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.

尽管学界普遍认为向极地的分布范围扩张是全球变化所致，但生态与进化因子的复杂交互作用，或共同促成了物种的扩张成功。本研究以中欧地区兼具医学重要性的黄袋蛛（Cheiracanthium punctorium）为研究对象，探讨其分布范围扩张过程。研究借助微卫星标记（microsatellite markers）、DNA序列、形态学与气候生态位分析手段，明确了与该蜘蛛扩张成功相关的各类驱动因子。结果显示，该物种的初始扩张由环境变化以及源种群的预适应（preadaptation）共同触发。尽管存在广泛的基因流（gene flow），扩张种群仍与本土种群保持着遗传与形态上的分化，且该分化与气候生态位差异显著相关。此外，扩张种群的黄袋蛛或许暂时摆脱了在本土范围造成高死亡率的卵囊寄生虫。综上，本研究结果揭示了与扩张成功相关的多类复杂因子。我们推测，扩张种群或可适应北欧地区的全新生态环境，这或将推动其分布范围实现远超单一环境变化驱动的大幅扩张。本研究的分布模型预测，该蜘蛛将很快在北欧大部分地区大规模扩散，进而引发显著的公共健康隐患。