If it is bigger than usual it is a red carpenter ant even regular red ants have black on their abdomen. It is a stinger it just blends in with black ants.
Do what ants normally do except in a close contained area/environment, they make ant farms so you can see the ants and what they do since it normally all happens underground, and ant farms are see...
it's because, the queen ant is the biggest and can hold the most eggs, so they all breed with her and she lays all the egggs while the other ants care for them