Microbial interaction networks and microbiome community structure from lab-reared and field collected mosquito vectors Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus.

It is emerging that microbial interactions are important in dictating microbiome composition and abundance in mosquitoes. However, we have a poor understanding regarding the scale and the nature of these interactions. To address the importance of microbe-microbe interactions and examine how blood feeding alters the microbiome of field mosquitoes we sequenced the bacterial microbiome of three mosquito vector, Aedes aegypti, Aedes albopictus and Culex quinquefasciatus caught in the field or reared in the lab. For field collections, we used traps that attracted host-seeking or ovipositing female mosquitoes to determine how physiological state affects the microbiome. Differences in specific genera, but not the overall microbiome composition, were seen when comparing mosquitoes caught in either trap, indicating that blood feeding alters particular bacterial taxa in the field. Our approach generated microbial interaction networks, which provide a global picture of microbe-microbe interactions, for Aedes mosquitoes. In general, we saw the networks from field mosquitoes were more complex compared to lab-reared insects and that Ae. aegypti microbiome networks contained hub taxa that were highly interconnected. To demonstrate that microbial interactions influence microbiome composition and abundance, we administered gut symbionts to Ae. aegypti larvae that either possessed or lacked their resident microbiota. Several bacterial symbionts infected mosquitoes that lacked their microbiota at a significantly greater prevalence and titer, indicating that the resident microbiota of mosquitoes inhibit bacterial colonization. Our results highlight that microbial interactions in mosquitoes are complex and are likely an important factor influencing microbiome diversity in mosquitoes.