Mosquito bites are a true nightmare for many people who become their favorite menu item, even when they are surrounded by other individuals whom, however, they completely ignore. We can’t ask why some people bite more than others, but there are certain factors that seem to influence their preferences, and a new study has found that the smell of the soap we use can have a lot to do with attracting or repelling bites. these insects.
We know that the type of soap we use in daily hygiene can change the perception that others have of our body odor, but can it increase or reduce the attraction we exert on mosquitoes? In addition to our blood, mosquitoes also like plant nectars, so if we impregnate ourselves with perfumes derived from these or that imitate them, this could influence their choices.
“Everyone smells different, even after applying soap; Your physiological state, the way you live, what you eat, and the places you go all affect the way you smell.” “And soaps drastically change the way we smell, not only by adding chemicals, but also by causing variations in the emission of compounds we already produce naturally,” biologist Chloé Lahondère, co-author of the study, explained in a statement. which has been published in the iScience magazine.
Stop being attractive to mosquitoes thanks to soap
The study was carried out by researchers from Virginia Tech University, in the United States, who analyzed the chemical odors emanating from four people before and after washing with four brands of soap –Dial, Dove, Native and Simple Truth–, who also studied . In the odor profiles of these hygiene products, they identified four chemicals related to mosquito attraction and three related to repulsion.
“Applying soap to the skin drastically changes the way we smell, particularly by adding many chemicals emitted by plants to the composition of our body odor.”
The participants washed one arm with the soap, while the other was left as it was, and covered with a nylon sleeve. This process was repeated with all the soaps. After an hour, the researchers placed the nylon sleeves in a mesh-covered cup filled with adult female Aedes aegypti mosquitoes, a species that transmits diseases such as dengue, yellow fever or Zika. They only used mosquitoes that had recently mated, because male mosquitoes only feed on plant nectar, while females only feed on blood after mating.
The researchers found significant differences in mosquito preferences before and after soaping, although to varying degrees based on soap brands and volunteers. “Our main results were that, in fact, applying soap to the skin drastically changes the way we smell, particularly by adding many chemicals emitted by plants to the composition of our body odor,” said Clément Vinauger, lead author and neuroethologist. .
“Our work also revealed the importance of the interaction between the specific chemicals in soap and the body odor of each specific individual in determining whether a person would become more or less attractive to mosquitoes after applying soap to the skin.”
In only a few volunteers, for example, mosquitoes were more attracted to their scent after washing with Dove and Simple Truth soap, while Native soap was more repellent to them. Potential chemicals in these soaps were also identified that appeared to be primarily responsible for attracting or repelling insects. Among them, a coconut-scented chemical appeared to be the most effective in keeping mosquitoes away.
“What really matters to the mosquito is not the most abundant chemical, but the specific associations and combinations of chemicals, not just from soap, but also from our personal body odors. All the soaps contained a chemical called limonene, which is a known mosquito repellent, but despite the fact that this was the main chemical in all four soaps, three of the four soaps we tested increased the attraction of mosquitoes,” he concludes. Vinauger.
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