Abstracts (first author)
Brood parasites and mimicry: a sensory ecology approach
Cuckoos and other brood parasites are cheats – they lay their eggs in the nests of other birds, leaving all parental care to the hosts. A striking outcome of coevolution in many systems is egg and chick mimicry by parasites to deceive host parents into accepting young that they would otherwise reject. To understand interactions between host and parasite requires investigating the use of sensory information by both parties. I will discuss work my collaborators and I have done to understand several parasitic systems by considering the visual system of the receiver and the use of sensory information in decision-making (e.g. egg/chick rejection). I will show how mimicry of host eggs by parasites can be highly refined in terms of bird vision, and in turn how hosts use the most reliable information to discriminate between and identify their own and foreign eggs. I will then discuss how coevolution can drive different host species down alternative lines of defence, such as egg polymorphism, highly refined rejection behaviour, or chick rejection. Furthermore, I will discuss long-term data indicating how interactions between host and parasite can lead to rapid changes in egg phenotype over short timescales, and the nature of this change. Finally, I will discuss how parasites can exploit limitations in host sensory and cognitive systems to defeat host defences.