Morphometric identification of sudano-sahelian populations of the groundnut seed-beetle, Caryedon serratus (Olivier) (Coleoptera Bruchidae)

Male individuals belonging to populations of the groundnut seed-beetle, Caryedon serratus (Ol.), which were reared from pods of five different host-plants(Arachishypogaea L., Bauhinia rufescens Lam, Cassia sieberiana DC., Piliostigma retkulatum (DC.) Hochst and Tamarindus indica L.) were compared using discriminant function analysis based on 22 morphological variables. When performed on raw data, the analysis indicated that body size was the main discriminating factor. T. indica populations had the largest body size, followed by A. hypogaea, P. reticulatum, C. sieberiana and B. rufescens. Raw data were then divided by maximum head width, considered as a reference variable. Analysis of transformed data revealed differences in body shape between populations: individuals obtained from T. indica differed markedly from all other insects through longer antennae, closer eyes, and a smaller number of femoral teeth. This method did not allow differentiation between populations reared from A. hypogaea and P. reticulatum.