What term describes the gathering of bees in a swarm?

The term that refers to the gathering of bees in a swarm is "aggregation." In the context of bees, aggregation specifically describes the collective behavior when a group of bees congregates for a common purpose, which, in the case of swarming, involves finding a new home. It is a social phenomenon facilitated by pheromones and communication among the bees that helps coordinate their movement and ensures that they stay together during the swarming process.

While terms like clustering, concentration, and grouping may seem related, they do not convey the same specific behavior associated with swarming. Clustering implies simply coming together in a close formation but lacks the emphasis on the purposefulness of the bees gathering as in aggregation. Concentration refers more generally to the density of bees in a location rather than the intentional behavior that defines a swarm. Grouping might suggest gathering as well, but it is too vague when compared to the distinct biological and social behaviors captured by the term aggregation. Thus, "aggregation" is the most accurate term to describe the intentional and organized nature of bees coming together in a swarm.