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It's Not Easy Being Green: Frogs and Predatory Reaction

November 11, 2015

New research from Trent University finds that tadpoles change responses to predators from exposure as embryos

Frog in wilderness

A new study conducted by Trent researchers and recently released by The Canadian Journal of Zoology proves that the experience of a frog egg when exposed to predators will change how a tadpole reacts to risky situations later in life.

The research, conducted by Environmental and Life Sciences Ph.D. graduate Dr. Amanda Bennett and her supervisor and Canada research chair in integrative wildlife conservation, bioinformatics, and ecological modelling, Dr. Dennis Murray, started by collecting Wood Frog and Northern Leopard Frog eggs from the Peterborough area. The research duo then exposed the tadpoles to either caged dragonfly larvae, which are known to eat both Wood Frog and Northern Leopard Frog tadpoles, or an empty cage.  When dragonfly larvae ate tadpoles, chemical cues were released to tell other tadpoles that a dangerous predator was nearby.

Dr. Bennett found that the embryo in a frog egg can actually detect these cues too, and that dictated the frog's reaction to predators later in its life as a tadpole. While Wood Frog tadpoles increased anti-predatory responses to dragonfly larvae as tadpoles, eggs of Northern Leopard frogs actually showed less of a response to the predatory cue than tadpoles that had never encountered predators at all.

“It’s a very rewarding experience to get your work published,” said Dr. Bennett. “It means that my research is now a part of our collective knowledge, that I've made a contribution to our understanding of ecology. Plus it means I get to talk tadpoles with a whole new audience of readers!”

This research answers an important question about whether early experiences shape an animal’s response to situations later in life. How a tadpole interprets and responds to a predator cue is, after all, a matter of life and death.

To learn more about Prof. Bennett and Prof. Murray’s research, visit: