Abstract
Mansonia humeralis is a neotropical mosquito common in floodplain ecosystems and a potential host of Mayaro virus in the Amazon region. Studies show that bacterial communities associated with the midgut of mosquito vectors can mediate insecticide detoxification and modulate vector competence. Understanding the characteristics of the intestinal microbiota, and the factors that shape them, is essential for effective mosquito control. This study investigated the influence of bacterial communities in water from the larval environment on the composition and bacterial diversity in Ma. humeralis larval intestines and characterized the midgut microbiota of adult females with and without apparent blood. Samples were obtained from the Jirau Hydroelectric Plant, Madeira River, AM, Brazil, and their bacteria characterized using the 16S rRNA molecular marker. A total of 402 bacterial Amplicon Sequencing Variants (ASVs) were identified to genus level. The sample groups (water, larvae, blood + and blood-) had distinct bacterial communities, especially the larvae, probably due to the intense feeding activity which occurs at this stage. The phylum Proteobacteria was dominant in water, blood + and blood- (52.5; 99 and 98%), respectively, while Firmicutes dominated in larvae (45%). The most abundant taxa in water were: ASV Comamonadaceae (11.7%) and hgcI_clade (9.6%), in larvae: ASV Synergistaceae (11.1%) and ASV Rhodocyclaceae (7.8%), in blood-: Serratia (46.9%) and Asaia (12.6%) and, in blood+: ASV Enterobacteriaceae (54.5%) and Serratia (21.1%). Some 19% of the taxonomic groups from water were also recorded in larvae, while 46.7% of blood- microbiota were present in blood+. Wolbachia, Acinetobacter and Enterobacter bacteria were recorded at low frequency in all samples. This result provides a powerful tool for understanding the ecology of the intestinal microbiota of Ma. humeralis and the relationships with the ambient microbiota derived from larval filter, and adult blood, feeding. The results will also be useful for future studies which focusing the development of potential tools for the biological control of this vector.