Host availability and host contacts of mosquitoes using environmental DNA

Host availability is an important parameter when studying vector-borne diseases, especially in the case of opportunistic mosquito vectors. To study host feeding patterns of mosquitoes in the field, we integrated three sources of information: 1) host feeding, by identifying the origin of DNA in bloodmeals; 2) host contact, inferred from eDNA detected on mosquito legs; and 3) host availability, estimated via airborne eDNA using the frequency of host detection via airborne eDNA as a proxy for their abundance. At four locations in the field, we deployed Burkard 7-day spore traps next to BG-sentinel 2 traps to capture airborne eDNA and blood-fed mosquitoes, respectively. We found that mosquitoes caught on dairy farms fed most frequently on the animal species that were among the most abundant species. However, Culex pipiens pipiens fed significantly more on birds compared to Cx. pipiens molestus, Anopheles daciae, An. messeae and Culiseta annulata (P < 0.01), which fed more on mammals. Animal DNA on mosquito legs could be detected, but results were inconsistent and prone to contamination, thereby limiting the use of mosquito legs to study host contacts. Policy implications: Integrating airborne eDNA monitoring with bloodmeal identification is a promising approach to study host-vector interactions with the aim to better assess vector-borne diseases risks.