Host corn earworm (Lepidoptera: Noctuidae) reared on meridic diet containing silks from a resistant corn genotype on Archytas marmoratus (Diptera: Tachinidae) and Ichneumon promissorius (Hymenoptera: Ichneumonidae)

Larvae of Helicoverpa zea (Boddie) fed on a meridic diet containing silks of a resistant corn genotype, 'Zapalote Chico 2451 no. (PC3)', were examined as suitable hosts for a larval-pupal parasitoid, Archytas marmoratus (Townsend), and a pupal parasitoid, Ichneumon promissorius (Erich). Host pupal weight, parasitoid weight, and developmental time were significantly reduced when host larvae were reared on a diet containing resistant silks compared with diet without resistant silks. Weight of A. marmoratus was strongly correlated with host weight for both host diets. Parasitoid developmental time for both parasitoids was also correlated with host pupal weight for hosts fed on a diet containing resistant silks. Fecundity of both parasitoids was not affected by host diet. Adult longevity of I. promissorius was significantly reduced when reared from hosts fed the diet containing resistant silks compared with hosts reared on the diet without resistant silks. Longevity of female A. marmoratus was not affected by host diet, but male A. marmoratus lived longer when reared from hosts fed the resistant diet. Despite a few negative effects (lower percentage emergence of A. marmoratus) of a resistant host diet on the parasitoids, these strategies could be compatible because the negative effects did not result in lower parasitoid fecundity or increased parasitoid developmental time