Further acquisitions on systematics relationships within the genus Orchesella (Collembola, Entomobryidae) using allozymes.

Inter- and intraspecific genetic variability has been studied in 17 populations of six different species of the genus Orchesella from central Italy by means of allozyme electrophoresis. The electrophoretic results are consistent with the determination of the species based on their patterns of pigmentation, revealing a very high level of genetic divergence between them as a result of the age of the genus and its long-time evolution from the mainland with populations from the Tuscan archipelago. Two different approaches for evaluating levels of interpopulational gene flow have revealed the presence of a remarkable genetic isolation between them. The reason for this differentiation has to be found in the paleogeographical rearrangements that occurred in the Mediterranean and the Apennine areas during the Tertiary and Quaternary.