Fannia canicularis: what do we actually know about this fly?
Diptera is one of the largest insect orders, with some 85,000 species. It takes in house flies, mosquitoes, horse flies, stable flies, biting midges, blow flies and more.
Technical summary
- Focus
- Diptera is one of the largest insect orders, with some 85,000 species. It takes in house flies, mosquitoes, horse flies, stable flies, biting midges, blow flies and more.
- Approach
- The article structures the analysis around Within the family Fanniidae, Morphology and Biology.
- Use
- Useful for professionals who need context, diagnosis and operational decisions in public health and vectors.
Index
Diptera is one of the largest insect orders, with some 85,000 species. It takes in house flies, mosquitoes, horse flies, stable flies, biting midges, blow flies and more. Structurally, the Diptera are among the most highly specialised members of their class. Dipteran mouthparts may be of the sponging type, as in the common house fly; piercing-sucking with six stylets, as in mosquitoes; or with four stylets, as in blood-feeding flies. The larval forms are commonly called maggots. The adults of a great many species are diurnal, and most are either fond
of flowers, whose nectar they feed on, or frequently of decomposing organic matter of various kinds. Although these two habits predominate, a considerable number of flies are predators and feed on a range of insects. The name of the order comes from the characteristics of the wings: the first pair is membranous and crossed by veins, while the second pair is transformed into halteres — vestigial or prominent, ending in a knob or club — which appear to serve a balancing function in flight. (Di: two; pteron: wings.)
Within the family Fanniidae
This is a family containing few genera, one of them being Fannia. They share many characteristics with the family Muscidae, with dark tones and a grey abdomen. Members of this family are more active in warm weather. Fannia feeds on decomposing plant matter, excrement or organic matter with plenty of liquid. The larvae are adapted to float, which gives them good mobility. Both larvae and adults can pose a public health risk, since they breed in unhygienic conditions and act as vectors of pathogens; they can be found in homes and in food processing plants, and they are abundant in slaughter operations and in poultry farm management.
Morphology
The larvae are highly characteristic: dorsoventrally flattened, made up of eleven visible segments, and bearing expansions and branched hairs arranged in longitudinal rows. The adults are relatively small flies, between 3 and 4 mm. Males have large eyes that take up almost the whole head, described as holoptic; female Fannia, by contrast, have dicoptic or separated eyes. The five main abdominal segments are visible. The abdomen is heart-shaped or elongated, and generally grey or dark brown.
Biology
Life cycle characteristics: at 24–27 °C the egg
takes 20 to 48 hours to hatch; the larvae need 6 days to reach the pupal stage, which lasts 7 days. The cycle varies with temperature and humidity, and below 15 °C for 7 days an extreme slowing of the cycle is observed. Fannia, the lesser house fly, is often seen making circular flights inside animal barns or houses. Its life cycle is very short, and at high temperatures its offspring increase rapidly. Fannia lays 100–150 eggs on decomposing organic matter. The larvae develop in the organic matter and then seek out a drier place to pupate. They feed 2.5 to 4 times a day. They regurgitate more than
30 times. They vomit and defecate more than 50 times a day.
Consequences for animal and public health
The larvae breed in unhygienic conditions and act as vectors of pathogenic organisms. F. canicularis larvae are recognised as accidental agents of myiasis in humans and livestock (Mazza & Oribe, 1939; Oliva, 1997; Rozkosny et al., 1997). They carry disease-causing micro-organisms on their mouthparts, spreading infection when they regurgitate their digestive contents, and they also carry them on their body hairs and legs and in their faeces. Every time the fly lands it regurgitates everything in its stomach, making it a significant carrier
of micro-organisms; they defecate as they feed, which increases the risk of disease transmission.
Control strategies
- Identify the species involved.
- Inspection: breeding sites and points of entry.
- Integrate non-chemical and chemical control methods.
Among non-chemical controls, traps are one method, depending on the type of operation and the geographical setting.
IN CHEMICAL CONTROL
In biological control, examples include histerid beetles, mites, small wasps such as Spalangia sp. and Muscidifurax sp., and dung beetles such as Ontherus sulcator.