In colony-forming insects like ants, termites, and bees, the defense of a nest typically involves utilizing overwhelming numbers to neutralize an invader. They use their sharp mandibles to chew apart their foes or their stingers with acid to paralyze prey. These are the basics tools of defense that most social insects possess, allowing them to protect the most important thing — the queen and her young.
Some ant species take defense of the colony even further. Various types have evolved the ability to spray their acid on enemies, allowing the acid to corrode invaders. This can be used as a neutralizing agent, allowing allied ants to finish off the invaders.