Abstract: In order to understand the genetic differentiation and the phylogeographical structure ofEpisyrphus balteatus in Yanshan Taihang Mountains Area, a fragment with 658 bp from the mitochondria COI gene was extracted, expanded and sequenced for the specimens ofE. balteatus from Hebei, Inner Mongolia, Shanxi, Henan and adjacent places. In total, 36 sequences were obtained, the average content of A+T (69.9%) was obviously higher than C+G content (30.1%), and there were no insertions or deletions. The results showed that the Wuling Mountain population had the highest genetic diversity. The analysis of molecular variance revealed the significant genetic subdivision among the individuals within populations. The result of Mantel test indicated that there was no significant correlation between the genetic distance and geographic distance (P=0.639), so it did not conform to the inference of geographical isolation model. Phylogenetic analysis was constructed by using the maximum likelihood method, and results showed that the haplotype 3 from the Wuling Mountain population was well separated from others. The current study estimated the divergence time of populations, which was in the Pleistocene (0.02-0.94 Ma) and part of populations was without differentiation. We supposed that the reasons of differentiation ofE. balteatus in Yanshan-Taihang Mountains Area are the repeated changes of Quaternary glacial climate, and the Wuling Mountain should be one of the important refuges forE. balteatus in the last ice age of the Quaternary.

Key words: C, N and P, redundancy analysis, altitude, Mao’er Mountain, stoichiometry characteristics