Following the Apennines: updating the distribution of Formica clara and Formica rufibarbis in Italy (Hymenoptera, Formicidae)

Abstract

Formica clara is an ant species that was historically confused with other congeneric species such as F. rufibarbis until recent taxonomic developments. Due to such misunderstanding, while F. clara is known to occur across a very large Eurasian range, its actual distribution in the Mediterranean is often scarcely known. The distribution of F. clara and F. rufibarbis in Italy is remarkably obscure since almost all records, which spanned across the whole Italian peninsula and Sardinia, were published between 1834 and 1969, at times when the two species were treated as a single taxon. The few modern records of the species testify the presence of F. rufibarbis in the Alps, and F. clara in the Alps, the Po Plain and Sardinia. Here we present some new distributional data on the two species, extending the geographic range of F. rufibarbis south to the Northern Apennines (225 km) and that of F. clara throughout the Italian Peninsula south to Sicily (900 km). These results significantly change the previous understanding of F. rufibarbis as a widespread species while suggesting F. clara to be a common mountain species through the whole Apennines. Further investigations will be needed to verify whether F. rufibarbis occurs farther south.