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

Environmental conditions experienced by individuals early in life can extend into adult phenotypes with potential fitness consequences. Early life environmental effects can be relevant for hosts because bad early life conditions may impair host cognition increasing the risk of future parasitism or lowering parasite recognition. 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 costly 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 in adulthood and produced fewer offspring throughout their life. Egg discrimination behavior and lifespan of magpies were not influenced by the quality of natal environments. These results provide support for the idea that there exists annual environmental variation potentially promoting cohort effects in magpie hosts that may have an impact on cuckoo-host co-evolutionary dynamics