Phoridae

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Phoridae
Temporal range: Albian–Recent
Phorid fly2.jpg
Pseudacteon sp., showing the humped back that is characteristic of the family
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Section: Aschiza
Superfamily: Phoroidea
Family: Phoridae
Curtis, 1833
Subfamilies

The Phoridae are a family of small, hump-backed flies resembling fruit flies. Phorid flies can often be identified by their escape habit of running rapidly across a surface rather than taking to the wing. This behaviour is a source of one of their alternate names, scuttle fly. Another vernacular name, coffin fly, refers to Conicera tibialis . [1] About 4,000 species are known in 230 genera. The most well-known species is cosmopolitan Megaselia scalaris . At 0.4 mm in length, the world's smallest fly is the phorid Euryplatea nanaknihali . [2]

Contents

Description

For terms see Morphology of Diptera

Phora wing venation Dip-phoridae-phora-wing.png
Phora wing venation

Phorid flies are minute or small – 0.5–6 mm (1⁄64–1⁄4 in) in length. When viewed from the side, a pronounced hump to the thorax is seen. Their colours range from usually black or brown to more rarely yellow, orange, pale grey, and pale white. The head is usually rounded and in some species narrowed towards the vertex. The vertex is flat. In some species, the ocellar callus is swollen and highly raised above the surface of the vertex. The eyes are dichoptic in both males and females (eyes of males close-set, of females wide-set). The third segment of the antenna is large and rounded or elongated, and bears a long apical or dorsal arista directed sideways. The arista is glabrous or feathered. The third antennal segment in some species is unique in shape. Sexual dimorphism is often shown in the shape and size of third segment of antennae, and in males, the antennae are usually longer. The proboscis is usually short and sometimes with enlarged labella. The proboscis may be elongated, highly sclerotized, and bent at an angle. Maxillary palpi vary in shape and are sometimes large (species of genus Triphleba). The groups of bristles are developed on the head. Two pairs of supra-antenna1 bristles, sometimes one, are completely reduced. Above these are antenna1 bristles closer to (but still some distance from) the margin of eyes. Three bristles are spaced along the margin of eyes-anterolateral midlateral and posterolateral. Immediately before the ocellar callus are two preocellar bristles. The ocellar callus bears a pair of ocellar bristles and in some genera between the antennae and the preocellar bristles two additional, intermediate bristles occur. [3]

The convex mesonotum is usually covered with hairs and rows of bristles. An important taxonomic character is the precise location of the anterior spiracles on the pleura of the thorax. The metapleuron may be entire or divided by a suture into two halves, and either with a few long bristles glabrous, or pubescent. The legs have stout femora and the hind femora are often laterally compressed.

The wings are clear or tinged only rarely with markings. They have a characteristic reduced wing venation. The strong, well developed radial (R) veins end in the costa about halfway along the wing. The other veins (branches of the medius) are weaker and usually follow a diagonal course and are often parallel to each other. Crossveins are totally absent. The costa reaches only to the point of confluence of alar margins with veins R4+5 or R5. The ratio of first, second, and third sections of the costa is often a reliable specific character. Other costal indices (compared to other wing measurements) are used in the taxonomy. Two rows of well developed bristles are present on the costa and almost at a right angle to each other. The subcosta is reduced. Of the radial veins, only R1 and R4+5 are developed. R4+5 may furcate at end. R4 and R5 may merge into the alar margin separately or continue as a single vein to the end. Medial veins are represented by M1, M2, and M4. The anal vein may reach the alar margin, or is greatly shortened or almost atrophied.

The abdomen consists of six visible segments. Segments VII to X comprise the genitalia of the male (hypopygium), and in the female the terminalia. In some genera, segments VII to X in the female are highly sclerotized and extended into a tube ("ovipositor"). Segments VII and VIII of the male are more or less sclerotized in the genus Megaselia, but otherwise mostly membranous. Tergite 9 the (epandrium) is highly developed and usually fused at least on one side with the hypandrium (sternite 9). Only in the genus Megaselia is the hypandrium more or less distinctly separated from the epandrium. Unpaired sclerites (ventrites) developed at the distal end of the hypandrium vary in shape. They may be flat, swollen, or other. Sclerites are always present near the base of the cerci, which may be highly developed, and converted either into a tube (anal tube) or a pair of asymmetrical large outgrowths (Phora). The phallosome is rarely complex in structure.

The larva is small, rarely over 10.0 mm long and typically has 12 visible segments. The shape varies from fusiform with inconspicuous projections on posterior segments to short, broad, and flattened with conspicuous dorsal and lateral plumose projections especially on the terminal segment. The colour is whitish, yellowish white, or grey. The first instar is metapneustic, later instars are amphipneustic.

Pupation occurs in the last larval skin which hardens and becomes reddish. The puparium is oval, pointed at ends (because the larval extremities remain relatively unchanged). Abdominal segment 2 has a dorsal pair of long, slender pupal respiratory horns.

Classification

Traditionally, phorids were classified into six subfamilies: Phorinae, Aenigmatiinae, Metopininae (including tribes Beckerinini and Metopinini), Alamirinae, Termitoxeniinae, and Thaumatoxeninae. Disney & Cumming (1992) abolished the Alamirinae when they showed they were the 'missing' males of Termitoxeniinae, which were known only from females. [4]

Also in 1992, Brown [5] presented a revised, cladistic classification based on many new character states. This classification included subfamilies Hypocerinae, Phorinae, Aenigmatiinae, Conicerinae, and Metopininae (Termitoxeniinae and Thaumatoxeninae were not included in his study). Disney rejected the entirety of Brown's work, deeming it premature, and a lively debate ensued. [6] [7] [8] Further resolution of this controversy awaits new data.

The oldest fossils of the family are known from Cretaceous aged amber, with the oldest known being from Early Cretaceous (Albian) French and Spanish amber. [9]

Biology

Phora sp. in copula

Phorid flies are found worldwide, though the greatest variety of species is to be found in the tropics. The Phoridae show the greatest diversity of all the dipterous families. Larvae are found in the nests of social insects and in some aquatic habitats, in organic detritus such as dung, carrion, insect frass, and dead snails. Some are synanthropic. Some species feed on bracket and other fungi and mycelium or on living plants (sometimes as leaf miners). Some are predators or parasites of earthworms, snails, spiders, centipedes, millipedes, and insect eggs, larvae, and pupae. The adults feed on nectar, honeydew, and the juices exuding from fresh carrion and dung. Some adults feed on the body fluids of living beetle larvae and pupae, others prey on small insects. Several species have the common name coffin fly, because they breed in human corpses with such tenacity, they can even continue living within buried coffins. For this reason, they are important in forensic entomology. Most commonly, they feed on decaying organic matter. Because they frequent unsanitary places, including drain pipes, they may transport various disease-causing organisms to food material. The adults are conspicuous on account of their fast and abrupt running. In some species, the males fly in swarms. Megaselia halterata , the mushroom phorid, is a pest of mushroom cultures. Although it does not cause direct damage, it is an efficient vector of dry mould ( Lecanicillium fungicola ).

Life cycle

Phorid flies develop from eggs into larval, and pupal stages before emerging as adults. The female lays from one to 100 tiny eggs at a time in or on the larval food. She can lay up to 750 eggs in her lifetime. The time it takes from egg to adult varies on the species, but the average is about 25 days.

The larvae emerge in 24 hours and feed for a period between 8 and 16 days, before crawling to a drier spot to pupate. The phorid fly's egg-to-adult life cycle can be as short as 14 days, but may take up to 37 days.

Many species of phorid flies are specialist parasitoids of ants, but several species in the tropics are parasitoids of stingless bees. These affected bees are often host to more than one fly larva, and some individuals have been found to contain 12 phorid larvae. [10]

Other species, especially those of the giant genus Megaselia , develop in various fungi during their larval stage and may be pests of cultivated mushrooms. [11]

Myrmecophily

Hooked ovipositor of Pseudacteon curvatus Pseudacteon curvatus - ovipositor.jpg
Hooked ovipositor of Pseudacteon curvatus

Many species of phorid flies are known for their commensal or parasitic relationships with ants. Commensal myrmecophilous phorids most often live in waste piles, consuming food discarded by the ants. Parasitoid phorids typically attack foraging ants, using a species-specific strategy to land on a host and inject eggs within seconds using a sharp ovipositor. Some myrmecophilous phorids are kleptoparasites. Adult Metopina formicomendicula and Allochaeta longiciliata flies ride on host workers and use their legs to stimulate the ants' mouthparts, causing food to be regurgitated which the flies can consume. Myrmecophilous phorids may also practice kleptoparasitism as larvae: Metopina pachycondylae larvae use a "sucker-like posterior" to stick a host larva's body and wrap around its neck like a collar; the fly larva steals food given to the host larva by workers and is encased in the host larva's cocoon to pupate alongside it. The nature of the myrmecophily observed in certain species of phorid flies is unknown, such as the recently discovered ant larva-mimicking genus Vestigipoda , which live in brood piles and may feed on ant brood or receive care from nursing workers. [12]

Phorid flies may represent a hopeful means of controlling fire ant populations in the southern United States, where some species of fire ants were accidentally introduced in the 1930s. The genus Pseudacteon , or ant-decapitating flies, of which 110 species have been documented, is a parasitoid of ants. Pseudacteon species reproduce by laying eggs in the thorax of the ant. The first instar larvae migrate to the head, where they feed on the ant's hemolymph, muscle and nerve tissue. Eventually, the larvae completely devour the ant's brain, causing it to wander aimlessly for about two weeks. [13] After about two [14] to four [13] weeks, they cause the ant's head to fall off by releasing an enzyme that dissolves the membrane attaching the ant's head to its body. The fly pupates in the detached head capsule, requiring a further two weeks before emerging. Various species of Phoridae have been introduced throughout the southeast United States, starting with Travis, Brazos, and Dallas Counties in Texas, as well as Mobile, Alabama, where the non-native fire ants first entered North America. [13] [14] The native species of fire ants are also parasitized by some species of Pseudacteon; these native fire ants don't cause ecological damage the way introduced species do. Pseudacteon has a predominantly indirect effect on fire ant populations, as they do not destroy colonies outright by killing off large numbers of ants; rather, the presence of Pseudacteon in the vicinity of foraging trails elicits a significant defensive response which effectively distracts foraging workers and may reduce the colony's competition with native species. [15]

Colony collapse disorder

In January 2012, a researcher discovered larvae in the test tube of a dead honey bee believed to have been affected by colony collapse disorder. The larvae had not been there the night before. The larvae were Apocephalus borealis , a parasitoid fly known to prey on bumblebees and wasps. The phorid fly lays eggs on the bee's abdomen, which hatch and feed on the bee. Infected bees act oddly, foraging at night and gathering around lights like moths. Eventually, the bee leaves the colony to die. The phorid fly larvae then emerge from the neck of the bee. [16]

Identification

Other

A few cases of phorid flies opportunistically causing human myiasis have been reported. [17] [18]

Related Research Articles

<span class="mw-page-title-main">Fly</span> Order of insects

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 mechanosensory organs known as halteres, which act as high-speed sensors of rotational movement and allow dipterans to perform advanced aerobatics. Diptera is a large order containing an estimated 1,000,000 species including horse-flies, crane flies, hoverflies, mosquitoes and others, although only about 125,000 species have been described.

<span class="mw-page-title-main">Parasitoid</span> Organism that lives with its host and kills it

In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasitism, distinguished by the fatal prognosis for the host, which makes the strategy close to predation.

<span class="mw-page-title-main">Tachinidae</span> Family of insects

The Tachinidae are a large and variable family of true flies within the insect order Diptera, with more than 8,200 known species and many more to be discovered. Over 1,300 species have been described in North America alone. Insects in this family commonly are called tachinid flies or simply tachinids. As far as is known, they all are protelean parasitoids, or occasionally parasites, of arthropods, usually other insects. The family is known from many habitats in all zoogeographical regions and is especially diverse in South America.

<span class="mw-page-title-main">Conopidae</span> Family of flies

The Conopidae, also known as the thick-headed flies, are a family of flies within the Brachycera suborder of Diptera, and the sole member of the superfamily Conopoidea. Flies of the family Conopidae are distributed worldwide in all the biogeographic realms except for the poles and many of the Pacific islands. About 800 species in 47 genera are described worldwide, about 70 of which are found in North America. The majority of conopids are black and yellow, or black and white, and often strikingly resemble wasps, bees, or flies of the family Syrphidae, themselves notable bee mimics. A conopid is most frequently found at flowers, feeding on nectar with its proboscis, which is often long.

<span class="mw-page-title-main">Asilidae</span> Family of flies

The Asilidae are the robber fly family, also called assassin flies. They are powerfully built, bristly flies with a short, stout proboscis enclosing the sharp, sucking hypopharynx. The name "robber flies" reflects their expert predatory habits; they feed mainly or exclusively on other insects and, as a rule, they wait in ambush and catch their prey in flight.

<span class="mw-page-title-main">Agromyzidae</span> Family of flies

The Agromyzidae are a family of flies, commonly referred to as the leaf-miner flies for the feeding habits of their larvae, most of which are leaf miners on various plants. It includes roughly 2,500 species, they are small, some with wing length of 1 mm. The maximum size is 6.5 mm. Most species are in the range of 2 to 3 mm.

<span class="mw-page-title-main">Eucharitidae</span> Family of wasps

The Eucharitidae are a family of parasitic wasps. Eucharitid wasps are members of the superfamily Chalcidoidea and consist of four subfamilies: Akapalinae, Eucharitinae, Gollumiellinae, and Oraseminae. Most of the 42 genera and >400 species of Eucharitidae are members of the subfamilies Oraseminae and Eucharitinae, and are found in tropical regions of the world.

<i>Megaselia scalaris</i> Species of fly

The fly Megaselia scalaris is a member of the order Diptera and the family Phoridae, and it is widely distributed in warm regions of the world. The family members are commonly known as the "humpbacked fly", the "coffin fly", and the "scuttle fly". The name "scuttle fly" derives from the jerky, short bursts of running, characteristic to the adult fly. The name "coffin fly" is due to their being found in coffins, digging six feet deep in order to reach buried corpses. It is one of the more common species found within the family Phoridae; more than 370 species have been identified within North America.

<i>Apocephalus borealis</i> Species of fly

Apocephalus borealis is a species of North American parasitoid phorid fly that attacks bumblebees, honey bees, and paper wasps. This parasitoid's genus Apocephalus is best known for the "decapitating flies" that attack a variety of ant species, though A. borealis attacks and alters the behavior of bees and wasps. These flies are colloquially known as zombie flies and the bees they infect are colloquially known as zombees. Association with honey bees has so far only been documented from California, South Dakota, Oregon, Washington, British Columbia, and Vermont.

Dipteran morphology differs in some significant ways from the broader morphology of insects. The Diptera is a very large and diverse order of mostly small to medium-sized insects. They have prominent compound eyes on a mobile head, and one pair of functional, membraneous wings, which are attached to a complex mesothorax. The second pair of wings, on the metathorax, are reduced to halteres. The order's fundamental peculiarity is its remarkable specialization in terms of wing shape and the morpho-anatomical adaptation of the thorax – features which lend particular agility to its flying forms. The filiform, stylate or aristate antennae correlate with the Nematocera, Brachycera and Cyclorrhapha taxa respectively. It displays substantial morphological uniformity in lower taxa, especially at the level of genus or species. The configuration of integumental bristles is of fundamental importance in their taxonomy, as is wing venation. It displays a complete metamorphosis, or holometabolous development. The larvae are legless, and have head capsules with mandibulate mouthparts in the Nematocera. The larvae of "higher flies" (Brachycera) are however headless and wormlike, and display only three instars. Pupae are obtect in the Nematocera, or coarcate in Brachycera.

<i>Pseudacteon</i> Genus of flies

Pseudacteon is a genus of flies in the family Phoridae. There are over 70 described species of Pseudacteon fly. They are also known as ant-decapitating flies due to their parasitic larval stage. An egg is injected by the female fly into the shoulder joint of an ant worker. Soon after, the egg undergoes rapid inflation as it appears to absorb ant hemolymph. This first instar larva migrates into the ant head and consumes the jaw muscle and other tissues, leaving the mandibles hanging and preparing a future exit space. After about two weeks, the ant worker is termed a "zombie" because the fly larva has effectively taken control. The worker leaves the nest and dies in the leaf litter or in a crack in the soil. As it dies, the ant's head falls off, apparently because the fly larva releases an enzyme that dissolves the membrane attaching the ant's head to its body. The fly pupates in the detached head capsule, requiring a further two weeks before emerging through the ant's mouth. In tropical, subtropical areas the flies are active all year round, but in temperate regions they are active during all months except the winter months. Several Pseudacteon species were deliberately introduced to the United States to combat via biological control the invasive fire ant species Solenopsis invicta.

The mushroom phorid fly(Megaselia halterata) is a species of scuttle fly or hump-backed flies in the family Phoridae. "The mushroom phorid" is also used to refer to M. halterata. Megaselia halterata is a common pest of mushroom cultivation, attracted by the aroma of developing fungal mycelium. The larvae damage both the mushroom mycelium and gill tissues. Megaslia halterata can be found worldwide.

<i>Howardula</i> Genus of roundworms

Howardula is a genus of nematode that infests the larvae of mushroom-feeding flies, beetles, and other insects. Various Howardula species and strains infest mushroom-feeding Drosophila, including Howardula aoronymphium and Howardula neocosmis. Howardula husseyi can infest the mushroom phorid Megaselia halterata.

<i>Apocephalus paraponerae</i> Species of fly

Apocephalus paraponerae is a species of fly in the family Phoridae discovered by Borgmeier in 1958. This species is a parasitoid of the giant tropical ant Paraponera clavata and uses both visual and chemical cues to locate its host. A. paraponerae can locate fighting or injured ants through host-produced alarm pheromones. Female flies are attracted to the ant to feed and oviposit, while males are attracted to feed and locate females for mating. There is some evidence that suggests that A. paraponerae is a cryptic species complex of at least four genetically distinct species.

Pseudacteon tricuspis is a parasitoid phorid fly that decapitates its host, the imported Solenopsis invicta fire ant. There are over 70 described species within the Pseudacteon genus, which parasitize a variety of ant species. However, P. tricuspis is very specific to its host ant and will not attack other native ant species, making it a good biological control against the fire ant. P. tricuspis was also introduced into the United States for this purpose. Aside from the United States, P. tricuspis has also been found in South America, Europe, and Asia. Female P. tricuspis deposit their eggs directly into the fire ant host. Deposition into the ant host determines the sex of the egg, which grows within the host until adulthood, killing and decapitating the host in the process. Interestingly, P. tricuspis has a male-biased sex ratio, where the males are smaller than the females.

Diocophora is a genus of flies in the family Phoridae.

Metopina is a genus of flies in the family Phoridae.

Microselia is a genus of flies in the family Phoridae.

<i>Aenigmatias</i> Genus of flies

Aenigmatias is a genus of flies in the family Phoridae.

References

  1. ↑ Colyer, C.N. (1954) The 'coffin fly', Conicera tibialis Schmitz (Dipt., Phoridae). Journal of the Society for British Entomology, 4, 203–206.
  2. ↑ Brown, B.V. 2012: Small size no protection for acrobat ants: world's smallest fly is a parasitic phorid (Diptera: Phoridae). Annals of the Entomological Society of America, 105(4): 550–554. doi : 10.1603/AN12011
  3. ↑ Brown, B.V. (2012). "Small Size No Protection for Acrobat Ants: World's Smallest Fly is a Parasitic Phorid (Diptera: Phoridae)". Annals of the Entomological Society of America. Annals of the Entomological Society of America. Retrieved 11 December 2023.
  4. ↑ Disney, R.H.L. & Cumming, M.S. (1992) Abolition of Alamirinae and ultimate rejection of Wasmann's theory of hermaphroditism in Termitoxeniinae (Diptera: Phoridae). Bonner zoologische Beiträge, 43, 145–154.
  5. ↑ Brown, B.V. (1992). "Brown, B.V. 1992. Generic revision of Phoridae of the Nearctic Region and phylogenetic classification of Phoridae, Sciadoceridae, and Ironomyiidae (Diptera: Phoroidea)". Memoirs of the Entomological Society of Canada. 164: 1–144.
  6. ↑ Disney, R.H.L. (1993) Mosaic evolution and outgroup comparisons. Journal of Natural History, 27, 1219–1221.
  7. ↑ Brown, B.V. (1995) Response to Disney. Journal of Natural History, 29, 259–264.
  8. ↑ Disney, R.H.L. (1995) Reply to Brown. Journal of Natural History, 29, 1081–1082.
  9. ↑ Solórzano-Kraemer, Mónica M.; Bourdeau, Clément; Rosse-Guillevic, Simon; Hammel, Jörg U.; Xu, Chun-Peng; Brown, Brian V. (November 2021). "Parasitic hump-backed flies (Diptera: Phoridae) from Miocene ambers". Palaeoworld: S1871174X21000913. doi:10.1016/j.palwor.2021.11.002. S2CID   244126413.
  10. ↑ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.
  11. ↑ Disney, R.H.L., Kurina, O., Tedersoo, L. & Cakpo, Y. (2013) Scuttle flies (Diptera: Phoridae) reared from fungi in Benin. African Invertebrates, 54 (2), 357–371.
  12. ↑ Hölldobler, Bert; Kwapich, Christina L. (2022). The guests of ants: how myrmecophiles interact with their hosts. Cambridge, Massachusetts: The Belknap Press of Harvard University Press. ISBN   978-0-674-26551-6.
  13. 1 2 3 Hanna, Bill (May 12, 2009). "Parasitic flies turn fire ants into zombies". Fort Worth Star-Telegram. Archived from the original on May 22, 2009. Retrieved 2009-05-14.
  14. 1 2 "New weapon turns fire ants into headless zombies". San Francisco Chronicle. May 13, 2009. Archived from the original on May 16, 2009. Retrieved May 13, 2009.
  15. ↑ Morrison, Lloyd W. (January 2000). "Biology of Pseudacteon (Diptera: Phoridae) ant parasitoids and their potential to control imported Solenopsis fire ants (Hymenoptera: Formicidae)". Recent Research Developments in Entomology. 3: 1–13 – via ResearchGate.
  16. ↑ A New Threat to Honey Bees, the Parasitic Phorid Fly Apocephalus borealis
  17. ↑ T. L. Carpenter and D. O. Chastain: "Facultative Myiasis by Megaselia sp. (Diptera: Phoridae): A Case Report" in Journal of Medical Entomology, Vol. 29, No. 3 (1992), pp. 561–563.
  18. ↑ K. Komori, K. Hara, K.G.V. Smith, T. Oda, D. Karamine: "A case of lung myiasis caused by larvae of Megaselia spiracularis Schmitz (Diptera: Phoridae)" in Transactions of the Royal Society of Tropical Medicine and Hygiene, Vol. 72 (1978), No. 5, pp. 467–470.

Further reading

Species lists

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