||Local adaptation and ecological fitting in host use of the Drosophila parasitoid Leptopilina japonica
Kimura, Masahito T. ,
505 , 2015-05 , Springer
Local adaptation and ecological fitting are the major processes by which organisms colonize and persist in novel environments and form novel associations with unfamiliar species. In this study, we assessed the role of these two processes in the formation of associations between the parasitoid Leptopilina japonica and various host Drosophila species using laboratory populations from three different localities. Each L. japonica population was highly virulent to some Drosophila species from its original locality, meaning they used these Drosophila species as major hosts. However, major host species at a given locality were usually less successfully parasitized by parasitoid populations from different localities. These results indicate that the investigated parasitoid populations showed local adaptation in host use. We also observed cases in which unfamiliar Drosophila species were successfully parasitized or allopatric Drosophila populations were more successfully parasitized. These findings suggest that L. japonica can form novel associations with some Drosophila species in novel environments without undergoing adaptive changes, a phenomenon called ecological fitting. In this study, L. japonica also usually appeared to have oviposited well in D. melanogaster species group members irrespective of their suitability as hosts. This result suggests that the parasitoid makes oviposition decisions based on characteristics common to the drosophilids in this species group.