Eye Gnats

Some species are attracted to the genital organs of mammals; for example, H pallipes clusters around a dog’s penis. These gnats quietly approach their mammalian hosts. They usually alight some distance from their feeding site and then crawl over the skin, or fly intermittently and alight, thus avoiding annoyance to the host. They are persistent and, if brushed away, quickly return to continue engorging themselves.

They are nonbiting flies; however, the labellae have spines that scarify host tissue and allow entrance of pathogenic organisms. Hippelates flies often hover around the body orifices of calves, yearlings, pregnant heifers, and lactating cows. They feed on lacrimal fluid, fatty body secretions, milk droplets, and on secretions at the tips of the teats of animals. Hippelates flies also serve as vectors for Trueperella pyogenes (summer mastitis) and Moraxella bovis (pinkeye, see Infectious Keratoconjunctivitis).

These small flies have sponging type mouthparts. Although eye gnats have much smaller mouthparts, they closely resemble house flies in form and structure and have short aristate antennae.

Repellents, such as those recommended for mosquitoes, provide temporary relief from eye gnats. Applications of insecticides on a community-wide basis (as would take place with mosquito abatement) may provide temporary control of adults, but more adults invade the treated area after the insecticide has dissipated.