All species concepts are rooted in reproductive, and ultimately genealogical, relations. Genetic data are thus the most important source of information for species delimitation. Current ease of access to genomic data and recent computational advances are blooming a plethora of coalescent-based species delimitation methods. Despite their utility as objective approaches to identify species boundaries, coalescent-based methods i) rely on simplified demographic models that may fail to capture some attributes of biological species, ii) do not make explicit use of the geographic information contained in the data, and iii) are often computationally intensive.

Pheromones are known to play an important role in butterfly courtship and may influence both individual reproductive success and reproductive isolation between species. Recent studies have focused on courtship in Hipparchia butterflies (Nymphalidae: Satyrinae) emphasizing morphological and behavioural traits, as well as genetic differences. Behavioural observations suggested a role for chemical cues in mate and species recognition, where the androconial scales on the forewings of these species may be involved in chemical communication between individuals. Cchemical-mediated signals have received relatively little attention in this genus. Here, we report the results of a three-year investigation of the volatile organic compounds (VOCs) released by Hipparchia fagi and H. hermione in order to identify differences in VOCs between these species where they live in syntopy. Our study was carried out using an array of cross-selective sensors known as an "Electronic Nose" (EN) that operates by converting chemical patterns into patterns of sensor signals. While the identity of volatile compounds remained unknown, sensor signals can be compared to identify similar or dissimilar chemical patterns. Based on the EN signals, our results showed that: 1) the two sexes have a similar VOCs pattern in H. fagi, while they significantly diverge in H. hermione; 2) VOCs patterns were different between females of the two species, while those of males were not.

Twenty-five populations of Dolichopoda cave crickets from Central-Southern Italy have been surveyed for allozyme variation at the products of 15 structural gene loci. The samples, as characterized on morphological bases, included six local populations of D. schiavazzii, one of D. aegilion, three of D. baccettii, six of D. laetitiae and nine of D. geniculata. The genetic distances between conspecific populations range from 0.014 to 0.240, those between species range from 0.054 to 0.501. The analysis of the cladogram, derived from D values, does not show a clear-cut situation within the laetitiae-geniculata group. Multivariate analyses of allele frequency data (PCA and TRGRPS) suggest that geography rather than morphology is the main factor explaining the distribution of the laetitiae-geniculata populations on the scatter diagrams. Peripheral cave populations adjacent to the Tyrrhenian and Adriatic coasts show high degrees of genetic differentiation from each other and from the inland cave populations. Most inland populations, on the other hand, appear to be genetically related, regardless of the geographic distance separating them and of the differences in epiphallus morphology. Mayr's model of peripatric speciation seems to account satisfactorily for the revealed geographic pattern of population differentiation in Dolichopoda. However the genetic mechanisms involved in this model require careful testing.