What kind of fly is this?
July 31, 2009
They fly around in circles around each other in the middle of my covered patio. They fly slow and in a position where their rear ends are down much lower than their heads. They are smaller than normal house flies but much larger than fruit flies. They don’t care about fly paper. Nothing seems to get rid of them! What can I do to get rid of them? Thanks!
Your fly is Fannia canicularis, and it is commonly called the Little House Fly. Here is what Charles Hogue writes about the Little House Fly in his book Insects of the Los Angeles Basin: “This is the fly you see on hot summer days, in the garage, under trees, in doorways, and in other shaded places, hovering in the air, seeming never to land nor to have a place to go. this aimless flight immediately distinguishes this species from our other domestic flies, which fly with purposeful direction and frequently come to rest. Swarms of Little House Flies consist mainly of males; the females usually remain at rest nearby. the Little House Fly is 3/16 inch (5 mm) long, smaller that the House Fly, and it has a slightly more slender body. At rest its wigs overlap and are held together in parallel fashion. Although a maggot, the larva is atypical in that it is flat, oval in shape, and possesses numerous branched projections radiating from edges of the body. Breeding occurs in a wide variety of rotting organic materials. The larvae in our area show some preference for chicken manure, and the species abounds around poultry ranches. In urban areas breeding sites are similar to those of the other domestic flies.” The UC Davis Flies Management Guidelines web page has some good information on this species, and the Exploring California Insects page indicates: “Larvae breed in filth and are attracted by the smell of human urine.”
P.S. We will not be tagging your entry as Unnecessary Carnage, as we really don’t consider every insect that dies by human hands to warrant that distinction.