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.

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