Phorid flies, also known as humpbacked flies or coffin flies, are small insects often mistaken for other common household pests. These flies are a nuisance in many environments, from residential homes to commercial facilities. A common concern for many people is whether these small flies can bite, and the direct answer is no, phorid flies do not bite humans or animals.
Do Phorid Flies Bite?
Phorid flies lack the specialized mouthparts required to bite or pierce skin. Unlike mosquitoes or fleas, they possess sponging mouthparts designed for feeding on liquids by soaking them up from various surfaces.
These flies primarily feed on decaying organic matter like rotting fruits, moist filth, and fungi. They are also found on carrion, dung, or liquids from open wounds, but they do not create these wounds. Any perceived “bite” from a small fly is likely from a different insect, as phorid flies cannot bite.
Why Phorid Flies Are a Problem
Despite not biting, phorid flies are pests, primarily due to their association with unsanitary conditions. Their presence is annoying, especially in large numbers, as they fly erratically around living spaces or food preparation areas. They are frequently observed scuttling across surfaces rather than flying, a distinctive behavior.
Phorid flies pose a contamination risk because they breed and feed in decaying organic matter, harboring bacteria and pathogens. They pick up germs from unsanitary sources and transfer them to food surfaces, utensils, or open wounds, potentially spreading disease. Their presence frequently signals a hidden sanitation issue.
Eliminating Phorid Fly Infestations
Controlling phorid fly infestations requires identifying and eliminating their breeding source, as adult flies emerge until it’s removed. Common breeding sites include drains, especially those with organic debris or sewage leaks, and garbage disposals. Other sources include trash cans with leaky liners or residual liquids, and rotting produce.
Phorid flies also breed in spills under appliances, crawl spaces, or wall voids where plumbing leaks create damp conditions supporting mold or fungal growth. A significant infestation may indicate a more serious underlying issue, such as a dead animal in a wall or a broken sewer line under a slab, requiring extensive remediation.
Thorough sanitation is important for effective control. This involves regularly cleaning drains, removing decaying organic matter, and practicing proper waste management. Biological drain cleaners break down organic film in pipes where larvae develop, as bleach and hot water are often ineffective. While source elimination is paramount, physical control methods like sticky traps or apple cider vinegar traps can reduce the adult fly population. For persistent infestations where the source is difficult to locate or inaccessible (e.g., deep plumbing issues or a hidden carcass), professional pest control is often recommended.