The interaction between a bee and a flower is a prime example of mutualism, where both organisms benefit. For the plant, nectar and pollen ensure the transport of genetic material necessary for reproduction. For the bee, these floral offerings are the sole source of sustenance, providing the complete nutritional profile required for the colony’s survival and growth. Bees gather two substances that serve distinct roles: one as the colony’s fuel source (nectar), and the other as its essential building material (pollen).
Nectar as the Primary Energy Source
Nectar is the sweet, aqueous solution secreted by specialized plant glands called nectaries, serving as the colony’s primary carbohydrate source. Its composition is mainly water and dissolved sugars, typically sucrose, glucose, and fructose. This sugar provides the immediate and most readily available fuel for adult foraging bees.
The high-energy content of nectar powers the demanding physical activity of flight, requiring significant energy expenditure from the bee’s flight muscles. This carbohydrate fuel also supports colony processes like thermoregulation. Bees generate heat by vibrating their flight muscles to maintain the brood nest temperature around 93 to 95 degrees Fahrenheit. Nectar contains trace amounts of amino acids, vitamins, and minerals, but its main function is energy provision.
The collected nectar is stored in a specialized organ called the honey stomach or crop, not consumed immediately. While in transit, the bee begins converting raw nectar into honey by introducing enzymes like invertase, which breaks down complex sugars. Once deposited into honeycomb cells, worker bees engage in a communal dehydration process, fanning the liquid with their wings to evaporate excess water.
Raw nectar can contain as much as 70 to 80% water, but fanning reduces the moisture content substantially, typically to below 18%. This low-water, high-sugar concentration creates honey, a stable, long-term food source that resists spoilage. Honey sustains the colony through periods of scarcity, such as winter, acting as the concentrated energy reserve when no fresh forage is available.
Pollen as the Essential Building Block
Pollen, often referred to as “bee bread” once stored, is the colony’s singular source of protein, lipids, vitamins, and minerals. While nectar powers adult workers, pollen provides the raw materials necessary for growth, development, and glandular function. The nutritional quality of pollen varies greatly between plant species, but it generally contains a significant percentage of crude protein, ranging from 6% to 30%.
This protein is composed of essential amino acids, such as arginine, leucine, and valine, which are indispensable for the bees’ physiological processes. Pollen consumption is necessary for nurse bees, a specialized group of young workers. They consume large amounts of pollen to develop the hypopharyngeal glands needed to produce protein-rich royal jelly. Royal jelly is fed to the queen and young larvae, fueling their rapid growth.
For the developing brood, pollen is the most important food, supplying the high protein and lipid content required for larval growth and metamorphosis. Without an adequate supply of diverse and high-quality pollen, the colony cannot rear new bees, leading to population decline. The lipids in pollen, including essential fatty acids, are necessary for synthesizing structural components and maintaining general colony health.
Upon arrival at the hive, raw pollen is mixed with nectar, honey, and glandular secretions, beginning lactic acid fermentation. This mixture is compacted into honeycomb cells and sealed with a layer of honey, transforming it into “bee bread.” This fermentation process breaks down the tough outer wall of the pollen grain, enhancing the bioavailability and digestibility of the nutrients.
How Bees Acquire and Store Resources
Bees employ specialized anatomy to efficiently gather nectar and pollen. For nectar, the bee utilizes its elongated, tube-like mouthpart, the proboscis, to siphon the liquid from the flower’s nectaries. The collected nectar is stored in the honey stomach, an organ designed for transport that can hold a volume almost equal to the bee’s weight.
Pollen collection uses a different mechanism, involving the bee’s fuzzy body hairs and specialized leg structures. As the bee moves over the flower, pollen grains adhere to the tiny hairs covering its body. The bee brushes this loose pollen toward its hind legs, where it is moistened with nectar or saliva and compacted.
This moistened pellet of pollen is secured into the corbicula, or pollen basket, a concave area on the outer surface of the hind leg. The bee carries a distinct pellet of pollen in each corbicula, returning to the hive with visible cargo. Once inside the hive, both resources are stored in an organized manner within the hexagonal wax cells of the comb.
Honey is stored in cells, often capped with wax for long-term preservation. Processed bee bread is stored in other cells, usually closer to the brood area for easy access by nurse bees. This division of storage ensures the energy source and building material are optimized for the colony’s needs.