Glass Frogs Reveal Surprising Survival Mechanisms - via Herp Digest

by John Finn, July 30, 2012 -Ohio.com

WOOSTER, Ohio — On the island of Tobago, scientists from The College of Wooster have identified some surprising survival mechanisms among a species of glass frog (Hyalinobatrachium orientale) — adorable tiny green amphibians whose transparent underside provides a fascinating window to its organs, including a beating heart.

Richard Lehtinen, associate professor of biology at Wooster, and Andrew Georgiadis, a recent Wooster graduate (2011) and now a researcher at the University of Pittsburgh, made noteworthy observations about male frogs protecting their offspring and the unique ability of their tadpoles to escape danger. The findings are published in the current issue of the Phyllomedusa Journal of Herpetology.

It appears as though male frogs are more involved in the early development of their offspring than the females. “What we discovered is that the males stay near their larvae and rub their arms and legs over them or cover clutches (groups) of them entirely on the underside of the plants where they breed (some 12-15 feet above the freshwater streams of the forest),” said Lehtinen. “We don’t know why they do this, but we believe that they may be secreting a protective substance that kills aquatic fungi and other forms of mold that are often fatal to the larvae.”

Lehtinen will return to Tobago this week (with rising senior Jessica Pringle) to test his hypothesis by taking skin swabs of the frogs in the field to see if males do, in fact, secret a substance that inhibits fungal growth. “Most species of frogs don’t exhibit parental care,” he said. “Most lay eggs and then get out of there. This species is different, and we’d like to know more about its behavior.”

While in Tobago, Lehtinen made another interesting discovery when he came across a leaf that had apparently fallen to the ground with the developing embryos were still attached. Out of curiosity, he poked and prodded the clutch with a dissecting instrument when suddenly one of the embryos literally shot out of the egg. He continued prodding and the other tadpoles started launching forward in a manner that Lehtinen described as purposeful.

“I decided to start measuring the distance, and I found that they were traveling some 36 times their body length,” said Lehtinen. “That would be like a 6-foot human jumping 216 feet.”

Lehtinen believes that the action enables the tadpole to escape a potential predator, even though it might encounter greater danger in the water below. “It’s a very effective way to escape a threat,” he said. “We will be watching (the tadpoles) even more closely on our next visit.”