In the northern plains, most of the work of turning over soil was done by ants prior to European settlement.

Some species form mutualistic relationships with aphids.

The aphids feed on plant sap, secreting excess sugar (called "honeydew"), which are consumed by the ants.

In turn the ants protect the aphids from predators and may even construct mud shelters for their domesticated herd.

Some ants are also known to feed on elaiosomes of Common Blue Violet and Red Trillium (and dispersing the seeds).