Phylogeography of European dry-wood dwelling termites of the genus Kalotermes (Isoptera, Kalotermitidae).

The only native European dry-wood termites belong to the genus Kalotermes. Until recently, these termites were thought to belong to a single species, Kalotermes flavicollis. However, recent studies described two new species: K. italicus (Italy) and K. phoenicae (Cyprus, Middle-East). Moreover, molecular phylogenetic studies revealed divergent K. flavicollis sublineages in Corse-Sardinia and Southern France. As such lineages have been shown to frequently merge in same colonies, it is important to better understand the evolution of this genus in Europe. To widen the analyses on Kalotermes phylogeography, 22 colonies collected in 11 European localities were analyzed together with those obtained from previous studies, sequencing 912 bp of the mitochondrial genome (COI/tRNA-Leu/COII) in two individuals/colony. Phylogenetic analyses indicate that (i) K. italicus spreads from Central Italy to South France, (ii) the Corse- Sardinian lineage can also be found in the Italian peninsula, and (iii) the Southern France lineage extends to the Iberian peninsula. A time-calibrated phylogeny, computed on two mitochondrial markers (COI/tRNA- Leu/COII; 16S) on representative samples, showed that (i) extant European Kalotermes started differentiating ~32 Myr ago, with the separation of K. phoenicae; (ii) K. italicus and K. flavicollis split ~15 Myr ago; (iii) K. flavicollis sublineages diverged during and after the Messinian salinity crisis, ~6 Myr ago. Another European termite genus, Reticulitermes, comprises in the same area seven species/subspecies and all taxa showed marked intraspecific differentiation. Interestingly, recent analyses indicated that Reticulitermes differentiated in half time with respect to Kalotermes. The different nesting ecology and/or habitat constraints may explain this significant difference.