Sphaerocerid flies, also known as small dung flies or lesser dung flies, are tiny insects frequently encountered indoors. While small, they can become a significant annoyance when infesting homes or businesses. Their presence often indicates underlying issues with sanitation or moisture. Understanding these flies is key to managing their populations effectively.
Understanding Sphaerocerid Flies
Sphaerocerid flies belong to the family Sphaeroceridae within the order Diptera. Over 1,300 species are recognized globally, with more than 200 found in North America alone. These flies are characterized by their small size, typically ranging from 1 to 4 millimeters in length, and a generally dark coloration, usually black or dark brown.
A distinguishing physical feature of sphaerocerid flies is the thickened first segment of their hind legs, which appears less than 1.5 times as long as the second segment and is dilated. They are known for their short, jerky flight patterns, often appearing to hop rather than fly smoothly. Their life cycle, from egg to adult, can be completed in just a few weeks under favorable conditions, allowing for rapid population growth.
Habitats and Attractants
Sphaerocerid flies thrive in environments rich in damp, decaying organic matter, which serves as their breeding and feeding sites. Outdoors, common habitats include manure, compost piles, and rotting vegetation. They are frequently found in animal pens and areas with neglected pet waste.
Indoors, these flies are drawn to unsanitary conditions. Common attractants include clogged drains, garbage disposals, and areas where food debris accumulates, such as under kitchen equipment or in floor cracks. They can also infest neglected fruit or vegetables left out, unwashed recycling bins, and areas with standing water or moisture from pipe leaks or sewer backups. The presence of these flies often signals a hidden source of decaying organic material that needs attention.
Distinguishing Sphaerocerid Flies
Accurately identifying sphaerocerid flies is important because they are often confused with other small household flies. For example, fruit flies are usually lighter in color, ranging from brown to yellow, and are known for their prominent red eyes. They typically have a smoother, hovering flight pattern and are strongly attracted to fermenting fruits and vegetables.
Drain flies, also called moth flies, have a fuzzy, moth-like appearance with black or brown bodies and wings, and they often breed in the slimy film found in drains.
Phorid flies are recognized by their distinctive humpbacked appearance and their rapid, erratic running or “scurrying” behavior, often found in unsanitary environments like sewage-contaminated soil or drains.
Controlling Sphaerocerid Flies
Managing sphaerocerid fly infestations primarily involves eliminating their breeding sources and reducing moisture. The most effective approach is to locate and remove all decaying organic matter where the larvae develop, as they cannot survive without it. This includes thoroughly cleaning interior drain pipes, traps, and plumbing, and removing food waste from under kitchen equipment and floors.
For drains, simply pouring bleach or hot water is not sufficient; the organic film lining the pipes must be physically scrubbed away with a brush. Bio drain gels, which contain microbes that consume organic debris, can also be used. Outdoors, regularly removing wet organic matter like leaf litter, lawn clippings, and poorly maintained compost. Also, maintain standing water sources like bird baths and clogged gutters to help prevent infestations. If the infestation is severe or the source is difficult to pinpoint, professional pest control services can provide targeted solutions and inspections.