Population and evolutionary genetics of host specialization in common cuckoos
Coevolutionary arms races are often responsible for generating extreme phenotypic diversification. Fueled by positive feedback between highly specialized parasites and their attuned hosts, avian brood parasites provide an excellent system to understand the coevolutionary pressures generating phenotypic diversification. Common cuckoos, an obligate brood parasite, exhibit striking egg diversity across Eurasia which closely mimics their hosts. Here, we examine population and evolutionary genetic patterns perpetuating host specialization in common cuckoos and quantify the selective forces underlying egg diversification, allowing them to exploit hosts across the continent from the British Isles to the South China Sea.