A glacial relict in the Carpathian caves - population variability or a species complex?

Abstract

The collembolan Protaphorura janosik Weiner, 1990, is a widespread and abundant troglobiotic species with a distribution range limited to the Western and Eastern Carpathian Mountains, in Central Europe. Owing to limited dispersal ability, its populations are probably isolated to some extent in the subterranean environments of different geomorphological units. In five of nine populations examined for morphological variability, genetic analyses were also carried out. Analysis of 10 measurable or countable morphological traits by non-metric multidimensional scaling (NMS) showed a slight separation of neighbouring localities; however, no clear geographical pattern was evident among distant populations. In contrast, genetic analysis based on partial sequences of the mitochondrial COI gene showed a different pattern. Although only eight haplotypes out of 88 sequences were detected, their geographical distribution points towards a high population differentiation. One haplotype was shared by two populations from adjacent caves (the Nová Kresanica and Mylna caves), while all the others were unique to different populations. A Mantel test showed a significant correlation of the geographical and genetic distances. Genetic distances (K2P) between the populations ranged from 0.1% to 3.1%, suggesting the existence of geographical isolates. The bacterial genus Wolbachia was detected only in one population from a pseudokarst (sandstone) cave, while it was absent in the remaining populations occupying karst caves.