A phylogeographical survey of a highly dispersive spider reveals eastern Asia as a major glacial refugium for Palaearctic fauna

AimThe phylogeographical history of wide-ranging Palaearctic species is not well understood. Here, we present a range-wide phylogeographical study of the wasp spider, Argiope bruennichi (Scopoli, 1772), a highly dispersive and widely distributed Palaearctic species. We aim to identify glacial refugia and patterns of interglacial gene flow across the Palaearctic. LocationPalaearctic region, including the Azores, Madeira, Europe, North Africa and Asia. MethodsWe conduct a range-wide phylogeographical survey. Our study is based on nuclear and mitochondrial DNA markers, as well as morphological characters. We use species distribution models to predict the species' current range as well as its historical distribution during and shortly after the Last Glacial Maximum (LGM). ResultsAll analysed genetic markers and morphological characters support the divergence of a lineage in eastern Asia from the remainder of the Palaearctic. Within the Western Palaearctic, a less pronounced divergence into an Azorean and a European clade is found. Species distribution models predict a pronounced loss of suitable habitat for Western Palaearctic lineages during the LGM, whereas the range of East Asian populations remained largely unaffected. Main conclusionsOur results highlight the existence of non-European glacial refugia for Palaearctic species, particularly in East Asia. The current genetic structure is best explained by the recent recolonization of the Western Palaearctic from eastern Asia, or repeated interglacial contact of populations.