Ants usually form large colonies that have different types of members. First of all, there is the queen who’s only purpose is to constantly lay new eggs. Then there are the adult workers which are always responsible for building and maintaining the nest, for bringing food for the young ones and for the queen, and also for defending the nest.
An interesting fact is that all the adult workers are females. They are sterile and they do not lay eggs. Winged queens and male ants do exist, but they are present in the colony for only a short period of time. As soon as they emerge, they leave the colony in order to establish a new one somewhere else.
Workers in the colony can vary in size quite a lot. If they are all about the same size, they are called monomorphic. But there is also the case where large workers can be twice as big as small ones, and in this case they are polymorphic.
Ants have a strong division of labour, and certain workers only perform a certain task. This usually depends on their age. For example, young workers stay inside the nest and take care of the eggs and larvae, while later on they handle the construction and maintenance of the nest. Later in life, they will leave in search of food. This strong division of labour, amazing communication systems and cooperation allows ants to thrive in all sorts of environments.