DEVELOPMENT AND ENCAPSULATION OF THE ENDOPARASITOID, MICROPLITIS-CROCEIPES (HYM, BRACONIDAE), IN 6 CANDIDATE HOST SPECIES (LEP)

Encapsulation and development of the endoparasitoid, Microplitis croceipes (Cresson), were studied in six atypical lepidopteran host species whose usual host is Helicoverpa tea (Boddie). The candidate hosts examined were: the fall army worm Spodoptera frugiperda (J.E. Smith); the beet armyworm, Spodoptera exigua (Hubner); the cabbage looper, Trichoplusia ni (Hubner); the greater wax moth, Galleria mellonella (L.); the Indian meal moth, Plodia interpunctella (Hubner); and the diamondback moth, Plutella xylostella (L.). Both S. exigua and T. ni were completely unsuitable for M. croceipes development due to the high rate of eggs that were encapsulated within three days after parasitism. Encapsulation in S. frugiperda included mainly parasitoid eggs and was first detected six days after parasitization at 25 degrees C and two days at 30 degrees C. Encapsulation in C. mellonella occurred only in the larval stage of the parasitoid. In P. interpunctella, parasitoid, larvae reached the 3rd stadium, but none of them pupated. Only S. frugiperda and G. mellonella supported successful development of M. croceipes from egg to adult. The percentage of parasitoids reaching the adult stage in these hosts was higher at 30 degrees C than at 25 degrees C (13% vs. 4% in S. frugiperda, and 21% vs. 3% in G. mellonella, respectively). However, these percentages were too low to substitute them as a more economical host for rearing M. croceipes. This biological information will be useful in additional laboratory studies directed toward reducing the rate of encapsulation (e.g., manipulation of host rearing temperature) to increase production of M. croceipes on these hosts.