Abstract: 【Aim】 The Chinese honeybee (Apis cerana cerana) plays vital roles in pollination for agro-ecosystem and honey bee products. This study aims to investigate the population differentiation and genetic polymorphism among Apis cerana cerana populations across the Qinling-Daba Mountain Areas, and to explore possible factors contributing to genetic differentiation and difference of genetic polymorphism. 【Methods】 The genetic relationship was studied, and polymorphism was estimated among 979 colonies of A. c. cerana from 17 localities combined with two outgroups, A. c. cerana colonies from Changbai Mountain and Aba, based on eight microsatellite loci. 【Results】 The results showed that up to 95% of the variation was observed within sampling localities while less variation between localities. The genetic differentiation coefficient (Fst) among 17 localities ranged from 0.002 to 0.037, and the gene flow (Nm) was from 6.51 to 124.75, indicating that no population differentiation was detected. The mean expected heterozygosity (He), observed heterozygosity(Ho), number of alleles (Na), number of effective alleles (Ne), polymorphism information content (PIC) and Shannon’s information index (I )were 0.6877±0.1098, 0.6364±0.1367, 7.71±2.52, 3.7488±1.6201, 0.6418±0.1152 and 1.5026±0.3754, respectively, suggesting the abundant genetic polymorphism. The values of the genetic polymorphism indices including the expected heterozygosity, number of alleles, number of effective alleles and polymorphism information content were significantly lower in localities which underwent Chinese sacbrood virus pandemic recently than those in the virus uninfected areas. 【Conclusion】 In the context of the large population size and continuous distribution in Qinling-Daba Mountain Areas, there is no genetic differentiation among A. c. cerana populations across a distance of 650 km owing to a high level of gene flow. And the results also imply that the honeybee in Qinling-Daba Mountain Areas has rich genetic polymorphism. Significantly decreased polymorphism occurs in some localities that have undergone selective pressure from Chinese sacbrood virus prevalence.

Key words: Apis cerana cerana, genetic differentiation, genetic polymorphism, population, microsatellite markers