Bees are dependent on flowers for food. Pollen-their main source of protein, vitamins, minerals, and fat-is necessary for the development of all larval bees. Adult bees forage for pollen and nectar, the sweet liquid produced by flowers. In so doing, they inadvertently transfer pollen grains between flowers, thus pollinating, or fertilizing, plant seeds. Bees also collect nectar as an energy source. They either consume the nectar directly or convert it to honey in the hive.