Wingless adult flies observed on queen body; less commonly seen on workers, or as slightly elevated tunnels (caused by the fly maggots) in capped honey. These flies have six legs.
The bee louse, Braula coeca, is actually a wingless fly. Populations of the bee louse in hives, reported in a dozen states east of the Mississippi, are generally low. Fly adults are most commonly observed on the queen. Adults feed from the bee mouthparts. Eggs are laid on honey cappings, and maggots tunnel beneath cappings, leaving “trails’ that can be considered mildly disfiguring to comb honey. This damage is frequently misdiagnosed as wax moth tunnels, though wax moths tunnel in the area of developing brood cells, not in capped honey cells.
Extensive use of miticides for mite control has led to the near extinction of this unusual fly commensal of beehives in the U.S.
Adults may be misdiagnosed as phoretic varroa mites, but note that flies have six legs, while mites have eight. Bee louse maggots may be misdiagnosed as scavenger flies or small hive beetle larvae, but unlike small hive beetles, the maggots are not present on the bottom board or in hive debris on the bottom of or beneath the hive. Maggot tunnels cause only minor disfigurement in cappings of honey cells.
Ellis, Jamie D. 2017. Bee louse. https://entnemdept.ufl.edu/creatures/misc/bees/bee_louse.htm
Smith IB and Caron DM. 1984. Distribution of the Bee Louse Braula Coeca Nitzsch in Honeybee Colonies and its Preferences Among Workers, Queens and Drones. Journal of Apicultural Research. 23(3). https://www.tandfonline.com/doi/abs/10.1080/00218839.1984.11100628
