some ants will eat leaves and an ants nest can be bad forv the root system, however some say they are no problem. I think the breed of ant is key here. a leaf cutter ant can destroy a plant in no time at all.
i just hit em with sevin 5 dust... those fucks do eat ur plants, and they were red ants chowin on my stems... Edit: do not put any poisons such as sevin 5 dust on your buds at all.. just around the plant and possibly the main stalk...