What signals that a queen bee is about to swarm?

The presence of increased piping sounds in the hive is an important signal that a queen bee is about to swarm. Piping is a specific sound made by the queen and also by workers. This sound typically indicates that the queen is signaling her readiness to swarm and can serve to rally the worker bees in preparation for the swarming process. In anticipation of this natural reproductive behavior, the queen's signaling activates the hive, and you might also see other behaviors like bees clustering and preparing for departure.

While other factors may contribute to the overall understanding of swarming behavior, they do not communicate readiness as clearly as the sound of piping. Increased waggle dancing tends to reflect foraging activity and not a direct indication of swarming. Silence in the hive might indicate a lack of activity, which is not a sign of impending swarming. Lastly, the production of queen cells is indeed associated with swarming but typically occurs as a result of other signals rather than indicating that swarming is imminent. Thus, increased piping sounds are the clearest auditory cue that the queen is preparing to swarm.