From en.wikipedia.org:
[Order of insects] [the insect] [Flies] [Good article] [Pp-semi-indef]
[date=May 2016] {{Automatic taxobox | fossil_range = [245]<small>Middle
Triassic – Recent</small> | image = Six Diptera.jpg | image_upright = 1.2 |
image_caption = Diptera from different families: Housefly (Muscidae) (top
left) <br/>_Haematopota pluvialis_ (Tabanidae) (top right) <br/>_Ctenophora
pectinicornis_ (Tipulidae) (mid left) <br/>_Aedes notoscriptus_ (Culicidae)
(mid right) <br/>_Milesia crabroniformis_ (Syrphidae) (bottom left)
<br/>_Holcocephala fusca_ (Asilidae) (bottom right) | display_parents = 2 |
taxon = Diptera | authority = Linnaeus, 1758 | subdivision_ranks = Suborders |
subdivision = Nematocera (paraphyletic) (inc Eudiptera)<br/>Brachycera }}
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 more than 150,000 species including
horse-flies,{{efn |Some authors draw a distinction in writing the common names
of insects. True flies are in their view best written as two words, such as
crane fly, robber fly, bee fly, moth fly, and fruit fly. In contrast, common
names of non-dipteran insects that have "fly" in their names are written as
one word, e.g. butterfly, stonefly, dragonfly, scorpionfly, sawfly,
caddisfly, whitefly.[1] In practice, however, this is a comparatively new
convention; especially in older books, names like "saw fly" and "caddis fly",
or hyphenated forms such as house-fly and dragon-fly are widely used.[2]
Exceptions to this rule occur, such as the hoverfly (though some authors
prefer "hover fly"[3]), which is a true fly, and the Spanish fly, a type of
blister beetle.}} crane flies, hoverflies, mosquitoes and others.
Flies have a mobile head, with a pair of large compound eyes, and mouthparts
designed for piercing and sucking (mosquitoes, black flies and robber flies),
or for lapping and sucking in the other groups. Their wing arrangement gives
them great manoeuvrability in flight, and claws and pads on their feet enable
them to cling to smooth surfaces. Flies undergo complete metamorphosis; the
eggs are often laid on the larval food-source and the larvae, which lack true
limbs, develop in a protected environment, often inside their food source.
Other species are ovoviviparous, opportunistically depositing hatched or
hatching larvae instead of eggs on carrion, dung, decaying material, or open
wounds of mammals. The pupa is a tough capsule from which the adult emerges
when ready to do so; flies mostly have short lives as adults.
Diptera is one of the major insect orders and of considerable ecological and
human importance. Flies are major pollinators, second only to the bees and
their Hymenopteran relatives. Flies may have been among the evolutionarily
earliest pollinators responsible for early plant pollination. Fruit flies are
used as model organisms in research, but less benignly, mosquitoes are vectors
for malaria, dengue, West Nile fever, yellow fever, encephalitis, and other
infectious diseases; and houseflies, commensal with humans all over the world,
spread foodborne illnesses. Flies can be annoyances especially in some parts
of the world where they can occur in large numbers, buzzing and settling on
the skin or eyes to bite or seek fluids. Larger flies such as tsetse flies
and screwworms cause significant economic harm to cattle. Blowfly larvae,
known as gentles, and other dipteran larvae, known more generally as maggots,
are used as fishing bait, as food for carnivorous animals, and in medicine in
debridement, to clean wounds.
** Taxonomy and phylogeny
*** Relationships to other insects
Dipterans are holometabolous, meaning that they undergo radical metamorphosis.
They belong to the Mecopterida, alongside the Mecoptera, Siphonaptera,
Lepidoptera and Trichoptera.[4][5] The possession of a single pair of wings
distinguishes most true flies from other insects with "fly" in their names.
However, some true flies such as Hippoboscidae (louse flies) have become
secondarily wingless.[6][7]
The cladogram represents the current consensus view.<ref name=Kjer>[last1=Kjer
]
{{clade |label1=Holometabola |1={{clade
|1=Hymenoptera (sawflies, wasps, ants, bees) 70px
|label2=Aparaglossata
|2={{clade
|label1=Neuropteroidea
|1={{clade
|label1=Neuropterida
|1={{clade
|1=Raphidioptera (snakeflies) 70px
|label2=
|2={{clade
|1=Megaloptera (alderflies and allies) 70px
|2=Neuroptera (Lacewings and allies) 70px
}}
}}
|label2=Coleopterida
|2={{clade
|1=Coleoptera (beetles) 50px
|2=Strepsiptera (twisted-wing parasites) 70px
}}
}}
|label2=Panorpida|sublabel2=(Mecopterida)
|2={{clade
|label1=Amphiesmenoptera
|1={{clade
|1=Trichoptera (caddisflies) 70px
|2=Lepidoptera (butterflies, moths) 70px
}}
|label2=Antliophora
|2={{clade
|1= DIPTERA 70px
|2={{clade
|1=Mecoptera (scorpionflies) 70px
|2=Siphonaptera (fleas) 40px
}}
}}
}}
}}
}}
}}
*** Relationships between subgroups and families
The first true dipterans known are from the Middle Triassic (around 240
million years ago), and they became widespread during the Middle and Late
Triassic.[8] Modern flowering plants did not appear until the Cretaceous
(around 140 million years ago), so the original dipterans must have had a
different source of nutrition other than nectar. Based on the attraction of
many modern fly groups to shiny droplets, it has been suggested that they may
have fed on honeydew produced by sap-sucking bugs which were abundant at the
time, and dipteran mouthparts are well-adapted to softening and lapping up the
crusted residues.[9] The basal clades in the Diptera include the
Deuterophlebiidae and the enigmatic Nymphomyiidae.[10] Three episodes of
evolutionary radiation are thought to have occurred based on the fossil
record. Many new species of lower Diptera developed in the Triassic, about
220 million years ago. Many lower Brachycera appeared in the Jurassic, some
180 million years ago. A third radiation took place among the Schizophora at
the start of the Paleogene, 66 million years ago.<ref name="Wiegmann2011" />
The phylogenetic position of Diptera has been controversial. The monophyly of
holometabolous insects has long been accepted, with the main orders being
established as Lepidoptera, Coleoptera, Hymenoptera and Diptera, and it is the
relationships between these groups which has caused difficulties. Diptera is
widely thought to be a member of Mecopterida, along with Lepidoptera
(butterflies and moths), Trichoptera (caddisflies), Siphonaptera (fleas),
Mecoptera (scorpionflies) and possibly Strepsiptera (twisted-wing flies).
Diptera has been grouped with Siphonaptera and Mecoptera in the Antliophora,
but this has not been confirmed by molecular studies.[11]
Diptera were traditionally broken down into two suborders, Nematocera and
Brachycera, distinguished by the differences in antennae. The Nematocera are
identified by their elongated bodies and many-segmented, often feathery
antennae as represented by mosquitoes and crane flies. The Brachycera have
rounder bodies and much shorter antennae.[12]<ref name=TOL>[last1=Wiegmann ]
Subsequent studies have identified the Nematocera as being paraphyletic with
modern phylogenies placing the Brachycera within grades of groups formerly
placed in the Nematocera. The construction of a phylogenetic tree has been
the subject of ongoing research. The following cladogram is based on the
FLYTREE project.[13][14]
{{clade | style=font-size:100%;line-height:105%;
|label1= DIPTERA
|grouplabel1=[label1=" Nematocera " ]
|1={{clade |bar1=green
|1={{clade
|1=Ptychopteromorpha (phantom and primitive crane-flies) 60px
|2=Culicomorpha (mosquitoes, blackflies and midges) 55px
}}
|2={{clade
|1=Blephariceromorpha (net-winged midges, etc) 60px|bar1=green
|2={{clade
|1=Bibionomorpha (gnats) 55px|bar1=green
|2={{clade
|1=Psychodomorpha (drain flies, sand flies, etc) 55px|bar1=green
|2={{clade
|1=Tipulomorpha (crane flies) 65px|bar1=green
|label2= BRACHYCERA
|2={{clade
|label1=
|1={{clade
|1=Stratiomyomorpha (soldier flies, etc) 66px
|2={{clade
|1=Xylophagomorpha (stink flies, etc) 55px
|2=Tabanomorpha (horse flies, snipe flies, etc) 66px
}}
}}
|label2=Mus
|2={{clade
|1=Nemestrinoidea 66px
|2={{clade
|1=Asiloidea (robber flies, bee flies, etc) 66px
|label2=Ere
|2={{clade
|1=Empidoidea (dance flies, etc) 35px
|label2=Cyc
|2={{clade
|1=Aschiza (in part)
|2={{clade
|1=Phoroidea (flat-footed flies, etc) 55px
|2={{clade
|1=Syrphoidea (hoverflies) 55px
|label2=Sch
|2={{clade
|label1=Cal
|1={{clade
|1=Hippoboscoidea (louse flies, etc) 55px
|2={{clade
|1=Muscoidea (house flies, dung flies, etc) 55px
|2=Oestroidea (blow flies, flesh flies, etc) 55px
}}
}}
|2=Acalyptratae (marsh flies, fruit flies, etc) 55px
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
{{smalldiv|1= _Abbreviations used in the cladogram:_
- Cal= Calyptratae
- Cyc= Cyclorrhapha
- Ere= Eremoneura
- Mus= Muscomorpha
- Sch= Schizophora
}}
A 2023 study revised the phylogeny of the Nematocera. The grouping remains
paraphyletic with respect to the Brachycera, but is rearranged, with
Deuterophlebiidae basal (sister to the rest), Nymphomyiidae placed inside
Culicomorpha, and Blephariceridae within Psychodomorpha. Finally,
Anisopodidae becomes sister to the Brachycera.[15]
{{clade | style=font-size:100%;line-height:105%; |label1= DIPTERA
|grouplabel1=[label1=" Nematocera " ] |1={{clade
|1=Deuterophlebiidae |bar1=green
|2={{clade
|1=Tipulomorpha (crane flies) 65px |bar1=green
|2={{clade
|1=Axymyiomorpha 65px |bar1=green
|2=Ptychopteromorpha (phantom and primitive crane-flies) 60px |bar2=green
|3=Culicomorpha (mosquitoes, blackflies and midges, inc. Nymphomyiidae) 55px |bar3=green
|4={{clade
|1=Psychodomorpha (drain flies, sand flies, inc. Blephariceridae) 55px|bar1=green
|2={{clade
|1=Bibionomorpha (gnats) 55px|bar1=green
|2={{clade
|1=Anisopodidae (wood gnats) 60px |bar1=green
|2= BRACHYCERA
}}
}}
}}
}}
}}
}}
}}
*** Diversity
Flies are often abundant and are found in almost all terrestrial habitats.
They include many familiar insects such as house flies, blow flies,
mosquitoes, gnats, black flies, midges and fruit flies. More than 150,000
have been formally described and the actual species diversity is much greater,
with the flies from many parts of the world yet to be studied intensively.<ref
name=Pape2009>[last1=Pape ][16] The suborder Nematocera include generally
small, slender insects with long antennae such as mosquitoes, gnats, midges
and crane-flies, while the Brachycera includes broader, more robust flies with
short antennae. Many nematoceran larvae are aquatic.<ref
name=TolwebDiptera>[url=http://tolweb.org/Diptera ] There are estimated to be
a total of about 19,000 species of Diptera in Europe, 22,000 in the Nearctic
region, 20,000 in the Afrotropical region, 23,000 in the Oriental region and
19,000 in the Australasian region.<ref name=Pape>[last1=Pape ] While most
species have restricted distributions, a few like the housefly (_Musca
domestica_) are cosmopolitan.[17] _Gauromydas heros_ (Asiloidea), with a
length of up to [7 ], is generally considered to be the largest fly in the
world,[18] while the smallest is _Euryplatea nanaknihali_, which at [0.4 ] is
smaller than a grain of salt.[19]
Brachycera are ecologically very diverse, with many being predatory at the
larval stage and some being parasitic. Animals parasitised include molluscs,
woodlice, millipedes, insects, mammals,<ref name=Pape/> and amphibians.[20]
Flies are the second largest group of pollinators after the Hymenoptera (bees,
wasps and relatives). In wet and colder environments flies are significantly
more important as pollinators. Compared to bees, they need less food as they
do not need to provision their young. Many flowers that bear low nectar and
those that have evolved trap pollination depend on flies.[21] It is thought
that some of the earliest pollinators of plants may have been flies.[22]
The greatest diversity of gall forming insects are found among the flies,
principally in the family Cecidomyiidae (gall midges).[23] Many flies (most
importantly in the family Agromyzidae) lay their eggs in the mesophyll tissue
of leaves with larvae feeding between the surfaces forming blisters and
mines.[24] Some families are mycophagous or fungus feeding. These include the
cave dwelling Mycetophilidae (fungus gnats) whose larvae are the only diptera
with bioluminescence. The Sciaridae are also fungus feeders. Some plants are
pollinated by fungus feeding flies that visit fungus infected male
flowers.[25]
The larvae of _Megaselia scalaris_ (Phoridae) are omnivorous and may consume
such substances as paint and shoe polish.[26] The _Exorista mella (Walker)_
fly are considered generalists and parasitoids of a variety of hosts.[27] The
larvae of the shore flies (Ephydridae) and some Chironomidae survive in
extreme environments including glaciers (_Diamesa_ sp., Chironomidae[28]), hot
springs, geysers, saline pools, sulphur pools, septic tanks and even crude oil
(_Helaeomyia petrolei_<ref name="Biology of Shore Flies"/>).<ref name="Pape"/>
Adult hoverflies (Syrphidae) are well known for their mimicry and the larvae
adopt diverse lifestyles including being inquiline scavengers inside the nests
of social insects.[29] Some brachycerans are agricultural pests, some bite
animals and humans and suck their blood, and some transmit diseases.<ref
name="Pape"/>
** Anatomy and morphology
[Morphology of Diptera ]
Flies are adapted for aerial movement and typically have short and streamlined
bodies. The first tagma of the fly, the head, bears the eyes, the antennae,
and the mouthparts (the labrum, labium, mandible, and maxilla make up the
mouthparts). The second tagma, the thorax, bears the wings and contains the
flight muscles on the second segment, which is greatly enlarged; the first and
third segments have been reduced to collar-like structures, and the third
segment bears the halteres, which help to balance the insect during flight.
The third tagma is the abdomen consisting of 11 segments, some of which may be
fused, and with the three hindmost segments modified for reproduction.[30]<ref
name=Resh/> Some Dipterans are mimics and can only be distinguished from their
models by very careful inspection. An example of this is _Spilomyia
longicornis_, which is a fly but mimics a vespid wasp.[31]
Flies have a mobile head with a pair of large compound eyes on the sides of
the head, and in most species, three small ocelli on the top. The compound
eyes may be close together or widely separated, and in some instances are
divided into a dorsal region and a ventral region, perhaps to assist in
swarming behaviour. The antennae are well-developed but variable, being
thread-like, feathery or comb-like in the different families. The mouthparts
are adapted for piercing and sucking, as in the black flies, mosquitoes and
robber flies, and for lapping and sucking as in many other groups.<ref
name=Resh/> Female horse-flies use knife-like mandibles and maxillae to make a
cross-shaped incision in the host's skin and then lap up the blood that flows.
The gut includes large diverticulae, allowing the insect to store small
quantities of liquid after a meal.<ref name="IIBD" />
For visual course control, flies' optic flow field is analyzed by a set of
motion-sensitive neurons.<ref name=pmid11943823>[first1=Juergen ] A subset of
these neurons is thought to be involved in using the optic flow to estimate
the parameters of self-motion, such as yaw, roll, and sideward
translation.[32] Other neurons are thought to be involved in analyzing the
content of the visual scene itself, such as separating figures from the ground
using motion parallax.[33][34] The H1 neuron is responsible for detecting
horizontal motion across the entire visual field of the fly, allowing the fly
to generate and guide stabilizing motor corrections midflight with respect to
yaw.[35] The ocelli are concerned in the detection of changes in light
intensity, enabling the fly to react swiftly to the approach of an object.<ref
name=Ruppert>[title=Invertebrate Zoology, 7th edition ]
Like other insects, flies have chemoreceptors that detect smell and taste, and
mechanoreceptors that respond to touch. The third segments of the antennae
and the maxillary palps bear the main olfactory receptors, while the gustatory
receptors are in the labium, pharynx, feet, wing margins and female
genitalia,[36] enabling flies to taste their food by walking on it. The taste
receptors in females at the tip of the abdomen receive information on the
suitability of a site for ovipositing.<ref name=Ruppert/> Flies that feed on
blood have special sensory structures that can detect infrared emissions, and
use them to home in on their hosts. Many blood-sucking flies can detect the
raised concentration of carbon dioxide that occurs near large animals.[37]
Some tachinid flies (Ormiinae) which are parasitoids of bush crickets, have
sound receptors to help them locate their singing hosts.[38]
Diptera have one pair of fore wings on the mesothorax and a pair of halteres,
or reduced hind wings, on the metathorax. A further adaptation for flight is
the reduction in number of the neural ganglia, and concentration of nerve
tissue in the thorax, a feature that is most extreme in the highly derived
Muscomorpha infraorder.<ref name=IIBD>[last1=Hoell ] Some flies such as the
ectoparasitic Nycteribiidae and Streblidae are exceptional in having lost
their wings and become flightless. The only other order of insects bearing a
single pair of true, functional wings, in addition to any form of halteres,
are the Strepsiptera. In contrast to the flies, the Strepsiptera bear their
halteres on the mesothorax and their flight wings on the metathorax.[39] Each
of the fly's six legs has a typical insect structure of coxa, trochanter,
femur, tibia and tarsus, with the tarsus in most instances being subdivided
into five tarsomeres.<ref name=Resh/> At the tip of the limb is a pair of
claws, and between these are cushion-like structures known as pulvilli which
provide adhesion.[40]
The abdomen shows considerable variability among members of the order. It
consists of eleven segments in primitive groups and ten segments in more
derived groups, the tenth and eleventh segments having fused.<ref
name=Gibb>[last1=Gibb ] The last two or three segments are adapted for
reproduction. Each segment is made up of a dorsal and a ventral sclerite,
connected by an elastic membrane. In some females, the sclerites are rolled
into a flexible, telescopic ovipositor.<ref name=Resh/>
*** Flight
[Insect flight]
Flies are capable of great manoeuvrability during flight due to the presence
of the halteres. These act as gyroscopic organs and are rapidly oscillated in
time with the wings; they act as a balance and guidance system by providing
rapid feedback to the wing-steering muscles, and flies deprived of their
halteres are unable to fly. The wings and halteres move in synchrony but the
amplitude of each wing beat is independent, allowing the fly to turn
sideways.[41] The wings of the fly are attached to two kinds of muscles, those
used to power it and another set used for fine control.[42]
Flies tend to fly in a straight line then make a rapid change in direction
before continuing on a different straight path. The directional changes are
called saccades and typically involve an angle of 90°, being achieved in 50
milliseconds. They are initiated by visual stimuli as the fly observes an
object, nerves then activate steering muscles in the thorax that cause a small
change in wing stroke which generate sufficient torque to turn. Detecting
this within four or five wingbeats, the halteres trigger a counter-turn and
the fly heads off in a new direction.[43]
Flies have rapid reflexes that aid their escape from predators but their
sustained flight speeds are low. Dolichopodid flies in the genus
_Condylostylus_ respond in less than five milliseconds to camera flashes by
taking flight.[44] In the past, the deer bot fly, _Cephenemyia_, was claimed
to be one of the fastest insects on the basis of an estimate made visually by
Charles Townsend in 1927.[45] This claim, of speeds of 600 to 800 miles per
hour, was regularly repeated until it was shown to be physically impossible as
well as incorrect by Irving Langmuir. Langmuir suggested an estimated speed
of 25 miles per hour.[46][47][48]
Although most flies live and fly close to the ground, a few are known to fly
at heights and a few like _Oscinella_ (Chloropidae) are known to be dispersed
by winds at altitudes of up to 2,000 ft and over long distances.[49] Some
hover flies like _Metasyrphus corollae_ have been known to undertake long
flights in response to aphid population spurts.[50]
Males of fly species such as _Cuterebra_, many hover flies,[51] bee flies
(Bombyliidae)[52] and fruit flies (Tephritidae)[53] maintain territories
within which they engage in aerial pursuit to drive away intruding males and
other species.[54] While these territories may be held by individual males,
some species, such as _A. freeborni_,[55] form leks with many males
aggregating in displays.<ref name="ReferenceA"/> Some flies maintain an
airspace and still others form dense swarms that maintain a stationary
location with respect to landmarks. Many flies mate in flight while
swarming.[56]
** Life cycle and development
[Biology of Diptera]
Diptera go through a complete metamorphosis with four distinct life stages –
egg, larva, pupa and adult.
*** Larva
In many flies, the larval stage is long and adults may have a short life.
Most dipteran larvae develop in protected environments; many are aquatic and
others are found in moist places such as carrion, fruit, vegetable matter,
fungi and, in the case of parasitic species, inside their hosts. They tend to
have thin cuticles and become desiccated if exposed to the air. Apart from
the Brachycera, most dipteran larvae have sclerotised head capsules, which may
be reduced to remnant mouth hooks; the Brachycera, however, have soft,
gelatinized head capsules from which the sclerites are reduced or missing.
Many of these larvae retract their heads into their thorax.<ref
name=Resh/><ref name=Gullan/> The spiracles in the larva and pupa do not have
any internal mechanical closing device.[57]
Some other anatomical distinction exists between the larvae of the Nematocera
and the Brachycera. Especially in the Brachycera, little demarcation is seen
between the thorax and abdomen, though the demarcation may be visible in many
Nematocera, such as mosquitoes; in the Brachycera, the head of the larva is
not clearly distinguishable from the rest of the body, and few, if any,
sclerites are present. Informally, such brachyceran larvae are called
maggots,[58] but the term is not technical and often applied indifferently to
fly larvae or insect larvae in general. The eyes and antennae of brachyceran
larvae are reduced or absent, and the abdomen also lacks appendages such as
cerci. This lack of features is an adaptation to food such as carrion,
decaying detritus, or host tissues surrounding endoparasites.<ref name="IIBD"
/> Nematoceran larvae generally have well-developed eyes and antennae, while
those of Brachyceran larvae are reduced or modified.<ref
name=Lancaster>[last1=Lancaster ]
Dipteran larvae have no jointed, "true legs",<ref name=Gullan>[last1=Gullan ]
but some dipteran larvae, such as species of Simuliidae, Tabanidae and
Vermileonidae, have prolegs adapted to hold onto a substrate in flowing water,
host tissues or prey.[59] The majority of dipterans are oviparous and lay
batches of eggs, but some species are ovoviviparous, where the larvae starting
development inside the eggs before they hatch or viviparous, the larvae
hatching and maturing in the body of the mother before being externally
deposited. These are found especially in groups that have larvae dependent on
food sources that are short-lived or are accessible for brief periods.[60]
This is widespread in some families such as the Sarcophagidae. In _Hylemya
strigosa_ (Anthomyiidae) the larva moults to the second instar before
hatching, and in _Termitoxenia_ (Phoridae) females have incubation pouches,
and a full developed third instar larva is deposited by the adult and it
almost immediately pupates with no freely feeding larval stage. The tsetse
fly (as well as other Glossinidae, Hippoboscidae, Nycteribidae and Streblidae)
exhibits adenotrophic viviparity; a single fertilised egg is retained in the
oviduct and the developing larva feeds on glandular secretions. When fully
grown, the female finds a spot with soft soil and the larva works its way out
of the oviduct, buries itself and pupates. Some flies like _Lundstroemia
parthenogenetica_ (Chironomidae) reproduce by thelytokous parthenogenesis, and
some gall midges have larvae that can produce eggs (paedogenesis).[61][62]
*** Pupa
The pupae take various forms. In some groups, particularly the Nematocera,
the pupa is intermediate between the larval and adult form; these pupae are
described as "obtect", having the future appendages visible as structures that
adhere to the pupal body. The outer surface of the pupa may be leathery and
bear spines, respiratory features or locomotory paddles. In other groups,
described as "coarctate", the appendages are not visible. In these, the outer
surface is a puparium, formed from the last larval skin, and the actual pupa
is concealed within. When the adult insect is ready to emerge from this
tough, desiccation-resistant capsule, it inflates a balloon-like structure on
its head, and forces its way out.<ref name=Resh/>
*** Adult
The adult stage is usually short, its function is only to mate and lay eggs.
The genitalia of male flies are rotated to a varying degree from the position
found in other insects.[63] In some flies, this is a temporary rotation during
mating, but in others, it is a permanent torsion of the organs that occurs
during the pupal stage. This torsion may lead to the anus being below the
genitals, or, in the case of 360° torsion, to the sperm duct being wrapped
around the gut and the external organs being in their usual position. When
flies mate, the male initially flies on top of the female, facing in the same
direction, but then turns around to face in the opposite direction. This
forces the male to lie on his back for his genitalia to remain engaged with
those of the female, or the torsion of the male genitals allows the male to
mate while remaining upright. This leads to flies having more reproduction
abilities than most insects, and much quicker. Flies occur in large
populations due to their ability to mate effectively and quickly during the
mating season.<ref name="IIBD" /> More primitive groups mates in the air
during swarming, but most of the more advanced species with a 360° torsion
mate on a substrate.[64]
** Ecology
*** Trophic levels
left
As ubiquitous insects, dipterans play an important role at various trophic
levels both as consumers and as prey. In some groups the larvae complete
their development without feeding, and in others the adults do not feed. The
larvae can be herbivores, scavengers, decomposers, predators or parasites,
with the consumption of decaying organic matter being one of the most
prevalent feeding behaviours. The fruit or detritus is consumed along with
the associated micro-organisms, a sieve-like filter in the pharynx being used
to concentrate the particles, while flesh-eating larvae have mouth-hooks to
help shred their food. The larvae of some groups feed on or in the living
tissues of plants and fungi, and some of these are serious pests of
agricultural crops. Some aquatic larvae consume the films of algae that form
underwater on rocks and plants. Many of the parasitoid larvae grow inside and
eventually kill other arthropods, while parasitic larvae may attack vertebrate
hosts.<ref name=Resh/>
*** Habitats and ecological niches
Whereas many dipteran larvae are aquatic or live in enclosed terrestrial
locations, the majority of adults live above ground and are capable of flight.
Predominantly they feed on nectar or plant or animal exudates, such as
honeydew, for which their lapping mouthparts are adapted. Some flies have
functional mandibles that may be used for biting. The flies that feed on
vertebrate blood have sharp stylets that pierce the skin, with some species
having anticoagulant saliva that is regurgitated before absorbing the blood
that flows; in this process, certain diseases can be transmitted. The bot
flies (Oestridae) have evolved to parasitize mammals. Many species complete
their life cycle inside the bodies of their hosts.[65] The larvae of a few fly
groups (Agromyzidae, Anthomyiidae, Cecidomyiidae) are capable of inducing
plant galls. Some dipteran larvae are leaf-miners. The larvae of many
brachyceran families are predaceous. In many dipteran groups, swarming is a
feature of adult life, with clouds of insects gathering in certain locations;
these insects are mostly males, and the swarm may serve the purpose of making
their location more visible to females.<ref name="Resh" />
Most adult diptera have their mouthparts modified to sponge up fluid. The
adults of many species of flies (e.g. _Anthomyia_ sp., _Steganopsis
melanogaster_) that feed on liquid food will regurgitate fluid in a behaviour
termed as "bubbling" which has been thought to help the insects evaporate
water and concentrate food[66] or possibly to cool by evaporation.[67] Some
adult diptera are known for kleptoparasitism such as members of the
Sarcophagidae. The miltogramminae are known as "satellite flies" for their
habit of following wasps and stealing their stung prey or laying their eggs
into them. Phorids, milichids and the genus _Bengalia_ are known to steal
food carried by ants.[68] Adults of _Ephydra hians_ forage underwater, and
have special hydrophobic hairs that trap a bubble of air that lets them
breathe underwater.[69]
*** Anti-predator adaptations
[Anti-predator adaptation]
Flies are eaten by other animals at all stages of their development. The eggs
and larvae are parasitised by other insects and are eaten by many creatures,
some of which specialise in feeding on flies but most of which consume them as
part of a mixed diet. Birds, bats, frogs, lizards, dragonflies and spiders
are among the predators of flies.<ref name=Collins>[last=Collins ] Many flies
have evolved mimetic resemblances that aid their protection. Batesian mimicry
is widespread with many hoverflies resembling bees and wasps,[70][71] ants[72]
and some species of tephritid fruit fly resembling spiders.[73] Some species
of hoverfly are myrmecophilous—their young live and grow within the nests of
ants. They are protected from the ants by imitating chemical odours given by
ant colony members.[74] Bombyliid bee flies such as _Bombylius major_ are
short-bodied, round, furry, and distinctly bee-like as they visit flowers for
nectar, and are likely also Batesian mimics of bees.[75]
In contrast, _Drosophila subobscura ,_ a species of fly in the genus
_Drosophila_, lacks a category of hemocytes that are present in other studied
species of _Drosophila_, leading to an inability to defend against parasitic
attacks, a form of innate immunodeficiency.[76]
** Human interaction and cultural depictions
[Human interactions with insects]
*** Symbolism
Flies play a variety of symbolic roles in different cultures. These include
both positive and negative roles in religion. In the traditional Navajo
religion, Big Fly is an important spirit being.[77][78][79] In Christian
demonology, Beelzebub is a demonic fly, the "Lord of the Flies", and a god of
the Philistines.[80][81][82]
Flies have appeared in literature since ancient Sumer.[83] In a Sumerian poem,
a fly helps the goddess Inanna when her husband Dumuzid is being chased by
_galla_ demons.<ref name="BlackGreen1992"/> In the Mesopotamian versions of
the flood myth, the dead corpses floating on the waters are compared to
flies.<ref name="BlackGreen1992"/> Later, the gods are said to swarm "like
flies" around the hero Utnapishtim's offering.<ref name="BlackGreen1992"/>
Flies appear on Old Babylonian seals as symbols of Nergal, the god of
death.<ref name="BlackGreen1992"/> Fly-shaped lapis lazuli beads were often
worn in ancient Mesopotamia, along with other kinds of fly-jewellery.<ref
name="BlackGreen1992"/>
In Ancient Egypt, flies appear in amulets and as a military award for bravery
and tenacity, due to the fact that they always come back when swatted at. It
is thought that flies may have also been associated with the departing spirit
of the dead, as they are often found near dead bodies. In modern Egypt, a
similar belief persists in some areas to not swat at shiny green flies, as
they may be carrying the soul of a recently deceased person.[84]
In a little-known Greek myth, a very chatty and talkative maiden named Myia
(meaning "fly") enraged the moon-goddess Selene by attempting to seduce her
lover, the sleeping Endymion, and was thus turned by the angry goddess into a
fly, who now always deprives people of their sleep in memory of her past
life.[85][86] In _Prometheus Bound_, which is attributed to the Athenian
tragic playwright Aeschylus, a gadfly sent by Zeus's wife Hera pursues and
torments his mistress Io, who has been transformed into a cow and is watched
constantly by the hundred eyes of the herdsman Argus:[87][88] "Io: Ah! Hah!
Again the prick, the stab of gadfly-sting! O earth, earth, hide, the hollow
shape—Argus—that evil thing—the hundred-eyed."<ref name="Stagman2010"/>
William Shakespeare, inspired by Aeschylus, has Tom o'Bedlam in _King Lear_,
"Whom the foul fiend hath led through fire and through flame, through ford and
whirlpool, o'er bog and quagmire", driven mad by the constant pursuit.<ref
name="Stagman2010"/> In _Antony and Cleopatra_, Shakespeare similarly likens
Cleopatra's hasty departure from the Actium battlefield to that of a cow
chased by a gadfly.[89] More recently, in 1962 the biologist Vincent Dethier
wrote _To Know a Fly_, introducing the general reader to the behaviour and
physiology of the fly.[90]
_Musca depicta_ ("painted fly" in Latin) is a depiction of a fly as an
inconspicuous element of various paintings. This feature was widespread in
15th and 16th centuries paintings and its presence may be explained by various
reasons.<ref name=eoi>_Encyclopedia of Insects_, p. 242 (see
https://books.google.com/books?id=Jk0Hym1yF0cC&dq=%22musca+depicta%22&pg=PA242)
Flies appear in popular culture in concepts such as fly-on-the-wall
documentary-making in film and television production. The metaphoric name
suggests that events are seen candidly, as a fly might see them.[91] Flies
have inspired the design of miniature flying robots.[92] Steven Spielberg's
1993 film _Jurassic Park_ relied on the idea that DNA could be preserved in
the stomach contents of a blood-sucking fly fossilised in amber, though the
mechanism has been discounted by scientists.[93]
*** Economic importance
Dipterans are an important group of insects and have a considerable impact on
the environment. Some leaf-miner flies (Agromyzidae), fruit flies
(Tephritidae and Drosophilidae) and gall midges (Cecidomyiidae) are pests of
agricultural crops; others such as tsetse flies, screwworm and botflies
(Oestridae) attack livestock, causing wounds, spreading disease, and creating
significant economic harm. See article: Parasitic flies of domestic animals.
A few can even cause myiasis in humans. Still others such as mosquitoes
(Culicidae), blackflies (Simuliidae) and drain flies (Psychodidae) impact
human health, acting as vectors of major tropical diseases. Among these,
_Anopheles_ mosquitoes transmit malaria, filariasis, and arboviruses; _Aedes
aegypti_ mosquitoes carry dengue fever and the Zika virus; blackflies carry
river blindness; sand flies carry leishmaniasis. Other dipterans are a
nuisance to humans, especially when present in large numbers; these include
houseflies, which contaminate food and spread food-borne illnesses; the biting
midges and sandflies (Ceratopogonidae) and the houseflies and stable flies
(Muscidae).<ref name=Resh>[last1=Resh ] In tropical regions, eye flies
(Chloropidae) which visit the eye in search of fluids can be a nuisance in
some seasons.[94]
Many dipterans serve roles that are useful to humans. Houseflies, blowflies
and fungus gnats (Mycetophilidae) are scavengers and aid in decomposition.
Robber flies (Asilidae), tachinids (Tachinidae) and dagger flies and balloon
flies (Empididae) are predators and parasitoids of other insects, helping to
control a variety of pests. Many dipterans such as bee flies (Bombyliidae)
and hoverflies (Syrphidae) are pollinators of crop plants.<ref name=Resh/>
*** Uses
_Drosophila melanogaster_, a fruit fly, has long been used as a model organism
in research because of the ease with which it can be bred and reared in the
laboratory, its small genome, and the fact that many of its genes have
counterparts in higher eukaryotes. A large number of genetic studies have
been undertaken based on this species; these have had a profound impact on the
study of gene expression, gene regulatory mechanisms and mutation. Other
studies have investigated physiology, microbial pathogenesis and development
among other research topics.[95] The studies on dipteran relationships by
Willi Hennig helped in the development of cladistics, techniques that he
applied to morphological characters but now adapted for use with molecular
sequences in phylogenetics.[96]
Maggots found on corpses are useful to forensic entomologists. Maggot species
can be identified by their anatomical features and by matching their DNA.
Maggots of different species of flies visit corpses and carcases at fairly
well-defined times after the death of the victim, and so do their predators,
such as beetles in the family Histeridae. Thus, the presence or absence of
particular species provides evidence for the time since death, and sometimes
other details such as the place of death, when species are confined to
particular habitats such as woodland.[97]
Some species of maggots such as blowfly larvae (gentles) and bluebottle larvae
(casters) are bred commercially; they are sold as bait in angling, and as food
for carnivorous animals (kept as pets, in zoos, or for research) such as some
mammals,[98] fishes, reptiles, and birds. It has been suggested that fly
larvae could be used at a large scale as food for farmed chickens, pigs, and
fish. However, consumers are opposed to the inclusion of insects in their
food, and the use of insects in animal feed remains illegal in areas such as
the European Union.[99][100]
Fly larvae can be used as a biomedical tool for wound care and treatment.
Maggot debridement therapy (MDT) is the use of blow fly larvae to remove the
dead tissue from wounds, most commonly being amputations. Historically, this
has been used for centuries, both intentional and unintentional, on
battlefields and in early hospital settings.[101] Removing the dead tissue
promotes cell growth and healthy wound healing. The larvae also have
biochemical properties such as antibacterial activity found in their
secretions as they feed.[102] These medicinal maggots are a safe and effective
treatment for chronic wounds.[103]
The Sardinian cheese casu marzu is exposed to flies known as cheese skippers
such as _Piophila casei_, members of the family Piophilidae.[104] The
digestive activities of the fly larvae soften the cheese and modify the aroma
as part of the process of maturation. At one time European Union authorities
banned sale of the cheese and it was becoming hard to find,[105] but the ban
has been lifted on the grounds that the cheese is a traditional local product
made by traditional methods.[106]
** Notes
[notelist]
** References
[30em]
** Further reading
- Blagoderov, V.A., Lukashevich, E.D. & Mostovski, M.B. (2002)). " Order Diptera (see http://palaeoentomolog.ru/New/diptera.html) ". In: Rasnitsyn, A.P. and Quicke, D.L.J. _The History of Insects_ , Kluwer pp.–227–240. < !--on Evolution-->
- Colless, D.H. & McAlpine, D.K. (1991). _Diptera (flies)_ , pp. 717–786. In: The Division of Entomology. Commonwealth Scientific and Industrial Research Organisation, Canberra (spons.), _The Insects of Australia_ . Melbourne University Press.
- Hennig, Willi . "Diptera (Zweifluger)". _Handb. Zool. Berl_ . 4 (2) (31):1–337. General introduction with key to World Families [de] .
- Oldroyd, Harold (1965). _The Natural History of Flies_ . W. W. Norton.
- Séguy, Eugène (1924–1953). _Diptera: recueil d'etudes biologiques et systematiques sur les Dipteres du Globe_ (Collection of biological and systematic studies on Diptera of the World). 11 vols. _Part of Encyclopedie Entomologique_ , Serie B II: Diptera.
- Séguy, Eugène (1950). _La Biologie des Dipteres_ .
- [last=Thompson ]
** External links
[Flies] [Diptera] [Diptera]
GENERAL
- The Diptera.info portal with galleries and discussion forums (see http://www.diptera.info)
- FLYTREE – dipteran phylogeny (see http://wwx.inhs.illinois.edu/research/flytree/) . [url=https://web.archive.org/web/20200413095925/https://www.inhs.illinois.edu/research/flytree/ ] .
- The Dipterists Forum (see http://www.dipteristsforum.org.uk/) – The Society for the study of flies
- BugGuide (USA and Canada) (see http://bugguide.net/node/view/55)
- The World Catalog of Fossil Diptera (see http://hbs.bishopmuseum.org/fossilcat/)
- The Tree of Life Project (see http://tolweb.org/tree?group=Diptera)
ANATOMY
- Anatomical Atlas of Flies at CSIRO (see https://ento.csiro.au/biology/fly/fly_atlas.html)
- DrawWing venation - identification aid (see http://www.drawwing.org/insects/diptera)
DESCRIBERS
- Authors of fly names (see http://hbs.bishopmuseum.org/publications/pdf/tr51.pdf) (PDF)
[Diptera] [Orders of Insects] [Insects in culture] [from=Q25312] [Authority
control]
<!-- Category:Pollinators not all pollinators --> Category:Anisian first
appearances Category:Extant Middle Triassic first appearances Category:Insects
in culture Category:Animal taxa named by Carl Linnaeus Category:Triassic
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Category:Triassic insects