Genetic Diversity among different Geographical Populations of Rhyzopertha dominica in China as revealed by AFLP (Coleoptera: Bostrichidae)

Rhyzopertha dominica (Fabricius 1792) is one of the major coleopterous pests of stored products in China and around the world. It causes serious losses to stored grains. In this study, the genetic diversity and structure of 13 populations (97 individuals) of R dominica were examined using Amplified Fragment Length Polymorphism (AFLP) analysis. Four primer combinations were selected to identify a total of 128 polymorphic loci ranging from 50 to 450 bp. The percentage of polymorphic loci (Pp) was 51.88 % at the population level and 84.87 % at the species level, respectively. Nei's gene diversity (h) and Shannon's Information index (I) had similar trend with the percentage of polymorphism. Thus, the estimated genetic diversity using these three indicators revealed a high level of genetic variation within each R. dominica population. At the species level, Analysis of Molecular Variance (AMOVA) revealed a significantly greater genetic variation within populations (81.11 %) than among populations (18.89 %). The Mantel test of isolation by distance revealed that there was no significant correlation between Nei's genetic distance and geographical distance (Lg) among all populations (r = 0.20787, P = 0.0519 > 0.05). A Neighbour Joining dendrogram based on Nei's unbiased genetic distance revealed four distinct groups that did not correspond to the geographical regions. This result suggests that isolation by distance does not describe the pattern of gene flow among R. dominica populations. How different ecology of grain storage area and depot type could influence R. dominica population genetic structure were also discussed.