April 24 2013

12:00 LSB 2320

Martin Stevens
BBSRC David Phillips Senior Research Fellow, Center for Ecology and Conservation, Exeter University

Deception and camouflage in parasites and Prey


Evolutionary arms races between predators and prey, and parasites and hosts are a major force generating diversity among and within species. I will first discuss our recent work on brood parasites ('cuckoos') and their hosts. Cuckoos and other brood parasites are cheats, laying 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 mimicry by parasites to deceive host parents into accepting young that they would otherwise reject. I will discuss how we can understand mimicry and egg rejection by considering the visual system of birds and the use of sensory information in decision-making (egg rejection behaviour). I will show how mimicry of host eggs by African brood parasites can be highly refined, and in turn how hosts use the most reliable information to detect foreign eggs. I will then discuss how coevolution can drive different host species down alternative lines of defence, such as egg polymorphism and highly tuned rejection behaviour, and how parasites can exploit limitations in host sensory and cognitive systems to defeat these defences. For the latter part of the talk I will discuss our work on animal camouflage, specifically in ground nesting birds and shore crabs. I will discuss how different species of nightjar in Zambia use egg camouflage against predators, and how ghost crabs from SE Asia change colour to mediate camouflage from day-to-night.















































































































































































































































































































































































































































































































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