Strategy selection under conspecific brood parasitism: An integrative modeling approach

Conspecific brood parasitism (CBP), where females lay eggs in nests of conspecifics, is taxonomically widespread. Following recent calls to consider CBP in a more integrative manner, we explore breeding strategies related to CBP by using a model of competing strategies that incorporates variation in individual quality, relatedness, recognition of own versus parasite-laid eggs, as well as the costs of egg laying and postlaying care. Our model creates 5 main conclusions. First, variation in individual quality plays a central role in shaping breeding strategies. Second, kinship plays a central role in the evolution of CBP. Third, egg recognition ability may affect the prevalence of parasitism: If hosts recognize parasitic eggs, relatedness between host and parasite facilitates CBP. Fourth, the relative costs of egg laying and postlaying care play a so far underestimated role in determining the prevalence of parasitism. Fifth, natal philopatry may lead to a reduction in productivity. To sum up, our theoretical study combines factors known to affect both breeding in general and CBP in particular and shows that these factors can explain a large proportion of the variation in CBP strategies found in the wild and therefore facilitates the understanding of the mechanisms shaping these strategies.