If you feel like you're the victim of itchy mosquito bites more often than others, it may not be all in your head. Because there is some scientific evidence that mosquitoes have preferences for who to land and feed on.

Mosquitoes primarily rely on carbon dioxide to locate their targets. Body temperature and odour also play significant roles, so anything that alters these factors can make someone more or less attractive to mosquitoes.

Blood type matters sometimes: Several studies have shown mosquitoes prefer type O blood. One study published in the Journal of Medical Entomology found a mosquito species preferred to land on type O blood compared to others, but the difference was only significant between type O and type A.

Though it's often reported that mosquitoes prefer type O blood, it's worth considering the limitations of these studies.

Some studies have shown that there may be some correlation between blood type and mosquito preference, but in a comparative, there's always a winner. That doesn't necessarily mean it's the absolute winner all the time.

People who are intoxicated tend to put out more carbon dioxide and sweat more, which seems to attract mosquitoes—possibly along with other unknown factors.

Diet can also impact mosquito attraction, though the extent of its effect hasn't been fully explored. Garlic and vitamin B are often anecdotally reported to deter these bugs, but the evidence is limited.

Bananas and other high-potassium foods have shown to attract mosquitoes, perhaps because they lead to an increase in lactic acid production in the body, which helps mosquitoes locate animals.

This also impacts a person's skin microbiota, or the microorganisms living on the skin.

There is some research to support that changing your diet will make you give off different scents. "So, it may be possible to change your attractiveness to mosquitoes based on what you're eating.

Pregnancy attracts mosquitoes! 

Pregnant women also seem to attract more mosquitoes, primarily because of the increased CO2 output. It's estimated that women in the advanced stages of pregnancy exhale about a 21% greater volume than non-pregnant women. This goes along with other physiological changes, like increased body temperature, that together make pregnant women easier for mosquitoes to find.

Local flavour: Sometimes mosquitoes develop more specific tastes in a location over time as an evolutionary trait.

Mosquitoes in certain neighbourhoods can become accustomed to specific scents and start to prefer those over others. Their generations are about two weeks long, and urban mosquitoes that bite humans often don't travel far. As a result, they seem to get familiar with the local scents and prefer them.

Genetic predispositions: There's still much to uncover as far as mosquito preferences. There seems to be other genetic predispositions for what attracts mosquitoes, but these aren't all clear just yet.

If you wear dark clothes, then they will attract mosquitoes too!

So what can you do to stop these blood suckers from attacking you?

Staying covered and use  repellents.  Wear light colour clothes. Use mosquito nets while sleeping. 

Yoshikazu Shirai et al, Landing Preference of Aedes albopictus (Diptera: Culicidae) on Human Skin Among ABO Blood Groups, Secretors or Nonsecretors, and ABH Antigens, Journal of Medical Entomology (2009). DOI: 10.1603/0022-2585-41.4.796

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Mosquitoes sense infrared from body heat to help track humans down, study shows

While a mosquito bite is often no more than a temporary bother, in many parts of the world it can be scary. One mosquito species, Aedes aegypti, spreads the viruses that cause over 100,000,000 cases of dengue, yellow fever, Zika and other diseases every year. Another, Anopheles gambiae, spreads the parasite that causes malaria. The World Health Organization estimates that malaria alone causes more than 400,000 deaths every year. Indeed, their capacity to transmit disease has earned mosquitoes the title of deadliest animal.

Male mosquitoes are harmless, but females need blood for egg development. It's no surprise that there's over 100 years of rigorous research on how they find their hosts. Over that time, scientists have discovered there is no one single cue that these insects rely on. Instead, they integrate information from many different senses across various distances.

A team of researchers  has added another sense to the mosquito's documented repertoire: infrared detection. Infrared radiation from a source roughly the temperature of human skin doubled the insects' overall host-seeking behavior when combined with CO₂ and human odor.

The mosquitoes overwhelmingly navigated toward this infrared source while host seeking. The researchers also discovered where this infrared detector is located and how it works on a morphological and biochemical level. The results are detailed in the journal Nature.

Craig Montell, Thermal infrared directs host-seeking behaviour in Aedes aegypti mosquitoes, Nature (2024). DOI: 10.1038/s41586-024-07848-5. www.nature.com/articles/s41586-024-07848-5

Scientists Discover Mosquitoes Are Using Infrared to Track Humans Down

There's something about us that mosquitoes just love. In addition to our smell, and our breath, our exposed skin acts as a kind of neon sign advertising that this blood bar is open for business.

That's because mosquitoes use infrared sensing in their antennae to track down their prey, a new study has found.
In many parts of the world, mosquito bites are more than an irritation, capable of spreading pathogens like dengue, yellow fever, and Zika virus. Malaria, spread by the Anopheles gambiae mosquito, caused more than 600,000 deaths in 2022, according to World Health Organization statistics.

To avoid serious disease, or even just a case of maddening itchiness, we humans are pretty keen to find ways to prevent mosquito bites.

Research found that mosquitoes use infrared detection – along with other cues we already knew about, like a nose for the CO2 in our breath, and certain body odours, to seek out hosts.

https://www.nature.com/articles/s41586-024-07848-5

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Updates:

Are you tasty to mosquitoes? Study offers clues into when and why they bite

As mosquitoes and mosquito-borne illnesses like dengue fever spread across the world, researchers say that a key strategy to prevent these illnesses may be dissuading the insects from biting their victims in the first place. But while scientists have uncovered the ways that odor and heat help mosquitoes find humans, little is known about the role of taste once they've landed.

In a new study,  researchers have now shown how different tastes are encoded by neurons in mosquitoes and how they influence biting, feeding, and egg-laying. They also identify compounds in human sweat that increase biting behavior in mosquitoes as well as bitter compounds that suppress egg-laying and feeding behaviors—and reveal new insights into why some humans might be more enticing to mosquitoes than others.

These findings, they say, could inform methods to halt or reduce mosquito biting in the future.

The study, published in Nature, focused on the Asian tiger mosquito, a species once limited to Southeast Asia but now found across six continents.

This mosquito is capable of spreading many diseases, including dengue and chikungunya. And it's outcompeting other mosquito species, so it could be an even greater problem in our future.

To better understand the species' taste abilities, the researchers first took 46 different taste compounds—including sugars, salts, bitter compounds, and amino acids—and observed how neurons in the mosquito's taste organ responded to them. They found that some compounds, like sugars, excited many of the neurons. But surprisingly, some compounds actually inhibited neuronal activity.

Researchers have done a lot of research on taste in the fruit fly, and they haven't seen this kind of widespread inhibition before in flies. Having these two different responses—excitation and inhibition—gives mosquitoes an expanded ability to encode taste, meaning they can likely differentiate a wide variety of tastes.

After they also examined how different taste compounds affected mosquitoes' biting, feeding, and egg-laying behaviors, the researchers found that different tastes promoted or suppressed different behaviours.

For instance, some bitter compounds reduced mosquitoes' feeding behavior but had no effect on egg-laying. While salt and some amino acids typically found in human sweat had no effect on biting when presented separately, they promoted an increase in biting when combined.

And that makes sense. There are a lot of places in nature that have salt and a lot of places that have amino acids, but humans have both together on our skin. So maybe the mosquito is able to identify the combination and recognize our skin as a good place to bite.

Additionally, when the researchers offered mosquitoes human sweat samples, they found that the mosquitoes showed strong biting preferences for some samples over others. They think this could be part of the reason why some of us get bitten by mosquitoes a lot more than others. Some people may just taste better to mosquitoes.

Together, the findings help describe how mosquitoes that have landed decide whether to bite or fly away. That information, the researchers say, may help identify compounds that can sway mosquitoes to leave rather than bite.

This study may be helpful in identifying compounds that protect us from mosquito bites in a new way . Such compounds could be extremely useful, especially as climate change expands the range of mosquitoes and the diseases they spread.  

John Carlson, Gustation in the Asian tiger mosquito, Nature (2024). DOI: 10.1038/s41586-024-08047-y