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May the best morph win

October 31, 2014

May the best morph win

Allison Killius pounces on a blue poison dart frog, trapping the nickel-sized amphibian under a clear plastic dome. Jill Del Sol adds a red frog she wrangled nearby to the mini-coliseum

Allison Killius pounces on a blue poison dart frog, trapping the nickel-sized amphibian under a clear plastic dome. Jill Del Sol adds a red frog she wrangled nearby to the mini-coliseum. The frogs square off, chirp aggressively and have a tiny tussle. Killius and del Sol take score like ringside judges. Their experiment may lead to better understanding of one of the most extreme cases of color variation of any species on Earth.

The Strawberry Poison-Dart Frog is aptly named throughout most of its Central American range where it is uniformly bright red. But in Panama’s Bocas Del Toro Archipelago, its scientific name, Oophaga pumilio, might be a better choice. Populations of frogs on different islands sport brightly colored skin, from green to purple to yellow dotted with black.

Aguacate Peninsula is one of only two known locations where different color morphs overlap. This natural experiment allows Killius and Del Sol to ask whether color influences territory defense, mate selection and frog fitness. “We’re trying to see what potential selection pressures could be making them certain colors,” said Killius, a graduate of Tulane University where her advisor was Corinne Roberts-Zawacki, the principal investigator of the project hosted by STRI’s Bocas Del Toro Research Station.

Del Sol, an undergrad at Hendrix College in Arkansas, also takes the temperature of frog mimics made from agar that she places on different perches around the forest. One question is whether height above forest floor, which is advantageous for attracting mates, comes with a cost—overheating or drying out. “This could help us get at whether there’s a higher risk for a certain color morph,” she said.

Allison Killius and Jill Del Sol | Photo by Sean Mattson - STRI

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