Foraging behavior and Life History of the Stemborer parasitoid Cotesia flavipes (Hymenoptera: Braconidae)

The gregarious parasitoid Cotesia flavipes (Hymenoptera: Braconidae) attacks larvae of pyralid and noctuid stemborers by entering the stemborer tunnel. The short-range foraging behavior of female C. flavipes was studied on stemborer-infested plants, in patches with host-related products and in artificial transparent tunnels. In addition, the longevity under specific conditions and the potential and realized fecundity of female C. flavipes were determined. Larval frass, caterpillar regurgitate, and holes in the stem are used in host location by C. flavipes. The response to host products by C. flavipes seems not to be host species specific. Female C. flavipes respond to frass from four stemborer species and one leaf feeder. No differences are found in the behavior of C. flavipes on maize plants infested with the suitable host, Chilo panellus (Lepidoptera: Pyralidae), or the unsuitable host, Busseola fusca (Lepidoptera: Noctuidae). Attacking a stemborer larva inside the stem is risky for the parasitoid. The mortality rate of the parasitoids inside the stem is high: 30-40% of the parasitoids are killed by the spitting and biting stemborer larva. C. flavipes is relatively short-lived: without food the parasitoids die within 2 days; with food and under high-humidity conditions they die within 5-6 days. C. flavipes is proovigenic and has about 150 eggs available for oviposition. A relatively large proportion of the available egg load (20-25%) is allocated to each host, so female C. flavipes are egg depleted after parasitizing only five or six hosts.