Genetic variation and population structure of the Oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae) in China and Southeast Asia

Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), one species of phytophagous insects in Tephritidae family, is mainly distributed in Asia-Pacific Ocean regions. This fly can attack many commercial and economical cultivars and it is listed as the most important quarantine pest in many countries and regions. China and Southeast countries are important distributional regions of this fly in the world. China has been hypothesized pertain to the source area of B. dorsalis and a western orientated migration routes from China to the West are also proposed. To confirm these ideas and uncover the distributional pattern of this fly in China, we applying multilocus microsatellite makers to investigate the genetic variation and population structure of this pest in China and Southeast Asia. Genetic data showed Southeast Asia countries process a richer genetic variation. Synthesizing results of common ancestry and assignment analysis, Southeast Asia countries, especially Vietnam and Cambodia, are characterized many features of source populations and are more considered as source area of B. dorsalis. In China, south-west part shows a higher genetic diversity than that of south-east part. At least two routes are proposed that South-east Asian fly enter into China. Our data suggest south part of Yunnan, one of south-west province in China can be regarded as an important entrance where B. dorsalis of South-east Asia fly were introduced into.