Houseflies are annoying pests that can quickly ruin an outdoor or indoor event. They carry some of the most destructive diseases, including anthrax, typhoid fever, dysentery and conjunctivitis. Yet despite all their flaws, they do have a purpose in this world -- more than just keeping manufacturers of flyswatters and fly sprays in business.

You might think of houseflies as any flies found in the home. But housefly is the common name for the most common fly found in homes, Musca domestica. Houseflies are about 3/8 inch long and have four dark stripes on their thorax. Little houseflies (Fannia canicularis) are smaller than houseflies and don’t have stripes. Other flies that can be commonly found in homes include cluster, blow, drain and picture-wing flies.

Houseflies can be used to estimate the time of death. Although a number of fly species will visit a corpse, houseflies are one of the first to visit a corpse after death. Any eggs they lay will hatch between 8 to 24 hours later. The maggots then become pupae, followed by adults, within three to six days. By looking at the age of the houseflies on the body, forensic scientists can estimate how long the body has been dead.

Maggot debridement therapy is when fly larvae (maggots) are used to clean wounds and bone infections. The maggots not only eat the dead tissue, but they also secrete ammonia and calcium carbonate, which disinfects the wound. Only a few fly species can be used for this purpose, and Musca domestica is one of them. Maggot therapy might seem like a new discovery, but it has been used for hundreds of years, including during the Civil War and by Napoleon’s surgeons.

Maggots are also used as a source of protein in commercial fish and livestock feed, known as magmeal, which is much cheaper than fishmeal. The percentage of crude protein ranges from 39 to 61 percent. It is also high in phosphorus, trace elements and B complex vitamins and not contain any anti-nutritional or toxic elements that are sometimes found in vegetable protein sources.