You can always count on a mosquito bite to ruin a fun summer evening. But you've probably noticed that one of your friends (or maybe it's you) seems to have an uncanny ability to attract all the little fiends, while the rest of your crew gets off relatively easily. Although scientists don't know the full picture yet, they do have some pretty good ideas about why the little guys are so attracted to certain people — and how to make it stop.
You've probably heard that your blood type, sweat, or a multitude of other things can attract mosquitoes. While some of those "attractions" are more plausible than others (sorry, it's definitely not your blood sugar content), Joe Conlon, PhD, technical advisor to the American Mosquito Control Association, says it all comes down to the secretions your skin's putting out.
"There’s no question that everyone has a different odour about them," says Dr. Conlon. "The mosquitoes have honed in on this and have determined that some people should be on the menu more often than others."
One major factor is the amount of carbon dioxide you release. "Carbon dioxide acts more as an excitant," Dr. Conlon explains. "It’s not necessarily going to get them to land on you, [but] it gets them off of the leaf and into a pursuit mode." Some people, such as pregnant women, definitely exude more carbon dioxide than others.
Mosquitoes follow that carbon dioxide trail to you in a zig-zag pattern, and when they get within a foot of you, your body temperature starts to play a role. Mosquitoes favour those of us who sweat more, for example, because that helps waft our delicious scents toward the insects.
We don't all react the same way to a bite, either. For instance, Dr. Conlon says those with fairer or ruddier complexions may have more noticeably irritating reactions, even if they're not actually getting bitten more often than those with darker complexions.
As a recent study suggests, all of these factors may come down to an inherited genetic predisposition to being mosquito bait. "It's mostly to do with body odour, which is controlled in part by our genes," writes James Logan, PhD, lead author of the study, in an email.
There's still plenty more research to do. Because mosquitoes are responsible for transmitting some of the world's most serious life-threatening diseases, including things like malaria and dengue fever, scientists are continually interested in figuring out what attracts the insects — and what keeps them away.
Dr. Conlon explains that nearly all of the research has been done on just a few species of mosquitoes. So it's important to keep in mind that "there’s considerable difference in what each [species of] mosquito deems as attractive — [and] we’re only scratching the surface," he says.
For now, Dr. Conlon says we can stick to the tried-and-true methods of repelling the little beasts: Make sure to drain any standing water in your area to keep mosquitoes from breeding in your yard. Try wearing multiple layers of loose-fitting clothing, which may or may not be feasible in this oppressive summer weather. Or, you can try some tight-weave athletic wear that won't let mosquitoes bite through. And defend yourself using EPA-registered repellants, which are required to be safe and give you at least two hours of protection.
Yes, mosquitoes and their bites are an unfortunate fact of summer, but at least there are proven ways of getting them to go away — which is necessary for warding off both discomfort and disease. Here's to an itch-free summer.