Microbiome Composition and Microbial Community Structure in Mosquito Vectors Aedes aegypti and Aedes albopictus in Northeastern Thailand, a Dengue-Endemic Area

Simple Summary This study characterized the microbiota associated with Aedes aegypti and Aedes albopictus larvae and subsequently emerged adults relative to the microbiota in water from their breeding sites in Thailand, a dengue-endemic area. The adults were processed shortly after eclosion and had not fed. Thus, their bacterial community must have been carried through from the larval stage (transstadial transmission). However, there were substantial changes in the representation of many taxa between the larval and adult stages. More bacterial genera were associated with Ae. aegypti than with Ae. albopictus. Wolbachia was dominant and was present at a significantly higher frequency in the Ae. albopictus adult males. The genus Blautia was particularly abundant in Ae. aegypti. Abundance of the genus Aquabacterium decreased from larva to adult in Ae. aegypti and Ae. albopictus. Adult Ae. aegypti females had greater proportions of Wolbachia, Blautia, Clostridioides, and Shinella than did males. The microbial community of Ae. albopictus larvae was dominated by the genus Serratia, while the genus Wolbachia was very abundant in adults of both sexes. In addition to demonstrating transstadial transmission, our results provide important information about microbial dynamics across mosquito developmental stages. Bacterial content in mosquito larvae and adults is altered by dynamic interactions during life and varies substantially in variety and composition depending on mosquito biology and ecology. This study aimed to identify the microbiota in Aedes aegypti and Aedes albopictus and in water from their breeding sites in northeastern Thailand, a dengue-endemic area. Bacterial diversity in field-collected aquatic larvae and subsequently emerged adults of both species from several locations were examined. The microbiota was characterized based on analysis of DNA sequences from the V3-V4 region of the 16S rRNA gene and exhibited changes during development, from the mosquito larval stage to the adult stage. Aedes aegypti contained a significantly higher number of bacterial genera than did Ae. albopictus, except for the genus Wolbachia, which was present at significantly higher frequencies in male Ae. albopictus (p < 0.05). Our findings also indicate likely transstadial transmission from larva to adult and give better understanding of the microbial diversity in these mosquitoes, informing future control programs against mosquito-borne diseases.