Blood Type

Mosquitoes are attracted to certain blood types more than others. In a study, mosquitoes landed on people with Type O blood nearly twice as often as those with Type A. People with Type B blood fell somewhere in the middle. Additionally, about 85% of people secrete a chemical signal through their skin that indicates their blood type, and mosquitoes are more attracted to secretors than nonsecretors regardless of blood type.

Carbon Dioxide

Mosquitoes use their maxillary palp to detect carbon dioxide emitted in breath, and they can detect it from as far as 164 feet away. As a result, people who exhale more carbon dioxide, such as larger people, attract more mosquitoes. This is one reason why children get bit less often than adults.

Exercise and Metabolism

Strenuous exercise increases the buildup of lactic acid and heat in your body, making you more attractive to mosquitoes. Additionally, 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.

Skin Bacteria

The types and volume of bacteria that live on human skin affect our attractiveness to mosquitoes. Having large amounts of certain types of bacteria makes skin more appealing to mosquitoes, while having a greater diversity of bacteria species makes skin less attractive. This may be why mosquitoes are especially prone to biting ankles and feet, which have more robust bacteria colonies.

Beer

Drinking just one 12-ounce bottle of beer can make you more attractive to mosquitoes. However, researchers have not yet determined why. Neither the increased ethanol excreted in sweat nor the increased body temperature associated with drinking beer correlate with mosquito landings.

Pregnancy

Pregnant women attract roughly twice as many mosquito bites as others. This is likely due to the combination of exhaling about 21% more carbon dioxide and being on average about 1.26 degrees Fahrenheit warmer than others.

Clothing Color

Mosquitoes use vision, along with scent, to locate humans. Wearing colors that stand out, such as black, dark blue, or red, may make you easier to find.

Genetics

Underlying genetic factors are estimated to account for 85% of the variability between people in their attractiveness to mosquitoes. These factors can be expressed through blood type, metabolism, or other factors. Unfortunately, there is no way to modify these genes yet.

Natural Repellants

Some people rarely attract mosquitoes, and researchers are studying the reasons why in the hopes of creating the next generation of insect repellants. Scientists have found that these natural repellers tend to excrete substances that mosquitoes find unappealing. Incorporating these molecules into advanced bug spray could make it possible for anyone to ward off mosquitoes effectively.