There is always one. That person who, no matter what, always comes back from spending a warm summer evening sitting outside covered in mosquito bites. While there is some evidence to suggest that people are really bad at knowing whether or not they are the unlucky ones, there are things that can increase your likelihood of getting bitten. Although there is lots of anecdotal evidence from people about what influences the little critters to bite, from eating garlic to having “sweet” blood, there are some aspects that have been proven by science to genuinely increase your chances.
Unfortunately, not all of the causes are something you can actually do something about. Take blood type, for example. One study has found that while those who have blood type O coursing through their veins are more likely to get a less than friendly visit from a mosquito than other blood types, they’re only more attractive to the insects when compared with those with blood type A. They found that a particular sugar found in blood type O was attractive to the mosquitoes, though once a mosquito has picked its target, it's unlikely blood type will make much difference.
Another thing that we all have to do is breathe, and this isn’t great if you’re trying to avoid the pesky little biters. When homing in on their target, all mosquito species will use something called a maxillary palp to sense the carbon dioxide you’re exhaling. Mixed with the host’s body odor and both molecules have been found to induce a take-off and sustained flight of the insects. It is for this reason that people who breathe out more, including larger people and adults, tend to get bitten more than those who exhale less.