House
flies are a well-known and common insect
species. They are prevalent on farms and
in homes. Their presence transmits
disease and tries the patience of most
people.
House flies are small, two-winged
insects. Their bodies are gray-colored
and they have two velvety stripes, which
are silver above and gold below. They
measure approximately 1/4"-1/2" long.
Adult female flies begin laying eggs
just a few days after hatching from
their pupal stage. Over the course of
their lifetime, flies usually lay 5 to 6
batches of 75-100 small, white, oval
eggs. After 12 to 24 hours, the eggs
hatch into larvae or, as they are more
commonly known, maggots. These maggots
are cream-colored and burrow into the
material on which they are hatched.
After 4 to 7 days, the larvae contract
and harden into a shell in which the
pupae form. Once the pupae emerge as
flies, they can restart the mating and
reproduction process within a few hours.
Flies have the ability to reproduce many
young very quickly. Under ideal warm
conditions, two life cycles may be
completed within a month. If 75 to 100
eggs are yielded per egg deposit, one
fly can produce at least 150 flies by
the following month. Populations of
flies are always highest during the
early fall months. In some areas,
populations may develop indoors
throughout the winter.
Eggs are laid in warm, moist material.
Examples are animal manure, human
excrement, garbage, decaying vegetable
material, and areas on the ground
contaminated with these materials. The
fact that flies are in such frequent
contact with these materials make them
health hazards. After flies have been
around these materials, they very often
will enter homes and taint your food,
dishes, counters and living spaces with
contaminants and diseases that cover
their bodies and mouthparts.
Many people have heard stories about
maggots getting into open wounds and
wreaking havoc. Urban legend?
Unfortunately not. Myiasis is an
infection of fly larvae in animals that
is very common in sheep, cattle, and
deer. It can also happen to humans with
ulcerated skin. An adult fly will lay
eggs on a wound (a warm, moist place as
described above), after which they hatch
and burrow into the skin. This burrowing
may cause boil-like lesions, or the
maggots may wander through the body and
cause damage to various organs.
Intestinal myiasis occurs when humans
ingest food containing the eggs of
larvae.
Flies are attracted to a wide variety of
food material. They have mouthparts that
restrict them to consuming only liquids.
To digest solid foods, they regurgitate
saliva to liquefy the food, thereby
making it easy to ingest and pass into
the digestive track.
During daylight hours, flies can be
found in a number of places indoors and
outdoors. Indoors, they may be found
resting on ceilings, floors, and walls.
During the night hours, flies will rest
on ceilings, electric wires, and light
cords. Outdoors, plants, fences, wires,
garbage, and the ground all provide
suitable locations for houseflies. At
night, flies rest chiefly on fences,
electric wires, edges of buildings and
on plants. In all situations, flies
prefer to rest on corners and edges of
surfaces, and on thin objects such as
wires and strings.
Flies are an important health hazard not
to be overlooked. To illustrate this
point, they make cockroaches seem barely
a health issue.
As mentioned earlier, flies transmit a
whole host of diseases because they
travel straight from filth into the
living spaces of humans. Examples of
these diseases are typhoid, dysentery,
cholera, hookworm, tapeworm, bacillary,
infantile diarrhea, roundworm, and
whipworm. Pathogenic organisms are
picked up from sources such as garbage,
sewage, and other filth. Then, through
their vomitus and feces, they transmit
these organisms onto human and animal
food and throughout living spaces.
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