Mosquitoes are a common indoor nuisance, especially during warmer months, leading many to wonder what specifically draws them into homes. Understanding the factors that attract these insects is important for managing their presence.
The Irresistible Allure of Human Presence
Mosquitoes are highly attuned to cues emitted by human bodies. One primary attractant is carbon dioxide (CO2), which humans exhale with every breath. Mosquitoes can detect this gas from considerable distances using specialized receptors on their maxillary palps. This CO2 plume acts as a beacon, guiding them toward a potential host.
As a mosquito gets closer, other human signals become important. Body heat is an attractant, detected through thermal sensors that allow mosquitoes to pinpoint warm skin areas. People with higher body temperatures or who are exercising tend to be more attractive. Skin odor, a blend of chemicals from skin bacteria and sweat glands, also plays a role.
Chemical compounds in sweat and on the skin are appealing to mosquitoes. These include lactic acid, ammonia, and various fatty acids. Lactic acid builds up during physical activity, making those who have recently exercised more attractive. The combination and concentration of these chemicals, influenced by an individual’s skin microbiome, determine how attractive someone is.
Hidden Indoor Breeding Grounds
Standing water sources inside or surrounding a house are attractants for mosquitoes seeking places to lay eggs. Mosquitoes require stagnant water for larval development. Even small amounts of water can serve as suitable breeding sites.
Common indoor breeding grounds include water in potted plant saucers, containers, pet water bowls, and even clogged drains or leaky pipes. Air conditioner drip trays can also accumulate stagnant water, providing an environment for mosquito reproduction. The presence of these water sources attracts mosquitoes to the vicinity.
Light and Other Environmental Cues
Beyond human presence and breeding sites, environmental factors within or near a home influence mosquito attraction. While not as significant as human-emitted cues, light can draw some mosquito species. Mosquitoes are not generally drawn to light like moths, but certain wavelengths, particularly in the blue and ultraviolet (UV) spectrums, can attract them. Some day-biting mosquito species may be more attracted to light as they use it to find food.
Other environmental cues include color and sheltered areas. Mosquitoes are attracted to dark colors such as black, red, and orange. Dark colors may replicate shadows, providing visual targets and absorbing more heat, signaling a potential host or resting spot. Sheltered, humid areas within a home provide resting places for mosquitoes. However, these environmental factors typically act as secondary attractants, often in conjunction with the primary draw of human biological signals.