Mosquitoes love to feed on some of us more than others. I figure I’m one of the more appetizing humans; I get a lot of bites if I’m not wearing bug spray, and when I was pregnant I got tons. It turns out there are a few reasons why.
They follow your breath
We inhale oxygen, and we exhale carbon dioxide. That’s just a fact of our metabolism. And so mosquitoes (and many other biting insects) start their hunt for a target by looking for the carbon dioxide “plume” that emanates from a human or animal body.
The larger you are, the more carbon dioxide you breathe out. (This may partially explain why children don’t get as many bites as the rest of us.) If you’re exercising, you’ll be breathing even more.
Moving around disrupts that plume, though. If you go for a run, you’ll be breathing plenty of CO2, but you’re constantly outrunning it. A mosquito that finds itself downwind of you won’t be able to follow you and keep up.
Or to disrupt the cloud in another way, you can find a breezy spot to sit, or turn on a fan. By blowing the carbon dioxide away, you’re making yourself harder for mosquitoes to find.
After a mosquito sniffs you out, it will start looking for a large, warm object. (That’s you.) Some research suggests mosquitoes have an easier time finding you if you are wearing dark or bright colours, but people in light coloured clothes still get bitten plenty.
They smell and taste your skin
If you were to lick your skin, and that of your friends (please don’t), you’d probably find that everybody tastes just a little different. Research on mosquito preferences finds that some species prefer the flavours associated with certain genetics. We each have different bacteria living on our skin, and that seems to affect mosquitoes’ preferences as well.
But it’s hard to give blanket advice on how to make yourself less appetizing. Some studies have found that people get bitten more often if they’ve been drinking alcohol, or if they have a certain blood type, but those factors are likely to vary between mosquito species. (A lot of research is done with the mosquitoes that transmit malaria, for example; those aren’t the same type that are biting you at dusk in your backyard in the US.)
One thing a lot of mosquitoes look for is lactic acid, found in sweat. If you’ve been sweating, it might help to take a shower or wipe off the sweat (with baby wipes, perhaps?) before spending time in a mosquito-prone area.
Your body may react more strongly to the bite
Just because you get more itchy, annoying mosquito bites than a friend doesn’t mean you necessarily got bitten more; it may also be that your body reacts more strongly to them.
The itchiness of a mosquito bite is a reaction that your own immune system cooks up. You are, in effect, allergic to mosquito saliva. You can have a mild allergy or a more severe one, and this can even change throughout your life. For example, when I was pregnant, mosquito bites were itchy torture. At other times, they’re just a minor annoyance.