Early-life environmental conditions influence parasitism at adulthood and life-history of a cuckoo host

Abstract

Environmental conditions experienced by individuals early in life can extend into adult phenotypes with potential fitness consequences. Such environmental effects can be relevant for host species affected by parasitism, because poor early life conditions may lower parasite recognition or anti-parasite defenses and increase the risk of future parasitism. Here we provide a first test of this possibility by using data from a 16-year study of individually marked female magpie Pica pica hosts for which we know natal and adult environments, occurrence of great spotted cuckoo Clamator glandarius parasitism, egg discrimination ability and life history in detail. Females born in warmer years were more likely to be parasitized at adulthood and produced fewer offspring throughout their life. Egg discrimination behavior and lifespan of magpies were not influenced by the quality of natal environments. Our results provide support for the hypothesis that annual environmental variation promotes cohort effects in magpie hosts that may have an impact on cuckoo-host co-evolutionary dynamics.