Phylogenetic analysis of Phlebotomus species belonging to the subgenus Larroussius (Diptera, psychodidae) by ITS2 rDNA sequences

In the genealogy of Phlebotomus (Diptera: Psychodidae), morphological analyses have indicated that the subgenus Larroussius is a monophyletic group which is most closely related to the subgenera Transphlebotomus and Adlerius. We conducted a phylogenetic analysis of the relationships among six representative species of the subgenus Larroussius and one species representatitive of the Phlebotomus subgenus, assessing sequences of the Second Internal Transcribed Spacer (ITS2) of the ribosomal RNA (rRNA). Three of the species (P. perniciosus, P. ariasi and P. perfiliewi perfiliewi) were collected in different parts of the Mediterranean area. The trees estimated from parsimony and neighbour-joining analyses supported the monophyly of the Larroussius subgenus inferred from the morphological analysis. According to our data, P. ariasi may be a sister group to the rest of the Larroussius subgenus, although additional sequence data are needed to confirm this observation. Our results suggest that P. perniciosus and P. longicuspis are distinct species, in spite of the fact that there are only slight morphological differences. The strict congruence between the phylogeny of the Larroussius subgenus inferred from the ITS2 sequences and that based on morphological studies further confirmed the ability of the spacer sequence to identify recently-derived affiliations.