The house fly is a danger to the health of man and animals principally because it carries and spreads diseases that may be in the materials it breeds in, feeds on, or walks on.
Flies breed and lay eggs in garbage, animal feces, and decaying organic materials. They land upon any kind of filth. Over 100 different species of pathogens can survive by the millions on their outside surface and hairs, and in their digestive and blood systems.
On the feet of houseflies are tiny pads covered with hair which ooze a sticky liquid. These sticky hairs not only enable them to cling to any surface, but also are responsible for bacteria sticking to the feet.
Flies regurgitate their stomach contents to liquefy their food and defecate often while feeding, depositing pathogens.
Flies have been implicated in the transmission of at least 65 human and animal diseases, most notably:
Flies can carry these germs from filthy breeding sites to the dinner table or spread some diseases within animal herds or flocks.
House flies can easily move one to two miles. Longer distances are possible but require unique circumstances.
Some 120,000 different kinds of flies are now known. Some estimates indicate there may be more than 1,000,000 species living today.
There are four stages: egg, larva, pupa and adult. The housefly can go through complete metamorphosis in as few as eight days, when temperatures are warm. Other fly species have similar life cycles.
An adult housefly lives only 2 to 4 weeks, depending upon the temperature.
An adult female housefly may lay up to 2,400 eggs in her lifetime. In just one day, the female can lay 100-150 eggs in various locations. Three days after a housefly lays eggs, it will mate again. There can be 10 to 12 generations in a single summer.
Flies lay eggs in manure, wet feed, garbage or any moist decaying organic matter.
Flies can only ingest liquid food. The mouth parts of a house fly are adapted for sponging up liquids; they cannot bite. They feed on solid food by regurgitating saliva on it. This liquefies the solid material which is then sponged up.
On the feet of houseflies are tiny pads covered with hair which ooze a sticky liquid. These sticky hairs enable them to cling to any surface.