Population Genetics Analysis Of Apis Cerana Cerana From Hainan Island And Its Adjacent Mainland

Population genetic diversity and differentiation of Twenty samples of 1222 Apis cerana cerana colonies from Hainan Island and its adjacent Mainland were studied based on 33 morphormetric characters, ten microsatellites loci as well as a mitochondrial tRNAlue-COII fragment. The aim is to investigate the diversity and differentiation between A. c. cerana populations across the island and its adjacent Mainland, and to evaluate the influence of imported bees on the diversity of island population.The results showed that A. c. cerana from the Hainan Island significantly diverged from those from the adjacent Mainland. The recently imported bees showed similar body size and high level of diversity to the Mainland populations, but diverged from the insular local populations. The imported bees might have an impact on the diversity and structure of the local populations.（1） Genetic differentiation between Hainan populations and adjacent Mainland populationsThe A. c. cerana from the Hainan Island differentiated from the Mainland ones due to Qiongzhou Strait as barrier to gene flow. The island population evolved independently and clustered into a separate evolutionary branch against the Mainland branch based on morphormetrics and microsatellites analysis.The Mainland population showed larger body size and wing vein angle K19. The Fst based on microsatellite ranging from 0.052 to 0.178 between the mainland and island honeybees suggested a intermediate level of differentiation. The Hainan honeybees, consisting of unique mtDNA haplotypes Hap₁、Hap₄、Hap₅ and Hap₆, differed from those of Hap₂ and Hap₃ from the Mainland populations（2） the honeybee population structure of Hainan IslandThe Wenchang and Tunchang populations showed an intermediate level of differentiation from other local honeybees with Fst values ranging from 0.06-0.12 which was larger than those between local samples. Besides a unique mtDNA haplotype composition in Wenchang bees of Hap₄、Hap₆、Hap₇、Hap₁8 and Hap₂5 suggested the wenchang Honeybees evolved into a distinguished population adapted to local Coconut forests.（4） Effect of management on the honeybee population diversityThe imported honeybees increased the diversity of local populations, since a hierarch number of mainland haplotype Hap₂ were detected in the Hainan local populations such as Tunchang, Wenchang, Changjiang and Baoting which were adjacent to the imported bees.Heshan population from Mainland showed a low level of mtDNA haplotype diversity. Frequently queen breeding and the queen larva grafted from selected colonies could account for unique mtDNA haplotypes and low level of diversity detected in this study.This study contributed to the understanding of genetic diversity and structure of A. c. cerana in Hainan Island which attracted much attention, and this study further evidence that the Qiongzhou Strait probably acts as a barrier to gene flow between honeybee populations. The data enriched the population genetics of honeybee and provided theoritical support for efficiently preserving indigenous honeybee A. c. cerana for the future utilization.