Trans-stadial fate of the gut bacterial microbiota in Anopheles albimanus

Gut microbiota communities in mosquitoes are influenced among others, by developmental stage. There is evidence that the aquatic environment where larvae feed influences the mosquito gut bacterial community composition with only a subgroup of these bacteria been transmitted trans-stadially to adults. This study evaluated the gut bacterial composition of Anopheles albimanus larvae, emerged and circulating mosquitoes, as well as water from the larval habitat, to elucidate transitions in these bacterial communities and determine the final composition in circulating mosquitoes. A 16S rRNA Illumina sequencing allowed to determine that Proteobacteria was the most abundant phylum in larvae (72.4%), emerged mosquitoes (75%), circulating adults (45.4%) and water from the larval habitat (79.1%). A core microbiome analysis evidenced that Enterobacter, Bacillus and Staphylococcus genera were the core bacterial microbiota (OTUs detected in >90%) in the four groups evaluated. PCoA cluster based on Jaccard and Bray Curtis distances showed two main bacterial clusters, one comprising the emerged and circulating adults, and the other the larvae. The results indicated that the gut microbiota of An. albimanus larvae is composed of bacteria acquired from the larval habitat; then, a rearrangement of the bacterial communities occurs in the trans-stadial passage. However, the higher bacterial richness detected in circulating adults suggests bacterial acquisition from the terrestrial environment where the mosquito feeds. Finally, the trans-stadially passage of some bacteria makes of interest their evaluation as candidates for paratransgenic control.