This is a question that is asked time & time again, because its an important question.
I hope I can make this sound correct. After emergence the life span of a worker honey bee can range from a few days to about eight months. There are a variety of factors that need to be considered.
A young bee will consume a lot of pollen which causes the hypopharyngeal glands and the fat bodies to develop. (Fat bodies are the storage cells of the adult bee. The cytoplasm of the cell contains an oily liquid (fat, protein and sugar). These act as reserve foods for the winter bee.
The basic difference between Summer bee and Winter bee is I believe as follows.
The summer bee uses her reserves for brood rearing, by drawing on the hypopharyngeal glands in the form of brood food. I think the more brood a young bee rears the shorter her life becomes. So the summer bee -short life - high fat content - low protein content - maximum brood rearing.
Winter bee emerges in autumn where there is only small amounts of brood to rear so the hypopharyngeal glands remain plump. The fat bodies of the winter bee are stored the roof of the abdomen. The summer bees must produce a lot of pollen as its the main source of food for the winter bees. The winter bee does not need to use energy by foraging, brood rearing, comb building. With the onset of winter the winter bee can not get out for cleansing flights, so therefore her rectum will become inflated to nearly the whole of the abdomen. Finally the winter bee has an important job in spring to ensure the survival of the colony. So the winter bee - long life - low fat content - high protein content - minimum brood rearing.
I hope that has helped somewhat as the subject is quite long in details.