Published online by Cambridge University Press: 01 September 2008
The extent of genetic differentiation between native and groundnut-feeding forms of the groundnut seed beetle Caryedon serratus Olivier was studied. Sixteen samples (560 individuals of both sexes collected in four localities in Senegal) of C. serratus were reared from pods of four distinct host plants (Arachis hypogaea L., Bauhinia rufescens Lam., Piliostigma reticulatum (DC) Hochst and Tamarindus indica L.), and five microsatellite loci were analysed. Phylogenetic and statistical analyses indicated that host plants strongly influence the degree of genetic differentiation between sampled individuals. Within host plants, genetic differentiation was low. Genetic differentiation between hosts was highly significant (average θ = 0.374) and geographical distances between localities did not influence the genetic structuration of C. serratus populations from a given host plant. The results of this study show that C. serratus could be under a host race formation process.