All beekeepers know about nectar flows; they look forward to them with eager anticipation. Most nectar-producing plants have been cataloged and written about extensively. There is however, another side to the nutritional coin in beekeeping. There will be no honey if protein is not available to developing bees. Thus, flow of pollen is just as important, if not more so, than that from nectar.
Recent analysis from three colonies showed a pollen flow in April (maple and dandelion), July (various agricultural crops) and September (goldenrod and ragweed). Although the dates correlated with the traditional plants present at the time, the study did not give information about specific plants and how much they might have contributed to the protein supply. Given this set of data, the author suggests that the time pollen supplement/substitute would most benefit a colony would be early March, mid-May and August in the region. The time to trap pollen corresponds to April through early May and September. It pays to know these flows, which can vary greatly depending on region, the author concludes, to determine when supplemental feeding might be needed. Besides timing and quantity, the quality of the pollen flow these days needs much more examination.
It appears to be the most vulnerable part of the flower to environmental contamination and serves as a magnet for things like heavy metals, as shown by Dr. Jerry Bromenshenk at the University of Montana. Adverse conditions can also quickly erode its viability; studies in preservation of collected pollen provide abundant evidence of its ephemeral nutritional value. Pollen is plant sperm. Recent investigation on non-viability of sperm in animals from alligators to humans, thought to be the consequences of chemical contamination in both air and water, may also apply to that of plants. Though not as vulnerable as other kinds of sperm, being housed in a tough outer shell, pollen is nevertheless still a far more fragile commodity than honey.
Lack of pollen and consequent inadequate nutrition has been implicated in many conditions that have defied description. Although not proven to everyone's satisfaction, "disappearing disease", "autumn collapse", "May disease" and others may be directly related to genetically inclined to serve protein and thus, pollen deficiency. Some pollen is even toxic to colonies. A feeding study done in the Florida?s Panhandle was inconclusive concerning whether or not pollen deficiency had some impact on bee colony loss originally attributed to tracheal mites, but the symptoms were certainly similar to those conditions mentioned above.
Perhaps the most innovative use of pollen and protein monitoring occurs in Australia. There gross nitrogen is measured to determine whether bee colonies should be moved into and out of eucalyptus groves, notorious for poor pollen flows.