In the case of ants a swarm is a cloud of winged males and females which massively get out of the nest for the swarming or nuptial flight. Workers are apterous, wingless, hence they do not take part in the flight. During the swarm females and mates coputate, after which males die and the females will dig a chamber where she will found a new colony. That is why, the swarm takes place after heavy autumn or spring rains when the ground is soft enough for females to dig.

In the case of bees the swarm is formed with a group of bees which separates from an existing colony. This occurs when the colony becomes too crowded and a feeling of discomfort puts the swarm into motion. The bees force the queen to lay eggs in cells prepared by them. Out of these eggs new queens will eclose. Only one of them will keep the colony. The old queen, already carrying eggs, and her followers (a few drones and worker bees) leave the hive with a provision of honey for some days. They fly to a nearest tree or structure where they cluster. They stay there temporarily till the scout bees find the new home.