Mosquitoes are not primarily attracted to a specific food a person has just eaten, but rather to the chemical byproducts and physiological changes that result from consumption. The science points to a complex interplay of factors that make one individual more attractive than another. Attraction is driven by sensory cues, including gases, heat, and skin-emitted compounds, which are minimally influenced by diet.
Addressing the Immediate Food Question
The idea that a single food drastically increases mosquito attraction is a misconception, with one notable exception. Studies have consistently shown that consuming beer increases a person’s attractiveness to mosquitoes, although the exact mechanism remains unclear. Researchers initially theorized this was due to increased body temperature or a higher concentration of ethanol in sweat, but these factors did not correlate with increased landings in experiments.
It is possible that beer consumption leads to a subtle change in the volatile organic compounds (VOCs) released through the skin or breath, which mosquitoes can detect. Other foods, such as bananas, have been suggested to increase attractiveness, while garlic and Vitamin B supplements have been shown to have no proven repellent effect despite popular belief. Overall, the impact of diet is a minor factor compared to an individual’s core body chemistry.
How Mosquitoes Detect a Host
Mosquitoes, particularly the blood-feeding females, employ a multi-stage sensory system to locate a host. The first and longest-range signal they detect is carbon dioxide (\(\text{CO}_2\)), the gas exhaled with every breath. They can sense this \(\text{CO}_2\) plume from distances of up to 100 feet, which acts as a general beacon indicating a warm-blooded animal is nearby.
As the insect closes the distance, other cues begin to take over, including visual signals and heat. Mosquitoes are attracted to movement and high-contrast objects, favoring dark colors like black and navy blue over lighter hues. Upon approaching within a short range, they utilize specialized heat sensors to detect infrared radiation and convection heat, allowing them to precisely pinpoint landing spots. The combination of \(\text{CO}_2\), visual cues, and heat work together to ensure the mosquito efficiently finds a target for a blood meal.
The Role of Skin Microbiota and Metabolic Byproducts
The primary chemical basis for why some people are “mosquito magnets” lies in the cocktail of volatile organic compounds (VOCs) on the skin. This personal scent profile is generated by the interaction between human sweat, sebum, and the skin microbiota—the trillions of bacteria living on the epidermis. The composition and density of skin bacteria determine which VOCs are produced, which is why individual attractiveness varies so greatly.
Among the most powerful chemical attractants are lactic acid and ammonia, which are metabolic byproducts released through sweat. Lactic acid, in particular, is a known target for mosquitoes and is produced by common skin commensal bacteria like Staphylococcus epidermidis and Corynebacterium amycolatum as they metabolize sweat components. Other compounds, such as certain carboxylic acids, also play a significant role in creating an attractive scent profile. The concentration of these chemicals is stable, meaning the “mosquito magnet” status is a long-term characteristic tied to their unique biological makeup.
Reducing Your Chemical Attractiveness
Reducing chemical attractiveness involves managing the metabolic and bacterial signals that mosquitoes use for host-seeking. Since strenuous exercise increases both \(\text{CO}_2\) exhalation and the production of lactic acid in sweat, showering immediately after a workout can help wash away these powerful attractants. Wearing light-colored, loose-fitting clothing is a simple measure that reduces visual contrast and helps keep the body cooler, minimizing heat signatures that attract mosquitoes at close range.
The most effective method is the use of topical insect repellents containing active ingredients like DEET or picaridin. These repellents interfere with the mosquito’s olfactory system, blocking their ability to detect the human-emitted VOCs and \(\text{CO}_2\). For those who prefer non-chemical methods, avoiding highly scented soaps or perfumes can also reduce the chance of attracting mosquitoes, as they are drawn to certain floral and fruity odors.