The lesser house fly or little house fly, ''Fannia canicularis'', is somewhat smaller () than the common
housefly. 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.
...
e feed on all manner of decaying organic matter, including
carrion.
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
Holoptic refers to one of the ways in which the arthropod eye develops, particularly the eyes of various species of insects. Unlike dichoptic and cycloptic eyes, holoptic eyes meet along the median dorsal line of the head, in many species near ...
. 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
''Halteres'' (; singular ''halter'' or ''haltere'') (from grc, ἁλτῆρες, weights held in the hands to give an impetus in leaping) are a pair of small club-shaped organs on the body of two orders of flying insects that provide infor ...
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,
garbage truck
A garbage truck is a truck specially designed to collect municipal solid waste and transport it to a solid waste treatment facility, such as a landfill, recycling center or transfer station. In Australia they are commonly called rubbish truck ...
s, and other places where
food waste
Food loss and waste is food that is not eaten. The causes of food waste or loss are numerous and occur throughout the food system, during production, processing, distribution, retail and food service sales, and consumption. Overall, about o ...
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 a ...
, 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
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{{Taxonbar, from=Q238942
Diptera of Europe
Fanniidae
Insects described in 1761
Taxa named by Carl Linnaeus