Dispersal of the exotic parasitoid Cotesia flavipes in a new ecosystem

A study on the dispersal of the exotic larval endoparasitoid, Cotesia flavi pes Cameron (Hymenoptera: Braconidae), was conducted in a maize field in th e northern Kilifi District in the coastal area of Kenya. Because C. flavipe s did not previously occur in the release area, it was possible to use a un ique indirect method to estimate dispersal by examining the distribution of parasitised hosts. Parasitoids released in the centre of the field moved a s far as 64 meters during their life span, and dispersal was dependent on w ind direction. The level of parasitism was influenced by the location of ho sts in plants. The majority of parasitised stemborers (88.4%) were found in side the plant (stems and tassel stems), where 74.3% of the suitable hosts were found, which indicates that female parasitoids were not searching rand omly for hosts. Aggregation of parasitoids in response to plants with diffe rent host densities was not detected. Implications of the release of C. fla vipes on stemborers population in the agroecosystem of East Africa are disc ussed.