mutualist

/ˈmjuʧuəlɪst/

When two organisms are dependent on each other, they have a mutualist relationship. A bee feeding on a flower's nectar while helping to pollinate is a perfect example of a mutualist interaction.

Two species benefitting from a relationship or encounter is mutualist — it's mutually beneficial to both, in other words. This whole concept is known as mutualism in biology, and it describes interactions between birds eating annoying insects off the back of a larger animal or a clownfish hiding in the tentacles of a sea anemone while simultaneously scaring away the anemone's predators. You can also use this adjective for encounters between people that benefit each equally.

Definitions of mutualist

1. adjective

   mutually dependent
   synonyms: interdependent, mutually beneficial

   dependent

   relying on or requiring a person or thing for support, supply, or what is needed