Filth-Breeding Flies


Several species of flies may be encountered around the home. The house fly and various species of blow flies are among the more common of the larger flies. These flies are important household pests, not only because of the nuisance of their flying and buzzing, but because they are strongly suspected of spreading disease-carrying organisms (e.g., bacteria). House flies normally breed in fresh animal manure, but can also breed in decaying organic matter in garbage. Blow flies (bottle flies) usually develop in decaying animal carcasses (such as rodents) and in protein-rich organic matter in garbage.
House Fly

The housefly (also house fly, house-fly or common housefly), Musca domestica, is a fly of the suborder Cyclorrhapha. It is the most common of all domestic flies, accounting for about 91% of all flies in human habitations, and indeed one of the most widely distributed insects, found all over the world. It is considered a pest that can carry serious diseases.

The adults are about 5–8 mm long. Their thorax is gray or sometimes even black, with four longitudinal dark lines on the back. The whole body is covered with hair-like projections. The females are slightly larger than the males, and have a much larger space between their red compound eyes. The mass of pupae can range from about 8 to 20 mg under different conditions.

Each female fly can lay approximately 9,000 eggs in a life time, in several batches of about 75 to 150. The eggs are white and are about 1.2 mm in length. Within a day, larvae (maggots) hatch from the eggs; they live and feed on (usually dead and decaying) organic material, such as garbage or feces. They are pale-whitish, 3–9 mm long, thinner at the mouth end, and have no legs. Their life cycle ranges from 14 hours to 36 hours. At the end of their third instar, the maggots crawl to a dry, cool place and transform into pupae, coloured reddish or brown and about 8 mm long. The adult flies then emerge from the pupae. (This whole cycle is known as complete metamorphosis.) The adults live from two weeks to a month in the wild, or longer in benign laboratory conditions. Having emerged from the pupae, the flies cease to grow; small flies are not necessarily young flies, but are instead the result of getting insufficient food during the larval stage.

Stable Fly

Stomoxys calcitrans is commonly called the stable fly, barn fly, biting house fly, dog fly, or power mower fly. Unlike most members of the family Muscidae, Stomoxys calcitrans and others of its genus suck blood from mammals. Now found worldwide, the species is considered to be of Eurasian origin.

The stable fly resembles the common housefly (Musca domestica), though smaller, and on closer examination has a slightly wider abdomen and is spotted. Adults are generally about 6-8mm in length and a lighter color than the housefly. Unlike the housefly, where the mouth part is adapted for sponging, the stable fly mouth parts have biting structures.

As its name suggests, the stable fly is abundant in and around where cattle are kept. Its maggots are often seen in the rotting manure near cattle and poultry.

Black Soldier Fly

The black soldier fly, or Hermetia illucens is a common and widespread fly of the family Stratiomyidae, whose larvae are common detritivores in compost heaps. Larvae are also sometimes found in association with carrion, and have significant potential for use in forensic entomology.

Black soldier fly larvae (BSFL) may be used in manure management, for house fly control and reduction in manure volume. Mature larvae and prepupae raised in manure management operations may also be used to supplement animal feeds.

Larvae are sold as feeders for owners of herptiles and tropical fish, or as composting grubs. They store high levels of calcium for future pupation which is beneficial to herptiles.

Black soldier fly eggs take approximately four days to hatch and are typically deposited in crevices or on surfaces above or adjacent to decaying matter such as manure or compost.

Green Bottle Fly

The name green bottle fly (or greenbottle fly) is applied to numerous species of blowfly, in the genera Lucilia and Phaenicia (the latter is sometimes considered a subgenus of the former). These flies are found in most areas of the world,primarily the Western Hemisphere and especially California. and the most well-known species is the common greenbottle, Phaenicia sericata (or Lucilia sericata, depending on authority), though there are other common species such as Lucilia caesar, Lucilia cuprina, Lucilia coeruleiviridis, and Lucilia illustris. The maggots of this fly are known to preferentially consume dead tissue while leaving live tissue intact, and so have been sold for use in maggot therapy, primarily during the years before the widespread use of antibiotics and medicines and in modern times due to a resurgence of medical literature documenting their effectiveness. These flies are known to lay eggs in cadaver tissue in the wild within hours after death. The developmental stage of their larvae in the cadaver can be used to accurately predict the time death occurred.

Blue Bottle Fly

The blue bottle fly or bottlebee (Calliphora vomitoria) is a common blow-fly found in most areas of the world and is the type species for the genus Calliphora. Similar species include the green bottle fly, a close relative that can be distinguished by its bright green metallic colouring. Blue bottle fly adults feed on nectar, while the larvae feed on carcasses of dead animals. Adults are also pollinators to some flowers with strong odor.

It is 10–14 millimetres (0.4–0.6 in) long, slightly larger than a housefly. The head and thorax are dull gray and the abdomen is bright metallic blue with black markings. Its body and legs are covered with black bristle-like hair. It has short, clubbed antennae and 4 tarsi per leg. The eyes are red and the wings are transparent. The legs and antennae are black and pink. The chest is bright purple and has spikes to protect themselves against other flies. These insects like to fly in packs in order to detect possible prey more efficiently. If one fly detects food, it will disperse a pheromone which will alert the others to the meal.

Flesh Fly

Flies in the family Sarcophagidae (from the Greek σάρκο sarco- = flesh, φάγε phage = eating; the same roots as the word "sarcophagus") are commonly known as flesh flies. They differ from most flies in that they are ovoviviparous, opportunistically depositing hatched or hatching maggots instead of eggs on carrion, dung, decaying material, or open wounds of mammals, hence their common name. Some flesh fly larvae are internal parasites of other insects such as Orthoptera, and some, in particular the Miltogramminae, are kleptoparasites of solitary Hymenoptera.

Members of the subfamily Sarcophaginae are medium to large flies 0.08-0.7 in (0.2-1.8 cm) with black and gray longitudinal stripes on the thorax and checkering on the abdomen. Other key features include red eyes and a bristled abdomen. Abdominal sternites II and III are free and cover the margins of tergites. The posthumeral bristles are one or two in number, with the outermost pair missing.

Flesh flies can carry leprosy bacilli and can transmit intestinal pseudomyiasis to people who eat their larvae. Flesh flies, particularly Wohlfahrtia magnifica, can also cause myiasis in animals, mostly to sheep, and can give them blood poisoning, or asymptomatic leprosy infections.

Secondary Screwworm Fly

Cochliomyia is a genus in the family Calliphoridae, known as blowflies, in the order Diptera. Cochliomyia are commonly referred to as the New World screwworm fly. There are four species in this genus: Cochliomyia macellaria, Cochliomyia hominivorax, Cochliomyia aldrichi, and Cochliomyia minima. The two main species are Cochliomyia hominivorax and Cochliomyia macellaria.

Cochliomyia hominivorax are known as the primary screwworm because their larvae produce myiasis and feed on living tissue. This feeding causes deep, pocket-like lesions in the skin, which can be very damaging to the animal host. Cochliomyia macellaria are known as the secondary screwworm because their larvae produce myiasis, but feed only on necrotic tissue. This species is forensically important because it is often associated with dead bodies and carcasses. Both C. hominivorax and C. macellaria thrive in warm, tropical areas.

Black Blow Fly

The species Phormia regina, more commonly known as the black blow fly, belongs to the blow fly family Calliphoridae. Although some authorities merge both the blow fly group (Calliphoridae) and the flesh fly group (Sarcophagidae) together in the family Metopiidae, key distinguishable physical traits allow for this separation.

Being a member of the order Diptera (the fly order), it is attributed by the presence of only its pair of fore wings while the pair of hind wings has been highly reduced to halteres. These halteres function in aiding in stability and maneuverability during flight. Wings of this fly are specialized having a sharp bend halfway through the wing and they are also known to have a well-developed calypter. Blow flies are about the size of a house fly or a little larger, many are metallic blue or green. Key characteristics of this species include black gena, mostly white calypteres and anterior thoracic spiracles that appear to be orange yellow due to being surrounded by bright orange setae.

Like most other flies, the black blow fly feeds via sponging, having functional or nonfunctional mouthparts. They are known to feed on various foods, with emphasis on nectar, honey-dew, and the liquid products of decomposition. P. regina, like other flies, is poikilothermic; the growth and development of the fly is dependent on temperature. At room temperature, the egg to pupal stage lasts about 6–11 h. With an increase in temperature of the surrounding environment, metabolic rates of the blow fly typically increase, causing an increase in the rate of growth and development. In addition to an increase in the growth and development, temperature also has a profound impact on female oviposition. It is key to note the fluctuations between diurnal and nocturnal temperatures. Typically, blow flies will oviposit in the daytime due to the increase of temperature.