Host species determines the composition of the prokaryotic microbiome in Phlebotomus sand flies

Sand-flies of the subfamily Phlebotomine are vectors of the parasite Leishmania sp. which infects humans and mammals. Recent studies have unraveled the major role of the gut microbiome of insects as a major modulator of their biological cycle and infectivity. However, we still have limited knowledge about the factors shaping the gut microbiome of sand-flies. We tested the hypothesis that insect species is a major modulator of the gut microbiome of Phlebotomus spp. Sand-flies we collected in traps from the island of Leros, Greece and morphologically classified to P. papatasi, P. tobbi, P. neglectus, P. similis, the former being the most frequently collected species. The prokaryotic gut microbiome was determined via amplicon sequencing of the 16S rRNA gene. P. papatasi supported a largely different gut bacterial community compared to the other species which clustered closely together. This divergence stemmed from the dominance of two OTUs belonging to Wolbachia and Spiroplasma. P. neglectus also showed low bacterial diversity dominated by an OTU belonging to Wolbachia. Conversely, the bacterial microbiome of P. tobbi and P. similis was more diverse characterized by the presence of several less dominant OTUs. The archaeal community was not diverse with the most dominant OTUs belonging to Thaumarcheota, Euryarcheota and Nanoarchaeota. Our study provides pioneering data on the bacterial and archaeal microbiome of Phlebotomus sandflies and demonstrates for the first time the strong filtering effect of genotype on the composition of the gut prokaryotic microbiome. On-going studies will further address the interaction of Leishmania with the gut microbiota of Phlebotomus sandflies.