An association or colony of individuals that collectively functions like a single organism. The concept is best illustrated by the colonies of eusocial insects, such as ants, bees, wasps, and termites, which are characterized by high levels of self-organization, cooperation, division of labour, and communication. Castes of individuals are evident, whose members are specialized to perform certain tasks, and some members (e.g. worker castes) forgo reproduction to tend to the needs of reproductive members. More loosely, the term ‘superorganism’ is used in many contexts, e.g. to describe an individual human and their associated microbial community (microbiome) or human society in general. Even planet Earth can be viewed as a superorganism according to the Gaia hypothesis.