Lesser house fly
|Lesser house fly|
|Fannia canicularis male|
The lesser house fly or little house fly, Fannia canicularis, is somewhat smaller (3.5–6 mm (0.14–0.24 in)) than the common housefly. It is best known for its habit of entering buildings and circling near the center of rooms. It is slender, and the median vein in the wing is straight. Larvae feed on all manner of decaying organic matter, including carrion. It is the most common vector of myiasis within the Fanniidae.
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 more indistinct 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.
The females lay their eggs in batches of up to 50 and may lay altogether up to 2,000 eggs. The eggs, which are white with a pair of dorsal longitudinal flanges or wings, and have the ability to float in liquid and semiliquid decaying organic matter, especially poultry, cow and dog feces, kitchen wastes 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 trucks, and other places where food waste is stored. The eggs hatch after only two days (24 to 48 hours at 24–27 °C or 75–81 °F) 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.
Fannia canicularis is spread world-wide and has a life expectancy from two to three weeks. In Central Europe, 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.
- Rozkosny, R.; Gregor, F.; Pont, A. C. (1997). The European Fanniidae (Diptera). Institute of Landscape Ecology. p. 80 pp.
- Steve, Peter C. (1960), "Biology and Control of the Little House Fly, Fannia canicularis, in Massachusetts", Journal of Economic Entomology 53 (6): 999–1004.
- Zeil, Jochen (1986), "The territorial flight of male houseflies (Fannia canicularis L.)", Behavioral Ecology and Sociobiology 19 (3): 213–219, doi:10.1007/BF00300862.
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