Mosquitoes seem to have very specific tastes.
If you’re one of the lucky ones, the insects won’t want anything to do with you (although they’ll probably feed on you if they can’t find a more appetizing dish). If you’re unlucky, you won’t be able to leave a barbecue or campfire without scratching dozens of bites.
What is it about some people that seems to attract mosquitoes? More importantly, how do we stop the bugs from ruining our summers?
It’s helpful to understand how mosquitoes hunt.
They rely on sight and smell, according to professor Jonathan Day of the University of Florida in Vero Beach. They’re highly visual creatures, so they start out by looking for their victims.
Mosquitoes can easily see dark colors, including black, blue, and red. Like most insects, they’re also capable of picking up movement, so they’re more likely to home in on active targets (there’s another reason for this, which we’ll get to in a moment).
After they’ve spotted their prey, mosquitoes start to sniff.
Well, not “sniff,” exactly, but they rely on their sense of smell to help them track their targets.
The insects pick up on carbon dioxide, and if you’ve ever taken a middle-school biology class, you’ll know that you put out large amounts of carbon dioxide with every exhalation.
But not all breaths are created equal; people who are exercising will breathe more, and they’ll therefore become more attractive targets.
Likewise, larger people take larger breaths, so they’re more likely to discover a few mosquito bites after spending time outdoors.
That’s not the only cue that mosquitoes look for.
They’ll also look for acetone, estradiol (which the body creates when breaking down estrogen), and lactic acid.
There’s some evidence that pregnant women have an especially irresistible mix of chemical signals; a study published in The Lancet found that pregnant women attracted twice as many mosquitoes as their non-pregnant peers. Mosquitoes also seem to be capable of detecting body heat, which may have contributed to the outcome of that study.
Oh, and if you’re at a barbecue, we’ve got some bad news.
Another study indicated that “beer consumption consistently increased volunteers’ attractiveness to mosquitoes.” The alcohol seems to be the attractant, although we’ll need more research to confirm that theory.
But even if you abstain from your favorite summertime beverages, you might still be a target. A study published in the Journal of Medical Entomology demonstrated that mosquitoes have a preference for type O blood. The creatures’ least-favorite blood type was type A, while type B was in the middle.
If you want to avoid itchy red bumps, we’d recommend wearing bright, tightly woven clothing when heading outdoors in the summer. Use a mosquito repellant with DEET and/or lemon eucalyptus, as these seem to be the most effective way to mask your scent (all repellents work by masking, by the way—not by actually repelling). Oh, and don’t bother with citronella; according to a paper from the Journal of Insect Science, citronella torches are pretty much worthless.