Mosquitoes frequently target ankles and feet. This preference stems from a complex interplay of how mosquitoes detect hosts and specific attractants in these lower extremities.
How Mosquitoes Find a Host
Mosquitoes possess sophisticated sensory systems that enable them to locate potential hosts from a distance. Their initial detection often involves sensing plumes of carbon dioxide (CO2) exhaled by humans, which can be detected from over 30 feet away. This CO2 acts as a primary beacon, signaling the presence of a living, breathing organism.
As a mosquito draws closer, it integrates other sensory cues. Heat signatures from a body become important, acting as a short-range guide. They detect heat from human skin. They are attuned to various chemical cues and visual information, such as movement and dark colors, which help them pinpoint their target.
Primary Human Attractants
Humans emit chemical signals that mosquitoes find appealing. Carbon dioxide is a primary attractant, produced through respiration, with concentration varying by activity. Beyond CO2, organic compounds in human sweat and on the skin play a role. These include lactic acid, a potent lure produced during physical activity.
Volatile organic compounds like ammonia and uric acid are present in sweat, contributing to human attractiveness. The unique blend of these chemicals, influenced by an individual’s skin microbiome, creates a distinct scent profile. Body heat further enhances this attraction.
Why Ankles Are a Preferred Target
The ankle and foot area presents a particularly attractive combination of these factors for mosquitoes. Carbon dioxide, being denser than air, tends to linger closer to the ground, where ankles are located. This creates a more concentrated CO2 plume near the feet, making them an easier initial target for mosquitoes flying at lower altitudes.
Feet and ankles often harbor a unique composition of skin bacteria, thriving in the warm, humid environment of socks and shoes. These microbes break down sweat into volatile organic compounds like isovaleric acid, producing distinct odors highly attractive to mosquitoes. A higher concentration of sweat glands in these areas further contributes to these appealing chemicals.
The feet and ankles can be warmer and more humid, especially when covered, creating a microclimate that facilitates mosquito detection. This elevated temperature and moisture enhance the release of attractant odors. Ankles are frequently exposed even when other body parts are covered, presenting an an accessible target for mosquitoes that often lurk in low vegetation.