Effects of organic amendments on microbiota associated with the Culex nigripalpus mosquito vector of the Saint Louis and West Nile viruses. Effects of organic amendments on Culex microbiota

Pollution from nutrients in aquatic habitats has been linked to increases in disease vectors, including mosquitoes and other pestiferous insects. One possibility is that changes in mosquito microbiomes are impacted by nutrient enrichments and that these changes affect various traits including larval development, susceptibility to larval control agents, and susceptibility of the adult mosquitoes to pathogens. We tested this hypothesis using field mesocosms supplemented with low and high organic nutrient regimens, then sampled microbial communities associated with the naturally colonizing Culex nigripalpus mosquito vector. By high-throughput sequencing of 16S rRNA gene sequences, we found no significant differences in overall microbial communities associated with sampled mosquitoes, despite detecting discernable differences in environmental variables including pH, dissolved oxygen, and nutrient amendments. Nevertheless, indicator species analysis revealed that members of the Clostridiales were significantly associated with mosquitoes that originated from high nutrient enrichments. In contrast, members of the Burkholderiales were associated with mosquitoes from the low nutrient enrichment. High bacterial variability associated with the life stages of the Cx. nigripalpus were largely unaffected by levels of nutrient enrichments that impacted larval microbial resources, including bacteria, ciliates, and flagellates in the larval environments.