Japanese natural beekeeping：How a Bee Ball Kills Queen

I discovered a cluster of Japanese honeybees (Apis cerana japonica) forming a ball at the bottom of their hive. Surprisingly, inside this cluster was the queen bee. Japanese honeybees swarm in spring. They raise new queen bees, but they produce more queens than the number of swarms. The surplus queens are either killed at the pupal stage or expelled and killed after emerging.