What Is The Difference Between Face Flies And Eye Gnats, And Can Either Of These Fly Pests Transmit Disease To Humans Within Homes?
Horse flies, stable flies, black flies, and countless other fly species that resemble domestic house flies in both appearance and body-size belong to the Diptera order of insects. The Diptera order is composed of more than 100,000 species of two-winged insects, a small minority of which are frequent pests of homes. The most commonly controlled Dipteran fly pests of homes are house flies, fruit flies, drain flies, phorid flies and blow flies. Musca autumnalis is another Dipteran fly species that has become a widespread pest of homes throughout the US, and they are particularly abundant in the southern states.
autumalis is more commonly referred to as the “face fly” due to its habit of darting into the eyes, nose and mouth of cattle. This species is commonly mistaken for flies of the Liohippelates genus, which are frequently referred to as “eye gnats.” Adult female face flies lay their eggs on undisturbed manure piles located in open areas on ranches and farmland. Once larvae (maggots) hatch from these eggs, they consume nutrient-rich manure. After spending a short time developing on manure, maggots migrate between 25 and 30 feet away from the pile before diving beneath the ground to pupate into adults. Given the prevalence of cattle in Texas, face flies proliferate rapidly in the state, and they frequently transmit fecal matter to the mucous membranes of cattle, resulting in pink eye and other diseases. While face flies do not pose a significant health threat to humans, they do invade homes in massive numbers during the late summer, fall and early winter seasons in order to secure warm shelter for overwintering.
Much like face flies, the eye gnats mentioned above naturally consume mucous and other bodily fluids, but unlike face flies, eye gnats are not host-specific. That is, eye gnats feed on fluids secreted from wounds, eyes, nose, and other areas of humans as well as livestock and domestic pets. Naturally, eye gnats are also well known for transmitting fecal material to the mucous membranes and open wounds on humans and animals, resulting in pink eye and multiple other, more serious diseases in humans. However, eye gnats do not enter homes as readily as face flies are known to do during the colder months. That being said, eye gnats sometimes breed in moist soil and leaf litter in residential yards where they sometimes enter houses, and homeowners have been known to take costly measures to modify their homes to prevent eye gnats from transmitting disease indoors. Ultimately, however, the chances of contracting disease from indoor contact with eye gnats is highly improbable.
Have flies ever invaded your home in large numbers?