Cheese fly

Cheese flies
Piophila casei
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
Section:	Schizophora
Subsection:	Acalyptratae
Superfamily:	Tephritoidea
Family:	Piophilidae
Subfamilies
Neottiophilinae Piophilinae Thyreophorinae
Synonyms
Neottiophilidae Thyreophoridae

Cheese flies are members of the family Piophilidae of flies. Most are scavengers in animal products and fungi. The best-known member of the family is Piophila casei. It is a small fly, about four mm (1/6 inch) long, found worldwide. The fly's larva infests cured meats, smoked fish, cheeses, and decaying animals. The larva is about 8 mm (⅓ inch) long and is sometimes called the cheese skipper for its leaping ability - when disturbed, this tiny maggot can hop up to 15 cm (six inches) into the air.^[1] Adults are also known as "bacon flies" and their larvae as "bacon skippers", "ham skippers", "cheese maggots", and "cheese hoppers". In Sardinia, Italy the larvae are intentionally introduced into pecorino cheese to produce casu marzu.

If eaten (accidentally or otherwise), the larvae can pass through the digestive system alive (human stomach acids do not usually kill them) and live for some time in the intestines. This is referred to as an enteric myiasis. Cheese fly larvae are a leading cause of myiasis in humans, and are the insect most frequently found in the human intestine.^[2] The larvae can cause serious intestinal lesions as they attempt to bore through the intestinal walls. Symptoms include nausea, vomiting, pain in the abdomen, and bloody diarrhea. Living and dead larvae may pass in the stool.

Forensic entomology uses the presence of Piophila casei larvae to help estimate the date of death for human remains. They do not take up residence in a corpse until three to six months after death.^[3]

The adult fly's body is black, blue-black, or bronze, with some yellow on the head, antennae, and legs. The wings are faintly iridescent and lie flat upon the fly's abdomen when at rest. At four mm (1/6 inch) long, the fly is one-third to one-half as long as the common housefly. Liopiopila is a typical genus. [1]

The larvae accomplish their jumps by bending over, grabbing onto the rears of their own bodies with their mouth hooks, tensing their muscles, and quickly releasing the grip. Spring action propels them into the air.^[1] A series of photos illustrating this remarkable behaviour in larvae of the tiny piophilid Protopiophila litigata, commonly known as the "antler fly" (it breeds exclusively on discarded antlers of cervids such as moose and deer), can be seen at [2]. Prochyliza xanthostoma breeds on rotting carcasses and is highly sexually dimorphic, with males having greatly elongated heads, antennae and legs, relative to females. P. xanthostoma also has spectacular mating and fighting behaviours.[3]

Identification

This is a small family of 67 species in 23 genera, mainly Holarctic in distribution. The nomenclature is currently volatile, with two family names (Neottiophilinae and Thyreophorinae) recently in use becoming subsumed in the Piophilinae.

Recent works containing descriptive key sequences useful for accurate insect identification are:

• McAlpine JF. 1977. A revised classification of the Piophilidae, including 'Neottiophilidae' and 'Thyreophoridae' (Diptera: Schizophora). Memoirs of the Entomological Society of Canada 103: 1-66
• McAlpine JF. (ed.) 1989. Manual of Nearctic Diptera (Vol. 3). Agriculture Canada Monograph No. 32.
• Ozerov, 2000. Piophilidae. In: Papp, L. & Darvas, A. (eds). Contributions to a Manual of Palaearctic Diptera. Appendix Volume. Science Herald, Budapest.pp 355–365. ISBN 963-04-8840-X
• Shtakel'berg, A.A. Family Piophilidae in Bei-Bienko, G. Ya , 1988 Keys to the insectsof the European Part of the USSR Volume 5 (Diptera) Part 2 English edition

See also

• Cheese mite
• Casu marzu

Genera

• The subfamilies, tribes and genera of Piophilidae - Fauna Europaea

Species lists

• Palaearctic
• Nearctic
• Australasian/Oceanian
• Japan

Image galleries

• Images at Diptera.info

References

1. ^ ^{a b} Don C. Mote (1914). "The cheese skipper (Piophila casei Linne)" (PDF). The Ohio Naturalist 14 (7): 309–315. https://kb.osu.edu/dspace/bitstream/1811/1821/1/V14N07_309.pdf. 
2. ^ Aluja, Martin and Norrbom, Allen (1999). Fruit Flies (Tephritidae). CRC Press. ISBN 0-8493-1275-2.  p. 32
3. ^ "Discovery Channel: You're on the Case". Archived from the original on March 16, 2006. http://web.archive.org/web/20060316000328/http://dsc.discovery.com/fansites/onthecase/toolbox/tool_05.html. Retrieved November 14, 2005. 

• Berenbaum, May R. (1993). Ninety-Nine More Maggots, Mites, and Munchers. University of Illinois Press. ISBN 0-252-06322-8. 
• Lieutenant Brian F. Prendergast, USN (2001). Filth Flies: Significance, Surveillance and Control in Contingency Operations (.pdf format). Retrieved October 1, 2005.
• Robinson, W H (2005). Handbook of Urban Insects And Arachnids: A Handbook of Urban Entomology. Cambridge University Press. ISBN 0-521-81253-4.  pp. 180–181. Google Books

External links

• Family description and images
• An extensive bibliography on the Piophilidae

External links

• Piophila casei on the UF / IFAS Featured Creatures Web site