Meeting Abstract

4.5  Sunday, Jan. 4  Predator response to novel aposematic coloration in a poison dart frog STUART, Y.E.*; DAPPEN, N.; LOSIN, N.; Harvard University; University of Miami; Univ. of California, Los Angeles yestuart@fas.harvard.edu

Aposematism is the use of warning signals by prey to advertise their unprofitability to potential predators. The efficacy of an aposematic signal generally relies on a predator population quickly learning to associate the warning signal with unprofitability of the prey. Hence, it is possible that novel aposematic signals introduced at low levels into a population through mutation or immigration would be eliminated before predators learn to avoid the prey. Moreover, existing aposematic signals should be under stabilizing selection to remain the same. We conducted a field-based experiment at La Selva Biological Station, Costa Rica, to determine how predators respond to a novel, but real, aposematic phenotype of Dendrobates pumilio, a poison dart frog from Costa Rica and Panama. We created color clay models of the local La Selva color morph, of a novel but real color morph found only in Panama, and of two non-aposematic control color morphs. We placed the models in the forest and later examined them for signs of predation. We find that aposematic morphs are attacked at the same rate as control morphs, suggesting equal protection afforded by either crypsis or aposematism. However, after using two different methods to control for the disparity in detectability between morphs, we find that given discovery, predators attack the novel aposematic morph less than control morphs, but more than the local aposematic morph. This suggests imperfect stabilizing selection by predators in the La Selva population. If imperfect stabilizing selection is a general trend across the species range, then this mechanism may help explain the evolution of the diverse, aposematically-colored phenotypes found in D. pumilio.