Why Are Mosquito Bites Itchy?

As Canadians know, summer months bring the warmth and light that allow many of us to enjoy our vast wilderness playground. Unfortunately, enjoying the outdoors also means risking numerous bites from swarms of blood-hungry mosquitoes that seem to target us as soon us we step outside.

Have you ever wondered about the science behind the mosquito bite and why those bites leave you itchy? Check out the following video!

Misconceptions About Mosquitoes

You’re probably now wondering how to avoid being bitten by mosquitoes. Many theories exist regarding what attracts mosquitoes, and dozens of products are on the market claiming to repel these pests… but are such thoughts and methods supported by science? Read through the following statements, and identify which are true or false. Then check out the answers below.

True or False?
  1. Mosquitoes target the blood of pregnant woman over other individuals.

  2. Mosquitoes can detect the carbon dioxide in your breath from as far away as a length of a football field.

  3. Garlic can be used to deter mosquito bites.


1. True! Pregnant women produce more carbon dioxide and have a higher core body temperature.
2. False! Mosquitoes detect carbon dioxide up to 75 metres. The distance of a football field is 137 metres.
3. False! There is no scientific evidence to suggest the use of garlic succeeds as a repellent.

How Likely Are You to be Bitten by a Mosquito?

Why does it seem that mosquitoes prefer to bite some people over others? Use the following scenarios to find out how likely you are to attract a swarm of mosquitoes this summer.

Scenario 1

You are up early for your tee time at your favourite golf course. In addition to the dreary skies, the forecast calls for hot and humid weather.


What statement best describes your attire?

I’m wearing a pair of black shorts, a green t-shirt, ankle socks, and golf spikes.

You might be cool on the course, but you’ll likely be swimming through clouds of mosquitoes. Not only will your clumsy golf swing draw the attention of the bloody thirsty insects that use motion to detect their prey, you’re also wearing dark colours, and darker tones have been known to attract mosquitoes. Exposed skin should be avoided; however, you are wearing ankle-length socks. Mosquitoes are attracted by the bacterial colonies that naturally live on skin. Areas such as the ankles and elbows make great homes for these opportunistic parasites. Why? It’s quite simple – we often overlook or have difficulty cleaning these body parts!

I’m wearing my red microfiber running shirt and black waterproof pants.

Although your microfiber running shirt may dry quickly following a cloud burst, its red colour may attract the mosquitoes. Moreover, tight fitting clothing with little space between the fibre and your body minimizes the distance the proboscis of the mosquito must cross to reach your skin and increases your chance of being bitten. Try to avoid heat-trapping clothing that will make you perspire as mosquitoes rush to the smell of body odour. Substances that are commonly found in sweat, such as lactic acid, uric acid, and ammonium, are known to attract mosquitoes. In addition to your musky smell, exercise will also increase your body temperature and the amount of carbon dioxide you will produce. If you are hot, sweaty, and ten strokes over par by the ninth hole, you’ll likely be constantly grabbing for the bug spray as you finish out your round.


Scenario 2

The summer sun is slowly setting as the smell of BBQ wafts through the air. As you wait for your meal, your host graciously offers you a beverage.


What statement best describes your drink of choice?

It’s just not summer without a tall glass of lemonade.

There is nothing like a tall glass of lemonade to cool you down during a summer heat wave. In addition to providing relief from the heat, a cold beverage, such as lemonade, may help you avoid detection by a cloud of hungry mosquitoes. Female mosquitoes seeking a blood meal use body temperature and sweat on the skin to detect humans. Mosquitoes can smell your body odour? Yes. Mosquitoes can detect specific chemicals, such as uric acid, ammonia, and lactic acid found in sweat.

I’m 19 years of age and enjoy the occasional beer.

Some evidence indicates that beer consumption can make you more appealing to a blood thirsty mosquito. Why? Most people assume it’s the alcohol in beer; however, that’s not the case. Maybe mosquitoes like the hoppy aroma of suds on your breath!

I need my soda fix.

On its own, drinking copious amounts of soda will not make you more attractive to mosquitoes, but soda definitely correlates with clinical obesity. Overweight individuals provide a larger surface area to the mosquito and tend to produce more carbon dioxide and sweat than the average person does. Carbon dioxide in our breath and compounds in sweat, such as uric acid, ammonia and lactic acid, are known to attract mosquitoes. Surface area is also an issue for tall people and can partially explain why adults sitting around the picnic table are frustrated and constantly scratching their numerous bites, whereas small children are often left unscathed and carefree.


Scenario 3

You’re at the cottage for a long weekend with your family. As the sun rises against a clear blue sky, marking the start of another glorious summer day by the lake, you step out onto the back deck with your cup of coffee to contemplate your plan for the day.


Which of the following activities appeals the most to you?

Kicking the soccer ball around in the field behind the cottage.

Bring the bug spray. A common misconception is that mosquitoes are more attracted to stationary targets. The reality is that mosquitoes have the ability to detect movement from as far away as 30 metres and use motion to target their next victims. Why? Mosquitoes recognize that, in nature, living animals move around. Although a stationary object may be a human, it may also be a tree. To increase its chance of getting a meal, the mosquito targets moving objects. Physical exercise is a huge red flag when trying to avoid swarms of mosquitoes. Mosquitoes are drawn to raised levels of carbon dioxide, lactic acid, and the body odour you produce while doing physical exercise. While exercising outdoors is great fun, from the perspective of avoiding mosquitoes bites, you might as well be running around wearing a giant neon sign that says ‘bite me’.

Sitting on the deck in your Muskoka chair with a good book.

Unless you are indoors, there is nowhere you can go where you’ll be absolutely certain to avoid mosquitoes. Of all the activities suggested, this is likely your best option to reduce your number of bites. It may seem as though you are inviting bites by staying still, but to a mosquito that uses motion to detect its target your lack of movement can make it more difficult for them to detect your location. One of the most effective ways to keep the mosquitoes at bay would be to bring a fan with you out onto the deck. The gentle breeze should help to stop the advance of the tiny menaces and allow you to enjoy the day buried in the pages of your favourite novel.

Hiking through the forest to a nearby lookout to catch the setting sun.

Mosquitoes tend to live near standing water which is common to swampy, marshy areas in most Canadian forests. Hiking in this environment is like walking straight into the home of a family of starving mosquitoes. You can try your best to prevent the mosquitoes from biting you by applying bug repellants; however, you cannot reasonably expect to come through the forest without a few bites. One tip to avoid being ravaged by mosquitoes is to plan your hike during the middle of the day. Mosquitoes are most active between dusk and dawn and tend to rest during the day. You should still expect some bites. Drowsy as she may be, a hungry mosquito will not turn down the opportunity for a meal should it walk by!

Easy to Attract; Hard to Repel

As you can see from the scenarios above, many different factors draw mosquitoes to you, and many of these variables we can’t control. So, how do we limit our exposure to the little pests? Here are some tips for starters:



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