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Is it your imagination, a coincidence, or is there really a reason you attract more bites than others? Here’s what could be making you a magnet to the insects and how to keep them at bay. 

Do mosquitoes prefer the taste of certain blood types?

If only some people tend to be bitten by mosquitoes, you may think blood has something to do with this attraction and that would be true, according to Doug Currie, an entomologist and senior curator of insects at the Royal Ontario Museum. 

Although there’s a “whole constellation of factors” that make some people more attractive to mosquitoes than others, Currie said, blood type may play a role. 

Research suggests that the bloodsucking insects tend to prefer people with blood type O, Currie said.

Not all mosquitoes drink blood but most female mosquito species do, and they extract blood from humans to develop their eggs, Currie said.

“Most species will either favour something like humans or some specific animal group like mammals, birds, reptiles, or even amphibians, but most will have preference for one or more of those groups,” he said, adding that there are at least 80 different types of mosquito species in Canada.

The good news is that some critics say research about blood type being a factor is flawed, and has only been tested on anthropophilic mosquitoes — those that specifically feed on human blood. In Ontario, there are two invasive species of anthropophilic mosquitoes which are the Aedes aegypti and the Asian tiger mosquito found in Windsor-Essex county. 

“In my opinion, the relationship between human blood group and mosquito attractiveness has not been settled,” said Fiona Hunter, a professor of veterinary and medical entomology at Brock University. The research has not been done on homegrown species in Canada, she added.

For other mosquito species in Canada that drink human blood, “we’re just incidental hosts for them,” Hunter said. 

What makes humans attractive to mosquitoes? 

Mosquitoes are attracted to humans as they’re a source of blood supply for their offspring, but there’s a natural instinct humans do that draws the pests in: breathing. 

Humans emit carbon dioxide when we exhale and this gas is a thriving attractant to mosquitoes. 

Some people emit more carbon dioxide than others, and this might make you more at risk at being bitten by the pests. 

Other factors that draw mosquitoes in are human odours and body heat. Hunter said natural body odours that mosquitoes can smell are the product of sebaceous gland secretions or the breakdown products of those glands.

“It’s the bacteria that are living on human skin that breaks down those products and then produce volatile organic compounds that mosquitoes can cue in to,” she said.

Currie says this includes the compounds found in sweat such as lactic acid and those with higher levels of carboxylic acid in their skin, naturally produced within human sebum after it is broken down by specific skin bacteria, may also be at an increased attractiveness to mosquitoes.

“There are hundreds of volatile organic compounds that are released from human skin that we can’t smell, but those little molecules could definitely trigger the receptors on mosquito antennae. And then that brings them closer to the source,” Hunter said.

As mosquitoes get closer to humans, they are then very attracted to humans’ radiating body heat, and this could make some humans more of a target than others as some people’s bodies tend to be warmer than others. 

Who may be most at risk of mosquito bites? 

Those who emit more carbon dioxide and body heat while having certain body odours that mosquitoes like, can become prey to their infuriating bites. 

Pregnant women tend to be preferred due to increased carbon dioxide exhalation and elevated body temperature. Those with a fever or health conditions that result in harder, quicker breathing may also be targeted by the pests. 

People working out outside should be wary of mosquitoes as when engaging in physical activity, your body will heat up and you tend to exhale more, Currie says.

Be careful not to crack a cold one or a soda near a swarm of mosquitoes as the carbon dioxide in the drinks could be released and attract them. Currie also says those who drink alcoholic beverages tend to produce more carbon dioxide than those who don’t. 

Even artificial scents play a role in attracting mosquitoes, with some types of soaps drawing more mosquitoes to people while others repel them, according to research the Star previously reported on.

Do mosquitoes prefer adults over children? 

Studies suggest that mosquitoes tend to drink the blood of adults more than children, but that’s because adults release more carbon dioxide than children. 

Young children also generally produce less sweat than adults which attracts mosquitoes, and have a smaller skin surface area to bite. 

Are mosquitoes attracted to certain clothing? 

The colour of your clothing may be a factor in attracting mosquitoes. Dark clothing, especially black or navy blue, is more attractive to the insects than light clothing, Hunter says.

Those who wear tighter clothing may also be on the mosquito radar as mosquitoes “have a proboscis that they have to poke through your clothes to get to your skin and if you’re wearing skin tight clothes, chances are they can poke their proboscis through your clothing and get to the blood,” Currie said. 

How can I stay mosquito bite-free when outside this summer?

To avoid becoming a mosquito magnet this summer, make sure you’re prepared before heading out. 

Avoid having too much exposed skin, Hunter says, and although mosquitoes can bite through clothing, you can wear looser, baggier clothing with long sleeves and long pants to avoid becoming easily bitten. Mosquitoes are also not as attracted to lighter clothing than dark clothes, so try to opt for whites and yellows this summer. 

“I think we have to live with the fact that some people will always be more attractive to them,” Currie said, but repellents that contain Deet or picaridin could be an important protectant against mosquitoes.

The oil of lemon eucalyptus plants are “reasonably effective” against mosquitoes, however essential oils are not effective for very long as they wear off, he added.

Deet should be used in low concentrations and is best avoided by young children, Hunter said. 

At this time of the year, mosquitoes are most active early in the morning or at dusk. These are the times when they’re more likely to bite, so for those who want to avoid bites this summer, try to schedule outdoor activities to times when the sun is out.