Female mosquitoes require blood meals for egg production. Mosquitoes possess a refined sensory system to locate human hosts, relying on various body signals. This explains why some people are more susceptible to bites.
Mosquito Blood Type Preferences
Mosquitoes exhibit preferences for certain human blood types. Studies indicate Type O blood is most attractive, while Type A is least appealing. Type B falls into an intermediate range. For instance, a 2019 study observed that mosquitoes preferentially fed from Type O blood samples when given a choice among different blood types in feeders. Another key study from 2004 found that more mosquitoes landed on people with Type O blood compared to Type A, a difference that was statistically significant.
The Science Behind Blood Type Attraction
The observed preferences for certain blood types are linked to specific chemical markers on an individual’s skin. Human blood types (A, B, AB, O) are defined by the presence or absence of particular antigens on the surface of red blood cells. About 80% of people are “secretors,” meaning they release these blood type antigens into bodily fluids like sweat. Mosquitoes detect these secreted antigens on the skin, providing clues about a person’s blood type.
Research indicates that mosquitoes are more attracted to secretors than to non-secretors. Among secretors, individuals with Type O blood antigens appear to be particularly appealing to mosquitoes. The H antigen, which is a precursor to A and B antigens and is prominently found in Type O individuals, has been shown to attract mosquitoes more than the A antigen. The unique chemical composition of these secreted antigens plays a role in guiding a mosquito’s host selection. The ability of mosquitoes to sense these specific chemical profiles on the skin contributes to their documented blood type preferences.
Other Factors That Attract Mosquitoes
Mosquito attraction is influenced by a complex combination of signals beyond just blood type. Carbon dioxide (CO2) exhalation is a primary long-range attractant, which mosquitoes can detect from considerable distances, sometimes up to 50 to 100 feet. Individuals who exhale more CO2, such as those engaged in physical activity, larger individuals, or pregnant women, tend to be more attractive to mosquitoes. The presence of CO2 also enhances a mosquito’s ability to detect other sensory cues.
Body heat is another important factor, as female mosquitoes possess specialized sensors to detect warmth. Warmer bodies generally serve as a more appealing target. Lactic acid, released through sweat, is a significant attractant that mosquitoes can detect, especially when it combines with other volatile organic compounds emitted from human skin. Specific chemicals in sweat and body odor, which are influenced by an individual’s skin microbiota, also play a role in attraction. The unique blend of odors produced by the bacteria living on a person’s skin can make them more or less attractive. Genetic factors also contribute to an individual’s overall attractiveness, as they influence the composition and intensity of these various attractants. Studies involving identical twins have shown similar levels of mosquito attraction, suggesting a genetic component to body odor and overall appeal.