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.

尽管学界通常将物种向极地的分布范围扩张归因于全球气候变化，但生态与演化因子的复杂互作或许才是种群扩张成功的关键驱动因素。本研究以黄袋蛛（Cheiracanthium punctorium）为研究对象——该物种是中欧地区具有医学重要性的物种——通过微卫星标记（microsatellite marker）、DNA序列、形态学与气候生态位（climate niche）分析，明确了与该蜘蛛扩张成功相关的各类影响因子。研究结果显示，该物种的初始扩张由环境变化与源种群的预适应（preadaptation）共同触发。然而，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，扩张中的蜘蛛种群可能暂时逃脱了在本土分布区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影响因子的全貌。我们推测，扩张种群或可适应北欧地区的全新生态环境，这或将推动种群实现远超单一环境变化驱动下的大规模分布范围扩张。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，进而引发严重的公共健康隐患。