title: Rapid genetic and ecological differentiation during the northern range expansion of the venomous yellow sac spiderCheiracanthium punctoriumin Europe.
abstract: 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 spiderCheiracanthium 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.
authors.affiliation: Max Planck Institute for Evolutionary Biology Plön Germany; Environmental Science Policy and Management University of California Berkeley Berkeley California USA.
authors.forename: Henrik
authors.initials: H
authors.lastname: Krehenwinkel
authors.affiliation: Zoologisches Forschungsmuseum Alexander Koenig Bonn Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Rödder
authors.affiliation: Transdisciplinary Research Centre Landscape - Territory - Information Systems CeLTIS University of Bucharest Research InstituteI CUB Bucharest Romania; Tular Cave Laboratory Kranj Slovenia.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Năpăruş-Aljančič
authors.affiliation: Evolutionary Zoology Laboratory Biological Institute ZRC SAZU Ljubljana Slovenia.
authors.forename: Matjaž
authors.initials: M
authors.lastname: Kuntner
keywords: adaptation; global change; isolation by environment; range expansion; venomous spider