Roy Van Driesche University of Massachusetts DEB-9806599 "Range Reductions in Native Butterfly, ..." Conservation plans for native butterflies have usually focused on habitat loss as the primary driver of changes in distribution. It is also possible that native butterflies can be reduced in their population by parasitoids that have been introduced for biological control of other species. This proposal investigates the reasons behind range reductions for a native butterfly and specifically tests alternative hypotheses concerning host plant reductions and/or an introduced parasite. It would investigate a native pierid butterfly in Mass. as well as a related species that invaded more than one hundred years ago. Both butterflies may be influenced by a braconid wasp that invaded with the non-native butterfly but which has also been released as a biological control agent. This work can provide insights into basic questions on the ecology of shared parasitoids in insect communities and some of the consequences of biological control efforts.
