5 reasons mosquitoes bite some people more than others

Zika, West Nile, Malaria, Dengue … the disconcerting catalog of illnesses spread by the flying disease-delivery vehicles known as mosquitoes is an ever expanding thing. And along with vector-borne diseases, mosquitoes and their diabolic hypodermic mouthparts offer no shortage of itchy welts, meanwhile, their crazy-making hum can keep the soundest of sleepers swatting at their faces all night.
Day says that the two most compelling factors of mosquito attraction have to do with sight and smell – which seems obvious, but it’s not a given that the mysteries of mosquitoes would be clear. There are all kinds of wives’ tales about what attracts and repels – eating bananas actually doesn’t lure mosquitoes nor does vitamin B-12 repel them – but scientists think the following factors likely do come into play. Some of these we can't do much about, but anything to help avoid the pests and reduce the use of dicey chemicals is worth the effort.

1. Apparel 
As mentioned above, mosquitoes actually use their eyes to target victims. Jay explains that mosquitoes are highly visual, “especially later in the afternoon, and their first mode of search for humans is through vision.” Wearing dark colors (navy, black) and red makes you easier to spot, says Jay. (Note to self: Check camouflage summer wear.)
2. Blood type
It’s all about the blood for mosquitoes; well that and nectar. Adult mosquitoes survive on nectar for nourishment, but females rely on the protein in our blood for the production of eggs. So it’s little surprise that some blood types may be more desirable than others. Research has found, in fact, that people with Type O blood are found to be twice as attractive to mosquitoes than those with Type A blood; Type B people were in the middle. In addition, 85 percent of people produce a secretion that signals what blood type they are; mosquitoes are drawn to those 85 percent more than the non-secretors, regardless of blood type.

3. Gas
Mosquitoes can sense carbon dioxide up to 160 feet away; so the more one exhales, the more attractive they become. Larger people exhale more. Also to note, since human beings exhale carbon dioxide through the nose and mouth, mosquitoes are attracted to our heads, which explains the whole “mosquitoes buzzing about the ears all night” misery.
4. Heat and sweat
Mosquitoes apparently have a nose for other scents besides carbon dioxide; they can sniff down victims through the lactic acid, uric acid, ammonia and other compounds emitted in sweat. They also like people who run warmer; a hot sweaty human must seem quite delicious to them – couch potatoes, rejoice. Strenuous exercise increases the buildup of lactic acid and heat in your body, Smithsonian points out, while genetic factors “influence the amount of uric acid and other substances naturally emitted by each person, making some people more easily found by mosquitoes than others.”

5. Lively skin
Some research has shown that the types and amount of bacteria on one’s skin can play a role in bringing on the mosquitoes as well. Our dermal casing is naturally teeming with microscopic life, and the whole shebang creates a distinct fragrance. In one study, a group of men was divided into those who were highly attractive to mosquitoes and those who were not. The delicious ones had more of certain microbes on their skin than the unattractive ones, but fewer types – a larger community but less diverse. The bacteria factor could also explain why some mosquitoes are drawn to ankles and feet, an especially ripe source of bacteria.