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.