Mosquitoes use the same receptors to detect both carbon dioxide as well as skin odors, researchers from the University of California, Riverside report in the journal Cell.
The discovery helps explain why the pesky -- and often dangerous -- insects use carbon dioxide to track humans down before suddenly steering to exposed areas of the body, such as the ankles and wrists.
"It was a real surprise when we found that the mosquito's CO2 receptor neuron, designated cpA, is an extremely sensitive detector of several skin odorants as well, and is, in fact, far more sensitive to some of these odor molecules as compared to CO2," Anandasankar Ray, an associate professor in the Department of Entomology and the project's principal investigator, said in a statement.
Ray explained that the researchers had previously looked to the bug's antennae for clues to the bug's skin odor receptors, completely ignoring the maxillary palp organs where, it turned out, they were located.
Knowing what makes mosquitoes such effective hunters is a key step in disrupting the behavior and, ultimately, controlling the diseases they so often carry, including malaria, dengue fever and West Nile virus.
"Odors that block this dual-receptor for CO2 and skin odor can be used as a way to mask us from mosquitoes," Ray said.
What's more, the scientist explained that the odors could be used as a type of decoy to pull mosquitoes away from humans and into some kind of trap.
"These potentially affordable 'mask' and 'pull' strategies could be used in a complementary manner, offering an ideal solution and much needed relief to people in Africa, Asia and South America -- indeed wherever mosquito-borne diseases are endemic," he said.
Funding for the study was provided by the National Institute of Allergy and Infectious Disease, the National Science Foundation, University of California Global Health Institute and the Bill and Melinda Gates Foundation.