Coevolutionary struggle between a highly virulent brood parasite and its major host

One of the most well-established study systems of coevolution in vertebrates is avian brood parasitism where parasites evade costly parental care by laying their eggs into host nests. In this project, we will investigate defensive and counter-defensive behaviour in one of the most aggressive host species, the Great Reed Warbler (Acrocephalus arundinaceus) and its brood parasite, the Common Cuckoo (Cuculus canorus). We will focus on frontline interactions where both parties directly interact in the vicinity of the host nest before the parasite egg is laid. We will combine unique video recordings of natural parasitism with experimental methods to quantify the effect of various factors on host-parasite behavioural dynamics. In this way, we will examine the effect of parasitism timing, territory quality and parasite vocalization on the evolution of host adaptations and parasite counter-adaptations. We will also investigate whether the host defence can be fatal for the parasite and whether hosts may use the sight of the Cuckoo on the nest as a cue for rejection of the parasitic egg.