Braula

Distinguished from all other Diptera by complete winglessness and extreme dorsoventral flattening. Resembles lice or mites superficially but has six legs (not eight) and dipteran mouthparts. Distinguished from the related genus Megabraula by subtle morphological differences in body proportions. Within honey bee colonies, identified by presence on bee bodies and characteristic slow, clinging movement.

Wingless, dorsoventrally flattened flies approximately 1.6 mm in length. Body shape is oval and compact, with reduced or absent wing structures making them barely recognizable as Diptera. Legs are adapted for clinging to host bees. Eyes are reduced. Overall appearance resembles small arachnids or lice rather than typical flies.

Exclusively associated with colonies of the western honey bee (Apis mellifera). Adults occupy the interior of hives, clinging to workers, queens, and drones. Larvae develop within wax honeycomb. Adults occasionally found at external aggregation sites where bees congregate, including flowers and salt licks, where they await opportunities to transfer to new host colonies.

Cosmopolitan distribution, coincident with the range of its host Apis mellifera. Records from Europe (Denmark, Norway, Sweden), Africa, and other regions where honey bees are established.

Activity patterns follow those of host honey bee colonies; present year-round within hives in temperate regions, with continuous reproduction in managed colonies.

Adults feed by stealing food from the mouths of host bees during trophallaxis. They do not consume host tissues. Larvae presumably feed on wax or organic material within honeycomb tunnels, though specific diet is not well documented.

• Apis mellifera - obligate commensalprimary host; adults live on workers, queens, and drones
• Apis mellifera scutellata - obligate commensalAfrican honey bee subspecies; host of B. coeca

Eggs laid in wax honeycomb. Larvae tunnel through wax, creating galleries. Pupation occurs within tunnels. Adults emerge and seek host bees, attaching to workers, queens, or drones. Specific developmental duration and number of instars not well documented in available sources.

Adults select hosts using mandibular gland pheromones as chemical cues, showing preference for workers with higher levels of queen substance (9-oxo-2(E)-decenoic acid) and worker substance (10-hydroxy-2(E)-decenoic acid). This allows them to exploit bees with greater trophallactic dominance. Adults remount previously occupied hosts successfully. Transfer between colonies occurs at congregation sites.

Commensal with minimal to no demonstrated impact on host colony health. Debate exists regarding whether Braula causes meaningful damage to honey bees; generally considered a minor or incidental associate rather than a significant pest.

Known as "bee lice," these flies are familiar to beekeepers but are not considered economically important pests. Their presence may cause minor concern, but management is rarely warranted. Sometimes mistaken for Varroa mites by novice beekeepers due to small size and clinging behavior.

• MegabraulaRelated genus in family Braulidae; also wingless and commensal on honey bees; distinguished by morphological differences in body proportions
• Varroa destructorExternal parasite of honey bees; similar size and clinging behavior, but is an arachnid (mite) with eight legs, not a fly with six legs
• Braula coecaMost widespread and studied species in the genus; other Braula species distinguished by subtle morphological features and geographic distribution

Despite common name "bee louse," Braula are true flies (Diptera), not lice (Phthiraptera). Their status as pests is debated; some sources label them pests while others emphasize their commensal nature with minimal impact on host bees.

• wingless
• commensalism
• honey bee associate
• kleptoparasitism
• trophallaxis
• pheromone-mediated host selection
• cosmopolitan

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Beelouse, Braula coeca Nitzsch (Insecta: Diptera: Braulidae)
• Bee louse, bee fly, braulid, Braula coeca Nitzsch (Insecta: Diptera: Braulidae)
• Distribution of the Bee LouseBraula CoecaNitzsch in Honeybee Colonies and its Preferences Among Workers, Queens and Drones
• A Hitchhiker’s Ride: The Honey Bee Louse Braula Coeca (Diptera: Braulidae) Selects its Host by Eavesdropping