
Murphy suspects that toads at lower elevations are exposed to higher temperatures, making it too warm for the fungus.
He said the elevation for the toad's habitat in Colorado is anywhere between 1,000 to 2,000 feet higher than Wyoming, and that toads could need lower elevations to better resist the bacteria.
Toads at higher elevations, the researchers said, have a "smaller window" to achieve high body temperatures to reduce the growth of the fungus, which doesn't do well in dryer and hotter environments.
Murphy said the research will help determine if the ability of Western toads in Wyoming to resist the disease is because of their native habitat, or some other factor within the population itself.
Another part of the study involves lab work at Idaho State, where St. Hilaire has disease-free toads in 50 different tanks with varying temperature and humidity levels. She then exposes each toad to 1 milliliter of the bacteria for chytrid fungus.
"What we try do is mimic some of the environmental conditions," St. Hilaire said. "We tested their susceptibility to pathogen levels, and both (Western toads from Wyoming and Colorado) are susceptible under the lab conditions. This helps determine what environmental parameters are necessary for the disease to come out."
The research is being paid for with a $75,000 grant from the U.S. Geological Survey and the National Park Service.
WY Press: Scientists track toads with tiny transceivers