Nasonia (Hymenoptera: Pteromalidae) is a genus of small, haplodiploid, parasitoid wasps that lay their eggs in pupae of various fly species. We use the four Nasonia species (N. vitripennis, N. longicornis, N. giraulti and N. oneida) as a model system. For more information on the biology of Nasonia see here (www.sas.rochester.edu/bio/labs/WerrenLab/WerrenLab-NasoniaResearch.html ).