Swarm intelligence is a modern arti?cial intelligence discipline that is c- cerned with the design of multiagent systems with applications, e.g., in - timization and in robotics. The design paradigm for these systems is fun- mentally di?erent from more traditional approaches. Instead of a sophisticated controller that governs the global behavior of the system, the swarm intelligence principle is based on many unsophisticated entities that cooperate in order to exhibit a desired behavior. Inspiration for the design of these systems is taken from the collective behavior of social insects such as ants, termites, bees, and wasps, as well as from the behavior of otheranimalsocietiessuchas?ocksofbirdsorschoolsof?sh.Coloniesofsocial insects have mesmerized researchers for many years. However, the principles that govern their behavior remained unknown for a long time. Even though the single members of these societies are unsophisticated individuals, they are able to achieve complex tasks in cooperation. Coordinated behavior emerges from relatively simple actions or interactions between the individuals.