Demystifying Science | Who are the Mosquito Magnets?

Every week, our journalist answers readers’ scientific questions.

Why do some people attract more mosquitoes? – Pierre Latulippe

Because female mosquitoes are attracted to molecules that some individuals release more than others.

“It’s clear that some humans are more attractive to mosquitoes than others,” says Laura Duvall, a Columbia University biologist who studies the molecules that drive mosquitoes to feed on human blood. “It’s an area where there’s a lot of study, but still a lot of uncertainty.”

A study to which M^me Duvall collaborated on, but is not a co-author, she concluded in 2022 in the journal Cell that certain molecules called “carboxylic acids” present in human odors are more attractive to female mosquitoes. These molecules double the probability of being bitten by a mosquito.

Female mosquitoes bite humans – some species prefer other mammals – to produce eggs. Males do not bite. Both sexes need pollen to feed. M^me Duvall recently identified molecules on the preprint site bioRxiv that prompt female mosquitoes to bite when they are ready to produce eggs.

This avenue of research – determining which molecules in the female mosquito trigger the search for prey – is also very active. In June, in the journal PNASa study has identified another molecule involved in this vampiric drive. “It’s kind of like the human molecule that Ozempic inhibits,” says the author of the latest study, Michael Strand of the University of Georgia.

Attract to repel

Which of the two avenues of research holds the most promise for new insecticides? Interfering with the mosquito’s own molecules that drive it to feed is tricky because it could affect other species, Strand notes.

As for research into the molecules in human odors that most attract mosquitoes, it could lead to traps that would keep mosquitoes away. “You would think that you would put this odor in a place far from where you are barbecuing,” says M.^me Duvall.

Other avenues of research on molecules aimed at explaining why mosquitoes bite certain people more remain inconclusive for the moment. These include, among other factors, pregnancy, beer consumption, blood type, garlic consumption or B vitamins. An association with the human microbiota has also been suggested. It is also difficult to see whether the molecules studied so far are emitted in a stable manner by humans, an essential piece of information to clarify the enigma of “mosquito magnets”.

Do you have a scientific question? Write to us