The smell of coconut may help keep mosquitoes away: Study

What makes a person extra repulsive to a mosquito? It might be the scent of coconut.

That was one of the more curious findings of a small study published Wednesday in the journal iScience, which looked at whether different scented soaps made people more or less attractive to mosquitoes.

They found that the answer wasn’t as simple as use this soap, not that one. Instead, the interplay of scents between human bodies and the products they used proved to be much more complicated.

“It’s a simple question with a very complex answer,” said the lead study author, Clement Vinauger, an assistant professor of biochemistry at Virginia Tech who studies the molecular genetics of how mosquitoes choose their prey. “What really matters is how the chemicals in the soap combine with the chemicals of the individual person.”

That could explain why coconut seemed to repel mosquitoes, while citrusy scents known to repel the pesky insects instead appeared to attract them.

A winning combination

Only female mosquitoes seek out blood, and only after they mate, when they need its nutrients for their eggs to develop.

The rest of the time they feed on sweetly scented flowers.

When we use perfumed products on our skin, “we are blurring the lines between humans and plants,” Vinauger said. “Mosquitoes have a single resource that smells like both.”

A person’s scent comes from a unique combination of more than 350 chemicals, some of which are produced by the body and others that are produced by bacteria that live on and in us.

Everyone has the same chemicals, just in different ratios, some more attractive to mosquitoes than others, said Ali Afify, an assistant professor of biology at Drexel University in Philadelphia, who wasn’t involved with the new study.

There are a few known variables. Pregnancy or illness can change the chemical ratios and alter your attractiveness to mosquitoes. So can drinking beer or being physically active. Perfumes, soaps and lotions also play roles.

“Everything you use on your skin can make you more or less attractive to mosquitoes,” Afify said.

It could be that certain scents amplify repellent or attractive compounds that naturally exist in humans, rather than eliciting those responses themselves, said Christopher Potter, an associate professor of neuroscience at the Johns Hopkins University School of Medicine in Maryland who studies mosquito olfaction.

In the end, the team identified four chemicals that were associated with being slightly more attractive to mosquitoes and three that appeared to repel them, but the results were generally weak and variable for all chemical scents tested except one: coconut.

The new research was a proof-of-concept study, meaning the team set out to determine whether or not there was a phenomenon that warranted future research.

It’s still unclear whether the coconut scent itself repels mosquitoes or whether it enhances one of the naturally occurring chemicals on human skin that is a repellent. It’s also unclear whether that is true for all of the roughly 200 species of mosquitoes that feed on humans or just the Aedes aegypti mosquitoes used in the study.

NBC News

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