Abstract: 【Aim】 Helionothrips mube has become a common pest on the taro (Colocasia esculenta) in recent years. This study aims to investigate the genetic differentiation among different geographic populations of H. mube in southwestern China. 【Methods】 The mitochondrial COI gene sequences of 132 individuals of H. mube from 21 geographic populations were obtained through Sanger sequencing, and the genetic diversity, genetic differentiation and molecular variance were analyzed by MEGA, DnaSP, Arlequin and Network software. 【Results】 Thirty-four variable sites were observed and 16 haplotypes were defined based on the 132 mitochondrial COI sequences (643 bp) from 21 geographic populations of H. mube, of which H1 had the highest frequency and the widest distribution. High levels of genetic diversity (Hd=0.712, Pi=0.00413, K=2.655) and genetic differentiation (Fst=0.3443), and low gene flow (Nm=0.96) were detected in the total population of H. mube. The analysis of molecular variance (AMOVA) indicated that the genetic differentiation of H. mube was mainly attributed to the intra-population. The Mantel test showed a positive correlation between the geographic distance and genetic distance. The neutral test showed that Tajima’s D value was significantly negative, but Fu’s Fs was not significant, and the mismatch distribution curve showed multiple peaks based on the whole datasets. The results of genetic distance among populations, haplotype phylogenetic tree and median-joining network all supported that the population genetic differentiation among the three populations of Chengdu, Sichuan (CHD), Changning, Yunnan (CHN) and Zunyi, Guizhou (ZY) were greater than that among other populations. 【Conclusion】 The H. mube populations in southwestern China are characterized by high genetic diversity and obvious genetic differentiation, the gene flow among populations might be affected by geographical distance, and the population of H. mube has not experienced recent expansion.

Key words: Helionothrips mube, geographic population, genetic differentiation, population dynamics, mitochondrial COI gene