Studies of Parasite-Host Interaction. II. Reproductive and Developmental Response of the Parasite Nasonia vitripennis (Hymenoptera: Pteromalidae) to Strains of the House Fly Host, Musca domestica1,2

Abstract

House fly, Musca domestica L., populations from New York and Florida were used to study host strain effects on the reproductive success of the parasite Nasonia vitripennis Walker. Standardized parasites reared on a neutral host, Phaenicia scricata (Meigen), were supplied house fly pupae from either strain, for oviposition. The differences in numbers of eggs per host and lst-stage larvae per host between the host strains were not significant. During the larval period, parasites developing on pupae of the New York strain showed 20% greater mortality than those developing on pupae of the Florida strain. Out of 50 pupae of each strain exposed to 10 female parasites for 24 hr, 20.4 New York pupae and 37.9 Florida pupae produced parasite progeny. The average number of parasite progeny produced per replicate was 146.6 and 389.4 for the New York and Florida strains, respectively. These results demonstrate that variation in the nutritive qualities of the host resulting from possible genetic differences assert profound effects on the dynamics of attacking parasite populations. Such differences in response to host strains with which parasites had no prior contact, suggest that the genetics of the local host population is an important variable to be considered in introductions for biological control programs.