Dispersal pattern of Bradysia odoriphaga populations in Shandong, China as revealed by microsatellite markers: implications of human activities

Although Bradysia odoriphaga (Diptera: Sciaridae) is a well-known, economically important pest of Chinese chive, Allium tuberosum (Asparagales: Amaryllidaceae), little is known regarding the population dynamics of this pest in the field. To identify the gene flow in field populations of this pest, the genetic structure of ten populations collected from Shandong Province, China were analyzed using eight microsatellite loci. The results demonstrated that the genetic diversity of B. odoriphaga populations in the region are not drastically different (e.g. the He values ranged from 0.2627 to 0.3907). There was no significant heterozygosity excess in any of the populations under the IAM, TPM, or SMM models. The B. odoriphaga populations in the region can be grouped into two genetic clusters based on BAPS software. There were no significant differences between the Fst values in any of the populations. Additionally, no significant relationship was found between Fst and geographical distance. These results suggest that there is extensive gene flow between the populations in this region, which is likely associated with human activities. The results provide insight into the dispersal pattern of this pest in field settings in Shandong, China. It is hoped that this information will aid in the area-widely sustainable management of this economically important pest.