Bee's food source is the flowers pollen (nectar), which may not find in winter. They mix the nectar they gather in the summer with a special fluid issued from their bodies. This mixture produces a new nutritious substance -honey- and save it for next winter.
And thy Lord inspired the bee, saying: Choose thou habitations in the hills and in the trees and in that which they thatch; (68) Then eat of all fruits, and follow the ways of thy Lord, made smooth (for thee). There cometh forth from their bellies a drink divers of hues, wherein is healing for mankind. Lo! herein is indeed a portent for people who reflect. (69)[Q.S An-Nahl(16) 68-69]
Honey they produces is not just for them only, but they deserve it human being too, us. Like other creatures in nature, bees also devoted themselves to service human being. As like the chickens that lay at least an eggs every day despite they do not need it, or cows that produce milk more then their children needs.