An evolutionarily stable strategy for aggressiveness in feeding groups

Abstract

Animals searching for food in groups display highly variable degrees of aggressiveness. In this paper I present an individual-based game theoretical model of how gregarious animals should adjust their level of aggressiveness to their environmental conditions. In accordance with behavioral observations, the predicted level of aggressiveness increases progressively with decreasing food availability and increasing animal density. The proposed model also predicts a positive influence of food energy value and handling time on the level of aggressiveness within the group. In addition, the model provides information about the influence of aggressive behavior on individual foraging success, interference, and population dynamics. Adaptive behavioral rules for aggressiveness in consumers are predicted to respond to both competitors and food density in a way that contributes to stabilization of the dynamics of population systems.