Sarcophaga haemorrhoidalis
Encyclopedia
Sarcophaga haemorrhoidalis, also known as the red-tailed flesh fly, is a fly
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...

 in the Sarcophagidae
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...

 family. This fly often breeds in 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...

 and feces, making it a possible vector for disease. The larvae of this species can cause myiasis
Myiasis
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....

, as well as accidental myiasis. It is potentially useful in forensic entomology
Forensic 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...

.

Taxonomy

Sarcophaga haemorrhoidalis was first described by Carl Fredrik Fallén
Carl Fredrik Fallén
Carl Fredrik Fallén was a Swedish botanist and entomologist.Fallén taught at the Lund University. He wrote Diptera Sueciae .In 1817, Fallen discovered the Muscina stabulans species of flies....

 (1764–1830), a Swedish botanist and entomologist, in 1817 during his tenure at Lund University between 1814–1827. Fallén first named this species Musca
Musca (genus)
Musca is a genus of flies. It includes Musca domestica , as well as Musca autumnalis . It is part of the family Muscidae.-Species List:*M. albina Wiedemann, 1830...

 haemorrhoidalis
in 1817 not knowing that Charles Joseph de Villers had already named an unrelated species Musca haemorrhoidalis in 1789. In 1826, Johann Wilhelm Meigen
Johann Wilhelm Meigen
Johann Wilhelm Meigen was a German entomologist famous for his pioneering work on Diptera.-Early years:Meigen was born in Solingen, the fifth of eight children of Johann Clemens Meigen and Sibylla Margaretha Bick. His parents, though not poor, were not wealthy either. The ran a small shop in...

, a German entomologist famous for his pioneering work on Diptera, described the same species that Fallén had described in 1817 as Sarcophaga cruentata following Meigen's description of the genus Sarcophaga. Since two different species can not share the same name, the Sarcophaga cruentata that Meigen coined would serve as the species name. According to Wharton, the exact nomenclature of this species is dynamic and currently has two accepted names: Sarcophaga haemorrhoidalis and Bercaea cruentata. Thomas Pape http://www.zmuc.dk/entoweb/sarcoweb/sarcweb/Sarc_web.htm, who is considered to be the World's foremost expert on Sarcophagidae
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...

 uses Sarcophaga but has assigned several subgenera, including Bercaea. Some current workers, including Ferrar, use Bercaea haemorrhoidalis. Sarcophaga comes from the Greek (sarkos-) meaning 'flesh,' and (phag) meaning 'eat.' Haemorrhoidalis comes from Greek roots (haemo-) meaning 'blood,' (rhoos-) meaning 'stream' or 'flowing,' and the Latin (alis) meaning 'extraordinary.'

Description

Sarcophagidae is the dipteran family commonly known as flesh flies, comprising approximately 2000 species. Many species of Sarcophagidae prefer to breed in carrion over other mediums, but there are several species that breed in dung. A large number of species are parasitoid
Parasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...

s or cleptoparasitoids
Kleptoparasitism
Kleptoparasitism or cleptoparasitism is a form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food...

 and never breed in carrion. It is difficult to identify the S. haemorrhoidalis species unless genitalia can be observed. Only males can be identified and classified within the genus. Sarcophagids are rather large in size ranging from 4 to 16 mm. Distinguishing characteristics include a checkerboard like pattern on the abdomen, stripes on the thorax and red eyes. Flesh flies are attracted to anything rotting, including feces. Sarcophagidae are unimpeded by rain and fly in any weather. Because of this trait, Sarcophagidae will often be the first flies to colonize a corpse after an extended period of rain. Flesh flies appear to prefer sunlight over shaded conditions. Sarcophaga haemorrhoidalis (Bercaea cruentata) is the one of the most common species of Sarcophagidae recovered from indoor crime scenes in the United States.

Life cycle

All members of the family Sarcophagidae are larviparous or ovoviviparous. Sarcophaga haemorrhoidalis (Bercaea cruentata) gives live birth to larvae with the female retaining the egg case in her abdomen. Flesh flies are strongly attracted to carrion or dry flesh. The female has a strong desire to lay larvae on the flesh and have even been noted to larviposit on the sleeve of a garment that has been previously soiled with blood. Oldroyd
Harold Oldroyd
Harold Oldroyd was a British entomologist, born in 1914. He specialised in the biology of flies, and wrote many books, especially popular science that helped entomology to reach a broader public. His "The Natural History of Flies" is considered to be the "fly Bible"...

 states that the larvae of Sarcophaga spp are voracious and will take anything of animal origin be it alive or dead. A larva is forced out of the larvipositor usually head first and soon disappears into the food material. Once larvae are deposited as 1st stage instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...

s, rapid development follows with 3rd instars usually being achieved by three to four days. Larviposition to adulthood generally takes around two weeks.

If the fly is forced to hibernate due to temperate climates, it will do so in the pupal stage.

Medical importance

Due to its attraction to feces and 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...

, S. haemorrhoidalis has been accounted for as a dipteran species that may serve as a mechanical vector for disease, especially if it intrudes homes. The family Sarcophagidae
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...

 is particularly attracted to human food and filth. Bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 can be transferred physically from the fly’s body, legs, or proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...

, to an animal, human food, or open sores. S. haemorrhoidalis has also been found to carry polio virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

. During a 1914 polio epidemic, samples of the virus were collected from S. haemorrhoidalis, among other dipterans. The sample was used to infect a monkey with polio, showing that it was an active virus. However, there is still no conclusive evidence as to whether or not this species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 actually transmits diseases to humans or animals.

The larvae of S. haemorrhoidalis may produce myiasis
Myiasis
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....

 on necrotic or dead flesh.
The first case of auricular myiasis (on the outer ear) on a human was reported in Iran in 1974.
Other myiasis cases have been recorded around the world in both humans and animals. Examples range from aural myiasis caused by S. haemorrhoidalis in four children in Israel (from 1990 to 1993) that produced symptoms of ear discharge , otalgia
Otalgia
Otalgia or an earache is ear pain. Primary otalgia is ear pain that originates inside the ear. Referred otalgia is ear pain that originates from outside the ear.Otalgia is not always associated with ear disease...

 and itching,
to the infection of a schnauzer in Umbria, Italy in 1994
by S. haemorrhoidalis maggots.

Accidental myiasis can also be caused by S. haemorrhoidalis larvae. When meat contaminated with live larvae is eaten, the maggots can make their way into the gastrointestinal tract and infest the intestines. The larvae are usually excreted with the feces.
In one documented case of gastrointestinal myiasis, a patient was admitted into a neurology
Neurology
Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...

 clinic, and after several days, maggots were found in his stool. They were identified as S. haemorrhoidalis through taxonomical means. The accidental myiasis did not contribute to or cause the patient's illness. Because S. haemorrhoidalis rarely invades living tissue, cases such as this are not seen often.

Forensic importance

S. haemorrhoidalis is hardly ever used in forensic investigations, due to its global distribution and the fact that little is known about them. Usually, other more researched flies and beetles, if present on the body, take precedence. The fly has a pupation time ranging from 93 hours to 153 hours. Development from 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 to adult can range from 252 to 802 hours. Knowing the pupation and life cycle times of S. haemorrhoidalis and taking into consideration that this species is ovoviviparous allows investigators to calculate how long the fly has been on the corpse. If time of colonization of the corpse by maggots is known, it can help determine the PMI, or post-mortem interval.
The larvae of S. haemorrhoidalis occur on carcasses in the early and advanced stages of decomposition
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...

. The maggots can live in amphibious habitats in which many other fly species may not be able to thrive or breed, making it possible for them to be the first dipterans on a corpse in wet weather.

Distribution

Sarcophaga haemorrhoidalis is a common species of flesh fly that appear worldwide in distribution and is commonly found in the United States.
It can be found throughout the year in the southern portion of the United States. The larvae are adaptable and can live in moist semi-aquatic habits that are unsuitable for most other fly species.

Overall, S. haemorrhoidalis is most likely to be found in climates with higher temperatures and will prefer high temperatures throughout its entire life cycle.

Research

Past research has been limited due to the name Sarcophaga haemorrhoidalis being attributed to many different species since Fallén
Carl Fredrik Fallén
Carl Fredrik Fallén was a Swedish botanist and entomologist.Fallén taught at the Lund University. He wrote Diptera Sueciae .In 1817, Fallen discovered the Muscina stabulans species of flies....

 initially described it. “The Classification of Townsend (1937,1938), which divided the Sarcophagidae into six tribes, was rather confusing and contributed little to the phylogeny of the family.” (Pape,11) Although limited now, research on colonization and degree day temperature growth rates at the species level would bolster Sarcophaga haemorrhoidalis (Bercaea cruentata) involvement and credibility as a crime scene post mortem interval witness in forensics.

Conclusion

Sarcophaga haemorrhoidalis (Bercaea cruentata) is an important fly with regard to human and animal health. The fly has interesting attributes particular to its family like being able to fly in the rain. This role in sometimes first colonizing corpses at crime scenes along with its capability of myiasis makes this a forensically relevant species.

External links

  • The world of flesh flies (Diptera: Sarcophagidae)
  • Sarcophaga haemorrhoidalis on the UF / IFAS
    Institute of Food and Agricultural Sciences
    The University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...

    Featured Creatures Web site
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