The Urban Pantheist

Urban species #054: Little house fly Fannia canicularis

The little house fly (distinct from the common house fly Musca domestica) comes indoors to seek warmth, but prefers access to poultry manure to breed. It seems likely that its association with humans first occured when humans began to associate with chickens. While house fly larvae are familiar white maggots, the larva of this fly (also called the lesser house fly) is brown and has fleshy spines. The spines help the maggot propel itself through the soft manure that serves as its habitat and food. Flies are fairly adaptable animals, and if there is no chicken manure to live in, other decaying organic matter can suffice. Little house flies are considered pests, potentially carrying disease-causing bacteria from such matter to household surfaces. In some especially rare and gruesome cases, they have been implicated in urinary myiasis, and if you don't know what that means, you're probably the better for it.

Thanks to badnoodles for the identification.