Summer in the northern hemisphere is a special time. For a few short months of the year, we get to shed our coats and sweaters and enjoy some warm weather and sunshine. While the hot temperatures and long days make many of us want to get outside and stay there as much as possible, it comes with one drawback: mosquitos.
For decades many enjoyable camping trips, bonfires, evening jogs, or patio beers have been marred by these pesky insects. They leave itchy, red bumps all over our bodies, and they’re on a relentless search for our blood. But have you ever noticed that some people seem to get bitten more often than others?
Certainly if you are one of those unlucky individuals you are well acquainted with this frustrating phenomenon, but it’s not just pure coincidence. While pinpointing the exact reason why you might be a more frequent target than your companions is difficult, there are a few factors that could make one person more appealing to mosquitos than another.
Why Mosquitoes Bite
No doubt at some point in your life, while you were scratching away at a particularly itchy bite, you’ve wondered why the mosquito even bit you in the first place. The answer to this is actually quite simple.
First of all, male mosquitoes don’t bite. This is because they consume pollen and nectar from plants as opposed to blood for sustenance. While the females do like flowers, they require blood so that they have enough protein to produce eggs. Once a female has a blood meal, she can produce and deposit thirty to three hundred eggs at one time .
Why Some People Get Bit More Often than Others
This question, unfortunately for those who seem to make a common meal for mosquitoes, is a bit more complex.
There are many factors that influence who the mosquitoes will flock to, and not all of them are well-understood, but in order to understand why you get bit more often than others, you first need to understand what attracts them in the first place.
1. Carbon Dioxide
Mosquitoes use an organ called a maxillary palp (essentially its version of a nose [see image below]), which has receptors that help it detect carbon dioxide from as far as 150 feet away. According to Joe Conlon, a medical entomologist and technical advisor with the American Mosquito Control Association, the pests follow a CO2 trail like a shark follows a blood trail .
Since we all emit carbon dioxide when we breathe, mosquitos can find us pretty easily. Research has shown that different species of mosquitoes may respond differently to carbon dioxide, but any increase in CO2 output will alert them that a potential host is nearby .
Anyone who has a higher metabolic rate, which means they are expelling more carbon dioxide, will be more attractive to mosquitoes. For this reason, you are more likely to get bitten while you are breathing heavily because of exercising, or if you are a larger person .
2. Body Odor
The human body exudes many other compounds besides CO2, and unfortunately the number and type of compounds that make up your body odor are largely out of your control.
One of these compounds is lactic acid. Lactic acid is ten to one hundred times more abundant on human skin than other animals, which could explain why people tend to get bit more often .
Ammonia is another compound found on your skin that attracts mosquitoes, and for some species may be just as attractive as lactic acid .
Scientists are still not certain as to why some people’s body odor makes them more of a target for mosquitoes than others, however it could be caused by genetics or having more of a certain type of bacteria on the skin.
If you are related to someone who seems to be more susceptible to mosquito bites, you likely will be too, and it appears that those with a high diversity of microbes on their skin are less susceptible [7,8].
Additionally, if you wear perfume or cologne, you may be inadvertently making yourself more of a target to the pests. This is because even the female insects like flowers, and a scent from perfume or even a scented lotion could draw them to you .
“Mosquitoes partially rely on their vision to find their hosts, and dark-colored clothing can make it easier for them to find you,” says Nancy Troyano, Ph.D., board-certified entomologist and director of operations education and training for Ehrlich Pest Control .
Basically, if you’re wearing a black shirt against a lighter backdrop, like the grass or the horizon, you’re easier to spot.
4. Heat and Water
Our bodies generate heat constantly, and the levels of water vapor on our skin will vary depending on the temperature of the air. A mosquito can detect this heat and moisture as it gets closer to you, helping it to find its target. Research has shown that mosquitos will move toward targets that are a desirable temperature .
This is another reason why you might be more attractive to mosquitoes during and after exercise- your body temperature is elevated and your skin has more moisture on it from sweat. That, coupled with an increased CO2 output and a stronger body odor makes you a perfect target.
While sitting on a patio at sunset with a cold beer is a favorite way to spend a summer evening for many, it may also make you more desirable to mosquitoes. A relatively small study in 2002 found that participants had many more mosquitoes land on them after they had consumed a beer than before .
While this hasn’t been investigated in-depth, it is something to consider next time you’re enjoying your evening backyard brew.
As if being pregnant wasn’t already difficult enough, it turns out that women may be more attractive to mosquitoes while they’re expecting. Research has determined two possible reasons behind this: greater carbon dioxide exhalation and higher body temperature.
It appears that pregnant women exhale 21 percent more CO2 than non-pregnant women, and their body temperatures are 0.7 degrees celsius higher, making them twice as likely to be bitten by mosquitoes .
7. Blood Type
There has been some research to suggest that people with type O blood are more susceptible to mosquito bites than those with type A or B. The reason for this, however, is still not yet understood and more research is required .
How to Prevent Mosquito Bites
Even if you have many of the aforementioned characteristics to make you more appealing to the blood-sucking insects, there are still steps you can take to prevent mosquitoes from treating you like an all-you-can-eat buffet.
First things first, wear bug repellent. The CDC recommends using one that has been registered with the Environmental Protection Agency, and with one of the following active ingredients:
- Picaridin (known as KBR 3023 and icaridin outside the US)
- Oil of lemon eucalyptus (OLE)
- 2-undecanone 
It is also wise to wear light-colored clothing and avoid going outside at peak mosquito times, which are at dawn and dusk. If you are going out during those times, try to wear long pants and long-sleeved shirts in order to reduce the area that’s available for mosquitoes to bite.
In order to reduce the number of mosquitoes in and around your home, get rid of any standing water in buckets or eaves troughs, and change the water in wading pools and birdbaths frequently. To keep mosquitoes out of your home, never leave doors or windows open without a screen covering .
How to Treat Mosquito Bites
If you’ve been bit by a mosquito, you want to try to minimize any swelling and of course, itching. In order to do this, follow these steps:
- Don’t scratch. It could make the swelling worse and if you break the skin the bite is more likely to become infected.
- Apply a cold compress. This could be a wet towel or a cold pack applied to the affected area. This helps to bring down the swelling and reduce the itch.
- Apply calamine lotion to relieve the itch.
- Use an over-the-counter antihistamine like Benadryl if you have a stronger reaction to a mosquito bite .
Enjoy Your Summer Itch-Free
Getting through the summer without a single mosquito bite may be wishful thinking. However, the bottom line is that as long as you take the necessary precautions, you can enjoy a summer of outdoor fun without getting attacked by mosquitoes constantly.
As with anything, prevention is your best line of defense, so do your best to protect yourself from bites. Doing so will ensure that your summer memories revolve around outdoor fun, and not scratching incessantly at dozens of mosquito bites.
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- “Why Do Mosquitoes Love Biting Some People More Than Others?” Discover Magazine. Cody Cottier. July 19, 2019.
- “Detection and perception of generic host volatiles by mosquitoes: responses to CO2 constrains host-seeking behaviour.” Royal Society Publishing. Shahid Majeed, et al. May 10, 2017.
- “L‐lactic acid: a human‐signifying host cue for the anthropophilic mosquito Anopheles gambiae.” Online Library. T. Dekker, et al. April 4, 2002.
- “Genes and Odors Underlying the Recent Evolution of Mosquito Preference for Humans.” Cell. Carolyn McBride. 2015.
- “Composition of Human Skin Microbiota Affects Attractiveness to Malaria Mosquitoes.” Journals. Niels O. Verhulst, et al. December 28, 2011.
- “Heritability of Attractiveness to Mosquitoes.” Journals. G. Mandela Fernández-Grandon, et al. April 22, 2015.
- “Olfaction, experience and neural mechanisms underlying mosquito host preference .” JEB. Gabriella H. Wolff, Jeffrey A. Riffell. February 27, 2018.
- “What does heat tell a mosquito? Characterization of the orientation behaviour of Aedes aegypti towards heat sources.” Science Direct. Paula F.Zermoglio, et al. July 2017.
- “Alcohol ingestion stimulates mosquito attraction.” Pub Med. Oshikazu Shirai, et al. June 2002.
- “Mosquitoes prefer pregnant women.” NCBI. Roger Dobson. June 2000.
- “Landing Preference of Aedes albopictus (Diptera: Culicidae) on Human Skin Among ABO Blood Groups, Secretors or Nonsecretors, and ABH Antigens.” Academic. Yoshikazu Shirai, et al. July 2004.
- “Prevent Mosquito Bites.” CDC
- “Best ways to relieve a mosquito bite.” Health Line. Jill Seladi-Schulman, Ph.D. October 8, 2019.