Colony reproduction in which one or more queens and a number of workers separate to establish a new colony:Swarming takes place when the queen, or queens, are accompanied by a small number of workers and they leave the main parental nest. This process of swarming is called "budding".

When major portions of the colony separate, each with one or more queens (as in army ants), the process is called "fission".

Swarming also applies to the mass exodus from the nests of reproductive forms at the beginning of the nuptial flight.