The multiplication of ant colonies by splitting the worker force into two or more groups each of which depart with their own fertile queens.

The multiplication of colonies by the departure of one or more reproductive forms: Colony fission is accompanied by groups of workers, from the parental nest, leaving behind comparable units to perpetuate the "parental" colony.

This mode is referred to occasionally as "hesmosis" in ant literature, and "sociotomy" in termite literature. Swarming honey bees can be regarded as a special form of colony fission.