· The house fly, Musca
domestica, may be the most common insect people encounter. But how much do
you really know about the house fly? Here are 10 fascinating facts about house
flies you may not know.
HOUSE FLIES
LIVE ALMOST EVERYWHERE THERE ARE PEOPLE.
· Though they are believed to be native
to central Asia, house flies now inhabit nearly every corner of the globe. With
the exception of Antarctica and perhaps a few islands, house flies live
everywhere people do.
· House flies are synanthropic organisms,
meaning they benefit ecologically from their association with humans and our
domesticated animals. As humans throughout history traveled to new lands by
ship, plane, train, or horse-drawn wagon, house flies were their travel
companions. Conversely, house flies are rarely found in the wilderness or in
places where humans are absent. Should humankind cease to exist, house flies
might share our fate.
HOUSE FLIES
ARE RELATIVELY YOUNG INSECTS ON THE EVOLUTIONARY TIMELINE.
· As an order, true flies are
ancient creatures that appeared on Earth during the Permian period, over 250
million years ago. But house flies seem to be relatively young, compared to
their Dipteran cousins. The earliest known Musca fossils are
only 70 million years old. This evidence suggests the closest ancestors of
house flies appeared during the Cretaceous period, just before the infamous
meteorite fell from the sky and, some say, triggered the
extinction of the dinosaurs.
HOUSE FLIES
MULTIPLY QUICKLY.
· Were it not for the reproductive
limits imposed by subpar environmental conditions and predation, we'd be buried
over our heads in house flies. Musca domestica has a short
life cycle – just 6 days if conditions are right – and a female house fly lays
an average of 120 eggs at a time.
· Scientists once calculated what would
happen if a single pair of flies were able to reproduce without limits or
mortality to their offspring. The result? Those two flies, in just 5 months'
time, would produce 191,010,000,000,000,000,000 house flies, enough to cover
the planet several meters deep.
HOUSE FLIES
DON'T TRAVEL VERY FAR, AND TAKE THEIR TIME GETTING WHERE THEY'RE GOING.
· Hear that buzzing sound? That's the
rapid movement of a house fly's wings, which can beat up to 1,000 times per
minute. That's no typo. It may surprise you to learn, then, that they're
generally slow fliers, maintaining a speed of about 4.5 miles per hour. House
flies move when environmental conditions compel them to do so. In urban areas,
where people live in close proximity and there is plenty of garbage and other
filth to be found, house flies have small territories and may only fly 1,000
meters or so. But rural house flies will roam far and wide in search of manure,
covering up to 7 miles over time. The longest flight distance recorded for a
house fly is 20 miles.
HOUSE FLIES
MAKE THEIR LIVING IN FILTH.
· House flies feed and breed in the
things we revile: garbage, animal dung, sewage, human excrement, and other
nasty substances.
· Musca domestica is probably the best known and most
common of the insects we collectively refer to as filth flies.
In suburban or rural areas, house flies are also plentiful in fields where fish
meal or manure is used as fertilizer, and in compost heaps where grass
clippings and rotting vegetables accumulate.
HOUSE FLIES
ARE ON AN ALL-LIQUID DIET.
· House flies have sponge-like mouthparts,
which are good for soaking up liquefied substances but not for eating solid
foods. So, the house fly either seeks out food that is already in puddle form,
or it finds a way to turn the food source into something it can manage. This is
where things get kind of gross. When a house fly locates something tasty but
solid, it regurgitates onto the food (which may be your food,
if it's buzzing around your barbecue).
· The fly vomit contains digestive
enzymes that go to work on the desired snack, quickly predigesting and
liquefying it so the fly can lap it up.
HOUSE FLIES
TASTE WITH THEIR FEET.
· How do flies determine that something
is appetizing? They step on it! Like butterflies,
house flies keep their taste buds on their toes, so to speak. Taste receptors,
called chemosensilla, are located at the far ends of the fly's tibia and tarsa
(in simpler terms, the lower leg and foot). As soon as they land on something
of interest – your garbage, a pile of horse manure, or perhaps your lunch –
they start sampling its flavor by walking around.
HOUSE FLIES
TRANSMIT A LOT OF DISEASES.
· Because house flies thrive in places
that are teeming with pathogens, they have a bad habit of carrying
disease-causing agents with them from place to place. A house fly will land on
a pile of dog poop, inspect it thoroughly with its feet, and then fly over to
your picnic table and walk around on your hamburger bun for a bit. Their food
and breeding sites are already overflowing with bacteria, and then they vomit
and defecate on them to add to the mess. House flies are known to transmit at
least 65 diseases and infections, including cholera, dysentery, giardiasis,
typhoid, leprosy, conjunctivitis, salmonella, and many more.
HOUSE FLIES
CAN WALK UPSIDE DOWN.
· You probably knew that already, but
do you know how they perform this gravity-defying feat? Slow motion video shows
that a house fly will approach a ceiling by executing a half roll maneuver, and
then will extend its legs to make contact with the substrate. Each of the house
fly's legs bears a tarsal claw with a sticky pad of sorts, so the fly is able
to grip almost any surface, from smooth window glass to a ceiling.
HOUSE FLIES
POOP A LOT.
· There's a saying, "Never poop
where you eat." Sage advice, most would say. Because house flies live on a
liquid diet (see #6), things move rather quickly through their digestive
tracts. Nearly every time a house fly lands, it defecates.
· So in addition to vomiting on
anything it thinks might make a tasty meal, the house fly almost always does
poop where it eats. Keep that in mind next time one touches down on your potato
salad.