What Do They Eat? You can find cluster flies almost everywhere in the United States and Canada. Dead cluster flies on the loft floor can lead to infestations of undesirable insects such as carpet beetle, which may subsequently invade the house and feed on fabrics. Unlike blow flies cluster flies are not associated with animal carcass, faeces, or woollens. They do not cause a health concern, because they do not lay their eggs in human food. The cluster fly is a parasite of earthworms and breeds outdoors in lawns and fields during the spring and summer. Cluster flies do not reproduce indoors, and home owners bothered by these pests do not need to fear the flies are "hatching" from a dead animal or other unpleasant material within the attic or walls. What Causes Cluster Flies in your home? Treating yards with insecticides to kill earthworms has not been shown to be effective in reducing the number of flies entering homes. Once a worm is found, the maggot burrows into it and begins feasting. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Immediately after the larvae hatch, they begin looking for worms. When temperatures warm in the spring, the flies attempt to find their way back outside to lay eggs. They can be observed buzzing around yards just above the ground. Cluster flies have a widespread distribution. Cluster flies develop as parasites inside the bodies of earthworms. Pollenia species are also numerous in Australia and New Zealand (over 30 species); they are common in North America. Cluster flies frequently use buildings for winter shelter and can be the most common fly found indoors during the cool season. When full grown, the parasitic maggot leaves the body of the host and enters the soil. The cluster fly is one of several species of insects that enter homes in late summer and early fall in search of protected sites in which to spend the winter. They do not harm woolens, fur or feathers, nor do they infest foods in kitchen cupboards. Cluster fly larvae feed on earthworm hosts for several days, at which time they molt and pupate in the soil. MSU is an affirmative-action, equal-opportunity employer, committed to achieving excellence through a diverse workforce and inclusive culture that encourages all people to reach their full potential. Masking tape applied over the opening will keep flies from entering through this route. Adult cluster flies feed on pollen from plants, and females lay their eggs in the bodies of earthworms. Many of these find their way into the living areas of the house rather than outside. Because the larvae feed on earthworms, rather than on garbage, cluster flies are not as much of a health hazard as are house flies, which sometime carry diseases from place to place. The larvae, or maggots, of cluster flies develop as parasites in the bodies of earthworms. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Cluster flies are strictly parasitic on earthworms. The spray should be applied by August 15 when the flies are beginning to congregate on outside walls. The cluster fly maggot is an internal parasite of earthworms and the flies are among the first to be active in the spring. The cluster fly maggot is an internal parasite of earthworms and the flies are among the first to be active in the spring. The larvae use earthworms as a food source.The larvae feed for about 22 days. The grass flies or cluster flies or attic flies are the genus Pollenia in the family Polleniidae are completely harmless to human health. As they mature, they enter the pupal stage, and after 1-2 weeks, they exit from the pupal case. Another option is hiring a professional pest control operator to treat the inside and outside of the house. Cluster Flies can also be a problem behind wall cladding whether it be a timber clad wall or a tile hung elevation. They do not transmit disease. These flies, which are a bit larger than regular house flies, are called cluster flies, and they actually come from earthworms living in the ground. If you have potted plants, then cluster fly larvae will dig into the soil in search of earthworms. Once they’re in, they’re in and there is not much we can do about it. The female cluster fly will lay her eggs near where earthworms burrow, either in the soil or on dead and rotting leaves, and then when the eggs hatch, the larvae or maggots will seek out earthworms and feed on them until they are fully grown. Howard Russell, Entomologist Diagnostic Services Michigan State University, Tags: fly, msu plant & pest diagnostics, pest. The cluster fly is a little larger than the common housefly and moves sluggishly. Gisondi S, Rognes K, Badano D, Pape T, Cerretti P (2020) The world Polleniidae (Diptera, Oestroidea): key to genera and checklist of species. Cluster flies seek refuge in cold weather and find their way into attic spaces and similar areas indoors. The adult flies emerge primarily in the autumn or even late summer. In heated structures, cluster flies may remain active during the winter months and may continually emerge from their hiding spots and find their way into living areas throughout the winter. Cluster flies seek refuge in cold weather and find their way into attic spaces and similar areas indoors. The worm does not usually survive the experience. Besides being a tremendous annoyance, cluster flies are harmless; they do not feed or lay eggs during the winter months. The larvae of the flies feed on earthworms in grass pasture or lawn areas. Cluster Fly Life Cycle When a female emerges from hibernation (or is otherwise ready), she will lay eggs in soil where earthworms are active. Cluster fly larvae develop inside earthworms so they tend to be more of a nuisance in homes that are surrounded by healthy turf areas that support large numbers of earthworms like pastures, golf courses, well-managed lawns, and cemeteries. Cluster flies like to lay their eggs on lawns, areas that have earthworms within the soil. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. They enter homes and other structures by squeezing through cracks around windows and doors, loosely hung siding, soffit vents, louvers and other similar entry points. Cluster flies resemble the common house fly but differ in that they have a patch of yellow hairs under their wings. Sealing cracks around electrical outlet boxes, switches and light fixtures, and around window and baseboard molding on the inside walls will help keep the flies trapped within the walls. Address drainage issues and other areas of moisture around the home. Also, their droppings will stain surfaces. Cluster flies are mostly nuisance pests, but preventing them from invading is important since they do so in large numbers and, once inside, are difficult to eradicate. To the layperson, cluster flies have no obvious characteristics that distinguish them from ordinary house flies. The 4-H Name and Emblem have special protections from Congress, protected by code 18 USC 707. "Family-Group Names in Diptera An annotated catalog", https://doi.org/10.3897/zookeys.971.51283, https://en.wikipedia.org/w/index.php?title=Cluster_fly&oldid=980997075, Taxa named by Jean-Baptiste Robineau-Desvoidy, Creative Commons Attribution-ShareAlike License, This page was last edited on 29 September 2020, at 17:55. Female Cluster Flies lay their eggs in cracks in the soil, which hatch in three days. Cluster flies found in buildings are in a dormant state and cannot reproduce indoors. Adult females lay their eggs near the openings of earthworm burrows. Cluster flies are not ‘filth’ flies, do not eat anything in our homes and do not carry any diseases. There are up to four generations of cluster flies in Michigan each year. Cluster Fly Cluster flies closely resemble house flies, but they are usually larger and have yellowish hairs on the thorax. These eggs hatch within a few days, after which larvae seek to enter the body cavities of earthworms. As larvae, cluster flies exist as parasites inside of earthworms. A vacuum cleaner is a pretty effective method of removing the sluggish, slow moving flies from the house as well. Cluster fly females lay their eggs singly in cracks in the soil; the larvae emerge in three days and begin to seek out their food source: earthworms. That is the time they can be quite a nuisance as they enter homes for purpose of hibernating. The eggs hatch in about four days and the maggots begin to search for earthworms. Description. P. rudis has spread widely in association with humans. In older homes with double-hung windows equipped with pulleys, flies commonly enter living areas through the pulley opening. Sealing exterior cracks and holes on the outside of the house with caulk, especially south and west facing walls, can help to reduce the number of flies that find their way inside. Their maggot larvae are parasites of earthworms, and adult females lay their eggs in the soil near earthworm burrows so that the larvae can … Complete control of cluster flies is almost impossible since the overwintering adults are concealed in walls, attics, etc. The cluster fly maggots live on “planet earthworm” until there’s not much left for them to feed on, then pupate into their adult shape. Cluster flies are typically slow-moving. These services can be expensive. Sounds strange, doesn't it? It's true. Yes. There may be four or more generations of cluster flies per season. Cluster flies are thought to be native to Europe and may have found their way to North America in the ballast of ships containing soil and the cluster fly host, earthworms. It is practically impossible to kill enough of them to make a difference once they have found their way into wall voids, ceilings voids and attics. MSU is an affirmative-action, equal-opportunity employer. The life cycle of cluster flies starts in the spring when the fertilized female lays eggs on the soil near an earthworm hole. ZooKeys 971: 105-155. After burrowing into the earthworm, the larvae feed for about three weeks before pupating. They develop inside the gut of EARTHWORMS! Then in autumn and early winter the adult flies will move into homes and other buildings to survive the winter. Cluster flies are actually a parasite of earthworms and thrive in areas where there is fertile soil. The larvae are parasites of earthworms and the adults feed on plant sap, fruit and flowers. Four to five weeks are required to complete a life cycle. They often emerge on warm days, and cluster at windows attempting to exit(hence the name). You can rid your potted plant soil of earthworms by using organically made insect killers. This information is for educational purposes only. Persistent insecticides include permethrin (sold under a variety of brand names), cyfluthrin (sold as Bayer Advanced Garden Insect Control for homeowners or Tempo for commercial applicators) or one of the Ortho products. Cluster flies develop by feeding on earthworms. Earthworms are a major source of food for Pollenia rudis. Why do I have cluster flies It can be recognized by the short, golden colored hairs on its thorax, the part of the body to which the legs and wings are attached. If the earthworms are gone, the larvae will have a shortage of a primary food source. The main species of earthworm that these cluster flies infect are Aporrectoda caliginosa, Aporrectoda chlorotica, Eisenia lucens, Lumbricus rubellus, and Lumbricus terrestris. You can find cluster flies almost everywhere in the United States and Canada, except for the Southern states bordering the Gulf of Mexico. Cluster flies are large, slow moving, hairy, flies around 10-15mm with a dark gray to black non-metallic abdomen. The cluster fly is often considered a parasite of earthworms and breeds outdoors in fields and lawns during spring and summer. They do not bite and they are not known to transmit diseases. It is adviseable to clear up dead flies where practical. After hatching from eggs the cluster fly larvae find and burrow into the body of an earthworm to feed. This process typically occurs during the spring and summer, and as fall arrives, these pests head indoors in search of shelter. The exposed flies that are killed by such treatments are quickly replaced by others emerging from the ‘woodwork’. They are strictly parasitic on earthworms; the females lay their eggs near earthworm burrows, and the larvae then feed on the worms. They often emerge on warm days, and cluster at windows attempting to exit(hence the name). The cluster flies are considered to be parasitic in nature as their larvae feeds on earthworms. They are strictly parasitic on earthworms; the females lay their eggs near earthworm burrows, and the larvae then feed on the worms. When September arrives the … Yard waste, lawn clippings, wood mulch, and piles of wood can be breeding grounds for cluster flies as these areas attract earthworms, which themselves attract cluster flies. Cluster flies do not harm earthworm populations. These insects are parasites of earthworms. Newly hatched maggots grab onto earthworms as they slither by and burrow into the worm to feed. Flies that develop inside worms? And don’t expect miracles. Cluster fly larvae burrow into earthworms and feed on them until the adult emerges several days later. They lay their eggs in cracks in the soil and the eggs hatch in about three days. The grass flies or cluster flies or attic flies are the genus Pollenia in the family Polleniidae are completely harmless to human health. They enter through cracks and crevices. After that, they g… There is no easy remedy for cluster fly problems. There are about four generations a year. Adult cluster flies then mate and continue this cycle throughout the warm season, making the home garden quite literally a hot bed for reproduction. For questions about accessibility and/or if you need additional accommodations for a specific document, please send an email to ANR Communications & Marketing at anrcommunications@anr.msu.edu. When fall approaches, the cluster flies begin to enter structures in large numbers. Cream coloured and shaped like an elongated wedge, cluster fly larvae feed on live earthworms for about 13 to 22 days before advancing to the pupal stage, which also takes place in the soil. The cluster fly is a parasite of earthworms and breeds outdoors in lawns and fields during the spring and summer. Cluster flies are very similar in looks to house flies, but they have a longer body and a yellow sheen on the thorax. Adult cluster flies (Fig. Adult Cluster flies outdoors live close to the ground level, and feed on flower nectar, plant sap, fruits, and other organic materials. Jeffrey W. Dwyer, Director, MSU Extension, East Lansing, MI 48824. This is because the larvae of a Cluster fly are an earthworm parasite that requires earthworms to grow into full adult Cluster flies. Spraying the outside walls of homes with a persistent insecticide, especially the south and west facing walls, in August can also help reduce the number of flies entering homes. Cluster flies complete 2 or more generations each summer. The poor worm does not usually survive the experience. The typical grass fly Pollenia rudis is about 7 mm long and can be recognised by distinct lines or stripes behind the head, short golden-coloured hairs on the thorax, and irregular light and dark gray areas on the abdomen. Cluster flies are generally just considered a nuisance when they decide to move into your house in the fall. Aggressive and costly insecticide applications will only temporarily reduce the number of flies inside the home because it is nearly impossible to treat every hidden area that may be harboring insects. Cluster flies are related to blowflies, but feed on different foods. Cluster flies prefer earthworms instead. Indoor aerosol insecticides are effective in killing exposed flies during the winter and spring months. Chances are you will continue to see flies even after ‘professional’ treatments. The maggots of cluster flies have never been reared on any other food but living earthworms. They can be observed buzzing around yards just above the ground. Once located, the earthworm is parasitized by the larva. They lay their eggs in cracks in the soil and the eggs hatch in about three days. 1) are slightly larger than the common house fly, Musca domestica . And the larvae of these flies develop in cocoons before hatching into adult flies. Control for cluster flies is exactly the same control used for all other fall home invaders. But while cluster fly larvae may rely on earthworms to feed and grow to their adult stage, adult cluster flies are far more interested in finding a warm place to ride out the long winter - and that’s where indoor spaces like attics, basements, and low-traffic closets can come into play. During summer, cluster flies are active outdoors, where they are parasitic on earthworms. The adult Cluster Fly emerges from its pupa after 12 to The cluster fly life cycle begins when a female lays her eggs in the soil in late summer or early fall. 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