Lucilia cuprina
Encyclopedia
The species Lucilia cuprina, formerly named Phaenicia cuprina, is more commonly known as the Australian sheep blowfly. It belongs to the blow-fly family Calliphoridae
, and while some authorities combine the blow flies (Calliphoridae) and the flesh flies
(Sarcophagidae) together into the Metopiidae family, distinguishable characteristics allow for the separation. Lucilia cuprina is a member of the order Diptera, has a pair of short but very strong membranous wings and a pair of hindwings reduced and modified to clublike balancers known as halteres
. This adaptation distinguishes the true flies (Diptera
) from the other orders with “fly” in their name, and serves as a sensory aid that acts as tiny gyroscope
s or inertial navigation system
. The mesothorax
is much enlarged while the prothorax
and metathorax
are reduced. Blow flies are about the size of a house fly
or a little larger, and though considered to be nuisances indoors are essential agents in the breakdown of organic matter. Most are metallic blue or green, and oftentimes have black gena, mostly white calypter
es and orange yellow anterior thoracic spiracles.
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.
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
.
. 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.
.
Flies have four stages of growth: egg
, larva
e, pupa
, and adult
. 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.
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.
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. 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
Insecticides have also been used often in prevention, but with improper application and heavy reliance throughout the years, insecticide resistance and residues within the wool have caused much concern. The primary reason for failures in using insecticides is attributed to poor application. Jetting, dipping, and backlining are the three most commonly used methods for insecticide application, and most of the chemicals used belong to three types of chemicals: synthetic pyrethroids, organophosphates, insect growth regulators and spinosins. Insect growth regulators can provide the long term protection against flies and when applied correctly provide protection during the susceptible times of the year. Resistance to this group of insecticide has been identified. Spinosins are good for short term control of flies and leave no residues in wool. Many government agencies mandate that the wool be free of insecticidal residues forcing withholding periods by farmers before shearing. During this time, the flock can become extremely sensitive to flystrike.
Baited traps are a good monitoring tool and provide for some supression of fly populations. Traps are a good addition to an integrated fly management program. A simple to use non chemical fly trap is available called Lucitrap which targets lucilia cuprina (see reference below) This trapping system is now sold under the name Lucilure (www.bioglobal.com.au). There have been many attempts to find an alternative. Vaccinations are currently being developed to help, but none has yet proved effective in the prevention of flystrike.
L. cuprina cuprina is distributed in Neotropical, Oriental and Southern Neartic Regions, while L. cuprina dorsalis is found in Australasian, East and Sub-Saharan Afro tropical Regions..
The maggots of L. cuprina have been used by medical doctors for Debridement
therapy for patients who suffer from wounds that are healing slowly. The maggots cleanse the wound by eating the dead and infectious skin and preventing gangrene and further infection.
of flies’ eggs. Egg ultrastructure has recently become exceedingly important in the field of forensic science. It is used to distinguish L. cuprina eggs from other Lucilia species, such as Lucilia illustris
and Lucilia sericata. This defining feature becomes relevant when determining the post-mortem interval because it will vary with each species. Other ongoing research includes bacteria and fungi associated with the insect. Numerous studies have been conducted to determine if the fly is a mechanical vector of bacteria. So far, many have been found only to be carriers and cannot transmit disease. There have also been studies on the taxonomic grouping of Lucilia based on geography. The use of RAPD
(Random amplified polymorphic DNA analysis) and mitochondrial DNA sequencing has been used to investigate genetic variation within the species.
Lucilia cuprina is a commonly used species in the field of forensic entomology. The information known about the species designates L. cuprina as a helpful resource at crime scenes as well as a nuisance to sheep. Ongoing research is constantly finding more effective ways to put the species to use.
Blow-fly
Calliphoridae are insects in the Order Diptera, family Calliphoridae...
, and while some authorities combine the blow flies (Calliphoridae) and the flesh flies
Flesh-fly
Flies of the Diptera family Sarcophagidae are commonly known as flesh flies. Most flesh flies breed in carrion, dung, or decaying material, but a few species lay their eggs in the open wounds of mammals; hence their common name...
(Sarcophagidae) together into the Metopiidae family, distinguishable characteristics allow for the separation. Lucilia cuprina is a member of the order Diptera, has a pair of short but very strong membranous wings and a pair of hindwings reduced and modified to clublike balancers known as halteres
Halteres
Halteres are small knobbed structures modified from the hind wings in some two-winged insects. They are flapped rapidly and function as gyroscopes, informing the insect about rotation of the body during flight....
. This adaptation distinguishes the true flies (Diptera
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...
) from the other orders with “fly” in their name, and serves as a sensory aid that acts as tiny gyroscope
Gyroscope
A gyroscope is a device for measuring or maintaining orientation, based on the principles of angular momentum. In essence, a mechanical gyroscope is a spinning wheel or disk whose axle is free to take any orientation...
s or inertial navigation system
Inertial navigation system
An inertial navigation system is a navigation aid that uses a computer, motion sensors and rotation sensors to continuously calculate via dead reckoning the position, orientation, and velocity of a moving object without the need for external references...
. The mesothorax
Mesothorax
The mesothorax is the middle of the three segments in the thorax of an insect, and bears the second pair of legs. Its principal sclerites are the mesonotum , the mesosternum , and the mesopleuron on each side...
is much enlarged while the prothorax
Prothorax
The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
and metathorax
Metathorax
The metathorax is the posterior of the three segments in the thorax of an insect, and bears the third pair of legs. Its principal sclerites are the metanotum , the metasternum , and the metapleuron on each side...
are reduced. Blow flies are about the size of a house fly
Housefly
The housefly , Musca domestica, is a fly of the suborder Cyclorrhapha...
or a little larger, and though considered to be nuisances indoors are essential agents in the breakdown of organic matter. Most are metallic blue or green, and oftentimes have black gena, mostly white calypter
Calypter
A calypter is either of two posterior lobes of the posterior margin of the forewing of flies between the extreme posterior wing base and the alula, which covers the halteres....
es and orange yellow anterior thoracic spiracles.
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.
Anatomy
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 halteresHalteres
Halteres are small knobbed structures modified from the hind wings in some two-winged insects. They are flapped rapidly and function as gyroscopes, informing the insect about rotation of the body during flight....
which are used for flight stabilization. Adults are easy to distinguish due to bristles on the meron
Meron
A meron or half-instanton is a Euclidean space-time solution of the Yang-Mills field equations. It is a singular non-self-dual solution of topological charge 1/2. The instanton is believed to be composed of two merons....
, in addition to the arista
Arista (biology)
In insect anatomy the arista is a simple or variously modified apical or subapical bristle, arising from the third antennal segment. It is the evolutionary remains of antennal segments, and may sometimes show signs of segmentation...
, 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
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
.
Habitats/diet
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 celcius, air temperatures above 17 degrees celcius and below 40 degress celcius. 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 entomologyForensic entomology
Forensic entomology is the application and study of insect and other arthropod biology to criminal matters. It is primarily associated with death investigations; however, it may also be used to detect drugs and poisons, determine the location of an incident, and find the presence and time of the...
. L. cuprina can fly up to ten miles looking for food, and can be found on anything ranging from carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...
to decaying fruit. Larvae are often found in shaded regions of carrion, while the adults prefer bright, open areas.
Stages of life
Lucilia cuprina, like all flies are holometabolous, meaning they go through a complete metamorphosisMetamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
.
Flies have four stages of growth: egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
, larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e, pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
, and adult
Adult
An adult is a human being or living organism that is of relatively mature age, typically associated with sexual maturity and the attainment of reproductive age....
. 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.
Effects on sheep
Blowfly strike, or flystrike is a serious welfare problem in the animal industry. This cutaneous myiasisMyiasis
Myiasis is a general term for infection by parasitic fly larvae feeding on the host's necrotic or living tissue. Colloquialisms for myiasis include flystrike, blowfly strike, and fly-blown. In Greek, "myia" means fly....
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.
Prevention
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, shearingSheep shearing
Sheep shearing, shearing or clipping is the process by which the woollen fleece of a sheep is cut off. The person who removes the sheep's wool is called a shearer. Typically each adult sheep is shorn once each year...
or crutching are some basic procedures that can be done. Crutching
Crutching
Crutching refers to the removal of wool from around the tail and between the rear legs of a sheep. It can also refer to removing wool from the heads of sheep or from the bellies of male sheep .-Motivation:...
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
Mulesing
Mulesing is a skilled surgical task that involves the removal of strips of wool-bearing skin from around the breech of a sheep to prevent flystrike in regions where it is common....
is an animal husbandry procedure that has currently faced much opposition throughout its practice. 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
Insecticides have also been used often in prevention, but with improper application and heavy reliance throughout the years, insecticide resistance and residues within the wool have caused much concern. The primary reason for failures in using insecticides is attributed to poor application. Jetting, dipping, and backlining are the three most commonly used methods for insecticide application, and most of the chemicals used belong to three types of chemicals: synthetic pyrethroids, organophosphates, insect growth regulators and spinosins. Insect growth regulators can provide the long term protection against flies and when applied correctly provide protection during the susceptible times of the year. Resistance to this group of insecticide has been identified. Spinosins are good for short term control of flies and leave no residues in wool. Many government agencies mandate that the wool be free of insecticidal residues forcing withholding periods by farmers before shearing. During this time, the flock can become extremely sensitive to flystrike.
Baited traps are a good monitoring tool and provide for some supression of fly populations. Traps are a good addition to an integrated fly management program. A simple to use non chemical fly trap is available called Lucitrap which targets lucilia cuprina (see reference below) This trapping system is now sold under the name Lucilure (www.bioglobal.com.au). There have been many attempts to find an alternative. Vaccinations are currently being developed to help, but none has yet proved effective in the prevention of flystrike.
Demographics
Today Lucilia cuprina can be found throughout the world in various warm locations. Australia is one of the many places L. cuprina are found, and the place where it has been known to cause the most havoc. Their wide distribution is due to movement patterns and the traveling of humans and livestock within the last century. Although they can now be found worldwide, the flies’ origins are linked to afrotropical and oriental regions of the world.L. cuprina cuprina is distributed in Neotropical, Oriental and Southern Neartic Regions, while L. cuprina dorsalis is found in Australasian, East and Sub-Saharan Afro tropical Regions..
Similar species
Lucilia cuprina is one of many species of the family Calliphoridae. Though many of its species have similar characteristics, L. cuprina’s closest relative is its sister species, Lucilia sericata. These flies are very similar in appearance and morphological characteristics, which can sometimes cause errors when trying to differentiate between them. They each exhibit specific genetic variations which can be distinguished by using random amplified polymorphic DNA and/or mitochondrial DNA sequences, and are known to cause myiasis (flystrike) in sheep. They are both one of the first blow flies to arrive at a corpse and each have smooth larva. Unlike L. cuprina, L. sericata does not usually infest live sheep. L. cuprina is a worldwide sheep pest though it is usually found in dry climates. L. sericata has a coastal distribution.Forensic importance
Lucilia cuprina is often used as a very helpful tool to aid medical and forensic professionals. It is known to be one of the first flies to occupy a corpse upon its death. Once it lands on a corpse, it continues in the formation of its next generation by laying its eggs. The eggs are followed by its larva, pupa and finally the adult. Forensic professionals may form a postmortem interval by the life stage found on the corpse. L. cuprina, although it is a worldwide pest, is very climate specific. It occupies dryer climates. A forensic investigator may conclude that a corpse has been relocated from its original location if it is found in a moist climate with L. cuprina on it.The maggots of L. cuprina have been used by medical doctors for Debridement
Debridement
Debridement is the medical removal of a patient's dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue...
therapy for patients who suffer from wounds that are healing slowly. The maggots cleanse the wound by eating the dead and infectious skin and preventing gangrene and further infection.
Ongoing research
Current research involving Lucilia cuprina and other Lucilia species range from identifying genetic variation between the different species to the ultrastructureUltrastructure
Ultrastructure is the detailed structure of a biological specimen, such as a cell, tissue, or organ, that can be observed by electron microscopy...
of flies’ eggs. Egg ultrastructure has recently become exceedingly important in the field of forensic science. It is used to distinguish L. cuprina eggs from other Lucilia species, such as Lucilia illustris
Lucilia illustris
Lucilia illustris is a member of the Calliphoridae family of flies commonly known as a blow fly. Along with several other species, L. illustris is commonly referred to as the green bottle fly. L. illustris is typically 6–9 mm in length and has a metallic blue-green thorax. The larvae develop in...
and Lucilia sericata. This defining feature becomes relevant when determining the post-mortem interval because it will vary with each species. Other ongoing research includes bacteria and fungi associated with the insect. Numerous studies have been conducted to determine if the fly is a mechanical vector of bacteria. So far, many have been found only to be carriers and cannot transmit disease. There have also been studies on the taxonomic grouping of Lucilia based on geography. The use of RAPD
RAPD
RAPD stands for random amplification of polymorphic DNA. It is a type of PCR reaction, but the segments of DNA that are amplified are random. The scientist performing RAPD creates several arbitrary, short primers , then proceeds with the PCR using a large template of genomic DNA, hoping that...
(Random amplified polymorphic DNA analysis) and mitochondrial DNA sequencing has been used to investigate genetic variation within the species.
Lucilia cuprina is a commonly used species in the field of forensic entomology. The information known about the species designates L. cuprina as a helpful resource at crime scenes as well as a nuisance to sheep. Ongoing research is constantly finding more effective ways to put the species to use.