4 Surprising Reasons Mosquitoes Attack You

From blood type to your beer habit, here’s why mosquitoes are more attracted to certain people — and what you can do if you’re one of them

Michelle Crouch,

AARP

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En español

Published August 16, 2023

woman scratching mosquito bites on her arm

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Have you ever noticed that some people always seem to be targeted by mosquitoes, while others are barely touched?

Experts say it’s no coincidence.

A growing body of research has identified a number of factors that appear to make some people more likely to be mosquito magnets. While some are within your control, like the color of your clothing, other factors aren’t, such as your blood type or how much bacteria you have on your skin.

“Roughly 85 percent of what makes you more desirable or less desirable (to mosquitoes) is hard-wired into your DNA,” says Timothy C. Winegard, a history professor at Colorado Mesa University and author of The Mosquito: A Human History of Our Deadliest Predator.

Winegard said female mosquitoes bite humans because they need our blood to nourish their eggs. “They are simply being good moms,” he says. “Unfortunately, pathogens hitch a free ride.”

In 2023, for the first time in 20 years, people were infected by malaria in the United States, alarming epidemiologists. Malaria is one of several dangerous diseases transmitted by mosquitoes. The insects can also spread Zika, West Nile, dengue and several types of encephalitis.

Mosquitoes rely on multiple clues to track down their human prey. Here are four things that might be making you a mosquito magnet:

1. Your blood type

When it comes to their meal of choice, some types of mosquitoes seem to prefer Type 0 positive blood, the most common blood type in the United States. More than one out of every three Americans have Type O positive blood.

In a 2019 study published in the American Journal of Entomology, researchers offered mosquitoes different feeders that contained all four blood types and found that the insects chose the Type O blood feeder more than any other.

Another study, in 2004, revealed that mosquitoes land on people with Type O blood significantly more often than those with other blood types, and nearly twice as often as on those with Type A blood.

Scientists aren’t sure why Type O blood is so attractive, but it could be related to the proteins or chemicals in the blood.

2. Your body odor

Recent research into mosquito preferences reveals that your particular scent also plays an important role.

“The sense of smell is something a lot of people don’t think about much, but for mosquitoes it’s first on their mind, and that is how they hunt us down and figure out their preferred target,” says Matthew DeGennaro, an associate professor in biological sciences at Florida International University who studies mosquito genetics and behavior.

Most of your natural body odor comes from your skin, and it’s created by a blend of many organic compounds. Scientists are working to determine which ones attract and repel different insect types.

For example, in a study published in October 2022 in the journal Cell, Rockefeller University researchers determined that people who had higher levels of a chemical compound called carboxylic acid are 100 times more attractive to one type of mosquito than those with lower levels.

DeGennaro says his lab is also examining which compounds in natural body odors attract mosquitoes. “What we’re finding is that people have different sets of microbes on their skin that cause them to produce slightly different odors, and different species of mosquitoes prefer different types of odors,” DeGennaro says.

3. Your breath

Mosquitoes have nerve cells that detect carbon dioxide, which is emitted every time we exhale. They can detect the presence of carbon dioxide from more than 30 feet away.

Some people, such as larger adults, naturally emit more carbon dioxide than smaller adults or children, making them easier for mosquitoes to hunt down.

One study showed that pregnant women, who produce over 20 percent more carbon dioxide, are bitten twice as often as those who aren’t pregnant.

4. Your beer habit

A cold beer might sound pretty good on a hot day, but it may increase your chances of being bitten.

A small study published in the Journal of the American Mosquito Control Association found that drinking a single beer increased mosquito attraction.

In another study, French researchers also found that mosquitoes preferred study participants who drank a beer compared to those who drank a glass of water.

Scientists aren’t sure if beer changes your body odor, if it increases your body temperature or if there is some other reason it attracts mosquitoes, but it’s a good idea to apply some repellent before you grab a pint at an outdoor event. Do the little blood suckers like wine and mojitos as well? Apparently, studies haven't been done yet to see whether other types of alcohol entice them in for human happy hour.

How to protect yourself

If you find yourself covered in welts whenever you spend time outside, experts say staying in screened areas and using mosquito repellent are the best ways to prevent bites.

The Centers for Disease Control and Prevention says mosquito repellents with the following chemicals are safe and effective: DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol or 2-undecanone.

DeGennaro, who has studied repellents, says DEET is still the gold standard, followed by picaridin. “Deet tends to last a little longer than (the others) and it’s stronger,” he says.

Experts stressed that preventing mosquitoes isn’t just about avoiding a nuisance. With malaria cases popping up in Florida and Texas in 2023, it’s also about avoiding disease.

“Female mosquitoes are hard-wired to bite for survival of their species,” Winegard says. “They are going to do their best to find your blood.”

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Michelle Crouch is a contributing writer who has covered health and personal finance for some of the nation’s top consumer publications. Her work has appeared in Reader’s Digest, Real Simple, Prevention, The Washington Post and The New York Times.