Abstract: Dolichus halensis (Schaller) (Coleoptera: Carabidae) is an important predator insect that is widely distributed in China. To reveal the genetic diversity and demographic history of D. halensis populations from the Qinling Mountains, a 1 601 bp fragment from the mtDNA gene (Cox1-tRNALeu-Cox2) was sequenced for 191 individuals from 24 local populations. Forty-five polymorphic sites were found, and 53 haplotypes were identified. The high haplotype diversity (H_d=0.796) was accompanied by lower nucleotide diversity (P_i=0.0033). Phylogenetic analysis (Bayesian inference) of the 53 haplotypes revealed two major clades. AMOVA analysis suggested that most of the variation occurred within populations (86.61%). SAMOVA and PERMUT analyses showed no phylogeographic structure. The results of neutrality tests and mismatch distribution analyses showed a sudden population expansion. The above analyses confirmed the existence of a postglacial population expansion.

Key words: Dolichus halensis, mitochondrial DNA, genetic diversity, population expansion, Qinling Mountains