Affiliation: | (1) Department of Crop Science and Seed Technology, Moi University, Eldoret, P.O. Box 1125, Kenya;(2) Laboratory of Entomology, Wageningen University, EH Wageningen, P.O. Box 8031, The Netherlands, 6700;(3) Indian River Research and Education Center, University of Florida, 2199 South Rock Road, Fort Pierce, Florida;(4) The International Centre of Insect Physiology and Ecology, (ICIPE), Nairobi, P.O. Box 30772, Kenya, G.P.O. 00100;(5) Netherlands Institute of Ecology, (NIOO-KNAW), BG Maarssen, P.O. Box 1299, 3600, The Netherlands;(6) Indian River Research and Education Center, University of Florida, 2199 South Rock Road, Fort Pierce, Florida |
Abstract: | Studies were conducted on the host searching behavior of the larval parasitoid Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) and the pupal parasitoid Dentichasmias busseolae Heinrich (Hymenoptera: Ichneumonidae), both of which attack lepidopteran (Crambidae, Noctuidae) cereal stemborers. The behavior of D. busseolae was observed in a diversified habitat that consisted of stemborer host plants (maize, Zea mays L. and sorghum, Sorghum bicolor (L). Moench (Poaceae)) and a non-host plant (molasses grass, Melinis minutiflora Beauv. (Poaceae)), while C. sesamiae was observed separately on host plants and molasses grass. In previous olfactometer studies, C. sesamiae was attracted to molasses grass volatiles while hboxD. busseolae was repelled. The aim of the present study was to investigate the influence of molasses grass on close-range foraging behavior of the parasitoids in an arena that included infested and uninfested host plants. Dentichasmias busseolae strongly discriminated between host and non-host plants, with female wasps spending most of the time on infested host plants and least time on molasses grass. Likewise, C. sesamiae spent more time on uninfested and infested host plants than it did on molasses grass in single choice bioassays. While on infested plants, the wasps spent more time foraging on the stem, the site of damage, than on other areas of the plant. Overall, the results indicate that presence of the non-host plant does not hinder close range foraging activities of either parasitoid. |