The metamorphosis of the fly is an interesting one; the fly undergoes many changes before it ends up being a fly, which is the last stage of its development. Therefore, flies do not turn into maggots, which is the second stage of a fly's development. At some point, however, and if all goes well, maggots turn into flies.
The Emergence of Maggots
Flies begin as eggs, which look like grains of rice. The eggs hatch between 8 and 20 hours after an adult fly lays them. What emerge from the eggs are larvae, also called maggots. Maggots can be half an inch long, are off-white and resemble worms. A maggot's head is the thin side. A visible mouth with a hook is found there. The other end of the maggot is thicker and displays two kidney-shaped markings. The maggot breathes from those kidney-shaped marks called spiracles.
A Maggot's Life
The maggot's role is to eat. Maggots begin eating whatever it is they are laid near and prefer rotting vegetables, manure and dead animals. After between 4 and 10 days of this feeding frenzy, maggots ready themselves for the next stage: pupa. The maggots typically migrate to a high and dry location to begin the pupa stage. The maggots make a reddish-brown shell around themselves. They stay in that protective environment, the pupa, for three to six days. They are developing into flies.
A Fly is Born
The fly emerges from the pupa, and its development is complete. Adult flies live between 15 and 30 days. Some female flies can begin laying eggs within a few hours after emerging from the pupa, and others need to be at least 2 days old. Female adult flies lay eggs throughout their lifespan.
Keep Flies and Maggots Away
If you do not wish to view the egg-maggot-pupa-fly development in your own home, keep your home as clean as possible. Don't leave food lying out on the countertop to thaw, and avoid leaving dirty dishes in the sink. Take out the garbage as soon as it's full. Clean up dog waste in your backyard.
The Useful Fly and Maggot
Flies serve a useful purpose. Maggots eat rotting flesh, and blowflies, one of the most common types, are the first insects to get to a corpse. Crime-scene detectives often use experts called forensic entomologists to help them solve murder cases. They can determine the time of death from when blowflies appear.
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