Cluster Flies

About Cluster Flies

Cluster flies are common pests in homes and buildings, particularly during the cooler months when they seek warmth. These flies belong to the genus Pollenia and are slightly larger than house flies. Cluster flies are known for their habit of gathering in large numbers, often clustering in attics, wall voids, and other secluded areas. They are generally a nuisance rather than a health threat, as they do not transmit diseases like some other fly species. Understanding their behavior and life cycle is crucial for effectively managing and preventing cluster fly infestations.

What Do Cluster Flies Look Like?

Cluster flies are slightly larger than house flies, typically measuring about 1/4 to 3/8 inch in length. They have a dark gray body with a distinctive checkered pattern on the abdomen and golden-yellow hairs on the thorax, giving them a somewhat fuzzy appearance. Their wings overlap when at rest, and their eyes are large and reddish-brown. Unlike house flies, cluster flies move more sluggishly and do not exhibit the same rapid, erratic flight patterns. These physical characteristics help in identifying cluster flies and distinguishing them from other common fly species.

Facts about Cluster Flies Gestation

Cluster flies have a unique life cycle that begins with eggs laid in soil during the summer. Female cluster flies lay their eggs in the soil, where the larvae hatch and seek out earthworms, their primary host. The larvae enter the earthworms and develop inside them, feeding on their host for several days. Afterward, the larvae leave the earthworms and pupate in the soil. The pupal stage lasts for about 11 to 14 days before adult flies emerge. Cluster flies typically have two to four generations per year, depending on environmental conditions. This life cycle allows them to build up populations rapidly, especially in areas with abundant earthworms.

Cluster Flies Habitat and Behavior

Cluster flies prefer to live outdoors during the warmer months, where they lay eggs in soil and the larvae parasitize earthworms. As temperatures drop in the fall, adult cluster flies seek out warm, secluded places to overwinter, such as attics, wall voids, and unused rooms in homes and buildings. They are attracted to the warmth and sunlight, often clustering around windows and other light sources. Cluster flies are sluggish and slow-moving, particularly during cooler weather. They do not feed or reproduce indoors but can become a nuisance due to their tendency to gather in large numbers and their persistent presence throughout the winter months.

What Are 5 Unique Facts About Cluster Flies?

1. Cluster flies are parasitic in their larval stage, developing inside earthworms before emerging as adult flies.
2. They have a unique habit of clustering in large numbers in warm, secluded areas during the winter months.
3. Cluster flies can enter homes through small cracks and crevices, seeking warmth and shelter as temperatures drop.
4. Unlike other common flies, cluster flies do not reproduce or feed indoors, reducing their potential as disease vectors.
5. Their sluggish movement and tendency to gather around windows make them easily distinguishable from other fly species during an infestation.

What Are the Problems Related to Cluster Flies?

Cluster flies primarily cause nuisance problems when they invade homes and buildings in large numbers. Their presence can be particularly bothersome during the fall and winter months, as they cluster around windows and other warm areas. The flies’ sluggish movement and tendency to gather in groups can create an unsightly and irritating environment. Additionally, dead cluster flies can accumulate in wall voids and attics, attracting other pests like carpet beetles. While cluster flies do not pose significant health risks, their persistent presence and potential to attract secondary pests necessitate effective management and prevention measures to maintain a comfortable living space.

What Are the Risks Associated with Cluster Flies?

The primary risks associated with cluster flies include nuisance issues and the potential attraction of secondary pests. While cluster flies do not transmit diseases or cause direct harm to humans and pets, their presence in large numbers can be highly irritating. Dead cluster flies can accumulate in wall voids and attics, providing a food source for other pests such as carpet beetles. These secondary pests can cause additional problems, including damage to fabrics, carpets, and stored goods. Effective control and prevention of cluster flies are essential to mitigate these risks and maintain a pest-free environment in homes and buildings.

Get Rid of Cluster Flies Treatment

To get rid of cluster flies, start by sealing entry points such as cracks, gaps, and openings around windows, doors, and eaves. Use caulk or weatherstripping to block their access. Inside the home, use a vacuum cleaner to remove any visible flies and dispose of the vacuum bag immediately. Consider installing screens on attic vents and other openings to prevent flies from entering. Insecticidal sprays can be applied to areas where cluster flies are found, such as around windows and in attics. For severe infestations, use foggers or contact a professional pest control service to implement more comprehensive treatment strategies. Regular maintenance and monitoring are key to preventing future infestations.

Cluster Flies Prevention Advice

Preventing cluster fly infestations involves sealing potential entry points and maintaining a clean environment. Inspect your home for cracks and gaps around windows, doors, and eaves, and seal them with caulk or weather-stripping. Install screens on attic vents and other openings to block flies from entering. Ensure that windows and doors fit tightly and are properly sealed. Use a vacuum cleaner to remove any flies that have entered the home and dispose of the vacuum bag immediately. Regularly check and clean areas where flies are likely to gather, such as attics and wall voids. Implementing these preventive measures can help keep cluster flies at bay and maintain a comfortable living space.