Bees do not live on honey alone.
Pollen = Protein
Like all living things, honeybees need protein. The protein that bees use comes from plant pollen. Grains of pollen contain amino acids, the building blocks of proteins. As bees gather from different flowers, a variety of amino acids are collected and complete proteins are available to the bee. Think of this as like when human vegetarians combine beans and rice to make a complete protein meal.
Bees utilize the protein by mixing pollen with digestive enzymes and a bit of nectar or honey. This creates a substance called "bee bread" which is then fed to worker bee larvae. Bee bread also contains enough antibacterial properties to be stored for a couple of months when there is a surplus. (Queens are fed royal jelly throughout their larval stage.)
Honeybees tend to choose pollen based on odor and physical configuration of the grains rather than the quality. Approximately 15 - 30 percent of worker bees foraging are collecting pollen as they visit various flowers. The hairs on their bodies pick up the pollen grains like a lint brush. As they visit flower after flower, some of these bits of pollen fall off and pollinate. The pollen that remains clinging to the bee is brushed into pollen baskets on their hind legs. If you watch closely when bees are visiting flowers you can see the pollen collected in these baskets. Look for tiny balls of color attached to their legs.
Between 33 and 121 pounds is required annually by an average sized colony to raise brood. Considering that a single bee carries a pollen load of about 18mg, that is a lot of trips back and forth to the hive. This pollen load may be up to 35 percent of their body weight. (1)
What Makes for Good Bee Pollen?
All pollens are not equally nutritious to bees. Different plants produce different qualities of proteins. For example, canola and almond produce a high quality protein pollen. Raspberries, blackberries, willow, and sunflower produce lower quality pollens but these are still attractive to honeybees. Pine trees produce a lot of pollen but it is not used by honeybees. Likewise the pollen on many ornamental plants is not useful to honeybees.
Pollen in the cells should be multi-colored as an indicator that the diet of the colony is varied. Just like humans, bees need a well balanced diet from a variety of nectar and pollen sources.
If you are thinking about planting flowers this spring, consider what might be useful to the honeybees. Crocus, flowering herbs such as thyme and basil, lavender and chives are possibilities. You might even consider letting the dandelions in your yard bloom.
1. Ellis, A., Ellis, J., O'Malley, M. and Nalen, C.Z. (2010) The Benefits of Pollen to Honey Bees. University of Florida Extension. Retrieved 4/2014 at www.Gardens.USF.edu