Variations in body size and some life history traits among Callosobruchus maculatus (Fab.) (Coleoptera: Chrysomelidae, Bruchinae) strains from different areas in three countries of West Africa

Abstract

In West Africa, Callosobruchus maculatus is the main pest of stored cowpeas (Vigna unguiculata Walp.). An effective control of this pest depends on a good knowledge of its population growth ability and the diversity of strains in cowpea crop areas. In this study strains from Dakar (Senegal), Niamey (Niger) and five localities of Burkina Faso were collected and compared in similar laboratory conditions. We found that body size and life history traits slightly varied among the strains studied. In general, females from the Dakar strain were smaller and had lower intrinsic rate of natural increase. Specifically the small size of Dakar females seems to have caused a decrease in lifespan and fecundity coupled with an increase of development duration. Such variations may also occurred to a lesser extent among populations from the same country as it was noticed for Burkina strains. These results show that despite the apparent homogeneity of C. maculatus populations in West Africa, morphological and biological diversity exists and should be better understood and integrated for optimal pest control methods.