Analysis of Midgut Bacterial Communities in Larvae and Adult Mosquitoes of Invaded by Three Different Microorganisms.

The midgut microbiota of is crucial for the mosquito's development, nutrition, and immunity. However, its communities are also distinctively influenced by the colonization of different microorganisms, influencing its susceptibility to pathogens and transmission capacity. In this study, we investigated the effects of infections with , , and on the midgut microbial composition of . These microorganisms were inoculated into the midguts of third-instar larvae using a soaking method. Midgut samples were then analyzed through high-throughput 16S rDNA sequencing to assess bacterial load and microbiota composition of fourth-instar larvae and female adult mosquitoes. The results reveal that -colonized fourth-instar larvae (CO_4W) exhibited 20 unique genera, whereas the -colonized group (S_4W) had operational taxonomic units assigned to 194 bacterial taxa, including a notable decrease in . In addition, infection led to a significant reduction of in larvae, decreasing from 42.9% in the control group (CK_4W) to 0.9% in the -infected group (B_4W). Distinct microbial profiles were also compared between adult mosquitoes and fourth-instar larvae. Significant abundance changes were found in Firmicutes, Bacteroidota, and Proteobacteria among different groups. Metabolic pathway predictions using PICRUSt suggested that microorganism invasion enriched the pathways involved in carbohydrate metabolism and amino acid metabolism. This enrichment suggests that the microbiota may undergo specific adaptive responses to pathogen presence. Overall, our results provide new insights into the relationship between the invasion of microorganisms and midgut bacterial communities in mosquitoes.