When Should I Worry About...

Why Are Mosquitoes Attracted to Some People More Than Others?

June 3, 2022 - Katie McCallum

There you were, enjoying a pleasant afternoon outdoors — until the mosquito swarm hit, that is. And as you were swatting at them left and right, the person next to you was totally untouched.

What gives?

Urban legend would have you believe that your blood tastes sweeter.

While it's true that mosquitoes are in search of something sweet when they need energy — the sugary nectar of various plants, for instance — that's not the reason for their blood sucking. Female mosquitoes bite you — yes, it's just the female mosquitoes that bite — because your blood contains nutrients they need to make eggs. It doesn't need to be sweet.

It's why you should wear an effective bug spray any time you plan to be outdoors during mosquito season. (Related: Is DEET Bad for You? & 4 More Questions About Bug Spray, Answered)

And, to understand why exactly some people get fed on more than others, we have to start with how mosquitoes even find us in the first place.

How do mosquitoes find you?

When hunting for a blood meal, a mosquito senses a variety of cues that signal a human is nearby, including:

  • Carbon dioxide
  • Skin odors
  • Body heat

First, a mosquito's taste sensors detect the carbon dioxide you release as you exhale. And it can sense this gas from quite the distance, upwards of 50 feet but maybe even as far as 100.

Drawing closer, its smell sensors are looking for skin odors — substances either released directly by your skin, such as lactic acid and ammonia, or the odorous byproducts created by the bacteria naturally living on your skin.

Some research suggests that sensing carbon dioxide and body odor might trigger a mosquito to pay closer attention to visual cues it would otherwise ignore or perhaps even heighten its visual sensitivity in order to help pinpoint your location.

And as the mosquito draws even closer, it senses your body heat to find you at last.

After landing on you, it then uses taste sensors in its legs to find the right spot to bite you and, well, you know how the rest goes.

It's with this combination of sensory cues that mosquitoes have become such efficient seekers of humans.

But we all breathe, we all give off heat, we all ... smell.

So why do you get bit more than the other people around you?

Are mosquitoes really more attracted to certain people?

Yes, it's true.

Several studies, some of which date back to the 1970s, show that mosquitoes prefer some people over others. One study in particular suggests that somewhere around 20% of people are more attractive to mosquitoes.

The details as to why this might be are only somewhat understood, though — not to mention controversial.

What is generally agreed upon is that mosquito preference toward a particular person depends on either the amount or type of mosquito attractants the person releases, or a combination of both. There are many factors that contribute to this, much of which is likely largely determined by your genetics.

Which attractants are most important for mosquito preference is still up for debate.

Some believe that it's the amount of universal attractants a person releases — carbon dioxide, skin odor and body heat — that dictate how likely he or she is to get bit.

Others argue that, while mosquitoes rely on these universal attractants to find humans generally, it's the more specific types of attractants — the particular combination of compounds that make up each person's distinct body odor — that guide the selection of whom exactly to bite. What makes a combination desirable is unknown.

This is all then further complicated by the fact that over 3,000 different types of mosquitoes exist, each of which type differs in the attractants that makes targets most suitable to them. 

Still, it's worth discussing what might skew you toward being more attractive to these pests.

6 reasons mosquitoes may bite you more than other people

1. Your size

The larger the person, the more carbon dioxide they release while exhaling. This, in turn, may make the person more identifiable to mosquitoes.

2. Your body temperature

Since mosquitoes use body heat as means of honing in on a target, it's thought that mosquitoes likely land most often on those with a higher body temperature — whether that's because your internal body temperature is higher due to being in the heat or because you run hotter than other people for some other reason.

3. How much you sweat

The sweat associated with increased body temperature and exercise (called eccrine sweat) is initially odorless to us humans, but not to mosquitoes.

And mosquitoes can not only smell our sweat, studies show they're attracted to the lactic acid and ammonia found in it.

Therefore, the more you sweat — whether you naturally sweat excessively or you have just finished exercising — the more attractive you may be to mosquitoes.

4. Pregnancy

As if there aren't enough bodily changes to deal with during pregnancy, many studies demonstrate that pregnant women are more attractive to mosquitoes.

It's speculated that this might be because pregnant women exhale more carbon dioxide (some studies suggest at least 20% more), but also because body temperature increases during pregnancy. It's a double whammy as mosquito attractants go.

5. The bacteria naturally living on your skin

It's finally time to talk about body odor, which is produced when the bacteria naturally living on your skin (your skin microbiota) metabolize the components found in your sweat and released by your skin into odorous byproducts.

Many of these byproducts are known to be mosquito attractants, so it's thought that body odor likely plays a large role in mosquito preference.

Since we all have different types and mixes of bacteria on our skin, our individual body odors vary. This variability is thought to help determine what makes one person more attractive to a mosquito than another — although, beyond this, the details aren't well understood.

However, one study demonstrated that having lower bacterial diversity within your skin microbiota may make you more attractive to mosquitoes, a higher bacterial diversity less attractive.

6. What you eat and drink, including beer

Another factor that influences your body odor is your diet.

What you eat can affect the type of compounds released from your skin, which bacteria can then metabolize into odorous molecules. Eating also affects your metabolic rate, which can increase your body temperature and sometimes even stimulate sweating.

Given all of this, some scientists think that your diet may also influence how attractive you are to mosquitoes. The studies linking what you eat to a mosquito's preference toward you are very limited, though.

What is known, however, is that eating foods rich in vitamin B and garlic doesn't help naturally repel mosquitoes — a myth that's officially been disproven. You'll need to continue to rely on mosquito repellent instead.

On the other hand, studies have shown that alcohol consumption — beer, specifically — may increase how attractive you are to mosquitoes. Another study saw similar results with bananas.

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Categories: When Should I Worry About...