Musca autumnalis

Definition

A synanthropic muscid fly species commonly known as the face fly or autumn housefly, native to the Palearctic and introduced to North America, where it is a significant pest of pastured cattle and horses. Adults aggregate on the faces of livestock to feed on ocular and nasal secretions, facilitating transmission of Moraxella bovis, the causative agent of bovine pinkeye (infectious bovine keratoconjunctivitis). Unlike the closely related house fly (Musca domestica), M. autumnalis is primarily an outdoor species associated with undisturbed cattle dung for larval development.

Etymology

Latin autumnalis, "of autumn," referring to seasonal abundance; Musca, Latin "fly."

Example

Face fly populations peak in late summer and autumn, with adults clustering around the eyes and muzzle of cattle to lap up protein-rich secretions—behavior that distinguishes Musca autumnalis from the more generalist Musca domestica.

Synonyms

• Face fly
• autumn housefly

Related Terms

• Musca domestica
• Muscidae
• Synanthropic
• dipteran
• bovine pinkeye
• Moraxella bovis
• pasture fly

Usage Notes

The common name "face fly" is sometimes applied loosely to other muscids that feed on livestock secretions, but properly refers to M. autumnalis. The species is distinguished from the house fly by its stronger association with outdoor cattle environments and its seasonal autumn peak in temperate regions. Taxonomic placement in Muscidae is supported by morphological and molecular data; it is not congeneric with the horn fly (Haematobia irritans), despite similar pest ecology.