Flies belong to the order Diptera, and their presence is rarely random; it is almost always linked to a specific need like food, moisture, or a site for laying eggs. These insects are common pests, often seeking resources that humans provide through sanitation habits or their own biology. Understanding the distinct types of flies and what specifically attracts them is the first step toward effective control. Addressing a fly problem requires identifying the source of the attraction, such as an unsealed garbage can.
Identifying the Common Nuisance Species
Identifying the exact species helps pinpoint the problem source, as different flies are drawn to different substances. The common house fly (Musca domestica) is a medium-sized, grayish-black insect recognized by four dark stripes on its thorax. It is attracted to decaying organic matter, including garbage and pet waste, and moves quickly between filth and human environments.
A much smaller pest is the fruit fly, identified by its tiny size and distinctive red eyes. Fruit flies are strongly attracted to fermenting matter, such as overly ripe fruit, sugary spills, and alcohol. A third common pest is the drain fly, which has a fuzzy, moth-like appearance and is frequently found near sinks and showers. These flies breed in the organic sludge and biofilm that accumulate inside plumbing.
Primary Environmental Attractants
Flies are primarily drawn into human environments by strong odor plumes that signal a rich source of nutrients or a suitable breeding location. Decaying organic matter is a major attractant, providing both food for adult flies and a site for their larvae, known as maggots, to develop. This includes unsealed kitchen garbage, compost piles, and any exposed animal waste in the yard.
Moisture is another significant factor, as flies require water to survive and often breed in damp conditions. Standing water, such as in clogged gutters or flower pots, can become a breeding ground, as can excess moisture around sinks and under appliances. Similarly, the organic buildup inside drains provides a constantly moist environment where insects like the drain fly can thrive.
Exposed food sources, including uneaten pet food, spilled drinks, and ripe produce left on counters, are powerful lures that bring flies into living spaces. House flies are drawn to a wide array of food, while fruit flies specifically seek out the odors of fermentation. Eliminating these external and household sources is the most effective method for reducing the overall fly population.
Why Flies Land on You
Flies land on the human body because they are constantly seeking liquid nutrients and salts, which they sense using specialized chemoreceptors on their feet. The moisture and salts found in human sweat are a resource for flies, helping them maintain physiological functions. The more a person sweats, the more attractive they become.
The carbon dioxide (CO2) that humans exhale is also a primary signal that attracts flies, guiding them to a potential host. They interpret the heat radiating from the body as an indication of warmth and a potential food source. Since flies lack chewing mouthparts, they must liquefy solid food by regurgitating digestive enzymes onto a surface before consuming it. When a fly lands on the skin, it is tasting the surface for residues of proteins, sugars, and other chemicals left by sweat or oils.
Eliminating the Source and Preventing Future Issues
The most effective way to prevent fly presence is through immediate and rigorous sanitation, focusing on removing attractants and breeding sites. For house flies, ensure all waste is properly contained using tightly sealed garbage bins, and frequently remove trash from the premises. Pet waste should be cleaned up immediately, as it is a major breeding and feeding site.
To prevent fruit flies, promptly refrigerate or consume ripe produce and thoroughly rinse out all beverage containers. For drain flies, clean the organic film from plumbing using a pipe brush or a combination of baking soda, salt, and vinegar, as common bleach is often ineffective. These cleaning methods destroy the larval habitat within the drain.
Physical barriers are an effective measure to keep adult flies from entering the home. Install fine-mesh screens on all windows and doors, and promptly repair any existing tears. Simple tools like the fly swatter offer immediate, non-chemical control. Additionally, installing fans near doorways creates a barrier of moving air, which flies struggle to fly against, further discouraging entry.