Fruit flies are common in homes, restaurants, supermarkets and wherever else food is allowed to rot and ferment. Adults are about 1/8 inch long and usually have red eyes. Fruit flies lay their eggs near the surface of fermenting foods or other moist, organic materials. Upon emerging, the tiny larvae continue to feed near the surface of the fermenting mass. The reproductive potential of fruit flies is enormous; given the opportunity, they will lay about 500 eggs. The entire lifecycle from egg to adult can be completed in about a week.
Fruit flies are especially attracted to drains, garbage containers, empty bottles and cans, trash containers, mops and cleaning rags. All that is needed for development is a moist film of fermenting material. Infestations can originate from over-ripened fruits or vegetables that were previously infested and brought into the facility. The adults can also fly in from outside through inadequately screened windows and doors.
Fruit flies have the potential to contaminate food with bacteria and other disease-producing organisms
Drain Flies are also called moth flies, sewer flies or filter flies. Their bodies and wings are covered with numerous hairs. If crushed they leave a powdery smudge. The flies are commonly found around drains, but they should not be confused with the Fruit fly, Phorid fly, or Sphaerocierid fly which also infest drains. These nuisance gnats can be found resting on walls or ceilings, and make short hopping flights if disturbed.
The Drain Fly or Moth Fly female lay eggs in moist to nearly saturated organic matter. In an urban environment, moth fly development often occurs in the gelatinous slimy organic matter coating drains. However, they may also be found developing in wet animal manure, sewage or even compost. Very large numbers of these flies in one area probably indicate a development site bigger than a few indoor drains. Once the eggs have been laid, they hatch in about 48 hours and continue to develop in the wet organic matter as larvae. The life cycle of drain flies can be completed in as little as 8 days but can take as long as 24 days depending on temperature.
Because the drain fly develop in the decaying organic matter they have the potential to carry pathogens acquired at these development sites to areas where sterility is important, such as health care facilities and food preparation areas. Drain or Moth flies may also affect human health when present in high numbers, because the bodies of dead flies may disintegrate to form potential allergens.
The Phorid Fly, Humpbacked Fly or Megaselia scalaris Phorid are small – 0.5–6 mm (1⁄64–1⁄4 in) in length. When viewed from the side, a pronounced hump to the thorax is seen. Their colours range from usually black or brown to more rarely yellow, orange, pale grey, and pale white. The female lays from one to 100 eggs at a time in or on the Food source. Laying up to 750 eggs in her lifetime. The time it takes from egg to adult varies on the species, but the average is about 25 days.
Phorid flies are common in many areas but thrive predominately in
moist unsanitary vicinities such as dumpsters, trash containers, rotting meat, vegetable remains, public washrooms, homes, and sewer pipes. Although referred to as scavengers, adults are known to feed primarily on sugars. The larvae, however, depend on moist decaying plant or animal material and feed on a wide range of additional decaying material. Because they frequent unsanitary places, including drain pipes, they may transport various disease-causing organisms to food material. The adults are conspicuous on account of their fast and abrupt running.