Bees rely entirely on the resources provided by flowering plants for their survival and the functioning of their colony. Their diet is composed of two primary floral resources: nectar, which supplies the necessary carbohydrates for energy, and pollen, which provides the protein and other nutrients. This dual-resource diet sustains every member of the hive, from the foraging adult worker to the developing larva. This specialized nutritional intake allows the complex social structure of the honey bee colony to thrive.
Nectar, Honey, and the Energy Supply
Nectar is the sugary liquid secreted by specialized plant structures, serving as the bee colony’s sole source of metabolic fuel. Foraging worker bees use their proboscis, a long, straw-like tongue, to draw the nectar and store it temporarily in the honey stomach, or crop. This solution, which is initially high in water content, contains complex sugars like sucrose, along with trace amounts of vitamins and amino acids.
Upon returning to the hive, the forager bee transfers the nectar to an interior house bee through a process known as trophallaxis. During this transfer, and while the nectar is in the honey stomach, the bee introduces enzymes, notably invertase, which begin the chemical conversion. This enzymatic action breaks down the complex sucrose into simpler, more digestible sugars: glucose and fructose.
The house bees process the liquid within the honeycomb cells to reduce its moisture content significantly. Through dehydration and enzymatic action, the water content is lowered to approximately 17 to 20%, transforming nectar into thick honey. The low water content and the slight acidity created by the addition of enzymes prevent fermentation. This allows the honey to be capped with beeswax and stored indefinitely as the colony’s long-term energy reserve.
Pollen: The Essential Protein Source
Pollen provides the colony with essential macronutrients. It is the primary source of protein, lipids, vitamins, and minerals necessary for growth, development, and overall health of all bees. The protein content in pollen is particularly important for the development of the brood and the production of glandular secretions in young worker bees.
During foraging, specialized hairs on the bee’s body collect pollen grains, which are then packed onto the corbiculae, or pollen baskets, located on the hind legs. The bee often moistens the pollen with a small amount of nectar or honey before packing it into a dense pellet for transport back to the hive. This method ensures the maximum amount of pollen can be carried back efficiently in a single trip.
Once delivered, hive bees mix the collected pollen with honey, and sometimes glandular secretions, to create “bee bread.” This mixture is packed tightly into honeycomb cells and allowed to ferment slightly through the action of beneficial microorganisms, such as lactic acid bacteria. This fermentation process makes the protein in the pollen more bioavailable and digestible, and preserves it for extended periods as a protein reserve.
Specialized Feeding Roles in the Hive
The diet within the colony is not uniform, as nutritional needs shift depending on the bee’s caste and developmental stage. Adult worker bees primarily rely on honey for the high energy requirements of flight and hive maintenance, while young nurse bees and developing larvae require significant amounts of protein. Young larvae, regardless of their future caste, are initially fed a protein-rich secretion produced by nurse bees.
This secretion, known as royal jelly, is produced by the hypopharyngeal glands of young worker bees and is rich in proteins, sugars, and fatty acids. A female larva destined to become a worker bee receives royal jelly for only the first three days of her life before her diet is switched to the less nutrient-dense bee bread and honey mixture.
A queen larva is continuously fed copious amounts of royal jelly throughout her entire larval period, a difference in nutrition that is responsible for her profound physical and reproductive development. Beyond food, worker bees also collect water, which is not a nutrient but is functionally important for two key purposes. Water is used to regulate the hive temperature through evaporative cooling and to dilute stored honey or bee bread when feeding the larvae.