Optimal foraging behavior with an explicit consideration of within-individual behavioral variation: an example of predation

Abstract

Animal behavior is flexible, and the same individual can exhibit variable expressions under the equivalent ecological situations (i.e., within-individual behavioral variation). This study examines the evolution of within-individual behavioral variation using an individual-based model. A common predation scenario is considered where a predator spends a period h to handle and consume a captured prey. The model assumes the handling time of the predator to be a random variable. The average and within-individual variance of handling time are described by µ h and (Formula presented.), respectively, where each individual has its own unique µ h and (Formula presented.). Using a genetic algorithm, the evolution of (Formula presented.) is traced. The results show that natural selection acts on both µ h and (Formula presented.), and the optimal behavioral variation depends on the density of prey. In particular, individuals with high behavioral variance (Formula presented.) are more likely selected when prey density is low. Individual based modeling can be a useful tool for studying the ultimate significance of within-individual behavioral variation and generating empirically testable predictions. The mechanisms of the evolution of within-individual behavioral variation and their ecological implications are discussed.