Abstract: 【Aim】 To investigate the genetic differentiation of different geographic populations of Loxostege sticticalis in China. 【Methods】 The mitochondrial COI, Cytb and COII sequences from 11 geographic populations of L. sticticalis in Northwest and North China were amplified by PCR, and the genetic distance, molecular phylogeny and degree of genetic differentiation were analyzed based on their sequence variation, Bayesian inference (BI) phylogenetic tree and haplotype network. 【Results】 The sequence fragments of mitochondrial COI, Cytb and COII from 11 geographic populations of L. sticticalis had 24, 12 and 69 variable sites, respectively (accounting for 3.6%, 2.7% and 8.8% of the total length, respectively), 22, 14 and 16 haplotypes with the haplotype diversity (Hd) of 0.7600, 0.5842 and 0.7341, respectively, and the average nucleotide difference (K) of 1.704, 0.752 and 3.997, respectively. The average genetic distance based on mitochondrial COI, Cytb and COII sequences between different haplotypes was 0.004, 0.005 and 0.013, respectively. Both the Tajima’s D and Fu’s Fs of the total population were not significant, suggesting that the genetic differentiation among different geographic populations of L. sticticalis is not significant and the population size remains stable. The phylogenetic tree and haplotype network based on the haplotypes showed that the haplotypes were highly mixed in different geographic populations, without clear geographical distribution pattern. 【Conclusion】 The genetic distance between geographic populations of L. sticticalis is not significantly correlated with their geographical distance, and there is no obvious genetic differentiation between these populations.

Key words: Loxostege sticticalis, mitochondrial gene, geographic population, genetic differentiation, phylogenetic tree, haplotype, China