Quelltext der Seite Benutzer:Pseudomaso/Chrysomya megacephala

{{Importartikel}}
{{Italic title}}
{{Taxobox
| name = ''Chrysomya megacephala''
| image = Ch.megacephala wiki.jpg
| image_caption = Female ''C. megacephala''
| image2 = Chrysomya megacephala male.jpg
| image2_caption = Male ''C. megacephala''
| regnum = [[Animal]]ia
| phylum = [[Arthropod]]a
| classis = [[Insect]]a
| ordo = [[Fly|Diptera]]
| familia = [[Calliphoridae]]
| genus = ''[[Chrysomya]]''
| species = '''''C. megacephala'''''
| binomial = ''Chrysomya megacephala''
| binomial_authority = ([[Johan Christian Fabricius|Fabricius]], 1794)
| synonyms =
*''Cosmina basalis'' <small>(Smith, 1876)</small>
*''Pollenia basalis'' <small>Smith, 1876</small>
}}

'''''Chrysomya megacephala''''', more commonly known as the '''oriental latrine fly''', is a member of the family [[Calliphoridae]] (blowflies). It is a warm-weather [[fly]] with a greenish-blue metallic box-like body. The fly infests corpses soon after death, making it important to forensic science. This fly is implicated in some public health issues; it can cause accidental [[myiasis]],<ref>Brundage, Adrienne. "Entomology". Forensic Entomology Class Lecture. Texas A&M University, College Station. 2 Mar. 2009.</ref> and also infects fish and livestock.

==Description==
''C. megacephala'''s eggs are "oval with one flat face and another convex".<ref>{{cite journal | last1 = José | first1 = Augusto de | last2 = David | first2 = Oliveira | last3 = Rocha | first3 = Thalita | last4 = Henrique Caetano | first4 = Flávio | year = 2008 | title = Ultramorphological characteristics of ''Chrysomya megacephala'' (Diptera, Calliphoridae) eggs and its eclosion | url = | journal = Micron| volume =  39| issue = | pages =  1134–1137| doi = 10.1016/j.micron.2008.06.002 }}</ref> Adult flies reflect a metallic blue-green color on their [[thorax]] and [[abdomen]] and have yellow gena, or cheeks.<ref>Jonathan A. Cammack. "A Survey of the Necrophilous Diptera on the Island of Dominica" Pg. 6 Department of Entomology at Texas A&M University, College Station, TX. http://dominica.tamu.edu/student%20projects/Dominica%20Projects%20pdf%20copy/Cammack_Jonathan.pdf</ref> Larvae vary in size according to instar and are shaped more thickly towards the rear.<ref>Jason H. Bryd, James L. Castner. "Forensic Entomology; The Utility of Arthropods in Legal Investigations" Pg. 33</ref> ''C. megacephala'' have large red eyes, those of males being close together, and those of females farther apart.<ref>Byrd, Jason H., and James L. Castner. Forensic Entomology. Florida: CRC Press, 2001.</ref> The ''cercus'' of the male is longer than that of the female.<ref>{{cite journal |title=Fine structure of the reproductive system of ''Chrysomya megacephala'' |journal=Parasitology Research |volume=102 |issue=5 |date=April 2008 |doi= 10.1007/s00436-007-0863-6|url=http://www.ingentaconnect.com/content/klu/436/2008/00000102/00000005/00000863 |pmid=18180955 |last1= Chaiwong |first1= Tarinee |last2= Sukontason |first2= Kom |last3= Olson |first3= Jimmy K. |last4= Kurahashi |first4= Hiromu |last5= Chaithong |first5= Udom |last6= Sukontason |first6= Kabkaew L. |pages= 973–80}}</ref>

==Distribution and habitat==
''Chrysomya megacephala'' has a wide geographical distribution. It is most common in the [[Orient|Oriental region]] and [[Australasia]].<ref>Wall Richard, and David Shearer. Veterinary Entomology: Arthropod Ectoparasites of Veterinary Importance. London: Springer, 1997.</ref> It is also found in [[Japan]] and the [[Palearctic ecozone|Palearctic region]]. The range of ''C. megacephala'' has grown since the 1970s, with the species expanding into [[New Zealand]] and [[Africa]],<ref>{{cite journal |vauthors=Williams KA, Villet MH |title=A new and earlier record of ''Chrysomya megacephala'' in South Africa, with notes on another exotic species, ''Calliphora vicina'' (Diptera: Calliphoridae) |journal=African Invertebrates |volume=47 |pages=347–350 |year=2006 |url=http://www.durban.gov.za/durban/discover/museums/nsm/pubs/recent-publications/Twilliams347-350.pdf |format=PDF}}</ref> along with [[South America|South]], [[Central America|Central]], and [[North America]]. ''C. megacephala'' entered the United States through harbors and airports.<ref>{{cite journal |vauthors=Williams KA, Villet MH |title=A new and earlier record of ''Chrysomya megacephala'' in South Africa |journal=African Invertebrates |volume=47 |pages=349 |date=December 2006 |url=http://www.durban.gov.za/durban/discover/museums/nsm/pubs/recent-publications/Twilliams347-350.pdf |format=PDF}}</ref> The fly has been found in California,<ref>{{cite journal |author=Gordoy WAC |title=Dynamics of Experimental Populations of Native and Introduced Blowflies (Diptera: Calliphoridae): Mathematical Modelling and the Transition from Asymptotic Equilibrium to Bounded Oscillations |journal=Memorias do Instituto Oswaldo Cruz |volume=91 |issue=5 |pages=639–40 |date=September–October 1996 |url=http://memorias.ioc.fiocruz.br/915/3096.html |pmid=9137751|display-authors=etal}}</ref> as well as Texas,<ref>{{cite journal |author=Wells JD |title=''Chrysomya megacephala'' (Diptera: Calliphoridae) has reached the continental United States: review of its biology, pest status, and spread around the world |journal=J. Med. Entomol. |volume=28 |issue=3 |pages=471–3 |date=May 1991 |pmid=1875378 }}</ref> Louisiana,<ref>Pharr, Lauren R. 2009. A Taphonomic Model of Concealment: Decomposition and the Postmortem Interval (PMI) in a 55-Gallon Barrel. M.A. thesis, Louisiana State University. http://etd.lsu.edu/docs/available/etd-07102009-110514/</ref> and Hawaii.<ref>Goff, M. Lee A Fly for the Prosecution: How Insect Evidence Helps Solve Crimes. Massachusetts: Harvard University Press, 2001.</ref> ''C. megacephala'' exists in two forms, the normal and the derived.{{citation needed|date=October 2014}} [[Tropical]] forests on the [[Pacific Islands]], such as [[Samoa]], are home to the normal form; the normal is considered to be the plesiomorphic form of ''C. megacephala''.{{citation needed|date=October 2014}} The derived form is thought to have emerged from [[Papua New Guinea]] and is said to be [[synanthrope|synanthropic]], or ecologically associated with humans.{{citation needed|date=October 2014}}

==Behavior and ecology==

===Climactic variation===
{{No footnotes|section|date=October 2014}}
''C. megacephala'' prefer warm climates, and display a correlation between warmer temperatures and higher [[fecundity]]. In [[tropical]] populations, such as in [[Brazil]], fertility is also lower in areas with high densities of larvae, where many in one small area compete for the same food source. A correlation between wing size and temperature as well as tibia size and temperature has also been found in this species. There was a similar relationship between wing and tibia size and fecundity. All three of these values variables, fecundity, wing size and tibia size, stay within the same range throughout the year, showing seasonal variation to be absent. This has been of interest to researchers, since this fly is present in high numbers in warm weather and low numbers in cold weather. The majority of [[Fly|Dipteran]] species that have had a life table constructed have demonstrated a tendency for smaller bodies in the warmer months. ''C. megacephala'' has a relatively{{clarify|date=October 2014|reason=what does "long" mean in this context?}} long lifespan as an adult which has helped the species become successful at invading new geographical areas. The long adult lifespan means that the parents are present to rear the offspring, ensuring their survival.<ref>{{cite journal |vauthors=Tomberlin JK, Reeves WK, Sheppard DC |title=First record of ''Chrysomya megacephala'' (Calliphoridae: Diptera) in Georgia, USA |journal=Florida Entomologist |volume=84 |issue=2 |pages=300–1 |year=2001 |doi=10.2307/3496184 |jstor=3496184 }}</ref>

===Reproduction===
[[File:Chrysomya megacephala on baby bird.jpg|thumb|right|Flies laying eggs on a dead baby bird.]]
The developmental stages of ''C. megacephala'' include [[egg (biology)|egg]], [[larva]] and [[pupa]]. A female fly may lay as many as 200 to 300 eggs, often in human feces, meat or fish.<ref>Doe, Peter E. "Fish Drying and Smoking" Production and Quality. CRC Press: 177, 179, 186. https://books.google.com/books?id=_eATME6TvigC&pg=PA177</ref> Larval stages include first, second and third instals or growth periods.<ref>M. Lee Goff. "A Fly for the Prosecution" How Insect Evidence Helps Solve Crimes. Pg. 40 https://books.google.com/books?id=DAa0BzT7Mf0C&pg=PA95</ref> The eggs take approximately one day to develop, while the larvae take 5.4 days and the pupae 5.3 days.<ref>{{cite journal |author1=Refaat M. Gabre |author2=Fatma K. Adham |author3=Hsin Chi. |title=Life Table of ''Chrysomya mecagecephala (Fabricius)'' (Diptera: Calliphoridae |journal=International Journal of Ecology, Acta Oecologica |volume=27 |pages=179–183 see p. 180 |year=2005 |doi= 10.1016/j.actao.2004.12.002|url=http://140.120.197.173/Ecology/Papers/Gabre-paper.pdf |issue=3}}</ref> Population numbers as well as body size are greatly influenced by temperature.<ref>{{cite journal |vauthors=Regada C, Godoy WA |title=Larval density, temperature and biological aspects of ''Chrysomya megacephala''(Diptera: Calliphoridae) |journal=Arq. Bras. Med. Vet. Zootec. |volume=58 |pages=562–6 |year=2006 |doi= 10.1590/S0102-09352006000400018|url=http://www.scielo.br/pdf/abmvz/v58n4/a18v58n4.pdf |issue=4}}</ref> The adult lifespan of the fly is approximately seven days.<ref>Doe, Peter E. "Fish Drying and Smoking" Production and Quality. CRC Press: 177, 179, 186. https://books.google.com/books?id=_eATME6TvigC&pg=PA177&dq=chrysomya+megacephala&ei=ApvBSaamK4XEzQTr_IDwCQ#PPR8,M1</ref> The development of ''C. megacephala'' is linked to the length of time spent feeding in the larval stage, as well as to temperature; the lower the temperature, the more slowly the larvae develop.<ref>{{cite journal |vauthors=Piangjai S, Siriwattanarungsee S, Sukontason KL, Sukontason K |title=Morphology and developmental rate of blowflies ''Chrysomya megacephala'' and ''Chrysomya rufifacies'' in Thailand: application in forensic entomology |journal=Parasitol Res. |volume=102 |issue= 6|pages=1207–16 |year=2008 |doi=10.1007/s00436-008-0895-6 |url= |pmid=18264799}}</ref> In laboratory studies conducted at 27&nbsp;°C., eggs hatch in 18 hours; the first molt occurs in 30 hours; the second molt in 72 hours; pupation after 144 hours; and the adult emerges after approximately 234 hours. These intervals vary depending on geographical location; other environmental factors also can determine how long flies will stay in the larval stage. Males tend to emerge two or three hours ahead of the females.<ref>{{cite journal |vauthors=Kurahashi H, Wells JD |title=Chrysomya megacephala development: rate, variation and the implications for forensic entomology |journal=Jpn. J. Sant. Zool |volume=45 |issue=4 |pages=303–9 |year=1994 }}</ref>

The reproduction and survival rates of ''C. megacephala'' are closely related to developmental factors, including the amount of available food, and competition from larvae of other species, such as ''C. rufifacies''.<ref name=Bunchoo07>{{cite journal |vauthors=Bunchoo M, Khantawa B, Piangjai S, Rongsiyam Y, Sukontason KL, Sukontason K |title=Comparison between ''Musca dometica'' and ''Chrysomya megacephala'' as carriers of bacteria in northern Thailand |journal=Southeast Asia J. Trop. Med. Public Health |year=2007 }}</ref> In the presence of competing larvae, those of ''C. megacephala'' spend less time feeding, leading to early pupation, smaller adults, and early reproduction. ''C. rufifacies'' is known to [[cannibalize]] maggot masses and is thus a huge competitor.{{clarify|date=October 2014|reason="cannibalize," strictly speaking, means eating its own larvae, which would not be relevant here. What exactly does the source say?}}<ref>{{cite journal |vauthors=Piangjai S, Siriwattanarungsee S, Sukontason KL, Sukontason K |title=Morphology and developmental rate of blowflies ''Chrysomya megacephala'' and ''Chrysomya rufifacies'' in Thailand: application in forensic entomology |journal=Parasitol Res. |volume=102 |pages=1207–16 |year=2008 |doi=10.1007/s00436-008-0895-6 |pmid=18264799 |issue=6 }}</ref>

===Predators and prey===
''Chrysomya albiceps'' is also known to prey on ''C. megacephala'' during the larval stage when they must compete for the same food source.<ref>Gomes, Leonardo, Marcos Rogério Sanches and Claudio José Von Zuben. 2007. Behavior of the Combined Radial Post-feeding Larval Dispersal of the Blowflies ''Chrysomya megacephala'' and ''Chrysomya albiceps'' (Diptera, Calliphoridae)</ref> Beetles are also known to prey on ''C. megacephala''. ''C. megacephala'' is not predaceous in the adult or larval form, preferring to feed on [[necrophagous]] material of any kind, such as fish, cows and humans.

===Larval competition===
''C. megacephala'' larvae are known to compete with ''C. rufifacies'' larvae for food in a mixed-species environment. Research has shown that under specific population densities, ''C. rufifacies'' will facultatively feed on other species of maggots and on its own species. When ''C. rufifacies'' and ''C. megacephala'' larvae are put into cultures separately from one another in high densities, ''C. megacephala'' has a higher rate of survival than ''C. rufifacies''. Both species had a lighter adult weight than normal and pupated earlier. The third instar of ''C. rufifacies'' will eat ''Chrysomya megacephala'' when the larvae are in high density. Despite this predation on ''Chrysomya megacephala'', both species had a lower survival rate, lighter adult weight and pupated early.<ref name=Shiao>{{cite journal |author1=Shiao, Shiuh-Feng  |author2=Ta-Chuan Yeh |title=Larval Competition of ''Chrysomya megacephala'' and ''Chrysomya rufifacies'' (Diptera: Calliphoridae): Behavior and Ecological Studies of Two Blow Fly Species of Forensic Significance |journal=J. Med. Entomol. |volume=45 |year=2008}}</ref>

==Forensic science==

===Importance in forensic science===
''C. megacephala'' is considered important to forensic science because it is one of the first flies to show up on a corpse, and so the time of death can easily be determined when ''Chrysomya megacephala'' larvae are found on a body. In many forensic entomology cases either ''C. rufifacies'' or ''Chrysomya megacephala'' are found on the decaying corpse; [[mitochondrial DNA]] is the main method used to determine which subfamily is present.<ref>{{cite journal |vauthors=Shiuh-Feng S, Yeh T |title=Larval competition of ''Chrysomya megacephala'' and ''Chrysomya rufifacies'': behavior and ecological studies of two blow fly species of forensic significance |journal=J. Med. Entomol. |volume=45 |issue=4 |pages=785–799 |year=2008 |doi=10.1603/0022-2585(2008)45[785:LCOCMA]2.0.CO;2 |pmid=18714884 }}</ref> The species' wide geographical distribution and high [[fecundity]] also make it useful in forensic cases; ''C. megacephala'' is among the most common blowflies found.

Larval dispersion patterns of ''C. megacephala'' also make it forensically important. Knowing that, to pupate, larvae move away from the food source to find a safe place to metamorphose, forensic entomologists can accurately calculate a [[post mortem interval]].<ref>Byrd, James H. and James L. Castner. Forensic Entomology: The Utility of Arthropods in Legal Investigations. CRC Press, New York. 2001.</ref> Knowledge of larval competition is also useful in forensic studies, because it could affect the estimate of the time of death. If only ''C. rufifacies'' is found on a body, it is not accurate to use only this species to calculate a time of colonization. The colonization of ''C. megacephala'' prior to ''C. rufifacies'' must be taken into account.<ref name=Shiao/>

===Larval-state poisoning detection===
In any part of the world that uses [[organophosphates]], ''C. megacephala'' could prove to be beneficial. Organophosphate compounds are used in agriculture and are highly [[toxic]].<ref name=Wallman97>{{cite journal |author=Wallman JF |title=First Record of the Oriental Latrine Fly, ''Chrysomya Megacephala'', from South Australia |journal=Transaction of the Royal Society of S. Aust. |volume=121 |issue=4 |pages=163–4 |year=1997 |url=http://www.samuseum.sa.gov.au/Journals/TRSSA/TRSSA_v121/trssa_v121_p163p164.pdf |format=PDF}}</ref> [[Organophosphate poisoning]] often causes death, and in many cases, by evaluating the body tissue and fluids, the toxin can be identified as the source of the poisoning. However, it is somewhat difficult to evaluate the body tissue in a body that is exceedingly decomposed. Nevertheless, a medical examiner in Hawaii worked on a case in which poisoning by [[malathion]], an organophosphate insecticide,<ref>"Organophosphate Toxicity." Department of Natural Resources. 2008. http://www.michigan.gov/dnr/0,1607,7-153-10370_12150_12220-27249--,00.html</ref> was thought to be the cause of death. The victim’s stomach contents and body fat were examined and found to have contained malathion. The fly larvae of ''Chrysomya megacephala'' and ''[[Chrysomya rufifacies]]'' were also present at the scene on the body and were tested for malathion. Both of these species did contain malathion, but there had been no previous record of organophosphates in their larvae. Studying larvae from decomposed remains may provide an effective method of determining the presence of these toxins in a body that is extremely decayed.<ref>{{cite journal |author=Gunatilake, and Lee Goff |title=Detection of Organophosphate Poisoning in a Putrefying Body by Analyzing Arthropod Larvae |journal=Journal of Forensic Sciences |volume=34 |issue=3 |pages=714–6 |year=1989 |doi= |url=http://www.astm.org/DIGITAL_LIBRARY/JOURNALS/FORENSIC/PAGES/JFS12698J.htm |pmid=2738573}}</ref>

==Use in other research==
''C. megacephala'' has a beneficial and practical value apart from being significant in forensic investigations; this blowfly is the source of [[pollination]] for mangos in the Australian region. While most areas wish to rid themselves of ''C. megacephala'', Taiwanese farmers have found ways to enhance the population of this [[Calliphoridae|blowfly]] so that more mangos will be pollinated.<ref>{{cite journal |author=Gabre RM |title=Life table of ''Chrysomya megacephala'' |journal=Acta Oecologica |volume=27 |issue= 3|pages=179–183 |year=2005 |url=http://140.120.197.173/Ecology/Papers/Gabre-paper.pdf |format=PDF |doi=10.1016/j.actao.2004.12.002|display-authors=etal}}</ref>

==Public health and agricultural issues==

===Myiasis in livestock===
''C. megacephala'' causes myiasis in humans and animals. This causes losses in cattle and fish industries all over the world. Studies are being done on ''C. megacephala'' to determine its role as a [[Vector (epidemiology)|vector]] for diarrhea-causing bacteria such as ''E. coli''.<ref name=Bunchoo07/>

===Public health importance and management control===
''C. megacephala'' are known to be the source of accidental (secondary) myiasis in humans, where the flies do not pierce the skin but invade an open wound.<ref name=Bunchu07>{{cite journal |author=Bunchu, Nophawan |title=Behavioral responses of ''Chrysomya megacephala'' to natural products |year=2007 |pmid=18026752 |doi=10.1007/s00436-007-0780-8 |url=http://parasitology.informatik.uni-wuerzburg.de/login/n/h/j_436-102-3-2007-11-17-780.html.html |journal=Parasitology Research |volume=102 |issue=3 |pages=419–29|display-authors=etal}}</ref> The first record of human miasis caused by ''C. megacephala'' and ''C. rufifacies'' was in Thailand, where a 53-year-old man had a tumor lesion where the larvae accumulated. Most recorded miasis cases, however, do not involve the fly.<ref>{{cite journal |author=Sukontason, Kabkaew L. |title=First Report of Human Myiasis Caused by ''Chrysomya megacephala'' and ''Chrysomya rufifacies'' in Thailand, and Its Implication in Forensic Entomology |journal=J. Med. Entomol. |volume=42 |issue=4 |pages=702–4 |year=2005 |doi= 10.1603/0022-2585(2005)042[0702:FROHMC]2.0.CO;2|url=http://www.med.cmu.ac.th/dept/parasite/KLS-PAPERPDF/LARVA/Firstmyiasis(JME).pdf |format=PDF |pmid=16119563|display-authors=etal}}</ref> ''C. megacephala'' is a carrier of pathogens, such as bacteria, protozoan cysts, and [[helminth]] eggs, to human food,  because it lays its eggs on human feces, and will land on human food soon after.<ref>Hui, Yiu H. Handbook of Food Science, Technology, and Engineering. Florida: CRC Press, 2006.</ref>

The flies also cause a huge economic problem in Asia, Africa, and the Pacific. In these areas sun-drying is the major method of preserving fish, as ice is typically unaffordable. However, blowfly larvae tend to infect these sun-dried fish when the weather is warm and humid. In an experiment, 95% of the infecting flies were found to be ''C. megacephala''.<ref>{{cite journal |vauthors=Wall R, Howard JJ, Bindu J |title=The Seasonal Abundance of Blowflies Infesting Drying Fish in South-West India |journal=Journal of Applied Ecology |volume=38 |issue=2 |pages=339–348 |date=April 2001 |doi=10.1046/j.1365-2664.2001.00588.x|jstor=2655802}}</ref> The flies can be controlled by using an odor that the flies are attracted to trap them.<ref name=Bunchu07/> Insecticides are also used, although this results in the development of resistance.<ref>{{cite journal |author=Sripakdee, Duanghatai |title=Effect of Microwave Irradiation on the Blowfly ''Chrysomya Megacephala'' |journal=Chiang Mai University Research Note |volume=36 |issue=4 |pages=893 |year=2005 |doi= |url=http://www.tm.mahidol.ac.th/seameo/2005_36_4/12-3584.pdf |format=PDF|display-authors=etal}}</ref>

==See also==
*''[[Chrysomya bezziana]]''
*''[[Chrysomya albiceps]]''
*''[[Chrysomya rufifacies]]''

==References==
{{reflist|2}}

{{DEFAULTSORT:Chrysomya Megacephala}}
<nowiki>[[Category:Calliphoridae]]
[[Category:Insects described in 1794]]
[[Category:Diptera of Australasia]]</nowiki>