Adult females pierce the skin and suck blood, causing great annoyance to animals, interrupting grazing, with loss of weight gain in beef cattle and reduction of milk yields from dairy cattle. Cattle and horses will often seek shelter in dense bush or in buildings to avoid horse and deer fly attack. History Life histories of our various species of horse and deer flies are not well known. Eggs are laid on stems and leaves of aquatic plants. Larvae live in the mud close to water, perhaps for a year or two, before pupating and emerging as adults.
Adults are most active on warm sunny days.
No satisfactory protective sprays are available. Temporary relief may be obtained from repellent sprays. Darkened shelters or areas of deep shade into which animals can escape from the flies should be made available. All Rights Reserved.