Polyethism
Polyethism is the change of caste of ants. It is implemented in RISKANT via the following function:
RISKANT.Core.polyethism! — Method
Polyethism happens to address the ratio of nurses to foragers. If there are not enough foragers, new ones are recruited from nurses. A nurse can be promoted to forager if it is old enough (i.e. has reached the configured age threshold).