The face fly is a tough-to-manage pest of pastured cattle. In addition to the irritation it causes while feeding, it can play a major role in the spread of the bacteria that causes pinkeye within and between herds.
Female face flies visit cattle for short periods of time to get the protein they need for egg production. Sources include tears, mucus and saliva of cattle. The fly’s sponging mouthparts have small, abrasive teeth that scratch tender tissue around the eye to stimulate tear flow; the tears are then blotted up by the fly’s specialized mouthparts.