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Arthropoda: Insecta DIPTERA (Flies, Gnats, Mosquitoes) (Contact) Please
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Photos to enlarge & underlined links for details: GENERAL CHARACTERISTICS OF DIPTERA [Also
See: <Diptera Family Key>]
Diptera is a
large order having over 105,000 known species. There is considerable variation in their habits both as adults
or immature stages. Adults are
usually most active at dawn and dusk, and their food may include plant nectar
and animal blood. Some species are
predatory. The larvae may be entirely
scavengers or parasitic on humans and animals. Some larvae are predatory on other insects. A few groups, such as the Tachinid Flies
and some scavengers are beneficial in reducing many kinds of decomposing
organic matter. The scientific names of some medically
important Diptera have been changed several times over the years. For example, Service (2008) refers to the
American screwworm as Cochliomyia
hominivorax. However,
Matheson (1950) used the U. S. Dept. of Agriculture name Callitroga americana, and noted that the generic name
may sometimes be Chrysomya and Cochliomyia. Confusion with the so-called "Secondary Screwworm" Cochliomyia (= Callitroga) macellaria) is also common. The bloodsucking habits of many
species and filth flies can spread diseases of humans and animals, causing
considerable distress. An array of
diseases are associated with many species, some examples being Dengue Fever,
Filariasis, Encephalitis, Malaria and Yellow Fever. The disease relationships of flies to humans and mammals was
summarized by Matheson (1950) as (1) Bloodsucking carries pathogenic
organisms, (2) Nonbloodsucking flies may lay eggs or live larvae in sores or
wounds or on food, resulting in Myiasis disease,
(3) Both bloodsucking and nonbloodsucking flies can serve as intermediate
hosts of worms in humans and animals, and (4) Nonbloodsucking flies hovering
around mucous membranes or feeding on animal wastes or wounds can spread
disease organisms. The Diptera -- <General Characteristics> <Juveniles> -- have only one
pair of functional wings, hence their name meaning "Two-wing". The hind pair of wings is reduced in size
to highly sensory stumps or halteres.
The mouthparts are usually suctorial but sometimes piercing or biting,
and elongated to form a proboscis.
The prothorax and metathorax are small and fused with the large mesothorax. They have a complete metamorphosis. The larvae are often worm-like and always
without legs. Their head is usually
small and retracted. The pupa is
either free or enclosed in a puparium that is made of the hardened last
larval skin. [For terminology please
refer to: Glossary] This is a
very large and specialized order of insects. The adults are mostly diurnal,
feeding on the nectar of flowers, but a number are predaceous living on other
insects (e.g. the robber-flies), while some, e.g. tachinids, are parasites.
Several families have acquired blood-sucking habits, the representatives of
which are of great importance because they harbor and transmit pathogenic
organisms, causing such diseases as malaria, sleeping sickness,
elephantiasis, yellow fever and some cattle fevers.
The food tube
is formed mostly by the conjoined labrum-epipharynx and the hypopharynx, and
at the lower end of the labrum where the latter structures do not reach the
full distance. The overlapping sides
of the labial groove form a food tube.
In this way food collected at the median part of the pseudotracheal
membrane to which the pseudotracheae converge is brought into contact with
the food tube and so with the pharynx. Calliphora feed largely on fluids, but
in the presence of soluble solid food the groove solution is affected by
regurgitating alimentary fluid onto it. In other cases the prestomal teeth
can abrade temporarily dried surfaces and so bring the regurgitated fluids
more effectively into contact with the food material. When the labellae are
completely retracted food enters the wide-open food tube irrespective of the
pseudotracheae and the passage is then large enough for semisolid food or
even the eggs of helminths to enter (Borradaile & Potts,
1958). It has been
suggested that in the evolution of the Diptera there has been a trend towards
surface fluid feeding involving the loss of piercing stylets. However, there
are forms, closely related to the blowfly type in which mandibular and
maxillary stylets are lacking, but which can pierce the skins of mammals,
using the labium., e.g., the tsetse fly Glossina
and the stable fly Stomoxys. In
these cases the labium has become so rigid that it cannot be folded under the
head. Therefore, with its contained labrum-epipharynx and hypopharynx, it
extends stiffly forwards. The labellar apparatus is reduced and consists of
three small, stout lobes that bear rasping teeth, some of which represent the
prestomal teeth of Calliphora Diptera larvae are among the most
specialized of all insects. Legs have been entirely lost, and the head and spiracular system have
undergone varying degrees of reduction. Thus the most generalized larvae are
at the same time eucephalous, i.e.
with a complete head capsule, and peripneustic,
i.e. with the lateral spiracles on the abdomen, e.g. Bibio. In the most specialized forms, the
acephalous larva's head capsule is absent, e.g. Musca. Such acephalous larvae may either be amphipneustic, with only prothoracic and
posterior abdominal spiracles, or metapneustic,
where only two spiracles exist at the posterior end of the body.
The first instar larva of Musca is
metapneustic, subsequent instars being amphipneustic.
The Suborder
Orthorrhapha includes
those flies which are liberated by means of a longitudinal split in the
mid-dorsal line of the pupal case
Such flies do not have a ptilinum. Many of these, the Nematocera, have
slender antennae and usually pendulous maxillary palpi. Their larvae are eucephalous with
transversely biting mandibles and their pupae are free. To this series belong
the crane flies the larvae of which often damage cereal crops by
devouring their roots. The Culicidae are
the gnats and mosquitoes, the piercing proboscis of which has already been
described. Their wings that are fringed with scales further distinguish them.
Both larvae and pupae are aquatic, the former being metapneustic, the latter propneustic (with anterior spiracles
only). With the blood-sucking habit of these flies has evolved an association
with certain organisms that when, transmitted to humans, cause disease. Anopheles is concerned with the
transmission of malaria. Stegomyia transmits
the pathogen of yellow fever, while Culex
fatigans, a widely distributed tropical form, is a carrier of the
threadworm Wuchereria bancrofti, the
cause of elephantiasis.
From this
great assemblage of flies the Tabanidae or
gadflies, the mouthparts of which reference has already been made, are of
stout build and possess large eyes occupying a great part of the head
surface. Though a few transmit disease organisms (Chrysops dimidiata, as the vector of the nematode worm Loa loa, is responsible for calabar
swelling in the natives of West Africa), the majority are harmful chiefly
through the annoyance that their bites cause. Tabanid eggs are usually laid
on the leaves of plants overhanging water and their carnivorous larvae are either aquatic or ground-dwellers. The
robberflies (Asilidae) are large hairy flies with a proboscis that
is pointed to the rear. They feed on all kinds of insects that they paralyze
with their salivary fluid, and their legs, which are strong and equipped with
powerful claws, are well adapted for grasping the prey. The Empidae, flies of more slender build,
exhibit similar habits. Their larvae are terrestrial as are also those of the
preceding tabanids. The Suborder Cyclorrhapha are flies that emerge from a pupa which is enclosed
in the last larval skin or puparium, and the commonly transverse or circular
split in the latter, for release of the adult, gives the name to this
suborder. Therefore, it is really a
characteristic of the larvae that establishes the position of these flies in
the classification.
= = = = = = = = = = = = = = = = = = = = = = Detailed Morphology & Habits All species
of Diptera have two wings, the hind ones being reduced as remnants to halteres, which vibrate in flight to
act as a kind of gyroscope. This aids
them in very rapid and agile flight.
There are many aquatic larvae and their size ranges from minute to 16
centimeters long. The larvae are
maggots with very few appendages.
There is much mimicking of wasps and bees found in the order. The Diptera are important for their
annoyance to or feeding on humans and animals, being disease carriers and
some species are also injurious to plants. The order is
especially homogenous and is divided into to principal groups: 1. Nematocera
have antennae with distinct segments varying from 5-30. Most larvae have a distinct head capsule,
and the tentorium is developed so that the mandibles are opposable. 2. Brachycera
have antennae with a reduced 3-4 segments. The head capsule is very much lost, and the larvae are
worm-like maggots. The mouthparts are
developed as hooks and function by moving up and down. ---------------------------------------------- Mouthparts. -- There are three types found in adults: (1) nectar-feeding or sucking, (2)
sucking-lapping or sponging and (3) true blood sucking that are rasping
sucking. Simplified diagrams of these
types are shown in the following: Sucking (mosquito) Sponging (housefly Rasping-sponging (horsefly)
Larval Spiracular Arrangement. --
The spiracles of dipterous larvae may be arranged in either of four
ways: (1) peripneustic,-- lateral spiracles on the abdomen. (2) amphipneustic-- only prothoracic and
posterior abdominal spiracles present, (3) metapneustic-- only two spiracles are retained at the posterior
end of the body. (4) propneustic
-- lateral spiracles on the thorax. Pupal
Spiracles. -- In many species the spiracles
of pupae are moved to the head and thorax.
Here they appear as "pupal
horns." = = = = = = = = = = = = = = = = = = Selected Families of Diptera The
following discussion includes only the most common or important families of
Diptera. For greater detail please refer to Borror et al. (1989), and for an expanded
treatment of Diptera taxonomy with 125 families noted please see < 207 Families>.
Additional information on <Habits>, <Adults> and <Juveniles> is included when available. Nematocera = "long antennae." Culicidae. -- <Habits>; <Adults> & <Juveniles> -- The mosquitoes
are identifiable by having scales present as patches on their
wings. Only the female mosquito is
capable of sucking blood. The eggs
are laid in water and the pupae are capable of locomotion. There are two
groups: The Anophelines and
Culicines: Anophaline-- Anopheles spp. The wings
are spotted with definite patches of scales.
Their feeding position is at a 45-degree angle with the surface. The aquatic larvae feed horizontal with
the water film due to short terminal spiracles. Members of the genus are the sole vectors of malaria. They have long palpi and the eggs are laid
singly.
Culicine -- Culex spp. The
wings are not spotted and mostly entirely clear. The feeding position angle is primarily horizontal with the
surface. The aquatic larvae have
developed an elongated siphon and feed hanging down from the water surface at
an angle. Members of the genus
include the common pest mosquitoes, which carry many viruses such as yellow
fever, dengue, encephalomyelitis and the filarial worm. They have short palpi and the eggs are
laid in masses. --------------------------------- Tipulidae. -- <Habits>; <Adults> & <Juveniles> -- The crane flies, which contain the
largest number of species in the order,
are recognized by their long, spindly legs. They have the appearance of giant mosquitoes, but there are no
biting mouthparts in the adults. But
their appearance can upset humans who believe they are mosquitoes.
There is a
distinct V-shaped suture between the scutellum and scutum, and the adults
lack ocelli.
Their habitat
is primarily in damp areas with abundant vegetation, the larvae feeding in
dead and decaying vegetation. The
larvae of most species are aquatic or semi aquatic, and a few species feed on
living plant tissue and thereby may cause damage to crops. There are even a few predatory
species. Adults derive their
nourishment from nectar. Other than
their resemblance to mosquitoes, they are of no significant medical
importance. --------------------------------- Psychodidae. -- The moth flies and sand flies have abundant scales on
their wings. They are small to very
tiny insects with a large number of hairs on their bodies. When at rest adults may hold their wings
roof like over the body. They become
pests in households by emerging from drains where the larvae develop.
The habitat
is in moist shady areas but can also be found in drainages or sewers. Adults may occur in bathrooms that they
enter via sink drains. Larvae inhabit
decaying vegetable matter, moss, mud or water. There are
some medically important species that are vectors of various fevers, such as Leishmania, Pappataci fever,
Kala-azar and Oroya fever, especially in tropical
regions. --------------------------------- Chironomidae. -- <Habits>; <Adults> & <Juveniles> -- The midges also appear as very large
mosquitoes, but they do not bite humans or animals. The male antennae are usually conspicuously plumose. They are one of the most abundant and
important foods for fish in freshwater habitats worldwide. Most species are small and resemble
mosquitoes but lack scales on their wings and are without a long proboscis.
The larvae of
most members are aquatic, but several species also occur in decaying
vegetable matter, under tree bark or in moist soil. Most are scavengers.
Aquatic species usually form tubes or cases in which they are
protected. Some species are red in
color from the hemoglobin in their blood, hence their name, "bloodworms." The larvae may exist at varying depths in
water, and they swim by whipping their bodies similar to that of mosquitoes. Chironomids
pose an annoyance because of the male's swarming habits. However, they are an important food source
for freshwater fish and other aquatic inhabitants. Their large numbers can cause slight injury to humans when
flying into eyes and clothing. --------------------------------- Simuliidae. -- The black
flies or buffalo gnats
are biting flies that draw blood, especially around the head region of humans
and animals. Their color is generally
dark and they have short legs, broad clear wings with 4-5 veins. Their thorax is enlarged so that they
appear hunch-backed. The females are
bloodsuckers and can become vicious biters.
Their bites may cause swelling or bleeding. In some parts of North America blackflies become so numerous
that their attacks on livestock can cause death. Even humans have succumbed.
Indeed, in areas of heavy infestation some communities hold "Blackfly Festivals" in late
springtime to "celebrate" the end of the worst season of their
occurrence.
They are
associated with moving streams where the larvae develop underneath submerged
stones to which they attach themselves with a disk like sucker at the rear
end of their body.. The larvae
possess gills, attachment hooks and characteristic respiratory horns. Blackflies
are vectors of animal diseases, especially of poultry, in some parts of the
world. Diseases include onchocerciasis caused by a filarial
worm, which may result in partial or complete blindness. --------------------------------- Ceratopogonidae (Heleidae). -- <Habits>; <Adults> & <Juveniles> -- The biting
midges, punkies and no-see-ums are biting flies, with
the Genera Culicoides and Leptoconops
being especially problematic.
Most species are very small and stout, with rather broad wings that
they hold flat over their abdomen when resting. They are very pestiferous due to their habits of sucking blood
from animals including other insects. The bites often result in painful
swellings. Some species may be
recognized by their spotted wings.
The primary
habitat is along the seacoast and the shores of lakes and rivers. The larvae are aquatic or semiaquatic in
the sand, decaying vegetation or mud and in tree holes containing water. Breeding along the seacoast is possible in
the intertidal zone. Their habit of remaining close to the larval
developmental sites allows one to simply move a short distance away to avoid
being attacked. --------------------------------- Cecidomyiidae. -- <Habits>; <Adults> & <Juveniles> -- The gall midges or gall gnats have
larvae that occur in plant tissues.
One important
species, the Hessian Fly, Mayetiola destructor (Say), attacks wheat stems in the larval stage. It was introduced into North America
during the Revolutionary War with the Hessian insurgents. It is an important pest of wheat, barley,
rye and some wild grasses. Injury is
caused when the larvae burrow into stems, which results in stunted grain and
sometimes in the death of the plant.
The puparia overwinter in the grain. There are one or two generations per year. Control has involved planting wheat so
that it germinates after danger of infestation is past, deep plowing grain
stubble and reducing volunteer grain.
Their entry into food products can upset humans. The genus Miastor is one
of the few examples of paedogenesis. The larvae give birth to progeny. They produce eggs, which produce more
larvae that also may produce eggs, etc. = = = = = = = = = = = = = = Brachycera = "short antennae" includes larger flies with
large eyes. Tabanidae. -- <Habits>; <Adults> & <Juveniles> -- The horse flies and deer flies are vicious biters, and
they inject toxic saliva into their hosts. The larvae are aquatic and
predaceous. The adults may spread
diseases such as tularemia and
anthrax. Control measures involve draining
swampland where the flies breed.
--------------------------------- Bombyliidae. -- <Habits>; <Adults> & <Juveniles> -- The bee flies mimic bees in their
appearance. Their bodies are fuzzy
and they have fast flight habits.
They are beneficial as their larvae are predaceous on many insect
pests of economic importance.
However, their bee-like appearance upset humans who encounter them.
--------------------------------- Asilidae. -- <Habits>; <Adults> & <Juveniles> -- The robber
flies are predators of other insects both as larvae and adults. They have what looks like a beard
underneath their mouthparts. Adults
can catch their prey on the wing.
Their size and appearance produce scare among humans and domestic
animals.
--------------------------------- Syrphidae. -- <Habits>; <Adults> & <Juveniles> -- The flower flies and syrphid flies adults are heavy
bodied and have larvae that are predators of aphids especially. The larvae that frequent liquid animal
dung are distinguished by having a rat-like tail. The wing has a spurious vein that is not a true vein, but is
very useful in distinguishing species.
Adult
syrphids are widespread in most habitats where they frequent flowers
especially. Their habit of hovering
around plants often gives them appearance of wasps or bees, especially those
that are brightly colored. Therefore,
they produce a scare in humans and domestic animals. The larvae
have variable habits and appearances.
Many species are predators of aphids while others occur in the nests
of social insects such as termites, ants and bees. Other species inhabit decaying vegetation and rotting wood or
polluted aquatic habitats. The
maggots sometimes cause intestinal myiasis in humans. --------------------------------- Drosophilidae. -- <Habits>; <Adults> & <Juveniles> -- The pomace flies or small fruit flies have been used
extensively in research on genetics.
They have a very rapid life cycle, good taxonomic characters and giant
chromosomes. They are especially
attracted to fermenting plant juices.
Their size is small, only 3-4 mm. in length and usually yellow in
color. They can also contaminate food
thereby causing revulsion and distress to humans.
Their primary
habitat is around decaying fruits and vegetation, where they can cause some
damage. The larvae live in decaying
fruits and fungi where they feed primarily on yeasts that are present. Several species are parasites of
Lepidoptera caterpillars and mealybugs. --------------------------------- Anthomyiidae. -- <Habits>; <Adults> & <Juveniles> -- The root maggots feed on roots up the crown
of plants, which allows rots to enter the plants. The damage is especially severe in cold wet springs. Adults are attracted to decaying organic
matter. The adults lay their eggs
around the bases of plants and the larvae resemble housefly maggots. They overwinter in puparia.
Three very important species are the seed corn maggot, Hylemya (Delia) platura (Meigen), which
is a pest on any vegetable seedling, the onion maggot, Hylemya antiqua
(Meigen) that is a pest primarily on onion, and the cabbage maggot, Hylemya (Delia) radicum (Wiedemann) that primarily attacks
cruciferous plants. Their presence in
food products causes revulsion.
Control has involved the
incorporation of insecticide into the soil, the chemical treatment of seed,
the removal of culled vegetables from fields and the placement of cheesecloth
over seedbeds. --------------------------------- Chloropidae. -- (Oscinidae) -- <Habits>; <Adults> & <Juveniles> -- The chloropids and eye gnats are small shiny black or
yellow and black. They occur commonly
in meadows and grassy places. They
feed on grass stems and thus can be pestiferous on cereal crops. Some species are also scavengers and a few
are predators or parasites.
The genus Hippelates has
members that breed in decaying vegetation and animal dung and are strongly
attracted to human and animal secretions.
They have been noted to vector yaws and pinkeye diseases of
humans. Considerable research has
been done in California to combat this group of chloropids, either
culturally, chemically or biologically (see ch-20.htm) --------------------------------- Tephritidae (Trypetidae). -- The fruit
flies are a group that has many economically important species. The apple maggot and Mediterranean fruit
fly are just two examples. The
tephritids are fruit and vegetable feeders that may spread bacterial diseases
to the fruit on which they feed.
Their picturesque wings, which bear dark areas, identify the adults. Many species have been attacked with
biological control because of the great difficulty in using other means of
containment. They may also assume
medical importance when the larvae enter food products and upset humans as
well as initiating allergic responses (see bc-44.htm).
The Mediterranean fruit fly, Ceratitis capitata
(Wiedemann) has been imported repeatedly into North America and was twice
eradicated in 1926 and 1956. It
attacks citrus and other fruits in subtropical areas. Although California has experienced an
incipient population through the 20th Century, there has been little damage
to fruit reported there. Climatic
limitations have been thought to be the reason for this. Nevertheless, there have been repeated
eradication attempts with no data other than a reduction in bait trap
collections following widespread insecticidal treatments. The Apple maggot, Rhagoletis pomonella
(Walsh) tunnels into apples and other orchard fruits, while some other
species of Rhagoletis
are serious pests of cherries (see ent181). The Oriental Fruit fly, Dacus dorsalis
Hendel, invaded Hawaii during World War II.
It caused widespread damage to fruits growing on the islands. Biological control projects have been
launched to control this pest (see ch-82.htm) The Walnut Husk Fly, Rhagoletis completa
Cresson, invaded California from Texas causing widespread damage to the
walnut industry. Parasites from the
Davis Mountains area of West Texas have been imported for biological control
(see efl231). --------------------------------- Muscidae. -- The house flies, face flies, horn flies,
stable flies, tsetse flies and little house flies are all serious
pests of humans and animals. The
family may be identified by fleshy lobes, called squamae, located underneath the halteres on the sides of the
thorax. Many species are also
identified by chaetotaxy (arrangement of hairs on the body) The
importance of this family as serious pests and vectors of diseases has led to
several biological control projects to contain them (see bc-37.htm). The housefly, Musca
domestica L. lays
its eggs in decaying vegetable matter or animal excrement. .
The legless larvae are maggots with mouth hooks, caudal and thoracic
spiracles. Their filthy habits of
regurgitating saliva and food cause them to be vectors of typhoid, cholera,
and dysentery. etc. Either feces or
regurgitations cause the flyspecks often found on surfaces. Houseflies have been the target of
biological control in California and elsewhere (see ch-50.htm)
The stable fly, Stomoxys calcitrans
(L.) can breed in vegetable matter. The
adult's mouthparts are of the biting type, and the adults resemble
houseflies, but are grayer in color.
The hornfly, Haematobia
irritans (L.) is also similar to the housefly but much
smaller. It is a pest of cattle
primarily and breeds in cattle dung. Glossinidae. -- Tsetse flies,
Glossina spp.,
are confined to the African Continent where they are vectors of trypanosomes
that cause sleeping sickness and related diseases of humans and animals. These large, noisy flies may cause severe
bites on humans with resultant swellings. In East Africa they are especially
prevalent around streams.
Fanniidae. -- Little house
flies, Fannia spp.,
breed in large numbers in animal dung, and are especially numerous around
poultry farms where they breed in such high numbers as to invade surrounding
areas causing annoyance to residents.
They appear as small houseflies hovering in huge masses. They have been the target of biological
control in California and elsewhere (see ch-50.htm)
--------------------------------- Calliphoridae. -- <Habits>; <Adults> & <Juveniles> -- The blowflies,
bluebottle flies and screwworm flies are flesh
feeders. They lay masses of eggs in
dead animal carcasses. The presence
of these flies is indicative of a dead animal.
Screwworm
flies are attracted to wounds and some species are parasitic and able to
penetrate living flesh. They are
especially prevalent in southeastern North America. Females lay their eggs in wounds and the larvae invade
surrounding tissue. They are
especially serious pests of sheep.
Screwworms
were periodically effectively reduced in number by the liberation of males
that have been sterilized with radioactive cobalt. The females, which copulate just once, cannot produce progeny
if their mate is a sterilized male.
The flies were even completely eradicated from one island by the
deployment of this technique.
Medication of
wounds on animals is effective in control, but it is necessary to be on
continuous alert for new wounds. Wool maggots
are attracted to soggy and wet wool of sheep, especially around the rump
area. Precautionary control measures
involve clipping the wool. The maggots
of some screwworm species are able to clean-up dead flesh from wounds and
thereby cause rapid healing, especially for very deep wounds. --------------------------------- Sarcophagidae. -- <Habits>; <Adults> & <Juveniles> -- The flesh flies are similar to
Calliphoridae, but they are usually black or gray with stripes on their
thorax. Adults feed on sweet foods
such as flower nectar, fruit juice and honeydew.
Their larvae
show diverse habits, but most feed on animal material, with many being
scavengers. Some species are
scavengers, some are parasites of other insects and a few are parasites of
vertebrates that develop in skin wounds. --------------------------------- Tachinidae. -- <Habits>; <Adults> & <Juveniles> -- The tachinid flies are a large family
with representatives widespread in almost every habitat. They are valuable in natural control
because their larvae are parasitic on other insects. Their appearance and movements can upset
humans.
Tachinids
tend to lay their eggs on the body of their host. The larvae then burrow into the host to feed internally. They leave the host to pupate. Some species that lay their eggs on plant
foliage give rise to flattened larvae that are known as planidia. These remain on foliage until they are
able to attach themselves to a host when it comes near. In other species a host caterpillar before
hatching must ingest the eggs. These
larvae then feed on the internal organs. --------------------------------- Oestridae (Gastrophilidae). -- The warble
flies and botflies lay
their eggs on the hair of the rear legs of animals. The larvae burrow into the shanks, pass into the intestines,
burrow through the intestinal wall and eventually come to lie in the back of
the animal just under the skin. This
results in the hide being reduced in value because of ensuing fly exit holes
in the back. Pupation occurs in the
ground. Systemic insecticides have
been used for control.
Several
serious botflies, Gasterophilus spp.,
are discussed as follows: Horse Botflies, -- These flies produce eggs that
are swallowed by horses, after which the hatched spiny larvae attach
themselves to the wall of the horse's intestines. Horses lose energy and weight following infection. The flies overwinter in their alimentary
canal and the larvae mature in late winter or spring. The maggots attach themselves to the
stomach lining. They detach in late
spring and burrow into the soil to pupate.
Adults emerge in early summer but do not bite.
Common Botflies. -- Female flies can lay over 800 eggs on hairs in the
upper portion of the front legs of animals.
The animal licks the area and the eggs hatch. The larvae live a short while in the
animal's mouth and then are swallowed. Throat Botflies. -- Eggs are laid on the throat, but stimulation by
licking is not required here. The
larvae hatch out and crawl into the animal's mouth where they feed along the
gum line. Later the larvae enter the
stomach where feeding continues. Nose Botflies. -- This is the most serious of all the botflies, although
it is less common. Eggs are laid on
the upper lip of the animal. Moisture
there induces hatching. The larvae
then tunnel through the lips and into the mouth, causing severe
soreness. They are then swallowed and
enter the digestive tract. Control
has involved keeping animals stabled during daytime, using repellent
materials, sponging off areas with warm water and phenol, and providing
internal dosages of carbon disulfide. ------------------------------ Cattle Grubs and Ox Warbles (Hypoderma
spp.). -- Included are the Heel Fly and Bomb Fly. They are primarily pests of cattle, often
infesting over 75 percent of a herd.
The animals will lose weight, the hides are ruined and milk production
falls.
During their
life history in winter the larvae exist as cysts in the backs of animals
under their hide. They feed on
secretions from the irritations they cause.
A breathing hole is cut through the hide. Maturity is in late winter.
In springtime the larvae wiggle through the breathing hole and drop to
the soil where they pupate. Adult
flies are found in pastures through the summer and into autumn. Adult flies
lay eggs on the belly or legs of the animals, which become very annoyed by
their buzzing. Bomb flies prefer to
lay the eggs in sunshine on the belly and legs, while heel flies lay eggs in
the shade on the heels. Ensuing
larvae of bomb flies go directly to the back of animals, while larvae of heel
flies migrate to the gullet area to feed, after which they move up to the
back. Sheep Nose or Bot Flies, e.g., Oestrus ovis L.) --
These attack sheep, goats, deer and rarely humans. They are responsible for nasal infections, insanity, blindness
and even death. The larvae are
deposited in the nostrils of animals after which they migrate to the brain
area through the sinuses. They remain
several months in the area underneath the horns. They then wiggle out through the nostrils and pupate in the ground. Containment involves painting the animal's
nostrils with a repellant, such as pine tar, and to run sheep into dark sheds
in daytime at the worst time of the year.
--------------------------------- Hippobosidae. -- The louse flies and sheep
ked eggs and larvae develop within the mother fly and are nourished
from glands. The "nits"
pupate immediately upon being released.
The adults are either winged or wingless. The winged species are dark brown and about the size of small
houseflies and are common on birds.
The sheep ked, Melophagus ovinus
(L.) is wingless and parasitic on sheep.
Control of
these flies is relatively simple.
Subjecting animals to various sprays, dips and dusts in autumn is
usually adequate. Also by removing
sheep from old pens and spraying the pen area with insecticides eliminates
the flies. -------------------------------- Biological Control Projects for
Medically Important Diptera Aquatic Diptera <ch-118.htm> Aquatic Midges <aqamidge.htm> Bush Fly, Musca sorbens Wiedemann <ch-119.htm> Chironomid Midges, Chironomus spp. <ch-19.htm> Chloropid Gnats (Hippelates, Leptoconops, etc.) <ch-20.htm> Flies in Accumulated Wastes, Musca domestica L., Stomoxys spp., etc <ch-50.htm> Flies in Field Dung, Musca autumnalis, Musca vetustissima, Haematobia spp. <ch-51.htm> Mosquitoes, Culex, Aedes,
Anopheles, etc. <ch-74.htm> American Mosquito Control Association North American Dipterist Society Tachinidae Overview = = = = = = = = = = = =
= = = Key References: <medvet.ref.htm> <Hexapoda> Brown, B.V. 2001. Flies,
gnats, and mosquitoes.. In Encyclopedia of Biodiversity, Volume 2. Academic Press. pp.
815-826. Howard, L. Ol, H. G. Dyar & F. Knab. 1912-1917. The mosquitoes of North and Central America and the West
Indies. Carnegie Inst. Wash., Pub. 387. Hurlbut, H. S. 1924.
A study of the larval chactotaxy of Anopheles
walkeri Theobald. Amer. J. Hyg.
4: 188-212. Hurlbut, H. S. 1938.
Further noes on the overwintering of the eggs of Anopheles walkeri with a description of
the eggs. J. Parasit. 24: 521-26. James, S. P. 1920.
Malaria at home and abroad. London Publ. James, S. P. 1926.
Epidemiological results of a laboratory study of malaria in
England. Trans. Roy. Soc. Trop. Med.
Hyg. 20: 143-65 James, S. P.
1927. History of a group of Anopheles mosquitoes infected with Plasmodium vivax (Grassi &
Feletti). Abb. Gebiete
Auslandsk., Hamburg Univ. 26, Ser. D
(Med.): 220-22. Legner, E. F. 1995. Biological control of Diptera of medical and veterinary
importance. J. Vector Ecology 20(1):
59-120. Legner,
E. F. 2000. Biological control of aquatic
Diptera. p. 847-870. Contributions to a Manual of Palaearctic
Diptera, Vol. 1, Science Herald, Budapest. 978 p. Matheson, R. 1950. Medical Entomology. Comstock Publ. Co, Inc. 610 p. Oldroyd, H. 1964. The
natural history of flies. Weidenfeld and Nicolson, London. 324 pp. Service, M. 2008.
Medical Entomology For Students.
Cambridge Univ. Press. 289 p Skevington, J.H. &
P. T. Dang, eds. 2002. Exploring the diversity of flies (Diptera). Biodiversity
3(4): 3-27. Walton, W. R. 1909. An illustrated
glossary of chaetotaxy and anatomical terms used in describing Diptera. Ent. News 10: 307-19 |
FURTHER DETAIL = <Entomology>, <Insect Morphology>, <Identification Keys>