Interacting Effects of Predator and Prey Behavior in Determining Diets

Abstract

A predator’s diet is the array of food types eaten by that predator. From an ecological and evolutionary standpoint, diets are particularly interesting when predators show non-random preferences; that is, when the relative abundances of different prey types in the diet differ from a random sampling of the environment (Chesson 1983). Non-random diets are ecologically important, because the effects of predators on prey communities often appear to be mediated by non-random predation (Paine 1966; Zaret 1980; Sih et al. 1985). Given that predator preferences are ecologically important, ecologists have been interested in the determinants of preference. In behavioral ecology, the dominant theme has been to interpret behavior in terms of its adaptive significance (Krebs and Davies 1984). To explain non-random diets, behavioral ecologists have used optimal diet theory (ODT) which, in its simpler forms predicts diets based on the notion that predators choose prey types that result in maximum net energy intake (Stephens and Krebs 1986).