Biology of Trichogramma galloi and T. pretiosum (Hymenoptera: Trichogrammatidae) Reared in Vitro and in Vivo

Abstract

The life cycle and parasitization of Trichogramma galloi Zucchi and T. pretiosum Riley were studied on natural and factitious hosts, and on artificial diets. Eggs of sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Pyralidae), and tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), were used as natural hosts of T. galloi and T. pretiosum , respectively. Eggs of Mediterranean flour moth, Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae), were used as factitious host for both parasitoids. T. galloi was reared in vitro on a diet of 70% hemolymph of larvae of corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), 20% chicken egg-yolk, 10% bovine fetal serum, and 0.2% streptomycin. T. pretiosum was reared on a similar diet, with 5% H. virescens egg juice replacing 5% bovine fetal serum. The egg-adult development of T. pretiosum reared on the artificial diet was delayed, whereas developmental differences were not found for T. galloi reared on natural or artificial diets. Survivorship was also reduced for both parasitoids reared on artificial diets. The parasitization and female longevity were reduced for parasitoids reared on the factitious host or artificial diets. No differences in adult size or in morphology of the genital apparatus were detected among parasitoids reared in vitro or in vivo; but wing and abdominal malformations occurred for parasitoids reared on artificial diets.