Why Do Mosquitoes Love You? Scientists Say Your Skin Might Be Exactly Their Type

Different mosquito species appear to prefer different combinations of human odor and skin microbes.

Do you ever feel like a mosquito magnet?

You know the scene. You are sitting outside with friends on a warm evening, swatting mosquitoes away every few seconds, while someone beside you seems to escape without a single bite.

For years, scientists have known that mosquitoes do not find all people equally appealing. But a new study suggests the explanation is more complicated than simply being a “mosquito magnet.” It may depend on which mosquito is doing the choosing.

Researchers tested 119 people against three common disease-carrying mosquito species and found that each species seemed to favor a different subset of volunteers. Someone highly attractive to one mosquito could be comparatively uninteresting to another.

No one was especially attractive to all three mosquito species.

So it seems that mosquito attraction emerges from a complicated mix of the chemicals drifting from our skin and the bacteria living there—a kind of personal scent signature that different mosquito species appear to read in different ways.

“We want to understand what people’s risks are for being bitten because all of these mosquitoes that we studied are vectors of disease,” Matthew DeGennaro, a neurogeneticist at Florida International University and senior author of the study, told Science News.

RelatedPosts

Blood-mimicking eco-insecticide baits and kills malaria-carrying mosquitoes
Scientists create fake skin which means people don’t need to get bitten in mosquito studies
A Malaria Drug Turns Mosquito Bites Into Vaccine Boosters (in Mice)
Here’s how Skrillex’s music could help fight Zika and dengue fever

Testing Human Scents

DeGennaro and his colleagues recruited 119 volunteers in Miami and tested them against Aedes aegypti, the yellow fever mosquito; Aedes albopictus, the Asian tiger mosquito; and Culex quinquefasciatus, the southern house mosquito.

×

Get smarter every day...

Stay ahead with ZME Science and subscribe.

Daily Newsletter
The science you need to know, every weekday.

Weekly Newsletter
A week in science, all in one place. Sends every Sunday.
No spam, ever. Unsubscribe anytime. Review our Privacy Policy.

Thank you! One more thing...

Please check your inbox and confirm your subscription.

For the two day-biting Aedes species, volunteers placed a forearm inside a 75-centimeter-long olfactometer. Thirty female mosquitoes waited at the opposite end, unable to bite but free to fly toward the volunteer’s scent.

Because Culex normally hunts at night, participants instead wore nylon sleeves for 12 to 16 hours, trapping their odor for later nighttime experiments.

The rankings barely lined up. Attraction to the two Aedes species showed only a weak correlation; comparisons involving Culex were weaker still. Some people attracted two species strongly, but nobody topped all three lists.

That finding adds an important wrinkle to earlier mosquito-magnet research. A 2022 Cell study found that people highly attractive to A. aegypti produced greater amounts of certain skin-derived carboxylic acids—and that their magnet status remained remarkably stable over several years. The new research does not contradict these previous results. Instead, it suggests that being a magnet for A. aegypti does not necessarily make you one for every mosquito.

The Scent Menu

To see what the mosquitoes were actually smelling, the researchers analyzed the cloud of chemicals coming off each volunteer’s skin. The results suggest that different mosquitoes are looking for very different things.

For A. aegypti, one compound was more abundant in people the mosquitoes favored: ethyl 2-methylbutanoate, a chemical with a fruity, apple-like smell to humans. But the stronger pattern ran in the opposite direction. People that the A. aegypti mosquito avoided tended to give off more of several compounds with piney, herbal, or citrus-like odors, including p-cymene and alpha-fenchene.

A. albopictus behaved differently. People it preferred had higher levels of 13 odor compounds, including sulcatone, which has a green, citrusy, fruity smell and has previously been linked to mosquitoes’ ability to recognize humans. Only one compound, 2-ethyl-1-hexanol—a mild, oily, slightly floral scent sometimes described as rose-like—stood out among people it found less attractive.

By comparison, A. albopictus seemed to follow attractive smells, while A. aegypti may rely more heavily on the absence of repellent ones.

The Culex species had a similar pattern to A. aegypti. People it found less attractive tended to give off more compounds such as limonene (lemony) and benzaldehyde (almond-like). The researchers suspect some of these chemicals may act as “do not land here” signals, although that still needs to be tested directly. People it favored tended to give off more alpha-fenchene (piney and camphor-like) and pseudolimonene (citrus-like) along with several other plant-like compounds.

Where do these smells come from? Partly from us, but partly from the bacteria living on our skin. Those microbes break down sweat and skin oils into airborne chemicals. That means your personal mosquito appeal may depend not just on your body chemistry, but on the microscopic community helping produce your particular scent.

This raises the obvious question.

Could We Make Ourselves Smell Worse to Mosquitoes?

That question has become an increasingly serious line of research.

In 2024, scientists genetically engineered common skin bacteria to produce less lactic acid, a mosquito attractant. When applied to mice, the altered microbes reduced mosquito attraction for up to 11 days, raising the prospect of long-lasting “living” repellents. It’s a start, but still far from a human product.

The new study could eventually make such approaches more precise. Instead of searching for one universal anti-mosquito smell, researchers may need repellents or microbial treatments tailored to particular mosquito species.

There are important caveats. The mosquitoes encountered people one at a time rather than choosing among several humans, and the Culex experiments used odor-soaked fabric rather than live arms. Chemical and bacterial signatures also remain correlations requiring experimental testing.

Still, the work offers an explanation for a familiar summer mystery. Your friend may not possess some magical immunity while you are universally delicious. You may simply be standing near a mosquito for whom your particular microbial perfume is exactly its type.

“We’re all trying to figure out how to stop people from getting sick,” Kaylee Marrero, a mosquito neurobiologist at Florida International University, told Science News. “Figuring out why [mosquitoes] are biting people is the best way to do that.”

The study was published in the journal iScience.