Face fly Musca autumnalis DeGeer

by Jeffrey M. Cumming

Distribution Identification Biology Damage, Economic Impact & Management

Distribution:

Musca autumnalis is widely distributed throughout Europe, central Asia and parts of Africa. The species was introduced into North America in the 1940's, and has spread throughout most of the region, south of 53°N latitude excluding Arizona, New Mexico, Texas, Louisiana, and Florida.

Identification:  

Face flies feed on various secretions (including blood) from wounds and orifices of livestock, particularly around the eyes and muzzle of the animal [fig.]. Adults average about 7 - 8 mm long and are the size of a large housefly. They are gray in colour with 4 dark stripes on the thorax, with a primarily gray black patterned abdomen; in the female the abdomen is dark above with little yellow or orange on the sides [fig.], in the male the sides of tergite 2 and 3 are generally yellowish-orange to orange-brown. Mouthparts form a fleshy proboscis, which is not visibly extended forwards from the head as a long slender piercing structure. In the male the eyes almost touch above [fig.].

Eggs of the face fly possess a terminal respiratory horn [fig.], unlike the eggs of most other muscid species.

Larvae (3rd instar) are yellowish white maggots about 12 mm long. They are cylindrical and taper anteriorly. Two narrowly to moderately separated "D"-shaped spiracles are located on the rear end. Each is outlined by a thin, dark band, with 3 sinuous-shaped slits surrounding a button located towards the inner edge.

Puparia are whitish to greyish in colour and 5 - 7 mm long. The respiratory horns found along the posterior border of the 4th segment are small but visible, and are darkened basally. The posterior spiracles are black with 3 sinuous-shaped yellow slits; the spiracles are "D"-shaped and narrowly to moderately separated from each other.

Biology:

Face flies are generally found outdoors, usually around the eyes and nose of livestock [fig.]. They only enter buildings during the fall to look for overwintering sites. Female flies feed on secretions from the wounds and orifices of cattle and horses. They may create superficial lesions with sharp prestomal teeth on their mouthparts in attempts to feed on blood. Females lay eggs in fresh cattle manure, arranging each egg so that its respiratory horn [fig.] projects above the surface of the pat. Larvae complete development and pass through 3 instars within approximately 1 week. Mature larvae move into the surrounding soil to pupariate and emerge as adults 1 to 2 weeks later. The entire life life cycle from egg to adult is usually completed within 2 to 3 weeks (17 days at 25°C), with a number of generations occurring throughout the summer. Face flies overwinter as adults in large clusters in barns and other buildings.

Damage, Economic Impact & Management:

Feeding by face flies on the eye of cattle irritates and damages the tissue, allowing for the transmission of pinkeye and other eye diseases. Presence of face flies around the eyes and muzzle causes distress in cattle and horses. Although cattle respond by aggregating and bunching (with less time spent grazing), weight gains and milk yields appear not to be significantly affected.

Current management practices primarily involve applying pesticides to cattle.

More detailed information on the economic impact and management of face flies can be found at the following sites: