After extensive study, scientists have clarified why some people attract mosquitoes more than others. The amount of carboxylic acids produced by the skin appears to determine a person’s degree of attractiveness to these insects. Individuals who emit higher levels of these compounds tend to become a “mosquito magnet” because the scent acts like a potent lure, while those with lower emissions are less likely to be bothered.
This conclusion comes from research conducted at Rockefeller University in New York, led by Leslie Vosshall and María Elena de Obaldia. The findings, published in Cell, settle several lingering theories about what draws mosquitoes to humans and provide a clear biological basis for individual variation in mosquito attraction. The scientists describe these skin emissions as a family of molecules produced in varying amounts by each person, forming a distinctive chemical signature that contributes to personal olfactory identity.
“There is a strong correlation between high levels of these fatty acids on the skin and the likelihood of being swarmed by mosquitoes,” explained Professor Vosshall.
64 volunteers with stockings on their arms
This discovery emerged after three years of careful experimentation. Researchers asked 64 volunteers to wear nylon stockings on their forearms long enough for their skin to leave behind its molecular footprint. Mosquitoes were subjected to 2,300 distinct tests, observing their responses to the scented stockings and selecting among them based on perceived attractiveness. The insects were allowed to sample the various conditions and show preference in a controlled setup.
Aedes aegypti, a major vector for diseases such as Zika, dengue, yellow fever, and chikungunya, was used in the study to monitor how mosquitoes track and move through different tubes toward a chosen medium. The study tracked the insects as they demonstrated clear selection patterns in response to the different sock-derived scents.
Among the tested volunteers, the most attractive individual was identified as Subject 33, who attracted four times as many insect visits as the next most-receptive participant and dramatically more than the least-driven subject.
Samples were anonymized during the trials, ensuring experimenters did not know which stocking belonged to which participant. Yet the distinctive response pattern emerged quickly in any test involving Subject 33, with bugs repeatedly flocking to the corresponding socks within seconds after the trials began, as noted by De Obaldia.
Subsequent analyses sought to identify the factors behind these differences. Using chemical profiling, researchers examined 50 molecular compounds found on the volunteers’ skin and compared them against measures of mosquito attraction. The result showed that those who were most attractive produced noticeably higher levels of carboxylic acids than others.
The acids in question are values naturally produced by skin bacteria, contributing to a scent that is personal to each person. This discovery suggests a biological basis for body odor variations among individuals and how those odors influence mosquito behavior.
From here, researchers see potential paths for reducing mosquito bites. If the production of these acids can be managed—either by altering skin bacteria or by neutralizing the acids themselves—it may be possible to create new repellents that diminish this natural attractant.
Although the initial experiments focused on the mosquito species mentioned earlier, the researchers believe the same principles would apply to other mosquito populations as well. This expands the relevance of the finding beyond a single vector and supports a broader approach to bite prevention.
Reference work: ScienceDirect 2022 study on skin-emitted compounds and mosquito attraction [Citation: ScienceDirect 2022].
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