Pleistocene survival on central Alpine nunataks: genetic evidence from the jumping bristletail Machilis pallida.

Mechanisms of survival during the Pleistocene glaciation periods have been studied for more than a century. Until now, molecular studies that confirmed animal survival on Alpine nunataks, that is, ice-free summits surrounded by glaciers, were restricted to peripheral areas. Here, we search for molecular signatures of inner-Alpine survival of the narrow endemic and putatively parthenogenetic Alpine jumping bristletail Machilis pallida combining mitochondrial and AFLP data from its three known populations. The mitochondrial data indicate survival on both peripheral and central nunataks, the latter suggesting that refugia in the centre of the Alpine main ridge were more widespread than previously recognized. Incongruences between mitochondrial and AFLP patterns suggest a complex evolutionary history of the species and may be explained via parallel fixation of parthenogenesis of different origins during the last glacial maximum. We suggest that the inferred parthenogenesis may have been essential for central nunatak survival, but may pose a serious threat for M. pallida in consideration of the present climatic changes.