Population structure, population history and DNA barcoding of fruit fly Bactrocera latifrons (Hendel) (Diptera: Tephritidae)

The fruit fly Bactrocera latifrons (Hendel) is an important pest of commercially significant plants such as chili, tomato and eggplant. The species is native to South and Southeast Asia, but has now invaded Japan, Hawaii and Africa. In this study, mitochondrial DNA sequences were used to infer genetic structure and demographic history of B.latifrons. The efficiency of DNA barcodes for identification of B.latifrons was also tested. Ninety-three specimens infesting four host-plant species were obtained from 11 sampling locations in Thailand. The mitochondrial haplotype network revealed no major divergent lineage, which was consistent with a phylogenetic analysis that found strong support for the monophyly of B.latifrons. Population pairwise F-ST revealed that most (65%) comparisons were not significantly different, suggesting a high rate of gene flow. Analysis of molecular variance (amova) found no significant genetic differentiation among populations from different host-plant species. Sharing of several haplotypes among flies from different host-plants indicates that the flies were moved freely across the plant species. Demographic history analysis revealed that the population has undergone recent expansion dating back to the end of the last glaciation. Thus, the results indicate that both ongoing and historical factors have played important roles in determining the genetic structure and diversity of B.latifrons. DNA barcoding analysis revealed that B.latifrons specimens were clearly differentiated from other species with 100% correct identification. Therefore, cytochrome oxidase I (COI) barcoding sequences could be effectively used to identify this important pest species, which could encourage monitoring and control efforts for this species.