Ant colonies are organized in dense heterarchies: communication occurs among most or all members and includes feedback loops from lower to higher units of organization. Much of the regulation is based on mass communication, in which information is transmitted from group to group or group to individual rather than from individual to individual. Feedback loops involving mass communication are more precise than individual responses, which often consist of simple 'rules of thumb' based on few stimuli. The loops also produce patterns that emerge at the level of the colony and are difficult to predict from a knowledge of individual behavior alone. Examples reviewed here are the control of foraging activity, oviposition by the queen, and emergency care of immature forms by the major worker caste. Copyright © 1988. Published by Elsevier Ltd.