Thursday, April 27, 2017,
- Location: Tea Time in MRB III First Floor Lobby, Seminar in MCN C-2303
Host-parasite coevolution within a tri-trophic interaction: evolution of parasite virulence and behavioral medication in the migratory monarch butterfly
Recent decades have seen great progress in understanding general evolutionary processes in host-parasite biology. However, most studies have addressed hosts and parasites in isolation, and ignored the ecological communities in which hosts and parasites interact. This is a problem because species outside the direct host-parasite interaction may directly and indirectly affect host resistance as well as parasite infectivity, virulence and transmission. Monarch butterflies are commonly infected with a protozoan parasite, which reduces monarch survival and migratory ability. Monarch butterflies use milkweeds as their larval food plants, and certain species of milkweed can strongly reduce parasite virulence and transmission. Dr. Jaap de Roode's studies have shown that butterflies can reduce parasite growth and virulence in their offspring by preferentially laying their eggs on medicinal food plants. However, his theoretical work also suggests that such behavioral medication can result in the evolution of increased parasite virulence by selecting for parasites that can overcome food plant-induced reductions in transmission. He is currently studying geographically separated monarch populations to investigate if the presence of toxic food plants, and the preferential use of these by monarchs, has driven the evolution of host resistance and parasite virulence on a world-wide scale. Dr. Roode will also discuss the population genetic and genomic work on monarch populations around the world, which has provided insights into worldwide dispersal and the genetics of seasonal migration.