The Effect of UV Radiation on Aggression Levels in Oophaga pumilio, the Strawberry Poison-Dart Frog
Authors:Nicholas Novella, Craig Sutter
Mentor:Lee Kats, Associate Dean For Research, Pepperdine
UV radiation from the sun has been shown to have profound and diverse effects on amphibians. The strawberry poison dart frog, Oophaga pumilio, is behaviorally sensitive to UV radiation and has been shown to avoid even low levels of UV radiation in the field. In this study we examined the impacts of UV radiation on the aggressive behaviors of male dart frogs. Males are known to defend territories from other conspecific males. We studied aggressive behavior in field experiments at the La Selva Biological Research Station in Costa Rica. We located calling frogs by walking trails in the rainforest. When vocalizing males were found we placed a model frog nearby and played a recording of a conspecific call. The model frog was illuminated by a portable light by shining either visible light on the model or elevated levels of UV-A radiation. As soon as playback was initiated we recorded several behaviors to quantify the reaction of the nearby vocalizing male frog. Our results suggest that vocalizing male frogs reacted differently to a nearby model frog depending on whether the model was illuminated by visible light or UV-A. Specifically, defending male frogs would get significantly closer to the model when under visible light than when under UV-A. Our results suggest that UV levels may influence male-male interactions in a tropical poison dart frog.