Lucilia cuprina

The species Lucilia cuprina, formerly named Phaenicia cuprina, is more commonly known as the Australian sheep blowfly. Lucilia cuprina also causes the condition known as 'sheep strike'. The female fly locates a sheep with an open wound in which she lays her eggs. The emerging larvae cause large lesions on the sheep, which may prove to be fatal. Lucilia cuprina is a species of blow fly characterized by a metallic outer appearance and reddish eyes. They usually have a shiny green or greenish/blue abdomen with bronze/coppery reflections. Because of this, Lucilia species are known as the bronze bottle flies. Their body shape is round to oval and their length varies from 4.5–10 millimeters. They have two pairs of wings, the first pair being membranous wings and the second pair being reduced wings known as halteres which are used for flight stabilization. Adults are easy to distinguish due to bristles on the meron, in addition to the arista, the prominent hair on the terminal antennal segment being plumose, or feathery. L. cuprina are most easily identified by their strong dorsal setae and their black thoracic spiracle. Although known as the Australian sheep blowfly, Lucilia cuprina can be found in other parts of the world including Africa and North America. These blow flies like warmer weather with soil temperatures above 15 degree Celsius, air temperatures above 17 degrees Celsius and below 40 degrees Celsius. They like low wind conditions with wind speeds below 30 km/hr. Adapted perfectly to the southern region of the United States, this fly is well known because of its importance in forensic entomology. L. cuprina can fly up to ten miles looking for food, and can be found on anything ranging from carrion to decaying fruit. Larvae are often found in shaded regions of carrion, while the adults prefer bright, open areas. Adult L. cuprina arrive early on carrion, appearing hours or even minutes after death. There, on the fresh body, they lay their eggs. The eggs then hatch into larvae which begin to feed and grow. After about five days, larvae enter the pupal stage. This is said to be an inactive stage, although many changes occur during this part of the flies’ life cycle. The pupa does not feed, but rather uses the time inside the casing to change from rice-like larvae into an adult fly with wings and six legs. The whole process can take anywhere from eleven to twenty-one days depending on environmental conditions including temperature and nutritional availability. In most cases warmer temperatures and better nutrition lead to a faster life cycle. L. cuprina can have between four and eight generations per year depending mostly on temperature. Blowfly strike, or flystrike is a serious welfare problem in the animal industry. This cutaneous myiasis or infestation not only causes severe discomfort or stress to the animal, but will also cause death when left untreated. Ewe lambs and female sheep are primarily affected and are struck predominately in the rear quadrant of the animal due to fecal staining. Due to the difficulty in controlling these flies, there are considerable losses in the sheep industry every year. Also, there is an increasing concern of the insecticidal use and the surgical procedures done to control L. cuprina, making this not only an animal welfare issue but also an economical one. The maggots of L. cuprina rapidly grow while eating the living flesh of the sheep while secreting ammonia, thus, poisoning the sheep. Sheep show signs of skin irritation by rubbing and biting the affected areas during the first few days after the eggs have been laid. This causes an inflammatory response in the sheep resulting in severe irritation and pyrexia. Once a flystrike has started other flies are attracted to the site. Although treatment is available, the delayed response time due to symptoms allows wool breakage in the affected area and fleece to be tender overall. There are many predispositions to the flystrike that make a host more favorable, including an infection with dermatophilosis and footrot, both of which can be treated and prevented. In some animals a weak resistance can develop, but this immune response is often associated with a decrease in productivity which is an undesirable trait. There are many options available to prevent infestation. Many of the precursors drawing the flies initially are sanitary problems which is where control measures are directed. Drenching, shearing or crutching are some basic procedures that can be done. Crutching is the trimming of excess wool from the breech area, and the timing of both shearing and crutching is critical in reducing the amount of flystrike. Surgical procedures are also performed in the sheep industry to help prevention, one of which is controversial due to the invasive nature. Tail docking to the correct length will reduce the amount of staining in the breech area due to urine and fecal matter. Pizzle dropping is a procedure that severs the connective tissue between the penis and the body. Not only does it reduce the incidence of relentless pizzle rot in sheep, but it decreases the amount of urine staining on the belly of the sheep. This procedure can greatly reduce the occurrence of flystrike on the belly area. Mulesing is an animal husbandry procedure that has currently faced much opposition throughout its practice. Large scissors are used to cut off the backs of the sheep's thigh region. This procedure is usually carried out by untrained farmers without the use of any analgesia. It flattens out the wrinkles around the breech of the sheep, reducing the places where moisture collects affecting the skin of the sheep resulting in liquid protein exudate which is attractive to Lucilia cuprina. Mulesing also increases the amount of bare skin around the vulva during the healing process, reducing urine staining and amount of flystrike. This procedure does cause pain, but since it is considered the most effective method to prevent breech strike, it is seemingly justifiable. Mulesing is as effective as breeding sheep for less wrinkle (score 2) which are resistant to flystrike. Mulesing is a good prevention until breeding can remove the need for the operation in flystrike prevention