Population dynamics of prey exhibiting inducible defenses: the role of associated costs and density-dependence

The effect of antipredator behavior on the dynamics of a resource-consumer model was analyzed in relation to the magnitude of associated costs, and the strength of density-dependence. For this purpose, I present a deterministic continuous resource-consumer model that exhibits biomass conversion, structural homogeneity, and competition for renewable and fixed resources as separate processes. Antipredator behavior is incorporated as an inducible response to consumer density, and has metabolic and feeding costs. By means of numerical methods, I show: (1) that antipredator behavior is stabilizing for certain parameter ranges, where other stabilizing forces do not dominate the dynamics; (2) intraspecific competition for both fixed and renewable resources have a stabilizing role; (3) metabolic cost is always stabilizing, and feeding cost can be stabilizing or destabilizing, depending on the relative strength of the two competition forces. (C) 2003 Elsevier Inc. All rights reserved.