Flies repeatedly landing on you can be an irritating experience. While it might feel like a personal invasion, specific biological factors drive this behavior, making it less about you and more about the resources your body provides.
What Draws Flies to Humans
Flies are equipped with highly sensitive sensory organs that help them locate necessary resources, and the human body offers several appealing elements. One such attractant is the warmth emanating from our bodies. Flies are ectothermic, meaning their body temperature is influenced by their surroundings, and the warmth of human skin can provide a comfortable environment, especially in cooler conditions.
Carbon dioxide (CO2) we exhale is another significant draw. Certain fly species possess specialized receptors that detect CO2 concentrations from a distance. This gas signals a living host, potentially offering other desirable elements.
Our skin is also covered in sweat and natural oils, which contain compounds that flies find appealing. Sweat includes salts, proteins, water, all of which are valuable nutrients or hydration sources for flies. The fatty acids present in our skin’s natural oils can similarly serve as a food source, attracting flies seeking sustenance.
The unique blend of human body odors acts as a powerful lure. These odors result from sweat interacting with skin bacteria. This microbial activity creates volatile compounds flies detect as signs of a food source or a suitable landing spot.
Understanding Fly Behavior on Your Skin
Once a fly lands on your skin, its activities are far from random; they are driven by a need to assess and acquire resources. Flies use their feet, which are covered in tiny hairs and chemoreceptors, to “taste” and sample the surface they have landed on. This allows them to quickly detect sugars, salts, and other organic compounds present in sweat or skin residue.
Flies often seek moisture or other liquid nutrients, like a sip of sweat to rehydrate or to absorb dissolved nutrients from your skin’s surface. This exploratory behavior is part of their foraging for food and water sources.
Sometimes, a fly lands to rest or groom. A human’s warm skin can provide a stable platform for these activities. During grooming, flies rub their legs together and over their bodies to clean off dust and debris, ensuring their sensory organs remain functional.
While exploring or resting, flies can inadvertently pick up and deposit microbes. As they move from one surface to another, they can act as passive transporters of bacteria and other microorganisms. This process is a natural consequence of their foraging and landing behaviors.
Simple Ways to Deter Flies
Managing personal hygiene reduces your attractiveness to flies. Regular bathing washes away sweat, skin oils, and bacterial byproducts that attract flies. Keeping your skin clean minimizes the accumulation of these attractants.
The colors of your clothing might also play a role in how often flies land on you. Lighter colors, such as white or light yellow, tend to be less attractive to flies compared to darker shades like black or dark blue. This is because darker colors can absorb more heat, potentially making you a more appealing warm spot, and may also be more visible against certain backgrounds.
Exercising caution with strong perfumes, colognes, or even scented lotions can also be beneficial. Some of the volatile compounds used in these products, particularly those with sweet or musky notes, might mimic natural odors that attract flies. Opting for unscented products or those with natural repellents could be helpful.
Being mindful of your surroundings can also reduce fly encounters. Areas with exposed food waste, stagnant water, or decaying organic matter are breeding grounds and gathering spots for flies. Moving away from such environments can significantly decrease the number of flies in your immediate vicinity. Finally, moving calmly rather than making sudden, jerky movements can make you less noticeable to flies. Erratic movements can attract their attention, whereas slow, deliberate actions might allow you to go unnoticed.