Data from: Rapid genetic and ecological differentiation during the northern range expansion of the venomous yellow sac spider Cheiracanthium punctorium in Europe

Although poleward range expansions are commonly attributed to global change, a complex interaction of ecological and evolutionary factors might contribute to expansion success. Here, we study the expansion of the yellow sac spider Cheiracanthium punctorium, a medically important species in Central Europe. Using microsatellite markers and DNA sequences, morphological and climate niche analyses, we identify factors associated with the spider’s expansion success. Our results indicate that the species’ initial expansion has been triggered by environmental change and preadaptation in the source populations. However, despite extensive gene flow, expanding populations maintain genetic and morphological differentiation from native ones, which is correlated with climatic niche differences. Moreover, expanding spiders might have temporarily escaped an eggsac parasite that causes high mortality in the native range. Hence, our results paint a complex picture of diverse factors associated with expansion success. We speculate that expanding populations might be capable of adapting to novel ecological conditions in Northern Europe. This could allow a substantial range expansion, much farther than by environmental change alone. Our distribution model predicts that the spider will soon massively spread over most of Northern Europe, bringing along considerable health concerns.

尽管向极分布范围扩张（poleward range expansions）通常被归因于全球变化，但生态与进化因子的复杂互作或许才是推动扩张成功的核心驱动因素。本研究以中欧地区具有医学重要性的黄囊蛛（Cheiracanthium punctorium）为研究对象，探讨其分布扩张过程。研究借助微卫星标记（microsatellite markers）、DNA序列、形态学分析以及气候生态位（climate niche）分析，筛选出与该蜘蛛扩张成功相关的各类影响因子。结果显示，该物种的初始扩张由环境变化及其源种群的预适应（preadaptation）共同驱动。尽管扩张种群与本土种群间存在广泛的基因流（gene flow），但二者仍维持着遗传与形态上的分化，且这种分化与气候生态位差异显著相关。此外，扩张中的蜘蛛种群或许暂时摆脱了在本土范围内造成高死亡率的卵囊寄生虫（eggsac parasite）。综上，本研究结果揭示了与扩张成功相关的多元复杂因子图景。我们推测，扩张种群或可适应北欧地区的全新生态环境，这将推动其实现远超单纯环境变化驱动的大规模分布扩张。我们的分布模型预测，该蜘蛛将很快在北欧大部分地区大规模扩散，届时将引发严重的公共健康隐患。