Influence of temperature and host on life history parameters of Catolaccus hunteri (Hymenoptera: Pteromalidae)

Catolaccus hunteri Crawford is an external parasitoid of cryptic Coleoptera, particularly of Bruchidae and Curculionidae in flowerbuds, small fruits, and seeds. It is the most common parasitoid of the pepper weevil, Anthonomus eugenii Cano, in the United States, Mexico, and elsewhere, and was introduced from Guatemala to Hawaii for control of this pest. Studies were conducted to assess effects of temperature and host on life history parameters of C. hunteri as a step toward eventual mass rearing and inoculative release for pepper weevil control. Oviposition, postoviposition period and adult longevity were shorter at 30 degrees C than at 20 or 25 degrees C. Mean number of eggs oviposited per female was greater at the lower temperatures than at the highest temperature. Duration of all development stages was shorter at 30 degrees C than at 20 and 25 degrees C. Developmental period of C. hunteri was longer and adult longevity was shorter on boll weevil, Anthonomus grandis Boheman, than any other host. Female wasps laid most eggs on the cowpea weevil, Callosobruchus maculatus (F.), larvae. Transferring of C. hunteri reared on C. maculatus to pepper weevil or boll weevil caused a reduction in the mean number of eggs/female. Age-specific life tables and age-specific fecundity for C. hunteri were analyzed using three constant temperature regimes and five sources of host. These tables were used to calculate the innate capacity of natural increase (r(m)), the finite rate of increase (lambda), the mean generation time (T), the net reproduction rate (R(o)), and the gross rate of reproduction. The results indicate that C. hunteri populations are capable of increasing in all of the environmental conditions tested in the current study. The optimum temperature for population increase for C. hunteri is 25 degrees C. With respect to host suitability, greater numbers of C. hunteri female progeny were produced when this parasitoid was reared constantly and invariably on C. maculatus larvae than on any other host.