Genetic differentiation between and within strains of the saw-toothed grain 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 strains reliably and unambiguously. The strains are maintained at a population size of 200 breeding adults. The marked divergence between strains is consistent with the small population size, which for the older strains, according to population genetics theory, implies that roughly half the original genetic variation should now be lost from within strains. However, there is no indication that the older strains have less inter-strain variation. The results demonstrate RAPD loci can reliably detect population subdivision, which in field populations of pest species is of fundamental importance in understanding the population genetics of insecticide resistance.