Meta-analyses ofCulexblood-meals indicates strong regional effect on feeding patterns
Authors: Griep Jet S. , Grant Eve , Pilgrim Jack , Riabinina Olena , Baylis Matthew , Wardeh Maya , Blagrove Marcus 
Published: May 2024

Understanding host utilization by mosquito vectors is essential to assess the risk of vector-borne diseases. Many studies have investigated the feeding patterns ofCulexmosquitoes by molecular analysis of blood-meals from field collected mosquitoes. However, these individual small-scale studies only provide a limited understanding of the complex host-vector interactions when considered in isolation. Here, we analyse theCulexblood-feeding data from 90 publications over the last 15 years to give a global insight into the feeding patterns ofCulexmosquitoes, with particular reference to vectors of currently emergingCulex-borne viruses such as West Nile and Usutu. Data on 26,857 blood-meals from 71 differentCulexspecies were extracted from published literature. The percentage of blood-meals on amphibian, avian, human, non-human mammalian, and reptilian hosts was determined for eachCulexspecies. Our analysis showed that feeding patterns were not significantly explained by mosquito species-level phylogeny, indicating that external factors play an important role in determining mosquito feeding patterns. ForCx. quinquefasciatus, Cx. pipienscomplex, andCx. tritaeniorhynchus, feeding patterns were compared across the world’s seven biogeographical realms.Culex tritaeniorhynchus, Cx. pipienscomplex andCx. quinquefasciatusall had significantly varied feeding patterns between realms. These results demonstrate that feeding patterns ofCulexmosquitoes vary between species but can also vary between geographically distinct populations of the same species, indicating that regional or population-level adaptations are major drivers of host utilization. Ultimately, these findings support the surveillance of vector-borne diseases by specifying which host groups are most likely to be at risk.

Author summary

Being aware of mosquito biting behaviour is essential to determine the threat of mosquito-borne diseases. Studying the feeding patterns ofCulexmosquitoes is crucial as these mosquitoes are vectors of currently emerging or re-emerging arboviruses such as West Nile and Usutu. Feeding behaviour ofCulexmosquitoes has been examined in many individual small-scale studies. These studies only focus on the feeding patterns in a specific area. To gain a more global understanding of these feeding patterns we analysed all availableCulexblood-feeding data from the last 15 years. In summary, data on 26,857 blood-meals from 71 differentCulexspecies was collected. For each species the percentage of blood-meals on different host groups was determined. We analysed the relationship between feeding patterns and mosquito phylogeny, which showed that phylogeny alone could not explain feeding patterns. These results indicate that external factors such as land use and climate could play an important role in determining feeding patterns. For further analysis we determined the feeding patterns for three important vector species,Cx. quinquefasciatus, Cx. pipienscomplex, andCx. tritaeniorhynchusin different biogeographical realms. All three species showed different feeding patterns in the included realms. Thus, the same species can have different feeding patterns in different regions, indicating the importance of local surveillance.