Colony defensive behaviour remains one of the major challenges in beekeeping. Honey bee queen pheromone influences many aspects of worker behaviour and physiology, and also can substitute for a queen when shipping worker bees long distances. We observed that colonies with queens are calmer when exposed to synthetic pheromone, and examined the effects of QMP on colony defensive behaviour. Defensive behavior was compared between colonies treated with queen pheromone and untreated control colonies, using colonies with and without queens.