What are fire ants? These are ants of tropical and subtropical America that feed on plant and animal materials and are stinging ants that can inflict a painful sting on you. Fire ants are very aggressive. When their nests or mounds are disturbed, they will somehow "take revenge", bite (sting) on any and everything they touch. When you spot fire ants and their nests, there are several ways to control a fire ant invasion. One way is to use worm castings. This is a good organic repellent for insect such as ants, and is considered a natural fire ant control.