Brood Parasitism

Abstract

Brood parasitism is a breeding strategy in which the brood parasite female evades all parental care by laying its eggs in host nests of the same (conspecific brood parasitism, CBP) or different species (interspecific brood parasitism, IBP) relying on unrelated foster parents to care for their parasitic offspring. Both CBP and IBP are widespread throughout the animal kingdom providing an extraordinary diversity of brood parasite – host interactions. Costs imposed by brood parasites on hosts selects for the evolution of host defenses, which in turn select for counter-defenses in the brood parasite, triggering improved host defenses, further parasitic adaptations, and so on, giving rise to a coevolutionary arms race. The relationships between brood parasites and their hosts have been studied in most detail in birds, where the subject of brood parasitism have provoked an explosion of compelling discoveries revealing the refinement and complexity of the strategies evolved by brood parasites and their hosts. Current evidence shows that adaptations and counter-adaptations may occur at any stage of the breeding cycle and that each defense and counter-defense will likely influence the evolution of subsequent defenses and counter-defenses, leading to different long-term trajectories and outcomes of coevolutionary interactions between brood parasites and their hosts.