This is the more common type of mutualism exemplified by plants producing fruits eaten by birds while the birds help on dispersing the seeds of the fruit when they excrete them on places far from the parent plant.
Word origin: L mūtu(us): mutual, reciprocal + Gk -ismos, -isma: often directly, often through.
Related forms: mutualist (noun), mutualistic (adjective).
Compare: obligative mutualism.
See also: symbiosis.