Sympatric Speciation In Carposina Sasakii Matsumura Complex Base On Mitochondrial COI And COII Gene Fragments

By means of mitochondrial COⅠand COⅡgene fragments, the sympatric speciation were studied in Carposina sasakii Matsumura complex under the selective pressures of host phenology and fruit nourishment differences.In the literature reviewing part, species concepts and speciation mechanisms are presented; the concept of host race are discussed; the applications of the skill of molecular biology in Carposina sasakii complex; and the research advances and current status on the Carposina sasakii complex are reviewed.The peach fruit borer, Carposina sasakii Matsumura, is a major pest of fruit trees in the East Asia, with its larvae boring in the fruits of over a dozen species of fruit trees, frequently causing significant damage to the fruits. On various fruits, C. sasakii formed host races or even sapient species. In this study, with Carposina coreana Kim as the out-group, their host race formation was investigated using gene sequence analyses of mitochondrial COⅠand COⅡfragments on the host races of the C. sasakii from seven different host plants, including apple (Malus pumila), hawthorn (Crataegus pinnatifida), peach (Prunus persica), apricot (Prunus armeniaca) and wild jujube (Zizyphus spinosus) in Shaanxi Province, and pear (Pyrus sorotina) in Liaoning Province. Phylogenetic relationships among C. sasakii complex were inferred from fragments of mitochondrial COⅠandⅡtotaling 1341bp, using Neighbor-Joining, Maximum-Parsimony methods and p-distance. The result shows that there exists genetic differentiation between these different host races. The COⅠgene genetic distance among the six sympatric host races of C. sasakii complex ranges from 0.000–0.016, with the apricot and pear races differs most markedly from other host races. Therefore, combining of biological information, we can determine the apricot race has been formed reproductive isolation with the other host races or already formed a new species.