Phylogeography and mitochondrial DNA divergence inDolichopodacave crickets (Orthoptera, Rhahidophoridae)

Abstract

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.

Phylogeography and systematics of the westernmost Italian Dolichopoda species (Orthoptera, Rhaphidophoridae)

“…The phylogeny in Figure 4 supports the major phylogenetic relationships previously demonstrated (Allegrucci et al 2005, 2011; Martinsen et al 2009). The Italian Dolichopoda species are separated in two main clusters, as expected.…”

“…To investigate this further we carried out a genetic distance analysis using COI gene as a barcode and p-distance between all studied Dolichopoda species (Allegrucci et al 2005, 2009, 2011; Martinsen et al 2009). Genetic distance values at intra- and interspecific levels are compared in Figure 3.…”

“…Both analyses were carried on the present samples and all Dolichopoda species previously analyzed (Table 2 and Allegrucci et al 2005, 2011; Martinsen et al 2009), considering only COI data set and only the common base pairs consisting of 964 bp.The ‘‘classical’’ DNA barcoding gap analysis was based on the pairwise genetic distances (p-distance). Distribution of genetic distance values was analyzed at different taxonomic levels.…”

Gone with the plate: the opening of the Western Mediterranean basin drove the diversification of ground-dweller spiders

“…The close relationships between Corsican and northern Italian species revealed in Parachtes have also been recovered in a diverse assemblage of arthropods, including cave crickets, wasps or isopods [20,49-51,32]. In most cases, these links originated as a result of active dispersal during the Pleistocene glacial cycles (2-0.5 Ma), when recurrent marine regressions led to the formation of land bridges between Corsica and Tuscany or when the Tuscany archipelago could have been used as stepping-stones.…”

Neuronal Regression of Internal Leg Vibroreceptor Organs in a Cave-Dwelling Insect (Orthoptera: Rhaphidophoridae: <b><i>Dolichopoda araneiformis</i></b>)

“…For Dolichopoda in particular, the invasion of their subterranean habitat by the forest populations is supposedly a relatively recent Color version available online event, promoted by the climatic changes of glacial and interglacial periods during plio-pleistocene [Allegrucci et al, 2011]. The genus Troglophilus is supported as being closely related to Dolichopoda [Allegrucci et al, 2005;Martinsen et al, 2009;Karaman et al, 2011], and it is a rather basal lineage in Rhaphidophoridae [Song et al, 2015] that apparently retained more ancestral habitat preferences [Karaman et al, 2011]. Hence, Dolichopoda species can be assumed to show secondary adaptations to cave habitats compared to other Ensifera.…”