Department Aquatic Ecology

Antagonistic coevolution between hosts and parasites may be the driving force behind many important evolutionary phenomena, including the maintenance of genetic polymorphism. It was found recently that coevolution between aphid hosts and their hymenopteran parasitoids is strongly influenced by facultative endosymbiotic bacteria that increase host resistance. This challenges existing models of host-parasite coevolution by adding another layer of complexity. We develop models describing the expected dynamics of symbiont-mediated coevolution and we empirically examine this process from the level of individual genotypes up to the level of the biological community, using the black bean aphid, Aphis fabae, and its parasitoid Lysiphlebus fabarum as a study system.