Fungal communities associated with larvae of two Culex spp. mosquitoes

In the aquatic habitat, mosquito larvae encounter diverse bacterial and fungal communities. While the impact of mosquito-associated bacterial community on mosquito life history has been recorded, knowledge of mosquito-fungus interactions is mostly limited to entomopathogens. The composition of mosquito-associated fungal communities and the drivers of their assembly remain largely unclear, particularly across mosquito species. In this study, we sampled water as well as the fourth instar of Culex restuans and Culex pipiens larvae from five and three sites in Manhattan, KS, USA, respectively. Fungal community composition was analyzed using metabarcode sequencing of the Internal Transcribed Spacer 2 (ITS2) on the Illumina MiSeq platform. Fungal taxa were assigned to operational taxonomic units (OTUs) using mothur (v.1.38.1) bioinformatics pipeline. Our analyses revealed variation in fungal community composition in larval breeding water across collection sites. In addition, we identified distinct fungal communities in guts and carcasses within each species. However, these patterns were less evident in Cx. restuans than in Cx. pipiens larvae. Together, this study provides the first insight into the fungal community composition and diversity in Cx. restuans and Cx. pipiens larvae. We identify the larval breeding site as the major determinant of mosquito fungal community assembly in these mosquito species. In addition, our data reveal that upon environmental acquisition of fungi the mosquito larval carcass provides an environmental filter, whereas this is not evident in mosquito guts. These findings recapitulate our previous analysis in Aedes albopictus larvae, suggesting a common pattern that shapes the fungal community associated with mosquito larvae.