Mosquitoes are a common nuisance, with some individuals attracting more bites than others. Scientific inquiry explores the biological reasons behind these varied interactions, including how mosquitoes locate human hosts and what chemical signals draw them in.
How Mosquitoes Find Their Meals
Mosquitoes use sensory cues to pinpoint human targets. A primary attractant is carbon dioxide (CO2), which humans exhale. Mosquitoes can detect CO2 from up to 164 feet away using specialized receptors. Increased CO2 levels alert mosquitoes to a potential host, prompting them to move toward that area.
Beyond CO2, mosquitoes are drawn to body heat and odors from human skin and sweat. Lactic acid, a metabolic byproduct in sweat, is a significant attractant for female mosquitoes. Other compounds like ammonia and uric acid, also in sweat, contribute to a person’s unique odor profile. These chemical signals, combined with body temperature, guide mosquitoes to feeding sites.
Blood Type and Mosquito Preference
Research indicates blood type influences a person’s attractiveness to mosquitoes. Studies suggest people with Type O blood are often more appealing, while Type A blood tends to be least attractive. A 2004 study found mosquitoes landed on Type O secretors more often than Type A secretors. A 2019 study similarly observed mosquitoes preferred Type O blood samples.
The basis for this preference lies in the antigens associated with blood types. Approximately 80% of people are “secretors,” meaning they secrete these blood type antigens into body fluids like sweat and saliva. Type O individuals secrete the H antigen, which is a precursor to A and B antigens. Mosquitoes may detect these secreted antigens, and the specific chemical signals associated with the H antigen in Type O secretors are thought to contribute to their increased attraction.
Beyond Blood Type: Other Factors
While blood type plays a role, other factors influence individual susceptibility. An individual’s unique skin microbiome, the community of bacteria living on the skin, significantly contributes to body odor and mosquito appeal. The metabolic byproducts of these bacteria, interacting with sweat components, create specific scents that mosquitoes detect. Studies suggest that a higher diversity of microbes on the skin might make some individuals less attractive to mosquitoes.
Genetic factors also contribute to variations in mosquito attraction. Research involving twins has indicated that an individual’s genetic makeup can influence the specific body odor profiles they emit, which in turn affects how attractive they are to mosquitoes. Metabolic rates, which influence the production of compounds like lactic acid, also contribute to a person’s unique attractiveness. Therefore, mosquito attraction is a complex interplay of various biological and environmental elements.