«Consequences of an arms race between a host and three brood parasites»
Biologist Mareike Wurdack (Tuttlingen, Germany, 1980), who won the AllGenetics-EMPSEB Award 2012, will be presenting her work at AllGenetics in April 2013.
After attending the universities of Ulm, Freiburg, and Turku, Mareike currently works as a PhD student at Dr. Thomas Schmitt Lab at Freiburg University.
During her PhD thesis ('Antagonistic selective pressures in the evolution of species specific cuticular hydrocarbon profiles in solitary Hymenoptera'), Mareike has been evaluating the interactions of different selective pressures in digger wasps of the genus Cerceris, in a comparative framework.
At next INFUSCIENCE, she will present her talk «Consequences of an arms race between a host and three brood parasites», on the evolutionary arms race undergone by a solitary host and its three host-specific brood parasites.
April 11th 2013 | 19 pm | Edificio de Servicios Centrales de Investigación. Campus de Elviña s/n. E-15071 A Coruña.
«Consequences of an arms race between a host and three brood parasites».
Parasites and their hosts have conflicting interests – to either successfully exploit the host or to defend against the parasite attack. This situation sets the board for an evolutionary arms race between both species. The species pair then follows a trajectory through repeated cycles of fine tuning of the parasite's attack strategies and evasive actions of the host. As a special case, brood parasites need to avoid detection by the host in order to neither be attacked while in the nest nor risk the nest to be abandoned by the host afterwards. Insect brood parasites may avoid olfactory detection by mimicking the host's cuticular hydrocarbon (CHC) profile. In this case, the arms race would lead to optimised chemical mimicry in the parasite. The host could e.g. change the CHC composition in order to escape a mimetic match.
The most straightforward parasitic associations consist of one enemy (the parasite) and one target (the host). More complex variations are possible: one parasite may use several hosts or several parasites may specialise in one single host. In this study, a solitary host (Hymenoptera: Eumenidae) and its three host-specific brood parasites (Hymenoptera: Chrysididae) serve as a model of such a multi enemy / single target system. We compare the CHC profiles and predict that a brood parasite whose intrusion is detectable by the host should develop chemical mimicry. The host in return should establish counterstrategies. Competition between parasites may fuel the perfection of mimicry or the development of completely new intrusion strategies.
We found two chemotypes of the host that differ greatly in their CHC composition. The split could allow part of a population to escape a parasite's mimicry. But two parasite species have evolved a close match of CHC composition – one for each chemotype. The third parasite produces its very own CHC bouquet – it has developed a new strategy for invading host nests and can no longer be fended off by the host.