Flies are more than just a mere nuisance. Their presence alone is often annoying to people, but they are also capable of spreading various dangerous diseases, including malaria, salmonella and tuberculosis. All over the country people are swatting, spraying, and hanging out sticky paper to catch the little buzzers.
Flies are insects in the Order Diptera, which means two-wings, with the original hind wings replaced by two small clubs that are used for balancing. In Australia, there are over 7700 species of flies, dispersing across the nation due to favoured climatic conditions by different species.
Flies can be found in a wide variety of breeding grounds including vegetation, soil, decaying organic matter, water, on other animals and most concerning to public health, in foods for human consumption.
Blowflies and Flesh Flies
Aside from the noticeable ‘buzzing’ noise emitted by blowflies, the reason for their name-sake is the attraction of female blowflies to exposed meat, including wounds of livestock.
Aside from the noticeable ‘buzzing’ noise emitted by blowflies, the reason for their name-sake is the attraction of female blowflies to exposed meat, including wounds of livestock. The female blowfly prefer to lay the eggs in these areas, thus the area being ‘blown’. This poses a serious threat to human health as the spread of disease from meat sources can often be transferred onto other items that the blowflies frequent, for example, cooking utensils.
Adult blowflies may range from 8 to 12mm in length. Their larger size also contributes to the conspicuous buzzing noise attributed to this type of fly. The general appearance of blowflies differs between species, however the most common colours on the thorax and abdomen of blowflies are metallic green, plain brown or brown and blue.
House Fly
The house fly is the most widespread fly in Australia. These flies are likely to harbour disease organisms on their bodies as they often frequent between foods for human consumption and waste materials (e.g. animal excrement). An abundance of house flies in a particular rural or urban area can be seen as an indicator of inefficient waste disposal, as this is where house flies prefer to breed.
The adult house fly is between 4 and 8mm long. The thorax and abdomen of the house fly are a grey colour, with the inclusion of four, darker longitudinal stripes also on the thorax. The house fly has a sponging mouth part to take in liquid food sources. As with all flies, the house fly has a two balancers in the place of hind-wings.
Fruit Fly
Fruit fly is one of the most insidious pests of summer fruit crops. They are active from spring to late summer, attacking the soft fruits of tomatoes, peaches, nectarines, plums, citrus and feijoas amongst others.
The reproductive potential of fruit flies is enormous; they have the ability to lay up to 400 eggs. The entire lifecycle from egg to adult can be completed in about a week. They lay their eggs on the skin of very ripe or fermenting fruit.
Adult fruit flies emerge from the soil in spring with males the first to arrive on the scene seeking out a mate. Over winter adult flies also become active and females sting and lay eggs in maturing fruit, the maggots develop in infested fruit and emerge to pupate in the ground. Populations will also increase as temperatures warm and suitable hosts become available.
Life Cycle
During their development, all flies undergo a complete metamorphosis. Female flies lay their eggs, or sometimes live young, in moist areas that will serve to feed their larvae. When available, larvae often consume great amounts of food, thus contributing to their development. The temperature of where the larvae commence their development also influences how quickly they feed and in turn how many moults (4 on average) the larvae will undergo before pupating.
Pupating will commence once the larvae are satisfactorily fed. The majority of terrestrial species (e.g. house flies) will move away from their original developmental ground, to a much drier location where they are less likely to be consumed by those around them. The pupal stage of development can last from a few days up to a number of months depending on the climatic conditions.
Adult flies emerge once the pupating stage is complete and male flies disperse by air to find a mate. Most adult females will disperse by air to find an appropriate egg-laying site to begin the life cycle over again.