In Vitro Rearing of Muscidifurax zaraptor (Hymenoptera: Pteromalidae) on Artificial Diets With and Devoid of Insect Material

We present the first report on in vitro rearing of Muscidifurax zaraptor Kogan and Legner, a pupal parasitoid of Musca domestica L. and other muscoid flies. We first tested seven artificial diets composed of different amounts (0, 25, and 50%) of a Mu. domestica pupal extract, 25% fresh chicken egg yolk, and 25% powdered milk solution. Then we compared one of the previously tested diets (25% of pupal extract) with three other diets in which either the egg yolk or milk or both were removed.We tested these four diets using insect material either from Mu. domestica or a nonhost insect source, which was Heliothis virescens (F.). We observed no significant differences in the rates of development to adult in the diets with 50 or 25% pupal extract. Almost no adults emerged from two diets without insect material, but in a third one about 8% of parasitoids completed development. Egg yolk significantly improved the yield of adults, while the addition of milk was not beneficial. Using the H. virescens pupal extract similar results were observed, indicating that insect material from a nonhost source is suitable for the development of M. zaraptor. The emerged adults mated and parasitized house fly pupae, producing viable offspring. The developmental time in vitro from egg to adult was slightly longer than that reported in vivo. The results we observed suggest that the highest yields of parasitoid adults from diets with insect material can be explained in terms of a better nutritional balance rather than advocating ‘‘host factors.’’