STATEN ISLAND, NY – Mosquitoes are among everyone’s least favorite summer pests, causing itchy bites and spreading disease as they fly from host to host.
Some people seem to be “mosquito magnets” while others remain largely unscathed by sneaky bugs, and a new study has found the disparity may be linked to how our skin smells.
The research, led by Rockefeller University in Manhattan and published in the journal Cell, probed what makes mosquitoes attracted to some people over others and found fatty acids emanating from the skin may be to blame.
“There’s a very, very strong association between having high amounts of these fatty acids on your skin and being a mosquito magnet,” said study author Leslie Vosshall, lead from Rockefeller’s Laboratory of Neurogenetics and Behavior, in a statement.
The study took 64 participants and pitted their scents against each other to see which mosquitoes were most attracted to.
The researchers asked the volunteers to wear nylon stockings over their forearms for six hours a day to pick up odors coming from the skin. The scientists then placed the nylon stockings in a Plexiglas chamber divided into two tubes that each ended in a box containing a stocking before the mosquitoes were placed in the main chamber.
This process was repeated in a tournament-like format to find out which bottom was preferred by mosquitoes, and the results were compelling.
One participant, “Subject 33”, was over four times more attractive to mosquitoes than the next strongest suitor and over 100 times more attractive than the participant with the least attractive bottom.
“It would be evident within seconds of starting the test,” study author Maria Elena De Obaldia said in the statement. “That’s the kind of thing that really excites me as a scientist. It’s something real. It’s not splitting hairs. It’s a huge effect.
Once the data from the mosquito trials was compiled, the researchers set out to find out what made the samples different.
Using chemical analysis techniques designed to identify molecular compounds, the researchers found that people most likely to attract mosquitoes had higher levels of carboxylic acids compared to less attractive volunteers.
Carboxylic acids, produced in the fatty layer of our skin, contribute to our unique human smell.
Over the course of about three years, researchers found that study participants who were initially thought to be mosquito magnets remained attractive to insects over time.
“Some subjects were in the study for several years, and we saw that if they were a mosquito magnet, they were still a mosquito magnet,” De Obaldia said. “A lot could have changed about the subject or his behaviors during this time, but it was a very stable property of the person.”
While the researchers hypothesized that covering the skin of a highly attractive person to mosquitoes with skin bacteria from an unattractive person might provide a masking effect that protects people, they noted that more Studies should assess the protective capacity of this process.
Additionally, the study only used the Aedes aegypti mosquito, which spreads diseases like yellow fever and Zika. Further testing will need to be done to see if other mosquito species are attracted to similar fatty acids on human skin.
“I think it would be really, really cool to find out if this is a universal effect,” Vosshall said.