![Anthomyiidae (female) (10144905255)](https://upload.wikimedia.org/wikipedia/commons/b/bb/Anthomyiidae_%28female%29_%2810144905255%29.jpg)
Flies are
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s of the
order Diptera, the name being derived from the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
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
''Halteres'' (; singular ''halter'' or ''haltere'') (from grc, ἁλτῆρες, weights held in the hands to give an impetus in leaping) are a pair of small club-shaped organs on the body of two orders of flying insects that provide infor ...
, 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
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
including
horse-flies,
crane flies
Crane fly is a common name referring to any member of the insect family Tipulidae. Cylindrotominae, Limoniinae, and Pediciinae have been ranked as subfamilies of Tipulidae by most authors, though occasionally elevated to family rank. In the most ...
,
hoverflies
Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, whi ...
and others, although only about 125,000 species have
been described.
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 maneuverability in flight, and claws and pads on their feet enable them to cling to smooth surfaces. Flies undergo complete
metamorphosis
Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...
; 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 like ''
Metopia argyrocephala
''Metopia argyrocephala'' is a species of satellite flies in the family Sarcophagidae
Sarcophagidae () are a family of flies commonly known as flesh flies. They differ from most flies in that they are ovoviviparous, opportunistically depositi ...
'' are
ovoviviparous
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...
, opportunistically depositing hatched or hatching
maggots
A maggot is the larva of a fly (order Diptera); it is applied in particular to the larvae of Brachycera flies, such as houseflies, cheese flies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and crane flies.
Entomol ...
instead of eggs on
carrion
Carrion () is the decaying flesh of dead animals, including human flesh.
Overview
Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures, c ...
, 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
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps wi ...
and human importance. Flies are important pollinators, second only to the bees and their
Hymenoptera
Hymenoptera is a large order (biology), order of insects, comprising the sawfly, sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are Par ...
n relatives. Flies may have been among the evolutionarily earliest pollinators responsible for early plant
pollination
Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds ...
.
Fruit flies
Fruit fly may refer to:
Organisms
* Drosophilidae, a family of small flies, including:
** ''Drosophila'', the genus of small fruit flies and vinegar flies
** ''Drosophila melanogaster'' or common fruit fly
** ''Drosophila suzukii'' or Asian fruit ...
are used as
model organism
A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...
s in research, but less benignly,
mosquito
Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
es are
vectors for
malaria
Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...
,
dengue
Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. Symptoms typically begin three to fourteen days after infection. These may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic ...
,
West Nile fever
West Nile fever is an infection by the West Nile virus, which is typically spread by mosquitoes. In about 80% of infections people have few or no symptoms. About 20% of people develop a fever, headache, vomiting, or a rash. In less than 1% of ...
,
yellow fever
Yellow fever is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains – particularly in the back – and headaches. Symptoms typically improve within five days. In ...
,
encephalitis
Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, ...
, and other
infectious diseases
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...
; and
houseflies
The housefly (''Musca domestica'') is a fly of the suborder Cyclorrhapha. It is believed to have evolved in the Cenozoic Era, possibly in the Middle East, and has spread all over the world as a commensal of humans. It is the most common f ...
, commensal with humans all over the world, spread food-borne 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
Tsetse ( , or ) (sometimes spelled tzetze; also known as tik-tik flies), are large, biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus ''Glossina'', which are placed in their own family, Glo ...
and
screwworms cause significant economic harm to cattle. Blowfly larvae, known as
gentles, and other dipteran larvae, known more generally as
maggot
A maggot is the larva of a fly (order Diptera); it is applied in particular to the larvae of Brachycera flies, such as houseflies, cheese flies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and crane flies.
...
s, are used as
fishing bait
Fishing bait is any substance used to attract and catch fish, e.g. on a fishing hook. Bait items are both selected from and placed within the environment to achieve enhanced prey capture success. Traditionally, fishing baits are natural fish food ...
and as food for carnivorous animals. They are also used in medicine in
debridement
Debridement is the medical removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue. Removal may be surgical, mechanical, chemical, autolytic (self-digestion), and by maggot therapy.
In p ...
to clean wounds.
Taxonomy and phylogeny
Relationships to other insects
Dipterans are
endopterygote
Endopterygota (from Ancient Greek ''endon'' 'inner' + ''pterón'' 'wing' + New Latin ''-ota'' 'having'), also known as Holometabola, is a superorder of insects within the infraclass Neoptera that go through distinctive larval, pupal, and adult s ...
s, insects that undergo radical metamorphosis. They belong to the Mecopterida, alongside the
Mecoptera
Mecoptera (from the Greek: ''mecos'' = "long", ''ptera'' = "wings") is an order of insects in the superorder Endopterygota with about six hundred species in nine families worldwide. Mecopterans are sometimes called scorpionflies after their lar ...
,
Siphonaptera
Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, ar ...
,
Lepidoptera
Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...
and
Trichoptera
The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the b ...
. 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
__NOTOC__
Hippoboscidae, the louse flies or keds, are obligate parasites of mammals and birds. In this family, the winged species can fly at least reasonably well, though others with vestigial or no wings are flightless and highly apomorphic. As ...
(louse flies) have become secondarily wingless.
The
cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...
represents the current consensus view.
Relationships between subgroups and families
The first true dipterans known are from the
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...
(around 240 million years ago), and they became widespread during the Middle and
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...
.
Modern flowering plants did not appear until the
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
(around 140 million years ago), so the original dipterans must have had a different source of nutrition other than
nectar
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...
. 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. The
basal clade
In phylogenetics, basal is the direction of the ''base'' (or root) of a rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to th ...
s in the Diptera include the
Deuterophlebiidae
The fly genus ''Deuterophlebia'' is the sole member of the small monogeneric family Deuterophlebiidae or mountain midges. Adults have broad, fan-shaped wings, and males have extremely long antennae which they employ when contesting territories ov ...
and the enigmatic
Nymphomyiidae
The Nymphomyiidae are a family of tiny (2 mm) slender, delicate flies (Diptera). Larvae are found among aquatic mosses in small, rapid streams in northern regions of the world, including northeastern North America, Japan, the Himalayas, and ...
.
Three episodes of
evolutionary radiation
An evolutionary radiation is an increase in taxonomic diversity that is caused by elevated rates of speciation, that may or may not be associated with an increase in morphological disparity. Radiations may affect one clade or many, and be rapid ...
are thought to have occurred based on the fossil record. Many new species of lower Diptera developed in the
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
, about 220 million years ago. Many lower Brachycera appeared in the
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
, some 180 million years ago. A third radiation took place among the
Schizophora
The Schizophora are a section of true flies containing 78 families, which are collectively referred to as muscoids, although technically the term "muscoid" should be limited to flies in the superfamily Muscoidea; this is an example of informal, hi ...
at the start of the
Paleogene
The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...
, 66 million years ago.
The phylogenetic position of Diptera has been controversial. The monophyly of
holometabolous
Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult). Holometabolism is a synapomorphic trait of all insects in the superorder Endopterygot ...
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
Panorpida or Mecopterida is a proposed superorder of Endopterygota. The conjectured monophyly of the Panorpida is historically based on morphological evidence, namely the reduction or loss of the ovipositor and several internal characteristics, ...
, along with Lepidoptera (butterflies and moths), Trichoptera (caddisflies), Siphonaptera (fleas), Mecoptera (scorpionflies) and possibly
Strepsiptera
The Strepsiptera are an order of insects with eleven extant families that include about 600 described species. They are endoparasites in other insects, such as bees, wasps, leafhoppers, silverfish, and cockroaches. Females of most species never ...
(twisted-wing flies). Diptera has been grouped with Siphonaptera and Mecoptera in the Antliophora, but this has not been confirmed by molecular studies.
![Lutzomyia adiketis](https://upload.wikimedia.org/wikipedia/commons/e/eb/Lutzomyia_adiketis.jpg)
Diptera were traditionally broken down into two suborders,
Nematocera
The Nematocera (the name means "thread-horns") are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae. This group is paraphyletic and contains all flies but species from suborder Brachycera (the name means "sh ...
and
Brachycera
The Brachycera are a suborder of the order Diptera. It is a major suborder consisting of around 120 families. Their most distinguishing characteristic is reduced antenna segmentation.
Description
A summary of the main physical characteristics i ...
, 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.
Subsequent studies have identified the Nematocera as being non-monophyletic 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.
Diversity
![Mydas sp](https://upload.wikimedia.org/wikipedia/commons/b/b1/Mydas_sp..JPG)
Flies are often abundant and are found in almost all terrestrial habitats in the world apart from Antarctica. 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.
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.
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.
While most species have restricted distributions, a few like the housefly (''
Musca domestica
The housefly (''Musca domestica'') is a fly of the suborder Cyclorrhapha. It is believed to have evolved in the Cenozoic Era, possibly in the Middle East, and has spread all over the world as a commensal of humans. It is the most common fly ...
'') are cosmopolitan. ''
Gauromydas heros
''Gauromydas heros'' is a species of giant fly belonging to the family Mydidae. It is the largest species of the entire order of Diptera or true flies.
Distribution
This species has a Neotropical distribution (Brazil, Bolivia, Paraguay).
Descr ...
'' (
Asiloidea
The Asiloidea comprise a very large superfamily insects in the order Diptera, the true flies. It has a cosmopolitan distribution, occurring worldwide. It includes the family Bombyliidae, the bee flies, which are parasitoids, and the Asilidae, ...
), with a length of up to , is generally considered to be the largest fly in the world, while the smallest is ''
Euryplatea nanaknihali
''Euryplatea nanaknihali'' is the world's smallest fly, measuring in size.
Due to its small size, the viscosity of air is problematic for the insect, and even the smallest air currents are a large impediment. Scientists expressed amazement tha ...
'', which at is smaller than a grain of salt.
Brachycera are ecologically very diverse, with many being predatory at the larval stage and some being parasitic. Animals parasitised include
molluscs
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant taxon, extant species of molluscs are recognized. The number of fossil sp ...
,
woodlice
A woodlouse (plural woodlice) is an isopod crustacean from the polyphyleticThe current consensus is that Oniscidea is actually triphyletic suborder Oniscidea within the order Isopoda. They get their name from often being found in old wood. ...
,
millipede
Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a resu ...
s, insects,
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s,
[ and ]amphibian
Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...
s. 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. It is thought that some of the earliest pollinators of plants may have been flies.
The greatest diversity of gall forming insects are found among the flies, principally in the family Cecidomyiidae (gall midges). 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. 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.
The larvae of ''Megaselia scalaris
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 ...
'' (Phoridae) are almost omnivorous and consume such substances as paint and shoe polish. The ''Exorista mella (Walker)
''Exorista mella'' is a tachinid fly of the genus '' Ezorista'' within the family Tachinidae of the order Diptera. They are typically found in the United States and Canada. Within the U.S in the state of Arizona they have been found in both mo ...
'' fly are considered generalists and parasitoids of a variety of hosts. The larvae of the shore flies (Ephydridae) and some Chironomidae survive in extreme environments including glaciers (''Diamesa
''Diamesa'' is a genus of non-biting midges in the subfamily Diamesinae of the bloodworm family Chironomidae.
Species
The genus includes the following species:
* '' D. aberrata'' Lundbeck, 1898
* '' D. alata'' Storå, 1945
* '' D. alpina'' T ...
'' sp., Chironomidae), hot springs, geysers, saline pools, sulphur pools, septic tanks and even crude oil (''Helaeomyia petrolei
The petroleum fly, ''Helaeomyia petrolei'', is a species of fly from California, USA. The larvae feed on dead insects and other arthropods that become trapped in naturally occurring petroleum pools, making this the only known insect species tha ...
''). Adult hoverflies
Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, whi ...
(Syrphidae) are well known for their mimicry
In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. Often, mimicry f ...
and the larvae adopt diverse lifestyles including being inquiline
In zoology, an inquiline (from Latin ''inquilinus'', "lodger" or "tenant") is an animal that lives commensally in the nest, burrow, or dwelling place of an animal of another species. For example, some organisms such as insects may live in the h ...
scavenger
Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...
s inside the nests of social insects. Some brachycerans are agricultural pests, some bite animals and humans and suck their blood, and some transmit diseases.
Anatomy and morphology
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 antenna
Antenna ( antennas or antennae) may refer to:
Science and engineering
* Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves
* Antennae Galaxies, the name of two collid ...
e, and the mouthparts (the labrum, labium, mandible, and maxilla make up the mouthparts). The second tagma, the thorax
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...
, 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
''Halteres'' (; singular ''halter'' or ''haltere'') (from grc, ἁλτῆρες, weights held in the hands to give an impetus in leaping) are a pair of small club-shaped organs on the body of two orders of flying insects that provide infor ...
, which help to balance the insect during flight. The third tagma is the abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...
consisting of 11 segments, some of which may be fused, and with the 3 hindmost segments modified for reproduction.[ 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
The Vespidae are a large (nearly 5000 species), diverse, cosmopolitan family of wasps, including nearly all the known eusocial wasps (such as ''Polistes fuscatus'', ''Vespa orientalis'', and ''Vespula germanica'') and many solitary wasps. Each ...
wasp.
Flies have a mobile head with a pair of large compound eye
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which disti ...
s on the sides of the head, and in most species, three small ocelli
A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-l ...
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.[ 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.]
For visual course control, flies' optic flow field is analyzed by a set of motion-sensitive neurons. 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. 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. The H1 neuron The H1 neuron is located in the visual cortex of true flies of the order Diptera and mediates motor responses to visual stimuli. H1 is sensitive to horizontal motion in the visual field and enables the fly to rapidly and accurately respond to opt ...
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. The ocelli are concerned in the detection of changes in light intensity, enabling the fly to react swiftly to the approach of an object.
Like other insects, flies have chemoreceptor
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...
s that detect smell and taste, and mechanoreceptor
A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are innervated by sensory neurons that convert mechanical pressure into electrical signals that, in animals, ...
s 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, 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.[ Flies that feed on blood have special sensory structures that can detect ]infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
emissions, and use them to home in on their hosts, and many blood-sucking flies can detect the raised concentration of carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
that occurs near large animals. Some tachinid flies (Ormiinae) which are parasitoids of bush crickets, have sound receptors to help them locate their singing hosts.
Diptera have one pair of fore wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...
s on the mesothorax
The mesothorax is the middle of the three segments of the thorax of hexapods, and bears the second pair of legs. Its principal sclerites (exoskeletal plates) are the mesonotum (dorsal), the mesosternum (ventral), and the mesopleuron (lateral) on ...
and a pair of halteres
''Halteres'' (; singular ''halter'' or ''haltere'') (from grc, ἁλτῆρες, weights held in the hands to give an impetus in leaping) are a pair of small club-shaped organs on the body of two orders of flying insects that provide infor ...
, or reduced hind wings, on the metathorax
The metathorax is the posterior of the three segments in the thorax of an insect, and bears the third pair of legs. Its principal sclerites ( exoskeletal plates) are the metanotum (dorsal), the metasternum (ventral), and the metapleuron (lateral) ...
. A further adaptation for flight is the reduction in number of the neural ganglia
A ganglion is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympatheti ...
, and concentration of nerve tissue in the thorax, a feature that is most extreme in the highly derived Muscomorpha infraorder. Some species of flies are exceptional in that they are secondarily 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
The Strepsiptera are an order of insects with eleven extant families that include about 600 described species. They are endoparasites in other insects, such as bees, wasps, leafhoppers, silverfish, and cockroaches. Females of most species never ...
. In contrast to the flies, the Strepsiptera bear their halteres on the mesothorax and their flight wings on the metathorax. Each of the fly's six legs
A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element ...
has a typical insect structure of coxa, trochanter, femur, tibia and tarsus, with the tarsus in most instances being subdivided into five tarsomeres.[ At the tip of the limb is a pair of claws, and between these are cushion-like structures known as ]pulvilli Pulvilli are soft, cushionlike pads on the feet of insects and other arthropods, such as the housefly and ixodid ticks. They are located at the base of the claws (#2 in the figure at right).
The pulvilli function as an adhesive system. Their sti ...
which provide adhesion.
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. The last two or three segments are adapted for reproduction. Each segment is made up of a dorsal and a ventral sclerite
A sclerite (Greek , ', meaning "hard") is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instead it refers most commonly ...
, connected by an elastic membrane. In some females, the sclerites are rolled into a flexible, telescopic ovipositor
The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...
.[
]
Flight
Flies are capable of great manoeuvrability during flight due to the presence of the halteres. These act as gyroscopic
A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rotat ...
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. The wings of the fly are attached to two kinds of muscles, those used to power it and another set used for fine control.
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 saccade
A saccade ( , French for ''jerk'') is a quick, simultaneous movement of both eyes between two or more phases of fixation in the same direction.Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishi ...
s 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.
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 5 milliseconds to camera flashes by taking flight. In the past, the deer bot fly, ''Cephenemyia
The name deer botfly (also deer nose botfly) refers to any species in the genus ''Cephenemyia'' (sometimes misspelled as ''Cephenomyia'' or ''Cephenemya''), within the family Oestridae. They are large, gray-brown flies, often very accurate mimic ...
'', was claimed to be one of the fastest insects on the basis of an estimate made visually by Charles Townsend in 1927. 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.
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 2000 ft and over long distances. Some hover flies like ''Metasyrphus corollae'' have been known to undertake long flights in response to aphid population spurts.
Males of fly species such as ''Cuterebra
''Cuterebra'', or rodent bots, is a genus of bot flies that attack rodents and similar animals.
Etymology
The genus name ''Cuterebra'' is a blend of the Latin words ''cutis'' : skin and ''terebra'' : borer with apparent shortening of expected '' ...
'', many hover flies, bee flies (Bombyliidae) and fruit flies (Tephritidae) maintain territories within which they engage in aerial pursuit to drive away intruding males and other species. While these territories may be held by individual males, some species, such as '' A. freeborni'', form leks
A lek is an aggregation of male animals gathered to engage in competitive displays and courtship rituals, known as lekking, to entice visiting females which are surveying prospective partners with which to mate. A lek can also indicate an avail ...
with many males aggregating in displays. 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.
Life cycle and development
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
The Brachycera are a suborder of the order Diptera. It is a major suborder consisting of around 120 families. Their most distinguishing characteristic is reduced antenna segmentation.
Description
A summary of the main physical characteristics i ...
, 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.[
]
Some other anatomical distinction exists between the larvae of the Nematocera
The Nematocera (the name means "thread-horns") are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae. This group is paraphyletic and contains all flies but species from suborder Brachycera (the name means "sh ...
and the Brachycera
The Brachycera are a suborder of the order Diptera. It is a major suborder consisting of around 120 families. Their most distinguishing characteristic is reduced antenna segmentation.
Description
A summary of the main physical characteristics i ...
. 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, 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
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
. Nematoceran larvae generally have well-developed eyes and antennae, while those of Brachyceran larvae are reduced or modified.
Dipteran larvae have no jointed, "true legs", but some dipteran larvae, such as species of Simuliidae
A black fly or blackfly (sometimes called a buffalo gnat, turkey gnat, or white socks) is any member of the family Simuliidae of the Culicomorpha infraorder. It is related to the Ceratopogonidae, Chironomidae, and Thaumaleidae. Over 2,200 speci ...
, Tabanidae
Horse-flies or horseflies are true flies in the family Tabanidae in the insect order Diptera. They are often large and agile in flight, and only the female horseflies bite animals, including humans, to obtain blood. They prefer to fly in s ...
and Vermileonidae
The Brachyceran family Vermileonidae (the sole family in the infraorder Vermileonomorpha) is a small family of uncertain affinities and unusual biology. It includes fewer than 80 described species, most of them rare and with restricted distributi ...
, have proleg
A proleg is a small, fleshy, stub structure found on the ventral surface of the abdomen of most larval forms of insects of the order Lepidoptera, though they can also be found on other larval insects such as sawflies and a few other types of in ...
s adapted to hold onto a substrate in flowing water, host tissues or prey. The majority of dipterans are oviparous
Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...
and lay batches of eggs, but some species are ovoviviparous
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...
, 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. This is widespread in some families such as the Sarcophagidae. In ''Hylemya strigosa
''Hylemya'' is a genus of root-maggot flies in the family Anthomyiidae. There are at least 30 described species in ''Hylemya''.
Species
These 31 species belong to the genus ''Hylemya'':
*'' H. agrestis'' ( Robineau-Desvoidy, 1830)
*'' H. alcath ...
'' (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
Tsetse ( , or ) (sometimes spelled tzetze; also known as tik-tik flies), are large, biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus ''Glossina'', which are placed in their own family, Glo ...
(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
Thelytoky (from the Greek ''thēlys'' "female" and ''tokos'' "birth") is a type of parthenogenesis in which females are produced from unfertilized eggs, as for example in aphids. Thelytokous parthenogenesis is rare among animals and reported in a ...
parthenogenesis
Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development ...
, and some gall midge
Cecidomyiidae is a family of flies known as gall midges or gall gnats. As the name implies, the larvae of most gall midges feed within plant tissue, creating abnormal plant growths called galls. Cecidomyiidae are very fragile small insects us ...
s have larvae that can produce eggs (paedogenesis
Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compare ...
).
Pupa
The pupa
A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...
e 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
A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...
, 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.[
]
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. 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
The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, d ...
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.
Ecology
As ubiquitous insects, dipterans play an important role at various trophic level
The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it i ...
s 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.[
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. 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.]
Most adult diptera have their mouthparts modified to sponge up fluid. The adults of many species of flies (e.g. ''Anthomyia
''Anthomyia'' is a genus of flies in the family Anthomyiidae. They look rather like small houseflies, but commonly have conspicuous black-and-white patterning. This appears to be a mild form of aposematic
Aposematism is the advertising by a ...
'' 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 or possibly to cool by evaporation. Some adult diptera are known for kleptoparasitism
Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when foo ...
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
''Bengalia'' is a genus of blow flies in the family Calliphoridae with one authority considering the genus to belong to a separate family Bengaliidae.Lehrer, A.Z., 2003, Bengaliidae n. fam. Une nouvelle famille de Diptera Cyclorrhapha. Entom. Croa ...
'' are known to steal food carried by ants. Adults of '' Ephydra hians'' forage underwater, and have special hydrophobic hairs that trap a bubble of air that lets them breathe underwater.
Anti-predator adaptations
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. Many flies have evolved mimetic resemblances that aid their protection. Batesian mimicry
Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both. It is named after the English naturalist Henry Walter Bates, after his work on bu ...
is widespread with many hoverflies resembling bees and wasps, ants and some species of tephritid fruit fly resembling spiders. Some species of hoverfly are myrmecophilous
Myrmecophily ( , ) is the term applied to positive interspecies associations between ants and a variety of other organisms, such as plants, other arthropods, and fungi. Myrmecophily refers to mutualistic associations with ants, though in its ...
, 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. Bombyliid bee flies such as ''Bombylius major
''Bombylius major'' (commonly named the large bee-fly, the dark-edged bee-fly or the greater bee fly) is a parasitic bee mimic fly. ''B. major'' is the most common type of fly within the ''Bombylius'' genus. The fly derives its name from its clos ...
'' are short-bodied, round, furry, and distinctly bee-like as they visit flowers for nectar, and are likely also Batesian mimics of bees.
In contrast, ''Drosophila subobscura
''Drosophila subobscura'' is a species of fruit fly in the family Drosophilidae. Originally found around the Mediterranean, it has spread to most of Europe and the Near East. It has been introduced into the west coasts of Canada, the United Stat ...
,'' a species of fly in the genus ''Drosophila
''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species ...
'', lacks a category of hemocytes that are present in other studied species of ''Drosophila
''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species ...
'', leading to an inability to defend against parasitic attacks, a form of innate immunodeficiency.
Human interaction and cultural depictions
Symbolism
Flies play a variety of symbolic roles in different cultures. These include both positive and negative roles in religion. In the traditional Navajo
The Navajo (; British English: Navaho; nv, Diné or ') are a Native American people of the Southwestern United States.
With more than 399,494 enrolled tribal members , the Navajo Nation is the largest federally recognized tribe in the United ...
religion, Big Fly is an important spirit being. In Christian demonology
Christian demonology is the study of demons from a Christian point of view. It is primarily based on the Bible (Old and New Testaments), the interpretation of these scriptures, the writings of early Christianity philosophers, hermits and the ass ...
, Beelzebub
Beelzebub ( ; he, ''Baʿal-zəḇūḇ'') or Beelzebul is a name derived from a Philistine god, formerly worshipped in Ekron, and later adopted by some Abrahamic religions as a major demon. The name ''Beelzebub'' is associated with the Cana ...
is a demonic fly, the "Lord of the Flies", and a god of the Philistine
The Philistines ( he, פְּלִשְׁתִּים, Pəlīštīm; Koine Greek (LXX): Φυλιστιείμ, romanized: ''Phulistieím'') were an ancient people who lived on the south coast of Canaan from the 12th century BC until 604 BC, when ...
s.
Flies have appeared in literature since ancient Sumer
Sumer () is the earliest known civilization in the historical region of southern Mesopotamia (south-central Iraq), emerging during the Chalcolithic and early Bronze Ages between the sixth and fifth millennium BC. It is one of the cradles of c ...
. In a Sumerian poem, a fly helps the goddess Inanna
Inanna, also sux, 𒀭𒊩𒌆𒀭𒈾, nin-an-na, label=none is an List of Mesopotamian deities, ancient Mesopotamian goddess of love, war, and fertility. She is also associated with beauty, sex, Divine law, divine justice, and political p ...
when her husband Dumuzid
Dumuzid or Tammuz ( sux, , ''Dumuzid''; akk, Duʾūzu, Dûzu; he, תַּמּוּז, Tammûz),; ar, تمّوز ' known to the Sumerians as Dumuzid the Shepherd ( sux, , ''Dumuzid sipad''), is an ancient Mesopotamian god associated with shep ...
is being chased by '' galla'' demons. In the Mesopotamian versions of the flood myth
A flood myth or a deluge myth is a myth in which a great flood, usually sent by a deity or deities, destroys civilization, often in an act of divine retribution. Parallels are often drawn between the flood waters of these Mythology, myths and the ...
, the dead corpses floating on the waters are compared to flies. Later, the gods are said to swarm "like flies" around the hero Utnapishtim
Ut-napishtim or Uta-na’ishtim (in the ''Epic of Gilgamesh''), Atra-Hasis, Ziusudra ( Sumerian), Xisuthros (''Ξίσουθρος'', in Berossus) ( akk, ) is a character in ancient Mesopotamian mythology. He is tasked by the god Enki (Akkadian: E ...
's offering. Flies appear on Old Babylonian
Old Babylonian may refer to:
*the period of the First Babylonian dynasty (20th to 16th centuries BC)
*the historical stage of the Akkadian language
Akkadian (, Akkadian: )John Huehnergard & Christopher Woods, "Akkadian and Eblaite", ''The Camb ...
seals as symbols of Nergal
Nergal ( Sumerian: d''KIŠ.UNU'' or ; ; Aramaic: ܢܸܪܓܲܠ; la, Nirgal) was a Mesopotamian god worshiped through all periods of Mesopotamian history, from Early Dynastic to Neo-Babylonian times, with a few attestations under indicating hi ...
, the god of death. Fly-shaped lapis lazuli
Lapis lazuli (; ), or lapis for short, is a deep-blue metamorphic rock used as a semi-precious stone that has been prized since antiquity for its intense color.
As early as the 7th millennium BC, lapis lazuli was mined in the Sar-i Sang mines, ...
beads were often worn in ancient Mesopotamia, along with other kinds of fly-jewellery.
In ''Prometheus Bound
''Prometheus Bound'' ( grc, Προμηθεὺς Δεσμώτης, ''Promētheús Desmṓtēs'') is an Ancient Greek tragedy traditionally attributed to Aeschylus and thought to have been composed sometime between 479 BC and the terminus ante ...
'', which is attributed to the Athenian tragic playwright Aeschylus
Aeschylus (, ; grc-gre, Αἰσχύλος ; c. 525/524 – c. 456/455 BC) was an ancient Greek tragedian, and is often described as the father of tragedy. Academic knowledge of the genre begins with his work, and understanding of earlier Greek ...
, a horse-fly, gadfly sent by Zeus's wife Hera pursues and torments his mistress Io (mythology), Io, who has been transformed into a cow and is watched constantly by the hundred eyes of the herdsman Argus Panoptes, Argus: "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." 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. In ''Antony and Cleopatra'', Shakespeare similarly likens Cleopatra's hasty departure from the Battle of Actium, Actium battlefield to that of a cow chased by a gadfly. 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.
''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.[''Encyclopedia of Insects'']
p. 242
/ref>
Flies appear in popular culture in concepts such as fly-on-the-wall documentary-making in filmmaking, film and television production. The metaphoric name suggests that events are seen Candid photography, candidly, as a fly might see them. Flies have inspired the design of miniature flying robots. 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.
Economic importance
Dipterans are an important group of insects and have a considerable impact on the environment. Some Agromyzidae, leaf-miner flies (Agromyzidae), Tephritidae, fruit flies (Tephritidae and Drosophilidae) and Cecidomyiidae, gall midges (Cecidomyiidae) are pests of agricultural crops; others such as tsetse fly, tsetse flies, screwworm and Botfly, 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 mosquito
Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
es (Culicidae), Black fly, blackflies (Simuliidae) and drain fly, drain flies (Psychodidae) impact human health, acting as Vector (epidemiology), vectors of major tropical diseases.
Among these, ''Anopheles'' mosquitoes transmit malaria
Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...
, filariasis, and Arbovirus infection, 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 Ceratopogonidae, biting midges and sandflies (Ceratopogonidae) and the Muscidae, houseflies and stable flies (Muscidae). In tropical regions, eye flies (Chloropidae) which visit the eye in search of fluids can be a nuisance in some seasons.
Many dipterans serve roles that are useful to humans. Houseflies, blowflies and Mycetophilidae, fungus gnats (Mycetophilidae) are scavengers and aid in decomposition. Asilidae, Robber flies (Asilidae), Tachinidae, tachinids (Tachinidae) and Empididae, dagger flies and balloon flies (Empididae) are predators and parasitoids of other insects, helping to control a variety of pests. Many dipterans such as Bombyliidae, bee flies (Bombyliidae) and hoverflies
Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, whi ...
(Syrphidae) are Pollination, pollinators of crop plants.[
]
Uses
''Drosophila melanogaster'', a fruit fly, has long been used as a model organism
A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...
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, Regulation of gene expression, gene regulatory mechanisms and mutation. Other studies have investigated physiology, Pathogenesis, microbial pathogenesis and development among other research topics. 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.
Maggots found on corpses are useful to forensic entomology, 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.
Some species of maggots such as Calliphoridae, blowfly larvae (gentles) and bluebottle larvae (caster (maggot), casters) are bred commercially; they are sold as fishing bait, bait in angling, and as food for carnivorous animals (kept as pets, in zoos, or for research) such as some mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s, 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.
Fly larvae can be used as a biomedical tool for wound care and treatment. Maggot therapy, Maggot debridement therapy (MDT) is the use of Calliphoridae, 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. Removing the dead tissue promotes cell growth and healthy wound healing. The larvae also have Biochemistry, biochemical properties such as Antibiotics, antibacterial activity found in their secretions as they feed. These medicinal maggots are a safe and effective treatment for chronic wounds.
The Sardinian cheese casu marzu is exposed to flies known as cheese skippers such as ''Piophila casei'', members of the family Piophilidae. 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, but the ban has been lifted on the grounds that the cheese is a traditional local product made by traditional methods.
Hazards
Flies are a health hazard and are attracted to toilets because of their smell. The New Scientist magazine suggested a trap for these flies. A pipe acting as a chimney was fitted to the toilet which let in some light to attract these flies up to the end of this pipe where a gauze prevented escape to the air outside so that they were trapped and died. Toilets are generally dark inside particularly if the door is closed.
Notes
References
Further reading
* Blagoderov, V.A., Lukashevich, E.D. & Mostovski, M.B. 2002
Order Diptera
In: Alex Rasnitsyn, Rasnitsyn, A.P. and Quicke, D.L.J. ''The History of Insects'', Kluwer pp.–227–240.
* 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.
* Willi Hennig, Hennig, Willi Diptera (Zweifluger). ''Handb. Zool. Berl''. 4 (2) (31):1–337. General introduction with key to World Families. In German.
* Harold Oldroyd, Oldroyd, Harold ''The Natural History of Flies''. W. W. Norton. 1965.
* Eugène Séguy, Séguy, Eugène ''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. 1924–1953.
* Séguy, Eugène ''La Biologie des Dipteres'' 1950.
*
External links
General
The Systema Dipterorum Database site
The Diptera.info portal with galleries and discussion forums
FLYTREE – dipteran phylogeny
The Dipterists Forum
– The Society for the study of flies
BugGuide
The World Catalog of Fossil Diptera
The Tree of Life Project
Anatomy
Fly: Anatomical Atlas
at CSIRO
Drawing Wing venation
Describers
Authors of fly names
Systema Dipterorum Nomenclator
{{Authority control
Flies,
Diptera by classification,
Taxa named by Carl Linnaeus
Anisian first appearances
Extant Middle Triassic first appearances
Triassic insects
Triassic animals of North America
Triassic animals of South America
Insects in culture