Mutualism

An interaction providing net benefits to both participants under specified conditions. It need not be obligatory or free of evolutionary conflict.

Conditional resource allocation in which a partner providing more service receives more resource. Reciprocal reward can help stabilize cooperation without guaranteeing equal exchange or universal host control.

A host response reducing the success of an established symbiont that provides less benefit. It differs from exclusion of a partner before association and need not imply conscious choice.

A mutual benefit arising as a consequence of actions favoured for an actor’s own immediate returns. It does not require delayed repayment.