The adaptiveness of defence strategies against cuckoo parasitism

摘要: Host bird species of the Eurasian Cuckoo, Cuculus canorus, often display egg-discrimination behaviour but chick-rejection has never been reported. In this paper, we analyse a host-cuckoo association in which both population dynamics and evolutionary are explored discrete-time model. We introduce four host types, each with their own defence behaviour, displaying either egg or chick rejection, neither both, also fitness functions for these types. Although can characterize long term many cases by simple heuristic argument is accordance common views ecology, there number other phenomena that not explained within framework: describe stable oscillatory coexistence two defensive scenarios rejection may establish itself give first explanation as to why trait recorded nature. find rejectors generally at an intrinsic disadvantage respect type rejects eggs. Hosts benefit more from rejecting cuckoo eggs than chicks, our model suggests chiefly responsible absence rejection. Moreover, even though it seems must be useful extra defence, shown hosts strategies less likely themselves competition egg-rejectors reject chicks only. These results provide insight extent adaptations perfected natural selection.