Some people really are “mosquito magnets” – and it probably has to do with the way they smell, according to a new study.
Researchers have discovered those who are most attractive to mosquitos, produce a lot of certain chemicals on their skin that are tied to smell.
And there is bad news for all those mosquito magnets: The bloodsuckers stay loyal to their favourites over time.
“If you have high levels of this stuff on your skin, you’re going to be the one at the picnic getting all the bites,” said study author Leslie Vosshall, a neurobiologist at Rockefeller University in New York.
To put mosquito magnetism to the test, the researchers designed an experiment pitting people’s scents against each other, explained fellow author Maria Elena De Obaldia.
A total of 64 volunteers from the university and nearby were asked to wear nylon stockings around their forearms to pick up their skin smells.
The stockings were put in separate traps at the end of a long tube, then dozens of mosquitos were released.
“They would basically swarm to the most attractive subjects,” Ms De Obaldia said. “It became very obvious right away.”
The biggest mosquito magnet was around 100 times more attractive to the mosquitoes than the last place finisher.
Mosquitos have ‘back-up plans’
The experiment used the Aedes aegypti mosquito that spreads diseases like yellow fever, Zika and dengue.
Matt DeGennaro, a neurogeneticist at Florida International University, said: “By testing the same people over multiple years, the study showed these big differences stick around.
“Mosquito magnets seem to remain mosquito magnets,” he added.
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The study found a common factor: Mosquito magnets had high levels of certain acids on their skin.
These “greasy molecules” are part of the skin’s natural moisturising layer, and people produce them in different amounts, Ms Vosshall said.
The healthy bacteria that live on the skin eat up these acids and produce part of our skin’s odour profile, she said.
The findings were published in the journal Cell and could help find new methods to repel mosquitoes.
Jeff Riffell, a neurobiologist at the University of Washington who was not involved with the study, said: “There may be ways to tinker with skin bacteria and change humans’ tantalizing smells.”
But he added, figuring out ways to fight off mosquitoes remained elusive, since the critters have evolved to be “lean, mean biting machines”.
Ms Vosshall added: “Mosquitoes are resilient. They have many backup plans to be able to find us and bite us.”
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