Structure and Diversity of the Microbiome in Amazonian Sand Flies: Insights into Vector–Microbe Interactions

This study uses high-throughput sequencing of the 16S rRNA gene and specific PCR to analyze the microbiome and identify secondary endosymbionts in sand flies from the Amazon region, important vectors of parasitic and viral diseases. Specimens of Psychodopygus, Trichophoromyia, Nyssomyia, Trichopygomyia and Brumptomyia were collected and analyzed. The results revealed that the richness, diversity, and composition of the microbiome are influenced by several factors, such as insect species specific composition, and insect sex. The core microbiome community was represented by 18 genera, with Novosphingobium, Cutibacterium, Methylobacterium and Staphylococcus being the most prevalent. The highest diversity at the genus level was observed in sand flies of epidemiological relevance as Psychodopygus and Nyssomyia, dominated by Novosphingobium (66.5%), Cutibacterium (29.4%) and Methylobacterium (20.4%), while in non-vectors such as Trichophoromyia, Delftia predominated (59.9%). Endosymbiont analysis showed a high prevalence of Cardinium (20%) and Wolbachia (33%), as well as the presence of Spiroplasma, Arsenophonus and Rickettsia. In addition, some bacterial genera related to the inhibition of parasite development, which have entomopathogenic activity and are involved in the degradation of insecticides were identified. Our results are relevant and contribute to the knowledge of the characterization of the microbiome and the endosymbionts in leishmaniasis vectors in the Amazon region and show promise for improving vector management, highlighting the importance of investigating their interaction with pathogens and their impact on vector biology.