The Pet Tree House - Where Pets Are Family Too : These Frogs Might Be Evolving Right In Front Of Us The Pet Tree House - Where Pets Are Family Too : These Frogs Might Be Evolving Right In Front Of Us

Sunday, October 12, 2014

These Frogs Might Be Evolving Right In Front Of Us

Scientists believe that the mimic frog, which is dividing into two increasingly distinct populations in Peru, may be on its way to speciation -- a division into multiple species.

Ranitomeya imitator is a poison dart frog that mimics one of two other poison species. One has yellow and black stripes on its body and blue spotted legs, and the other has an orange head that fades to blue legs, with black spots all over.

In an August Nature Communications study, researchers reported that these frogs might be the first vertebrates ever observed splitting into two species because of distinct mimicry. Only one other animal of any kind (a butterfly) has been observed doing the same, National Geographic reported.

The "striped" mimic frog is adapting to look like the species variabilis. (Evan Twomey)

Experiments confirmed that the frog populations are already wary of interbreeding with one another. This preference could lead to speciation within the next several thousand years, study co-author Kyle Summers, an evolutionary biologist at East Carolina University in Greenville, told National Geographic. The preference "suggests there has been some sort of negative consequence of breeding with the wrong morph," he said.

These distinct colorings serve as giant "keep away" signs for predators, especially when they're used by multiple species of poison frog. It's possible that the mixing of two types leads to offspring that look like neither, making predators more likely to take a bite.

It's not for certain that the color mimicry itself is what's driving the schism. Scientists would have to make sure that other differences -- like calls -- didn't exist to help pull them apart.

The "veradero" mimic frogs are taking a different approach. (Evan Twomey)

"The mate choice trials we conducted were done using actual frogs, so it is possible that the mating preference was based on some other, less obvious cue," said Evan Twomey, lead author of the study and a PhD student in Summers's lab. "It would be very interesting to follow up this study with an experiment to determine if color alone is responsible for the mating preferences we observed."

But if these frogs continue to show such a strong preference for one half of their species over the other, then more and more differences will arise between the populations as generations pass. And eventually, they may not be interested in mingling at all.

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