- Blood type
- Carbon dioxide
One of the key ways mosquitoes locate their targets is by smelling the carbon dioxide emitted in their breath—they use an organ called a maxillary palp to do this, and can detect carbon dioxide from as far as 164 feet away. As a result, people who simply exhale more of the gas over time—generally, larger people—have been shown to attract more mosquitoes than others. This is one of the reasons why children get bit less often than adults, on the whole.
- Exercise and Metabolism
In addition to carbon dioxide, mosquitoes find victims at closer range by smelling the lactic acid, uric acid, ammonia and other substances expelled via their sweat, and are also attracted to people with higher body temperatures. Because strenuous exercise increases the buildup of lactic acid and heat in your body, it likely makes you stand out to the insects. Meanwhile, genetic factors influence the amount of uric acid and other substances naturally emitted by each person, making some people more easily found by mosquitos than others.
- Skin Bacteria
Other research has suggested that the particular types and volume of bacteria that naturally live on human skin affect our attractiveness to mosquitoes. In a 2011 study, scientists found that having large amounts of a few types of bacteria made skin more appealing to mosquitoes. Surprisingly, though, having lots of bacteria but spread among a greater diversity of different species of bacteria seemed to make skin less attractive. This also might be why mosquitoes are especially prone to biting our ankles and feet—they naturally have more robust bacteria colonies.
- Beer
Just a single 12-ounce bottle of beer can make you more attractive to the insects, one study found. But even though researchers had suspected this was because drinking increases the amount of ethanol excreted in sweat, or because it increases body temperature, neither of these factors were found to correlate with mosquito landings, making their affinity for drinkers something of a mystery.
- Pregnancy
In several different studies, pregnant women have been found to attract roughly twice as many mosquito bites as others, likely a result of the fact the unfortunate confluence of two factors: They exhale about 21 percent more carbon dioxide and are on average about 1.26 degrees Fahrenheit warmer than others.
- Clothing Color
This one might seem absurd, but mosquitoes use vision (along with scent) to locate humans, so wearing colors that stand out (black, dark blue or red) may make you easier to find, at least according to James Day, a medical entomologist at the University of Florida, in commentary he gave to NBC.
- Genetics
As a whole, underlying genetic factors are estimated to account for 85 percent of the variability between people in their attractiveness to mosquitoes—regardless of whether it’s expressed through blood type, metabolism, or other factors. Unfortunately, we don’t (yet) have a way of modifying these genes, but…
- Natural Repellents
Some researchers have started looking at the reasons why a minority of people seem to rarely attract mosquitoes in the hopes of creating the next generation of insect repellants. Using chromatography to isolate the particular chemicals these people emit, scientists at the UK’s Rothamsted Research lab have found that these natural repellers tend to excrete a handful of substances that mosquitoes don’t seem to find appealing. Eventually, incorporating these molecules into advanced bug spray could make it possible for even a Type O, exercising, pregnant woman in a black shirt to ward off mosquitoes for good.
Now that you know, try your best to not let those mosquitoes munch on you!
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