Swarm Intelligence: Social Insects Don't have Friends

The term `societies' is generally applied both to human and other animal societies, including social insects. Social insects (e.g. termites, bees, ants) are very well studied and two important theoretical concepts are used to understand coordination in social insect societies, namely self-organization and stigmergy. Recently, models of swarm intelligence and their applications to problems like combinatorial optimization and routing in communications networks have been studied extensively [BDT99]. The concept stigmergy describes a class of mechanisms mediating animal-animal interactions. Generally, the behavior of each insect can be described as a stimulus-response (S-R) sequence (even for solitary species). If animals do not distinguish between products of others' activities and their own activity, then individuals can respond to and interact through stimuli. This does not require direct communication between individuals; individuals `communicate' indirectly, via the environment. Social insect societies and models thereof are typical examples of collective behavior which does not involve direct communication between individuals.