Varroa destructor mites are parasitic arachnids that have spread globally and now represent the single greatest threat to honeybee colony health and survival, causing both population welfare and individual bee welfare concerns.
Varroa welfare affects individual bees and colonies simultaneously. Individual bees parasitized by Varroa are smaller, shorter-lived, and immunocompromised — their welfare is directly diminished. Colony-level welfare depends on successful management: untreated colonies collapse, with the welfare cost of thousands of individuals dying as the colony fails. Beekeeper treatment choices involve welfare trade-offs between Varroa harm and treatment harm. Oxalic acid treatments are considered relatively low-impact; synthetic miticide residues in wax concern some researchers. The long-term solution — breeding Varroa-resistant bees — removes the treatment welfare trade-off entirely.