Regular house flies survive as larvae during winter by living in the decaying flesh of animals or other dead and decaying organisms that provide a suitable habitat during the colder months. While house flies survive by living in decaying flesh and maturing into adults when the weather becomes warmer, other flies, such as stone flies or may flies, survive the winter by living in water beneath the ice of streams, ponds and lakes.
Female flies will seek out warm areas to lay larvae, such as piles of fecal matter or garbage cans. Some flies will actually implant larvae into other living organisms, such as worms or live animals. The larvae, more commonly known as maggots, will feed as much as possible before shielding themselves in a protective cocoon. When the winter has passed and warmer weather has arrived, the maggots will come out of the cocoon to search for food and reproduce.