Data from: Low genetic diversity but strong population structure reflects multiple introductions of western flower thrips (Thysanoptera: Thripidae) into China followed by human-mediated spread

Historical invasion scenarios based on observational records are usually incomplete and biased, but these can be supplemented by population genetic data. The western flower thrips (WFT), Frankliniella occidentalis, invaded China in the last 13 years and has rapidly become one of the most serious pests in the country. To assess whether this invasion involved a single event or multiple events, we examined patterns of genetic diversity and population structure of WFT across 12 Chinese populations and a native US population based on mitochondrial DNA and/or 18 microsatellite loci. The average allelic richness and haplotype diversity in Chinese populations were significantly lower than in a population from its native range. The distribution of mitochondrial haplotypes suggested multiple independent invasions of WFT into China, including two invasions into the Beijing region. Based on microsatellite data, two distinct clusters were identified, with both of them splitting further into two clusters; in the Beijing region, the microsatellite data also provided evidence for two introductions. Both the absence of isolation by distance and the fact that distant populations were similar genetically suggest patterns of WFT movement linked to human activities. Our study therefore suggests multiple introductions of WFT into China and human-assisted spread.基于观测记录构建的历史入侵场景通常存在不完整性与偏倚性，但可通过种群遗传学数据予以补充完善。西花蓟马（western flower thrips, WFT），学名*Frankliniella occidentalis*，于近13年入侵中国，并迅速成为国内最为严重的农业害虫之一。为明确该入侵过程为单次还是多次入侵事件，本研究基于线粒体DNA（mitochondrial DNA）及/或18个微卫星位点（microsatellite loci），对中国12个西花蓟马种群与1个美国本土种群的遗传多样性模式及种群遗传结构开展分析。中国种群的平均等位基因丰富度与单倍型多样性均显著低于其本土分布区种群。线粒体单倍型的分布格局表明，西花蓟马曾多次独立入侵中国，其中北京地区存在两次入侵事件。基于微卫星数据，本研究鉴定出两个显著分化的遗传聚类群，且二者均进一步拆分为两个亚聚类群；在北京地区，微卫星数据同样佐证了两次入侵事件的存在。种群遗传分化未呈现距离衰减效应，且地理距离遥远的种群遗传相似度较高，上述结果均表明西花蓟马的扩散模式与人类活动密切相关。综上，本研究证实西花蓟马曾多次入侵中国，并通过人类活动辅助完成种群扩散。