Mosquitoes are a common source of discomfort during warmer months. Understanding what attracts them can help minimize their presence and avoid bites. This exploration reveals the complex interplay of cues mosquitoes use to locate a host.
Mosquitoes and Color Perception
Mosquitoes exhibit a preference for certain colors, primarily darker shades like black, navy, and dark green. These colors may mimic shadows, helping mosquitoes visualize a silhouette against the horizon to identify a potential host. Beyond general darkness, specific wavelengths within the visible light spectrum also attract mosquitoes, including red, orange, and cyan. Research indicates that human skin, regardless of pigmentation, emits a strong red-orange signal to a mosquito’s eyes.
Conversely, lighter colors like white, green, blue, and light pastels are generally less attractive to mosquitoes. Some studies suggest that lighter colors might be perceived as a threat, as mosquitoes are susceptible to dehydration and often avoid direct sunlight where light colors would be more prominent. The attraction to specific colors, however, is often conditional; for instance, the yellow fever mosquito (Aedes aegypti) only shows a preference for red, orange, and cyan after detecting carbon dioxide.
Beyond Color: Other Attractants
While color plays a role, other sensory cues are significantly more influential in attracting mosquitoes. Carbon dioxide (CO2), exhaled by humans and animals, acts as the primary long-range attractant for mosquitoes. Mosquitoes possess specialized receptors on their antennae that are highly sensitive to CO2 levels, allowing them to detect even slight changes in concentration and guide them towards potential hosts from distances of 10 to 50 meters. This CO2 detection triggers a heightened activity level, prompting the mosquitoes to then search for visual cues.
Beyond CO2, mosquitoes also sense body heat, which becomes a factor as they approach a host, typically within 2.5 feet (70 cm). They can detect infrared radiation emitted from human skin, with studies showing that adding infrared heat similar to skin temperature doubled host-seeking activity when combined with CO2 and human odor. Certain chemical compounds in human sweat and skin odor, such as lactic acid, ammonia, and specific fatty acids, also act as attractants. These non-visual cues often override color preferences, serving as the main drivers once a mosquito is within closer range.
Practical Tips for Avoiding Mosquitoes
Based on how mosquitoes find their hosts, several practical steps can reduce the likelihood of bites.
- Wear light-colored clothing, such as white, beige, or light pastels, to minimize visual attraction.
- Cover exposed skin with loose-fitting, long-sleeved shirts and long pants for a physical barrier against bites.
- Minimize carbon dioxide output by avoiding strenuous activity in mosquito-prone areas, especially during peak activity times like dusk and dawn.
- Use EPA-approved repellents containing ingredients like DEET or picaridin on exposed skin.
- Regularly eliminate standing water around the home, such as in buckets, old tires, and bird baths, to remove breeding grounds and reduce mosquito populations.