Understanding what attracts mosquitoes to humans is important for effective personal protection. This article clarifies common beliefs, especially regarding human waste, by presenting science-backed information on mosquito attraction.
Key Mosquito Attractants
Female mosquitoes, which are the ones that bite, locate hosts through a combination of cues. Carbon dioxide (CO2) is a primary long-range attractant, detectable by mosquitoes from distances up to 150 feet. Humans and animals constantly exhale CO2, and larger individuals, pregnant women, or those engaged in physical activity produce more, making them potentially more noticeable.
Mosquitoes also sense body heat, which signals the presence of a warm-blooded host. Elevated body temperatures, such as those resulting from exercise, can increase a person’s attractiveness. Alongside heat, specific volatile compounds emitted from human skin play a role. These include lactic acid, which accumulates during physical exertion, and substances like ammonia and uric acid found in sweat.
Skin microbiota, the unique communities of bacteria living on human skin, produce a blend of odors, including carboxylic acids. These fatty acids attract mosquitoes, and their levels can remain stable on an individual’s skin over time, explaining why some people consistently seem to be “mosquito magnets.” Decanal and undecanal, components of human sebum, also contribute to this scent profile.
Is Urine a Mosquito Attractant?
Human urine, in its typical excreted form, does not directly attract mosquitoes. Scientific evidence indicates that urine lacks the specific volatile compounds and chemical signals mosquitoes seek when locating a host. Fresh urine is primarily composed of water, urea, salts, and other metabolic waste products.
While certain components like ammonia are present in both urine and sweat, the chemical context and concentration in fresh urine are not attractive to mosquitoes. The misconception that urine attracts mosquitoes may stem from its odor. However, decomposing urine can release ammonia, which might attract other insects like flies, potentially leading to an indirect presence of mosquitoes in the area, but not a direct attraction to the urine itself.
Practical Mosquito Prevention
Understanding what attracts mosquitoes allows for more effective prevention strategies. EPA-registered insect repellents are an effective way to deter bites. These products contain active ingredients such as:
DEET
Picaridin
IR3535
Oil of lemon eucalyptus (OLE)
Para-menthane-diol (PMD)
2-undecanone
Repellents should be applied to exposed skin, while permethrin-treated products are suitable for clothing and gear, but never directly on skin.
Wearing loose-fitting, long-sleeved shirts and long pants can provide a physical barrier, reducing exposed skin for mosquitoes to bite. Opting for lighter-colored clothing is beneficial, as dark colors can retain heat and attract mosquitoes. Reducing strenuous outdoor activity during peak mosquito biting times, typically dawn and dusk, can help minimize the production of CO2 and lactic acid, making one less appealing.
Showering after exercise helps remove sweat and its attractive chemical compounds from the skin. Avoiding scented products like perfumes and lotions with floral fragrances is advisable, as these can mimic natural attractants. Eliminating mosquito breeding grounds is important; mosquitoes lay their eggs in standing water. Regularly emptying, scrubbing, or covering containers that collect water, such as old tires, buckets, birdbaths, and flowerpot saucers, can significantly reduce mosquito populations around a home.