Development and Survival of the EndoparasitoidCampoletis sonorensis(Hymenoptera: Ichneumonidae) Reared from Gossypol-ExposedHeliothis virescens(F.) (Lepidoptera: Noctuidae)

Abstract

Effects of the cotton allelochemical, gossypol, on the development and survival of Campoletis sonorensis (Cameron) were studied in Heliothis virescens (F.) larvae exposed for different lengths of time and dose to the chemical. We used three feeding methods: exposure of the host to gossypol from neonate stage onward, from 24 h before parasitization, and 24 h after parasitization. A gossypol concentration of 0.013% (wt gossypol/fresh wt diet) from the neonate stage onward positively affected the growth of the endoparasitoid, probably due to the stimulated growth of H. virescens . However, this dose of gossypol did not induce significant positive parasitoid growth when fed to the host after parasitism. When the gossypol dose before parasitism was increased to 0.1% and above, the growth and weight of the adult parasitoid were significantly reduced. Although the weights of the parasitoids were affected, C. sonorensis were capable of developing from hosts exposed to a dose that precluded development of Heliothis to the adult stage. Exposure of Heliothis to 0.4% doses and higher before parasitism resulted in host death, which led to parasitoid mortality. Time to cocoon formation and time to adult parasitoid emergence increased significantly at the dose of 0.2% and above. Gossypol at doses of 0.013–0.4% in the diet of H. virescens did not show any significant effect on longevity of C. sonorensis adults.