Comparisons of composition and temporal variability between the chironomid (Diptera: Chironomidae) and mosquito (Diptera: Culicidae) larval microbiomes and their Influence on larval development

Research concerning the microbiome composition and function in aquatic insects remains limited. Chironomids and mosquitoes are two distinct insect families that are both widespread and occupy similar aquatic habitats during the larvae stage. The proximity of their larval habitats and the potential overlapped route of microbial acquisition raise many questions as to how their microbiomes may overlap or differ in composition and function. In mosquitoes, the gut microbiomes have been shown to be highly variable depending on host species, geography, seasons, etc, but interestingly, different bacterial species may be equally capable of stimulating larval development. Less is known about the environmental variability and developmental function of the chironomid microbiome, despite that the chironomid larvae have been implicated as a natural environmental host for Vibrio cholerae, a significant human pathogen that causes cholera. In this study, we use 16S rRNA gene sequencing to examine how the microbiome composition and temporal variability differ between the mosquito and chironomid larvae collected from the same microenvironments (using experimental potholes) at different times. The results suggest that the microbiomes differ substantially, with a greater seasonal variation in the mosquito microbiome compared to that of chironomids. Microbiome transplantation experiments in axenic chironomids will be performed to test whether the taxonomically distinct microbiomes between the chironomid and mosquito larvae may similarly support chironomid larval development.