SUITABILITY OF THE MAIZE WEEVIL AND ANGOUMOIS GRAIN MOTH AS HOSTS FORTHE PARASITOIDS ANISOPTEROMALUS-CALANDRAE AND PTEROMALUS-CEREALELLAE

Two parasitoids, Pteromalus cerealellae (Ashmead) and Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae), were compared for thei r ability to parasitize two important internally-developing insect pes ts of stored maize (Zea mays L.). Parasitism by P. cerealellae was gre ater on Angoumois grain moth, Sitotroga cerealella (Olivier), than on maize weevil, Sitophilus zeamais Motschulsky, in no-choice experiments . Anisopteromalus calandrae parasitized more maize weevils than did P. cerealellae. The former parasitoid parasitized only a few Angoumois g rain moths successfully in maize, but parasitized many in wheat if the hosts were younger than 3 weeks old. Thus, both host age and type of grain affect suitability for parasitism. The effects of parental host (species on which the female developed) and experimental host (species exposed to parasitism) on parasitism rate of P. cerealellae were test ed in a host-switching experiment. Parasitism by parasitoids reared on maize weevils was 23% lower than that of parasitoids reared on Angoum ois grain moth. This effect was independent of which host the filial g eneration of parasitoids was tested on. However, the experimental host species had a much greater effect on parasitoid fecundity than the pa rental host species. Female progeny had smaller body sizes when emergi ng from maize weevil than from Angoumois grain moth, which may explain the parental host effect on fecundity. There was also a slight interg enerational effect of host species on parasitoid body size.