SURVIVAL AND MORTALITY OF GRASSHOPPER EGG PODS IN SEMIARID CEREAL CROPPING AREAS OF NORTHERN BENIN

Surveys of egg pods of agriculturally important grasshoppers were carr ied out in northern Benin between 1992 and 1995. Searches were made of oviposition sites under shrubs of the perennial legume Piliostigma th onningi along field margins. Ln 1993 and 1995, surveys were extended t o include sorghum, Sorghum bicolor, and the perennial thatch grass Vet iveria nigritana. The four principal grasshopper species found at thes e oviposition sites were Hieroglyphus daganensis Krauss, Cataloipus fu scocoeruleipes Sjostedt, Kraussaria angulifera (Krauss) and Tylotropid ius gracilipes Brancsik comprising 86% of 4545 identified egg pods whi le 651 egg pods could not be identified to species level. Predation by meloid beetles (Epicauta, Mylabris and Psalydolytta spp.) varied betw een 0 and 50% for the four dominant grasshopper species. From 1993 and 1994 data, nymphal eclosion from egg pods damaged by meloids was sign ificantly lower than emergence from undamaged egg pods. The hymenopter ous parasitoids Scelio africanus Risbec and S. mauriticanus Risbec wer e reared from the four dominant grasshopper species and parasitism lev els of 0.0-3.3% were recorded from these hosts. There were significant differences in nymphal emergences between parasitized and unparasitiz ed egg pods of H, daganensis.