Abstract: 【Aim】 The melon fly, Bactrocera cucuribitae is an important invasive pest with wide host range, causing serious harm. This study aims to explore its population differentiation and genetic variation in China. 【Methods】 The genetic diversity of a total of 190 individuals collected from 21 regions of 7 provinces in China was analyzed using nine polymorphic microsatellite loci as the molecular markers. 【Results】 For the 21 geographical populations of B. cucuribitae, the average percentage of polymorphic loci was 97.08%, Shannon’s diversity index(I) was 0.8841, and the genetic differentiation coefficient among populations (F_ST) was 0.12806, suggesting that genetic differentiation occurs among the 21 geographical populations. The UPGMA cluster analysis showed that the populations of Hainan (excluding Sansha), Guangdong, Guangxi, Yunnan and Sansha of Hainan were clustered into one clade, while the populations of Fujian, Jiangxi and Sichuan clustered into separate clades, respectively. 【Conclusion】 A certain degree of genetic differentiation has occurred among the melon fly populations in China, but the accumulated variability is limited.

Key words: Bactrocera cucuribitae, geographical population, microsatellite molecular markers, genetic diversity, genetic differentiation