Studies in Warning Coloration and Mimicry VIII. Further Evidence for a Frequency-Dependent Model of Predation

Abstract

Laboratory experiments were conducted using toads, Bufo terrestris, and tree- frogs, Hyla cinerea, as predators and honeybees, Apis mellifera, as models. Bees from which the stinging apparatus had been removed served as mimics. Model and mimic bees were offered randomly with the models at frequencies of 10%, 30%, and 50% to the toads and 10%, 20%, and 50% to the treefrogs. The corresponding percentages of the model-mimic population eaten were 53.6%, 35.3%, and 19.8% (toads) and 29.6%, 17.4%, and 7.0% (treefrogs). The frequencies of bees eaten as a function of percent models in the prey population can be described by the mathematical model of predation presented previously (Huheey, 1964, 1976). Predator memory values (n) of 8.0 (toads) and 28.7 (treefrogs) were obtained. Various factors affecting the behavior of the predator with respect to the value of n are discussed: toxicity vs. distastefulness, alternate prey, and predator strategy. It is concluded that n is better viewed as a risk-taking strategy on the part of the predator than as a simple memory parameter.