What are the different types of filth flies?

There are mainly two types of filth flies based on their appearance and food preferences, small and large filth flies. House flies, blowflies and flesh flies, are relatively larger, soft-bodied insects with large eyes and occur on manure, carrion, garbage and are strong fliers. Drain flies, fruit flies, and phorid flies are smaller ones and occur in drain sludge, organic debris, rotting plant materials. They are comparatively smaller with more delicate bodies and legs.

LARGE FILTH FLIES

House Fly (Musca domestica)

House flies are dull grey in color, quarter-inch long with four dark stripes on the middle section (thorax) of their body. They lay eggs on animal feces and garbage. Their white and apodous or legless maggots (the larval stage)  hatch from eggs to grow half an inch long.

Fully grown larvae crawl away from their food sources to enter the pupal stage, in which they form a dark brown cocoon, the puparium.  Adult house flies can fly one or two miles in search of suitable egg-laying sites.

Blow Flies (Calliphoridae spp.)

They are shiny blue and green in color and make sounds by beating their wings when they fly. Large numbers of blowflies indoors indicate a dead mouse or bird inside your home. The larvae develop inside the bodies of dead animals, causing the carrion to have a bloated appearance.

Flesh Flies (Sarcophagidae spp.)

Flesh flies lay their eggs in carrion. Adults are dark-colored, and, either grey or black. Common flesh fly species have three dark stripes on the thorax and are slightly larger than house flies and have a checkerboard pattern on the abdomen.

Stable Fly (Stomoxys calcitrans)

These flies feed on the blood of animals, including humans and though they deliver painful bites they are not known to transmit diseases to humans. Females lay eggs in rotting straw, manure, and moist surfaces.

SMALL FILTH FLIES

Fruit Flies (Drosophila spp.)

They are small, winged insects commonly found swarming around overripe, unrefrigerated produce in food areas. They are attracted to sweet or fermented liquids like liquor, syrup, carbonated beverages, and vinegar. Females lay almost 500 eggs in their life cycle. The gnat-sized adults typically have tan-colored bodies and red eyes.

Phorid Flies (Phoridae spp.)

Phorid flies resemble fruit flies and are tiny, dark-colored flies. They are humpbacked flies because of their arched thorax. Their larvae feed on decomposing organic debris of plants or animals and their population growth is rapid.

Drain Flies (Psychodidae spp.)

These are ash color flies of about one-eighth of an inch long. They have hairy wings and are most commonly found in sewage and near drains. Adults often rest on bathroom walls and their submerged larvae can survive in the gelatinous muck of floor, sink, and toilet drains. For breathing, when submerged, they extend their breathing tubes to the surface for air. Adults lay 30-100 eggs and their eggs hatch in forty-eight hours. Their life span is 8-21 days.

Why are flies dangerous?

Seeing flies at your home is a sign of unhygienic conditions because they can transmit diarrhea, cholera, and dysentery.

Flies have spongy mouthparts and spurs on their body which carry lots of unsafe germs as they travel from dirty trash to your food. House flies regurgitate their stomach contents onto your food to liquefy it before ingesting it. They also may contaminate food and surfaces by defecating on them. When they move across your food after landing on it, they contaminate it with disease-causing pathogens.