Of mud and mosquitoes: Investigating the microbiome of Deinocerites cancer

Microbial communities play a critical role in influencing mosquito life cycles by impacting reproduction, development, immunity, and pathogen transmission. While larval habitat is known to influence mosquito microbiota, the ecological drivers of microbe-host dynamics remain understudied. This project examines the specialized crabhole mosquito Deinocerites cancer to assess how seasonal and spatial variability in larval habitat impacts microbial diversity across life stages. Adults, larvae, and their surrounding matrix (water and sediment) were sampled from at least ten crab burrows per season near two distinct water bodies during summer 2024 and spring 2025. Principal Component Analysis of physico-chemical parameters revealed consistent environmental differentiation by water body type and season, driven by sulfide, nitrate, and conductivity. Preliminary microbiome analyses revealed a striking pattern: microbial richness declined sharply from water and sediment to larvae and then to adults, suggesting strong microbial filtering during development. Larval microbiomes were compositionally reduced and dominated by taxa associated with aquatic and nitrate-rich environments. Contrary to prevailing assumptions, interindividual variability among larvae was low. Adult microbiomes were even more reduced and highly sex specific. Females were found to be predominantly colonized by Cardinium, an endosymbiont which, while known to manipulate reproduction in arthropods, had not previously been documented in mosquitoes. These findings underscore the role of environmental filtering and host sex in shaping mosquito-associated microbiomes and raise new questions about symbiont function in D. cancer. Ongoing sequencing will further clarify how environmental context shapes mosquito-microbe interactions and may reveal novel microbial candidates for vector control.