''Chrysomya'' is an
Old World
The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by the ...
blow fly genus of the family
Calliphoridae. The genus ''Chrysomya'' contains a number of species including ''
Chrysomya rufifacies
''Chrysomya rufifacies'' is a species belonging to the blow fly family, Calliphoridae, and is most significant in the field of forensic entomology due to its use in establishing or altering ''post mortem ''intervals. The common name for the spe ...
'' and ''
Chrysomya megacephala''. The term “Old World blow fly” is a derivative of both the associated family, Calliphoridae (blow flies), and the belief that the genus ''Chrysomya'' originated in Asia and migrated to North America only relatively recently. ''Chrysomya’s'' primary importance to the field of medico-criminal
forensic entomology
Forensic entomology is the scientific study of the colonization of a dead body by arthropods. This includes the study of insect types commonly associated with cadavers, their respective life cycles, their ecological presences in a given environme ...
is due to the genus’ reliable life cycle, allowing investigators to accurately develop a
postmortem interval
The post-mortem interval (PMI) is the time that has elapsed since an individual's death. When the time of death is not known, the interval may be estimated, and so an approximate time of death established. Postmortem interval estimations can ra ...
. ''Chrysomya'' adults are typically metallic colored with thick setae on the meron and plumose arista. The name comes from the word ''chrysos'', meaning “golden” in reference to the metallic sheen of the genus’ species, and ''-mya'', a derivation from the word ''myia'', meaning “fly”.
Description
Adults
![Close-up_of_Chrysomya_(Old_World_blow_fly)_on_a_green_leaf](https://upload.wikimedia.org/wikipedia/commons/3/31/Close-up_of_Chrysomya_%28Old_World_blow_fly%29_on_a_green_leaf.jpg)
Identifying traits of the genus ''Chrysomya'' include:
* 10–12 mm bodies
* Metallic bodies
* Blue/green bodies
* Thick Setae on the meron
* Plumose arista
Keep in mind, however, that not all species will conform completely to these guidelines. Adults feed on many things including decaying matter, excreta, and flowers. In their six-week lifespan, (specific length may differ as a result of temperature, weather, etc.) females lay egg masses typically consisting of 50-200 eggs.
[Byrd, Jason H]
''Hairy Maggot Blow Fly''
Featured Creatures. January 1998. University of Florida. 06 Mar 2009 Different species within this genus exhibit varying egg laying procedures. The species ''
Chrysomya bezziana
''Chrysomya bezziana'', also known as the Old World screwworm fly or screwworm, is an obligate parasite of mammals. Obligate parasitic flies require a host to complete their development. Named to honor the Italian entomologist Mario Bezzi, this ...
,'' for example, lay their eggs exclusively on live mammals.
[HA Central Committee on Infectious]
''Fact Sheet on: Chrysomya bezziana''
Hospital Authority. February 2005. 09 Mar 2009 In contrast, most ''Chrysomya'' species prefer to perform
oviposition
The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...
on dead organisms. And, as with many fly genera primary and secondary
myiasis is possible but unlikely.
Larvae
![Chrysomya rufifacies Larva 1](https://upload.wikimedia.org/wikipedia/commons/a/ab/Chrysomya_rufifacies_Larva_1.JPG)
The genus ''Chrysomya'' contains 12 species,
several of which cause primary and secondary myiases of domestic animals. The larvae of one species, ''
Chrysomya rufifacies
''Chrysomya rufifacies'' is a species belonging to the blow fly family, Calliphoridae, and is most significant in the field of forensic entomology due to its use in establishing or altering ''post mortem ''intervals. The common name for the spe ...
'', have very distinct thorn-like processes covering its entire body, giving it the common name “hairy maggot blow fly”.
The hairy appearance of ''C. rufifacies'' makes it easy to distinguish 2nd and 3rd instars from close relative, ''Chrysomya megacephela''. Although the 1st instars are fairly similar, ''C. megacephela'' are characterized by thicker spiracle hairs in the 2nd and 3rd instars.
Life cycle
''Chrysomya'' like other fly genera are
holometabolous and develop along four stages: egg, larva, pupa, and adult. This short life cycle is extremely important in determining a post mortem interval when studied accurately in
medico-criminal entomology. Depending on temperature, the entire life cycle involving development from egg to adult takes from 190 to 598 hours. The pupal stage ranges from 134 hours to 162 hours, and finally the adult emerges around the 237th hour to the 289th hour.
Chrysomya rufifacies
''Chrysomya rufifacies'' is a species belonging to the blow fly family, Calliphoridae, and is most significant in the field of forensic entomology due to its use in establishing or altering ''post mortem ''intervals. The common name for the spe ...
Eggs are approximately 1 mm long and are laid in a mass typically consisting of 50 to 200 eggs. If females participate in group
oviposition
The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...
, the results are much larger masses containing thousands of eggs that may completely cover a decomposing carcass.
These eggs are typically yellowish or white in color and, when laid, look like rice balls.
The eggs hatch in as little as eight hours. This of course depends on air temperature and the ability of larvae to feed on carrion, until consuming enough calories to progress through the instar stages and pupate. Once this is achieved, third instars travel away from the corpse, usually into shallow soil and pupate. During this time, the larval skin which was initially milky white actually shrinks and hardens to form a dark brown puparium. This stage may last as long as 12 days, while some adults emerge in seven to eight days, again depending on temperature. Generally the warmer the temperature, the faster the life cycle is completed. Once in adult form, ''C. rufifacies'' oviposits approximately five days after mating, and lives an average of six weeks.
Myiasis
Myiasis is the infestation of vertebrate tissue by
dipterous
Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...
larvae. These larvae feed on the dead or living tissue of their vertebrate hosts. Several species of ''Chrysomya'' are known to cause myiasis in animals and/or humans. One species, ''Chrysomya albiceps'', feeds on only diseased tissue of a host.
A second species, ''Chrysomya rufifacies'', is a predator of primary parasites and was once used as a treatment for
osteomyelitis.
Another species, ''
Chrysomya bezziana
''Chrysomya bezziana'', also known as the Old World screwworm fly or screwworm, is an obligate parasite of mammals. Obligate parasitic flies require a host to complete their development. Named to honor the Italian entomologist Mario Bezzi, this ...
'', is one of the most important causes of myiasis in the Old World. Cattle are the main host of this larvae, as well as humans and other domestic animals.
Predation
The majority of ''Chrysomya'' species are known for being voracious predators of other blow fly species during the maggot stage. Two of the major predatory species of the family Calliphoridae include: ''Chrysomya rufifacies'' and ''C. albiceps''. ''
C. albiceps'' is thought to be a mechanical vector of various diseases due to its association with filth.
''C. rufifacies'' predation of other fly species can have a profound effect on PMI estimates and actual survivorship of the host fly species. Studies showed that predation by ''C. rufifacies'' on ''
Cochliomyia macellaria
''Cochliomyia macellaria'', also known as the secondary screwworm, is a species of blow fly in the family Calliphoridae.
These screwworms are referred to as "secondary" because they typically infest wounds after invasion by primary myiasis-ca ...
'' caused a dramatic decrease in survivorship, from 36.3% to 10%.
Selected species
''Chrysomya rufifacies''
Geographical Location
''Chrysomya rufifacies'' is found widespread throughout the southern US, including southern California, Arizona, Texas, Louisiana, and Florida. It is known to occupy areas of Central America, Japan, and India. ''Chrysomya rufifacies'' was not discovered in the United States until 1980 and is believed to be a recent immigrant.
The fact that this species of fly has only been found in America recently but has been found in most tropic countries of the “
Old World
The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by the ...
” for some time leads to its surname, the “Old World blow fly”.
New research has shown evidence of ''C. rufifacies'' in Ontario during the fall season. As temperatures increase due to global warming, colonies of ''C. rufifacies'' are predicted to spread well into southern Ontario and Quebec.
''Chrysomya megacephala''
![Ch](https://upload.wikimedia.org/wikipedia/commons/8/86/Ch.megacephala_wiki.jpg)
Geographical Location
''C. megacephala'' exhibits a widely ranged distribution throughout the Asian regions, South Africa, and South America. This species has recently become well established within the southern United States, as well. ''C. megacephala'' is one species that prefers higher temperatures and undergoes the bulk of activity during peak heat periods of the afternoon.
Characteristics
The larvae of ''Chrysomya rufifacies'' are the most easily identified stage of the species. The larvae can get up to approximately 14mm in length with a yellow/orange color and have conical fleshy tubercles down the length of their bodies that give these maggots a slightly hairy appearance even though it does not possess any true hairs. The larvae of ''C. rufifacies'' are predatory, meaning that they are typically secondary colonists to a fresh corpse and will devour the maggots of the primary colonist species. If resources are especially scarce, the larvae of ''C. rufifacies'' may become
cannibalistic and prey upon other ''C. rufifacies'' larvae. Third instar ''C. rufifacies'' larvae are capable of potentially expelling other maggots from a feeding site with use of their large fleshy tubercles.
The pupae of ''C. rufifacies'' typically resemble rodent droppings or cockroach egg casings.
The adult ''C. rufifacies'' are typically between 10 and 12mm in length with a metallic colored body. The adult fly’s body color is generally a metallic blue/green. While color does play a role in distinguishing between members of the family
Calliphoridae, the arrangement of setae is the most accurate way to distinguish most species. All species of ''Chrysomya'' possess setae on the meron, and black abdominal tergites. The easiest way to distinguish ''C. rufifacies'' from ''
C. megacephala'' is to examine the anterior thoracic spiracle, on the adult fly’s body. ''C. rufifacies'' has a pale colored anterior thoracic spiracle while ''C. megacephala'' has a dark brown or dark orange anterior thoracic spiracle. The ''C. rufifacies'' adult possesses three faint thoracic stripes in the pronotal region.
C. megacephala are typically a shorter, more stout bodied fly with its tell tale signs being a larger head and prominent red eyes.
Forensic importance
''Chrysomya rufifacies'' adults are usually the first to colonize a fresh corpse. In the southern U.S., this can happen within hours, sometimes minutes, of the host's death.
This “hairy maggot blow fly” is the most common maggot found on corpses, and its consistent developmental time is extremely helpful when establishing a
post mortem interval. However, ''C. rufifacies'' can have the opposite effect since its second and third instar larvae are known to be predacious, feeding on other maggots that might have colonized the body first. In addition, ''C. rufifacies'' are known to be cannibalistic as when the second and third instars feed on young first instars.
The larvae are able to burrow inches into the ground to reach food and inhabit a buried corpse.
It is proven that organic chemistry can be used to determine the age of post-feeding larvae. The hydrocarbon composition of the larvae was found to correlate with age. This is a huge discovery since cuticular hydrocarbon composition is a more accurate method of determining post-feeding larvae age as compared to previous methods of measuring larval crop length, for example.
Species
* ''
Chrysomya albiceps
''Chrysomya albiceps'' is a species belonging to the blow fly family, Calliphoridae.
Taxonomy
''Chrysomya albiceps'' is considered conspecific with '' Chrysomya rufifacies'' by some authorities. The two species have a similar biology and the mo ...
''
( Wiedemann, 1819)
* ''
Chrysomya bezziana
''Chrysomya bezziana'', also known as the Old World screwworm fly or screwworm, is an obligate parasite of mammals. Obligate parasitic flies require a host to complete their development. Named to honor the Italian entomologist Mario Bezzi, this ...
''
Villeneuve, 1914
* ''
Chrysomya chloropyga
''Chrysomya'' is an Old World blow fly genus of the family Calliphoridae. The genus ''Chrysomya'' contains a number of species including '' Chrysomya rufifacies'' and ''Chrysomya megacephala''. The term “Old World blow fly” is a derivative ...
''
( Wiedemann, 1818)
* ''
Chrysomya fulvicruris
''Chrysomya'' is an Old World blow fly genus of the family Calliphoridae. The genus ''Chrysomya'' contains a number of species including '' Chrysomya rufifacies'' and ''Chrysomya megacephala''. The term “Old World blow fly” is a derivative ...
''
Robineau-Desvoidy
André Jean Baptiste Robineau-Desvoidy (1 January 1799 in Saint-Sauveur-en-Puisaye – 25 June 1857 in Paris) was a French physician and entomologist specialising in the study of Diptera (flies) and to some extent of the Coleoptera (beetles).
Ach ...
, 1830
* ''
Chrysomya inclinata
''Chrysomya'' is an Old World blow fly genus of the family Calliphoridae. The genus ''Chrysomya'' contains a number of species including '' Chrysomya rufifacies'' and ''Chrysomya megacephala''. The term “Old World blow fly” is a derivative ...
''
Walker, 1861 (Synonyms: ''C. grienieri''
Rickenbach, 1959, ''C. roubaudi''
Séguy, 1926, ''C. tellinii''
Bezzi, 1908)
* ''
Chrysomya marginalis
''Chrysomya marginalis'', the regal blowfly, also referred to as the regal bluebottle or the bordered blowfly is an uncommon and relatively large species of fly that was described by Weidemann in 1830. It is found in Africa to the south of the ...
''
( Wiedemann, 1830)
* ''
Chrysomya megacephala''
(Fabricius Fabricius ( la, smith, german: Schmied, Schmidt) is a surname. Notable people with the surname include:
*people from the Ancient Roman gens Fabricia:
**Gaius Fabricius Luscinus, the first of the Fabricii to move to Rome
* Johann Goldsmid (1587 ...
, 1794)
* ''
Chrysomya obscura
''Chrysomya'' is an Old World blow fly genus of the family Calliphoridae. The genus ''Chrysomya'' contains a number of species including '' Chrysomya rufifacies'' and ''Chrysomya megacephala''. The term “Old World blow fly” is a derivative ...
''
Bigot, 1891
* ''
Chrysomya pinguis''
(Walker), 1858
* ''
Chrysomya putoria''
( Wiedemann, 1830)
* ''
Chrysomya rufifacies
''Chrysomya rufifacies'' is a species belonging to the blow fly family, Calliphoridae, and is most significant in the field of forensic entomology due to its use in establishing or altering ''post mortem ''intervals. The common name for the spe ...
''
Macquart, 1843
* ''
Chrysomya villeneuvi
''Chrysomya villeneuvi'', or hairy maggot, is a South East Asian fly species of forensic importance because the maggots of this species have been collected from human corpses.
Study of the feeding behaviour of the hairy maggot is also underway t ...
''
Patton, 1922
References
External links
*
*
{{Taxonbar, from=Q3675987
Calliphoridae
Oestroidea genera
Taxa named by Jean-Baptiste Robineau-Desvoidy