Sympatric speciation in the Simuluim arcticum complex (Diptera: Simuludae)

Five separate data sets were included in our analyses: Alaska (Shields and Procunier 1982), Montana, Idaho, and eastern Washington (Shields 2013; Shields 2014; Shields and Shields 2017 and Shields, unpub. data); throughout the range of S. arcticum (Conflitti et al. 2016); western Canada (Procunier, unpub.); and throughout the range of S. arcticum (Adler et al. 2004. Locations for 299 sites were determined with varying accuracy. There were 125 sites associated with recent collections using GPS capture that have an accuracy of plus or minus 5 m. There were 90 legacy sites with good location descriptions with coordinates captured with Google Earth that we are confident are within 1 km of the collection location. Finally, 84 sites had poor location descriptions often listing only a county. We used the centroid of the county location for these sites resulting in a spatial accuracy of approximately 100 km. Both the GPS coordinates and the Google Earth capture location used the datum WGS 1984. Locations for each site along with associated sibling species and cytotypes were used to create an attribute table.

本研究分析共纳入5组独立数据集：分别为阿拉斯加数据集（Shields与Procunier，1982）、蒙大拿州、爱达荷州及华盛顿州东部数据集（Shields，2013；Shields，2014；Shields与Shields，2017，以及Shields未公开研究数据）、北极堇菜（S. arcticum）全分布区数据集（Conflitti等，2016）、加拿大西部数据集（Procunier未公开研究数据），以及北极堇菜（S. arcticum）全分布区数据集（Adler等，2004）。

299个调查点位的定位精度存在差异：其中125个点位对应近期采集的标本，采用GPS进行定位，精度为±5米；90个为历史遗留点位，位置描述清晰，坐标通过Google Earth获取，经确认与实际采集点位的偏差不超过1公里；剩余84个点位的位置描述较为模糊，通常仅标注所属县级行政区域，本研究采用该县域的几何中心作为此类点位的坐标，由此产生的空间精度约为100公里。

GPS采集的坐标与通过Google Earth获取的坐标均采用WGS 1984大地基准面。研究人员将各调查点位的坐标信息及其对应的姊妹种与细胞型数据进行整合，构建了属性数据表。