A Test of Aposematism in the Dendrobatid Poison FrogOophaga pumilio: The Importance of Movement in Clay Model Experiments

Abstract

Abstract Brightly colored frogs of Dendrobatidae contain alkaloid-based chemical defenses which appear to be utilized as a deterrent to predators. The conspicuous coloration of these frogs is generally considered to be an aposematic signal to color-visioned predators. A previous field-based experiment tested this hypothesis in the dendrobatid frog Oophaga pumilio (Strawberry Poison Frog) from the La Selva Biological Station using a stationary clay model experiment to assess natural predation. Avian predation rates on brown frog models were almost twice that of red frog models, supporting the hypothesis that coloration in O. pumilio is aposematic. A criticism of clay model experiments has been that they do not accurately represent natural organisms, especially with regard to movement. Many predators utilize movement in prey selection and, therefore, may not perceive motionless clay models as prey. In an attempt to understand the importance of movement better in assessing natural predation rates using clay ...