Mutualism benefits both species in an interspecific relationship.

Some acacia trees have hollow thorns that house ants which feed on sugar secreted by nectaries and on protein-rich swellings.

In turn, the ants attack small herbivores, and even clear invading vegetation.

Ants can also be mutualistic with fungi and caterpillars.

Other examples include mycorrhizae , cleaner shrimp and gobies .