Abstract
Female mosquitoes are reproductively obligate bloodfeeders which feed on vertebrate blood to obtain nutrients required for egg production (driving transmission of vector-borne pathogens in the process), and which rely on plant sugars for their non-reproductive energy requirements. Male mosquitoes, on the other hand, are thought to rely exclusively on plant sugars for their energetic needs; indeed, this dichotomy is one of the central tenets of medical entomology. Here, we show that male Culex tarsalis and Aedes aegypti mosquitoes will readily take blood from a membrane feeder when reared under dehydration conditions with no toxic effects. Mosquitoes with impaired humidity detection do not increase their bloodfeeding rates when dehydrated compared to wild-type controls. While conventionally reared males ignore a human host, dehydrated males are attracted to and attempt to probe, with some success, although they cannot access host capillaries. However, they will take blood from a vertebrate host wound. When fed a blood meal containing West Nile virus, male mosquitoes can become infected with and orally transmit the pathogen at rates and titers equivalent to females. Finally, vertebrate DNA, likely from blood, was detected in wild-caught specimens of male Culex quinquefasciatus mosquitoes from Texas. These data suggest that under some circumstances male mosquitoes may be able to probe and/or ingest blood and transmit pathogens to vertebrate hosts, and that their role in maintaining pathogen transmission cycles should be re-examined.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
New data have been added (generated by Laroche and Holley) about vertebrate DNA detection from wild male mosquitoes collected in Texas. These data suggest that male mosquitoes may actually be feeding on vertebrates in nature and give further context to previous laboratory results. In addition, several new references have been added and the text slightly altered for clarity within context of these new added results, and a new Supplementary table added. Holley and Laroche have been added as new co-authors on this revised manuscript version.