The worker bee is a female bee that is not capable of reproducing. Depending on her age she has many different roles throughout her life in the hive.
Younger worker bee's will start as cleaners. Their very first responsibility is to clean their own cells to prepare them for the next larvae or to store nectar and pollen.
Nurse bee is the next stage, they will nuture and feed the bee larvae, attend to the Queen, then move on to processing incoming nectar aswell as making & capping the nectar. As she grows older she moves on to guarding the entrance of the hive to protect it from unwanted visitors.
Then finally she is given the task of foraging and collecting pollen, nectar and propolis for the hive. Worker bee's are essential for the survival of the colony.