Ants are mostly a nuisance in a garden—especially if they're the biting kind and you get yourself mixed up with a group of them—but there are ants that can damage plants. Imported fire ants feed on plant seeds and other insects, which can offset the balance in your garden. Ants also act as body guards for aphids, keeping away trouble and then helping them destroy plants. You may need to consult an exterminator or pest control company if your ant problem is really bad.