GENETIC DIFFERENTIATION BETWEEN AND WITHIN STRAINS OF THE SAW-TOOTHEDGRAIN BEETLE, ORYZAEPHILUS-SURINAMENSIS (COLEOPTERA, SILVANIDAE) AT RAPD LOCI

Nine strains of Oryzaephilus surinamensis have been kept in laboratory culture for periods ranging from 5 to 30 years (30-180 generations). Two RAPD primers provided sufficient information to separate the strai ns reliably and unambiguously, The strains are maintained at a populat ion size of 200 breeding adults. The marked divergence between strains is consistent with the small population size, which for the older str ains, according to population genetics theory, implies that roughly ha lf the original genetic variation should now be lost from within strai ns, However, there is no indication that the older strains have less i nter-strain variation, The results demonstrate RAPD loci can reliably detect population subdivision, which in field populations of pest spec ies is of fundamental importance in understanding the population genet ics of insecticide resistance.