If their life cycle was too long, their environment might disappear before they could complete development. They lay their eggs on the surface of fermenting fruit or organic matter. Within two days the eggs hatch and by the end of eight days new adults can be found. Sometimes breeding sites may be difficult to detect, such as with damp mops fermenting due to the presence of food particles or with unrinsed drink cans waiting for recycling. Not very much is known about fungus gnats.
All types have long, thin wings and legs, and most are black in color.
These may be difficult to identify without the help of an expert. Usually when fungus gnats are found indoors, they are associated with wet soil in potted plants, atriums in larger buildings, or moisture from leaks in walls and ceilings. Most often they feed on fungus found in these sites. While they are harmless, their numbers can be annoying and they can carry germs into clean environments. House fly young develop in very unclean places, such as fresh manure or garbage.