Stigmergy, a term coined by French biologist Pierre-Paul Grasse[2] is interaction through the environment.

Self-Organization in social insects often requires interactions among insects: such interactions can be direct or indirect. Direct interactions are the "obvious" interactions: antennation, trophallaxis (food or liquid exchange), mandibular contact, visual contact, chemical contact (the odor of nearby nestmates), etc. Indirect interactions are more subtle: two individuals interact indirectly when one of then modifies the environment and the other responds to the new environment at a later time. Such an interaction is an example of stigmergy. [1, p.14]