The lesser house fly or little house fly, ''Fannia canicularis'', is somewhat smaller () than the common

housefly The housefly (''Musca domestica'') is a fly of the suborder Cyclorrhapha. It is believed to have evolved in the Cenozoic Era, possibly in the Middle East, and has spread all over the world as a commensal of humans. It is the most common fl ...

. It is best known for its habit of entering buildings and flying in jagged patterns in the middle of a room. It is slender, and the median vein in the wing is straight.

Larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e feed on all manner of decaying organic matter, including

carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures, c ...

Morphology

''Fannia canicularis'' is a slim fly reaching a length of from 4 to 6 mm. The white-bordered eyes meet above in the male, a condition described as holoptic. In females, the eyes do not meet. The brown-grey thorax has three black, longitudinal stripes in the males. These are much less distinct in the female. The first two segments of the abdomen are translucently yellow with a dark-brown basal colour. The dark trapezoid marks of the males are hardly recognizable in the females. The halteres are yellowish.

Development

The females lay their eggs in batches of up to 50 and may lay up to 2,000 eggs altogether. The eggs, which are white with a pair of dorsal longitudinal flanges or wings, can float in liquid and semiliquid decaying organic matter, especially poultry, cow and dog feces, kitchen waste such as the end of putrid potatoes or carrots, silage and compost, cheese, bacon, and drying fish. They are commonly found in garbage depots,

wheelie bins A waste container, also known as a dustbin, garbage can, and trash can is a type of container that is usually made out of metal or plastic. The words "rubbish", "basket" and "bin" are more common in British English usage; "trash" and "can" a ...

, garbage trucks, and other places where food waste is stored. The eggs hatch after only two days (24 to 48 hours at ) and the larvae require six or more days to reach pupation, which lasts seven or more days, so they usually take about 2–4 wk to develop into adults, depending upon temperature. The cycle repeats in very damp, putrid excrement, liquid manure, etc.

Behaviour

''Fannia canicularis'' is spread worldwide. They have a life expectancy of two to three weeks. In

Central Europe Central Europe is an area of Europe between Western Europe and Eastern Europe, based on a common historical, social and cultural identity. The Thirty Years' War (1618–1648) between Catholicism and Protestantism significantly shaped the area' ...

, about seven generations can develop per year. They are often found on excrement and on vertebrate animals. Because of their oscillating between excrement and human food, they are considered possible disease carriers. From May to October, the lesser housefly comes frequently into buildings and is noticeable by its peculiar, silent flight in the room center, where it circles down-hanging articles, particularly lamps. It changes the flight direction jerkily. This is a patrol flight, in which the males supervise, if necessary, their district and attack intruders. During short breaks and in the night hours, the flies sit on lamps or on walls and leave their small excrement marks. In the wild, tree branches serve the flies for their swarm dances.

References

*. *. {{Taxonbar, from=Q238942 Diptera of Europe Fanniidae Insects described in 1761 Taxa named by Carl Linnaeus