Olfactory responses of the parasitoid wasp, Anisopteromalus calandrae (Hymenoptera: Pteromalidae) to odors from hosts and stored grain

The ability of parasitoids in locating hosts determines their success in suppressing the pest population. Chemical stimuli emitted from food products and hosts provoke the searching behavior of parasitoids. Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) is a generalist idiobiont ectoparasitoid of coleopteran pests in stored products. In the current study, the behavioral responses of A. calandrae females were evaluated regarding host food and different life stages of the host, Callosobruchus maculatus F. (Coleoptera: Chrysomelidae), using a Y-tube olfactometer. The parasitoid was offered uninfested chickpea kernels, damaged chickpea without larvae of C. maculatus, damaged chickpea with preferred stage (4th instar) larvae of C. maculatus, uninfested chickpea + C. maculatus adults, and eggs of C. maculatus on chickpea. In another test, the preference of A. calandrae for either damaged chickpea without larva of C. maculatus or damaged chickpea with non-preferred stage (1st instar) larvae of C. maculatus was studied. The results showed that the females did not prefer uninfested chickpea kernels and adults of C. maculatus. However, they were attracted to damaged kernels with or without larvae, and the kernels containing eggs of C. maculatus. When the female parasitoids had a choice between damaged chickpea without larva of C. maculatus and damaged chickpea with 1st instar larva, they did not prefer one over the other. The results of this investigation can be helpful for using A. calandrae as a biological control agent in stored products.