Data from: Genetic structure and inferences on potential source areas for the invasive oriental fruit fly Bactrocera dorsalis (Hendel) based on mitochondrial and microsatellite markers

Bactrocera dorsalis (Diptera: Tephritidae) is mainly distributed in tropical and subtropical Asia and in the Pacific region. Despite its economic importance, very few studies have addressed the question of the wide genetic structure and potential source area of this species. This pilot study attempts to infer the native region of this pest and its colonization pathways in Asia. Combining mitochondrial and microsatellite markers, we evaluated the level of genetic diversity, genetic structure, and the gene flow among fly populations collected across Southeast Asia and China. A complex and significant genetic structure corresponding to the geographic pattern was found with both types of molecular markers. However, the genetic structure found was rather weak in both cases, and no pattern of isolation by distance was identified. Multiple long-distance dispersal events and miscellaneous host selection by this species may explain the results. These complex patterns may have been influenced by human-mediated transportation of the pest from one area to another and the complex topography of the study region. For both mitochondrial and microsatellite data, no signs of bottleneck or founder events could be identified. Nonetheless, maximal genetic diversity was observed in Myanmar, Vietnam and Guangdong (China) and asymmetric migration patterns were found. These results provide indirect evidence that the tropical regions of Southeast Asia and southern coast of China may be considered as the native range of the species and the population expansion is northward. Yunnan (China) is a contact zone that has been colonized from different sources. Regions along the southern coast of Vietnam and China probably served to colonize mainly the southern region of China. Southern coastal regions of China may also have colonized central parts of China and of central Yunnan.

橘小实蝇（Bactrocera dorsalis，双翅目：实蝇科）主要分布于亚洲热带、亚热带区域及太平洋地区。尽管其具有重大经济危害性，目前针对该物种的大范围遗传结构与潜在起源地的研究仍较为匮乏。本预实验旨在推断该害虫的原生分布区及其在亚洲的定殖扩散路径。研究结合线粒体（mitochondrial）标记与微卫星（microsatellite）标记，对采集自东南亚及中国的实蝇种群开展遗传多样性水平、遗传结构及种群间基因流的评估。两类分子标记均检测到与地理格局相契合的复杂且显著的遗传结构，但两类分析得到的遗传结构均相对薄弱，且未检测到距离隔离（isolation by distance）模式。该结果可通过该物种的多次长距离扩散事件与多样的寄主选择行为加以解释。上述复杂格局或受人类介导的害虫跨区域运输，以及研究区域复杂地形的共同影响。针对线粒体及微卫星数据，均未检测到种群瓶颈事件与奠基者事件的信号。不过，缅甸、越南与中国广东的种群展现出最高的遗传多样性，且检测到不对称的迁移模式。本研究结果间接表明，东南亚热带区域与中国南部沿海地区或为该物种的原生分布范围，种群扩张方向为北向。中国云南为一处接触带，存在来自不同源种群的定殖事件。越南南部沿海与中国南部沿海区域可能主要作为源种群，定殖了中国南部地区。中国南部沿海区域或同时定殖了中国中部及云南中部区域。