Inter-individual variation in parasite avoidance behaviors and its epidemiological, ecological, and evolutionary consequences

Abstract

Abstract Parasites drive the evolution of numerous defense mechanisms in their hosts, including the complex physiological immune system. Growing evidence across animal species highlights the importance of the “behavioral immune system” because behaviors may act as first lines of defense against parasites. This chapter describes recent contributions to this field. In the first section reviews different adaptive avoidance strategies observed throughout the animal kingdom and places them into a cost-benefit framework, emphasizing close relationships between the ecology of host–parasite systems, and associated host behavioral responses. The chapter also synthesizes recent evidence on individual flexibility in the expression of avoidance behaviors and proposes hypotheses to explain such variation. The second section shows that behavioral responses to parasites are possibly as efficient as physiological defenses in mitigating disease risk, and it discusses the epidemiological, ecological, and evolutionary consequences of parasite avoidance. Understanding how individuals minimize parasite exposure depending on their life-history traits and ecological environment will improve our ability to model disease spread and provide researchers with a new framework for studying host–parasite interactions.