Why mosquitoes bite some people more than others

mosquitoFLORIDA, United States, Tuesday January 6, 2015 – While there is currently no concrete scientific evidence as to why some of us are more attractive to mosquitoes than others, researchers believe they are getting closer to determining why the little flying pests feed on some people more than others.

Urban myths abound about the power of diet in keeping the bloodsuckers at bay, with popular tips including the consumption of garlic and/or high doses of Vitamin B, and the avoidance of too much sugar, but these remain unproven.

On the other side of the coin, Australian mosquito expert Dr Cameron Webb told 9NEWS that some studies have shown that consuming beer or alcohol can make you more attractive to some types of mosquito.

Dr Webb nevertheless said he believes his team has found a more scientific answer to why some of us are more appealing to the tiny pests than others.

“We think it comes down to the carbon dioxide we breathe out, but also the carbon dioxide we breathe out on our skin,” he said.

Dr Jonathan Day, a medical entomologist and mosquito expert at the University of Florida concurs. He believes that your metabolic rate, or the amount of carbon dioxide (CO2) your body releases as it burns energy, could be the most important factor of all.

According to Dr Day, mosquitoes use CO2 as their primary means of identifying bite targets.

“All vertebrates produce carbon dioxide, so what better way could there be for a mosquito to cue in on a host?” he said.

And while it’s true that you can moderate your metabolic rate through diet and exercise, you can only change your metabolism so much, he told time.com.

“Pregnant women and overweight or obese people tend to have higher resting metabolic rates, which may make them more attractive to mosquitoes,” he explained, adding that drinking alcohol or physically exerting yourself raises your metabolic rate—and your appeal to winged biters.

Although CO2 detection is the primary technique mosquitoes and other blood-sucking bugs use to spot hosts, they also rely on secondary cues, some of which can be controlled, Day said.

Dark clothing, for example, is more attractive to mosquitoes than lighter-coloured outfits because mosquitoes have problems flying in even a slight wind, so keep close to the ground, according to Day. Down there, they spot hosts by comparing their silhouette to the horizon. Dark colours stand out, while lighter shades blend in, he says.

A lot of motion also distinguishes you from your surroundings, making you a prime target.

Some factors nevertheless remain beyond our control and appear to validate the old-fashioned notion that some people’s skin is just sweeter than others.

Dr Day agrees that there’s some truth to that.

“Some people produce more of certain chemicals in their skin,” he explained. “And a few of those chemicals, like lactic acid, attract mosquitoes.”

To add to the mix, there’s even evidence that one blood type (O) attracts mosquitoes more than others, and since our genes dictate our blood type and chemical makeup, there’s little that can be done beyond adhering to all the conventional wisdom for keeping mosquitoes at bay.

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