Ant colonies may have thousands of swarming little insects, but one of them matters the most. She is the queen. When the colony loses its queen, whether through old age, rebellion, human interaction or tragic natural circumstances, the colony is pretty much doomed. There are a few caveats, however, as killing off a queen may not be as simple as it seems.
TL;DR (Too Long; Didn't Read)
When the queen ant dies, no more ants will be born, so the colony will die off.
Role of the Queen
The queen ant has but one function in the colony: to reproduce. She lays dozens or even millions of eggs which then hatch into new workers. When the queen ant dies, the colony dies, according to the "Smithsonian Zoogoer." The death of the colony will not be immediate, but will slowly die off over time as no new members will be added.
Queen ants are the largest in the colony. They are about double the size of the smallest minor workers and significantly larger than the major workers, according to the University of Minnesota Extension website. Her third segment is notably longer and fatter than her second segment, making it easier for her to lay dozens of eggs.
Several colonies have more than one queen. A single queen is the norm for some colonies, like those of the carpenter ant; she can live up to 30 years, the Terro website says. Other types of ants are infested with queens. An Argentine ant colony, for example, may have hundreds of queens.
Death by Workers
In some colonies, ants will take care of any excess queens on their own, according to the Live Science website. Queens will lay their eggs and produce thousands of young worker ants. The worker ants may turn on the queens, with the goal of killing all but one of them, so that one queen will reign supreme. However, as is sometimes the case with revolutions, the workers get carried away and end up killing all the queens and thus kill off their own colony.
Death by Humans
If it is your aim to kill the queen ant to rid your property of an ant colony, you can choose one of several different methods. These tactics target the entire colony with the hopes the queen will go down with all other ants that perish. One methods is to drown the colony with a bucket of boiling or soapy water, another is to kill them off with a mixture of a half-bar lye soap melted in 5 gallons of water.