Common European Greenbottle Fly

Appearance

The defining characteristic of "Lucilia sericata", and most used when identifying the adult fly is the presence of three bristles on the dorsal mesothorax. This body region is located on the middle of the back of the fly. "L. sericata" is almost identical to its sister species, "Lucilia cuprina". Identification between these requires microscopic examination of two main distinguishing characteristics.

As opposed to "L. cuprina" which has a metallic green femoral joint in the first pair of legs, "L. sericata" is blue-black. Also, when looking at the occipital setae, " L. sericata" has 6–8 bristles on each side while "L. cuprina" have only one.

Distribution

Lucilia sericata is common all over the temperate and tropical regions of the planet, including Europe, Africa and Australia. It prefers warm and moist climates and accordingly is especially common in coastal regions, but can also be found in arid areas.

The female lays her eggs in meat, fish, animal corpses, infected wounds of humans or animals, and excrement. The larvae feed on decomposing tissue. The insect favours species of the genus Ovis, including domestic sheep in particular. This can lead to Blowfly strike, causing problems for sheep farmers, though "Lucilia sericata" is not a major cause of blowfly strike in most regions.

Behavior

The life cycle of "Lucilia sericata" is typical of flies in the family Calliphoridae in that the egg hatches into a larva that passes through three instars, enters a prepupal and then a pupal stage before emerging into the adult stage or imago. The female lays a mass of eggs in a wound, a carcass or corpse, or in necrotic or decaying tissue.

The eggs hatch out in about 8–10 hours in warm moist weather, but may take as long as three days in cooler weather. In this they differ from the more opportunistic Sarcophagidae, that lay hatching or completely hatched eggs. A single female "L. sericata" may produce 100 to 200 eggs in its lifetime. The pale yellow or grayish conical larvae, like those of most blowflies, have two posterior spiracles through which they respire. These larvae are moderately sized, ranging from 10 to 14 millimeters long.

The larva feeds on dead or necrotic tissue for about 3 to 10 days, depending on temperature and the quality of the food. During this period the larva passes through 3 larval instars. At a temperature of 16˚C the first larval instar lasts about 53 hours, the second about 42 hours and the third about 98 hours.

At higher temperatures the first larval instar lasts about 31 hours, the second about 12 hours, and the third about 40 hours. Third instar larvae then drop off the host onto soil, where available, where they will enter a pupal stage which usually lasts from 6 to 14 days. However, if the temperature is suitably low, a pupa might overwinter in the soil until the temperature rises. After emerging from the pupa the adult will feed opportunistically on nectar or other suitable food, such as carrion, while it matures.

Adults usually lay eggs about 2 weeks after they emerge. Their total life cycle typically ranges from 2 to 3 weeks, but this varies with seasonal and other circumstances. "L. sericata" usually completes 3 or 4 generations each year in cold temperate climates, and more in warmer regions.