Phylogeography and colony structure of dry-wood dwelling termites of the genus Kalotermes (Isoptera, Kalotermitidae) in Southern Europe

According to the most recent phylogenetic and phylogeographic investigations, the Kalotermes genus (Kalotermitidae) includes three different mitochondrial lineages of K. flavicollis and the new K. italicus species. In some Italian populations extreme colony fusion events were observed, with mixed families composed by up to nine maternal lines belonging to different genetic lineages or even to different species. In termites with the same nesting type, colony fusions lead to the death of queens and kings allowing false workers (pseudoergates) to evolve into reproducers and to inherit the colony (Accelerated Nest Inheritance). To widen the analyses on Kalotermes phylogeography and colony structure, we sequenced 912 bp of the mitochondrial genome, corresponding to COI/tRNA-Leu/COII, in two individuals from each of the 21 colonies collected in 11 European localities. In four colonies showing haplotypes of different genetic lineages/species, five-eight individuals per colony were further analyzed. A more detailed biogeographic scenario is obtained, with overlapping distribution areas of the considered lineages/species. Moreover, data confirm that mixed colonies with haplotypes of different genetic lineages/species may show more than two maternal lines. On the whole, colony fusions appear to occur more frequently than expected on the basis of eusociality models. Moreover, the possibility of hybridization between different genetic lineages or species could facilitate the fusion of more than two colonies wiping out mechanisms of nest-mate recognition. This analysis, therefore, demonstrates that dry-wood dwelling termites might be an interesting framework to study the evolution and maintenance of eusociality.