Flies frequently land on humans, often perceived as an annoyance. This occurs because flies are drawn to specific cues from the human body and its environment. Their behavior is driven by their sensory capabilities and basic needs for sustenance and survival.
The Irresistible Reasons Flies Land on You
Flies possess a highly developed sensory system to detect human attractants. They are drawn to carbon dioxide exhaled during breathing. Flies also sense body heat, particularly from areas like the face, using it for temperature regulation as cold-blooded creatures. Moisture from sweat, containing salts, sugars, and proteins, acts as a strong attractant, providing nutrients and water.
Human skin emits a complex array of scents, including lactic acid, carboxylic acid, skin oils, and dead skin cells, which flies detect with specialized chemoreceptors on their antennae. Some species are also attracted to fermented smells or food residues. When a fly lands, it “tastes” the surface with chemoreceptors on its feet to determine if the substance is edible. If solid food is encountered, houseflies may regurgitate digestive enzymes to liquefy it before consuming it.
Flies search for food, moisture, and suitable places to lay eggs. Their frequent landings on humans are part of this exploratory behavior, as the human body offers a mobile source of compounds they seek.
Beyond the Buzz: Potential Health Considerations
Flies land on various surfaces, including decaying matter and feces, acting as mechanical vectors for pathogens. They pick up bacteria, viruses, and parasites on the tiny hairs covering their legs and bodies. When they land on human skin or food, these microorganisms can be transferred.
Beyond physical transfer, flies transmit pathogens through regurgitation and defecation. As they feed, they may vomit partially digested material containing microbes. This process, combined with defecating where they land, can contaminate surfaces and food.
Flies can carry over 65 types of infectious diseases. Common bacteria such as E. coli and Salmonella, which can cause foodborne illnesses, are frequently associated with flies. Maintaining good personal hygiene and practicing food safety measures can help mitigate these potential risks.
Effective Ways to Discourage Unwanted Visitors
Minimizing attractants on and around the body deters flies. Regular bathing removes sweat, skin oils, and dead skin cells that draw flies. Changing clothes, especially after physical activity, also reduces these appealing odors and residues.
Controlling the environment is another practical approach. Keeping living spaces clean, promptly wiping up spills, and properly disposing of food waste in sealed containers reduces the availability of food sources for flies. Ensuring windows and doors have intact screens prevents flies from entering indoor areas.
Certain scents act as natural deterrents for flies. Essential oils such as lavender, peppermint, eucalyptus, citronella, and lemongrass can be used in sprays or diffusers to create an unwelcoming environment. Some commercial insect repellents contain active ingredients like DEET or picaridin, which can be applied to skin or clothing for added protection outdoors.