Phylogeny of the Old World Phlebotomine Sandflies (Diptera: Psychodidae) with Special Reference to Structural Diversity of Female Spermathecae

Abstract

The degree of structural variation of the spermathecae among phlebotomine sandflies, the vectors of leishmaniases in warm parts of the world, is unique among the blood sucking Diptera. The spermathecal structure is redefined using a series of new characters obtained from ultrastructure study together with a revised morphological terminology is adopted for male genitalic features to bring phlebotomines in line with other families. A cladistic analysis of 33 taxa, representing all the subgenera of Old World phlebotomines based on spermathecal characters and male genital characters suggests that: (i) the Old World phlebotomines are monophyletic in origin relative to the outgroup, Sycorax sp.; (ii) Idiophlebotomus sp and Spelaeophlebotomus sp are basal lineage showing sister-group relationship; (iii) the genus Sergentomyia is polyphyletic and encompasses the genera Chinius and Grassomyia, the subgenus Ph. (Australaphlebotomus) sp.; (iii) the genus Phlebotomus is a monophyletic taxon and its subgenera form sister group relationship between ( Larroussius sp + Transphlebotomus sp.) + Adlerius sp and ( Kasaulis sp. + Euphlebotomus sp. + Oriental Anaphlebotomus sp.) + ( Phlebotomus + Synphlebotomus sp. + Paraphlebotomus sp.), the subgenus Anaphlebotomus appears to be paraphyletic among the subgenera of Phlebotomus s.l.; (v) Co-cladogenesis (parasite-vector co-speciation) provides support for monophyletic evolution of leishmaniases and Phlebotomus sensu lato i.e. ( Leishmania infantum infantum + Le. donovani) and Le. major + Le. tropica being transmitted by the species of subgenera ( Larroussius sp & Adlerius sp. + Euphlebotomus sp.) and ( Phlebotomus + Synphlebotomus sp. + Paraphlebotomus sp.) respectively.