What to do about ants?!
Common, small brown ants are not a threat to trees. However, because they love the honeydew that aphids produce, they will set up housekeeping with them. And the aphids can be damaging. So whenever you see ants, check for aphids. An exception to the above would be the Fire ants/Harvester ants that are large, red, black or red and black. They do eat leaves.