Relicts from Glacial Times: The Ground Beetle Pterostichus adstrictus Eschscholtz, 1823 (Coleoptera: Carabidae) in the Austrian Alps

SIMPLE SUMMARY: The extant distribution of many plants and animals is the result of the dynamics of the last ice ages with their recurrent advances and retreats of the northern ice sheet and the glaciers in the mountains. The arctic-alpine distribution is a special case where a species occurs in the subarctic/arctic regions and locally restricted in the alpine mountain regions of central or southeastern Europe. Among the ground beetles, several species display this type of distribution, one of which is Pterostichus adstrictus. In Europe, this ground beetle has been thought to have its southernmost occurrences in Wales and southern Scandinavia. In this study, we provide the first reliable record of P. adstrictus from the Austrian Alps based on morphological determination and comparison to other closely related species as well as molecular genetic data. Furthermore, the seasonal occurrence as well as empirical habitat preferences of P. adstrictus in the Austrian Alps are described. ABSTRACT: The last ice age considerably influenced distribution patterns of extant species of plants and animals, with some of them now inhabiting disjunct areas in the subarctic/arctic and alpine regions. This arctic-alpine distribution is characteristic for many cold-adapted species with a limited dispersal ability and can be found in many invertebrate taxa, including ground beetles. The ground beetle Pterostichus adstrictus Eschscholtz, 1823 of the subgenus Bothriopterus was previously known to have a holarctic-circumpolar distribution, in Europe reaching its southern borders in Wales and southern Scandinavia. Here, we report the first findings of this species from the Austrian Ötztal Alps, representing also the southernmost edge of its currently known distribution, confirmed by the comparison of morphological characters to other Bothriopterus species and DNA barcoding data. Molecular data revealed a separation of the Austrian and Finish specimens with limited to no gene flow at all. Furthermore, we present the first data on habitat preference and seasonality of P. adstrictus in the Austrian Alps.