Phylogeography and mitochondrial DNA divergence in Dolichopoda cave crickets (Orthoptera, Rhahidophoridae).

Dolichopoda cave crickets are found in caves in the northern Mediterranean region from the Pyrenees in the west to the Caucasus in the east. In this study we analysed the phylogeny within the genus Dolichopoda using parts of the mitochondrial cytochrome oxidase I and 16S ribosomal genes, and explored biogeographic patterns through a dispersal-vicariance analysis (DIVA). Phylogenetic analyses grouped the 15 species into the four geographically restricted main lineages corresponding to the Caucasus, Greece, the Pyrenees and Italy, respectively. The species occur largely in allopatry. The Caucasian and Greek species were basal in the phylogeny, as was the clade including the nine Italian species, which grouped into two major lineages, one mainly including species from western Italian coastal regions and islands, and the other including species with a predominantly inland distribution. Thus it seems likely that there have been two main immigrations into Italy followed by multiple consecutive speciation events. The DIVA analysis supported the assumption of an east-west migration route, and indicated that there have been four major dispersal events. Since the statistical support for the basal node connecting D. remyi and D. hussoni with the west Mediterranean species is low, alternative interpretations for the colonization of the Mediterranean, namely parallel colonization of the main areas of the current Dolichopoda distribution, i.e. the Caucasus, Greece, Italy, and the Pyrenees is also possible. Particular emphasis was put on the D. geniculata-laetitiae species complex. D. geniculata included several recently diverged lineages and constitutes a paraphyletic species complex, also embracing the closely related D. laetitiae.