Why do Mosquitoes Bite Some People More than Others?
Boston University researchers hope the science of smell can help stop mosquito bites—and deadly diseases
Why do Mosquitoes Bite Some People More than Others?
Why do Mosquitoes Bite Some People More than Others?
They’re the planet’s deadliest animal—and they can fit on your fingernail. Mosquitoes are the cause of more than half a million deaths globally per year—spreading life-threatening infectious diseases like malaria and dengue—with three quarters of the fatalities being children under the age of five.
And the problem could get worse: environmental changes are amplifying mosquitoes’ reach and impact, while recent research suggests the insects can even learn to love common repellents.
In her Boston University lab, researcher Meg Younger is looking for innovative new ways to stop mosquitoes, beginning with a big question: why do they bite some people more than others?
A BU College of Arts & Sciences assistant professor of biology, Younger believes the answer might be found in a mosquito’s sense of smell. She and her team use methods borrowed from neuroscience, including gene editing and brain mapping, to observe how mosquitoes detect different odorants and how that shapes their behavior—in this case, whether or not they bite someone.
“People have worked on mosquitoes for a long time and there have been a lot of great foundational studies, a lot of great behavior work,” says Younger, “but we weren’t able to really use the kind of genetic tools that we’re able to use in model organisms in mosquitoes until recently.”
Human odor contains hundreds of chemicals that differ from person to person, and Younger hopes to figure out which combination of specific chemicals are the most attractive to mosquitoes.
“There are over 3,700 species of mosquitoes. Only a handful bite humans, so many exist by drinking blood from very different animals. A few don’t drink blood at all,” says Younger. “Most of the mosquitoes that spread diseases to humans need the protein in a blood meal to mature their eggs.”
The majority of mosquito bites in the United States are nothing but an itchy annoyance, but the flying insects are responsible for a rising number of West Nile virus and eastern equine encephalitis cases—both are potentially fatal.
To test different odors, Younger has study participants insert their arm into the end of a flight tube, blocked off by a screen; on the other end of the tube, scientists release mosquitoes, and count how many become attracted to the scent and fly toward the arm.
Younger hopes that by understanding what specifically makes certain humans more enticing to mosquitoes, her research can eventually be used to create more effective traps and repellents.
“Imagine repellents that lasted for days instead of hours, that you didn’t have to reapply constantly, that weren’t so gross that they stopped people from wanting to use them,” Younger says. “I think those are a reality that can happen during my lifetime.”
Imagine repellents that lasted for days instead of hours, that you didn’t have to reapply constantly, that weren’t so gross that they stopped people from wanting to use them. I think those are a reality that can happen during my lifetime.
With this research, Younger says she’s had the opportunity to work with BU faculty who specialize in mechanical engineering, statistics, and biomedical engineering to answer different questions about mosquitoes and scents: How does odor move toward mosquitoes? Which mosquito species are statistically more likely to be around humans?
“I’ve found that the environment here is incredibly collegial, and BU also hired a lot of junior faculty around the time I was hired,” says Younger. “So, there was a lot of energy coming in and it’s been really fun to collaborate with people to come up with new projects.”
In the video above, watch as Younger demonstrates her mosquito research.
Younger’s research is supported by the Pew Charitable Trusts.
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