Geographic variation in the spotted-wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), based on mitochondrial DNA sequences

Abstract

The spotted-wing drosophila (SWD), Drosophila suzukii (Diptera: Drosophilidae), is an economically damaging pest that feeds on most thin-skinned fruits. It was originally native to a few Asian countries, including Korea, but is now found in North America and Europe. In this study, we sequenced portions of the mitochondrial (mt) COI and ND4 genes from a total of 195 individuals collected mainly from Korea. We then combined GenBank-registered COI sequences from all ancestral-range and introduced-range populations with our own COI data to assess the worldwide diversity, divergence, and relatedness of SWD haplotypes. A total of 139 haplotypes were obtained from the concatenated COI and ND4 sequences. Most haplotypes were confined to single localities, but 12 of them were found in more than two localities, and one haplotype (SWDCN61) was found from Korea to Canada. A dataset combining GenBank sequences with our own data identified a total of 94 worldwide COI haplotypes with a maximum sequence divergence (MSD) of 5.433% (32 bp). Although most haplotypes were found in only a single country, a few haplotypes were found commonly in China, Korea, and Japan; these occurred at a higher frequency and were often involved in introductions. A rough estimate of genetic diversity in each country showed higher diversity in ancestral distributional ranges, but the invasion over Asian countries seems to have been substantial because haplotype diversity was only 2.35 to 3.97-fold lower in the U.S.A, Canada, and Italy than that in the populations’ ancestral ranges.

Keywords:

• Spotted-wing drosophila
• Drosophila suzukii
• mitochondrial DNA
• ND4 gene
• COI gene
• genetic diversity
• invasion

Acknowledgements

We thank Dr Yi Yu at Shandong Academy of Agricultural Sciences, China, for the collection of Chinese SWD. We also thank Dong-Sung Im for his help with sequencing.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

This work was supported by a grant from the Research Program for Exportation Support of Agricultural Products, Animal and Plant Quarantine Agency, Republic of Korea.