Bees for development Journal 116 September 2015
Practical Beekeeping – Healthy bees by natural keeping
Fresh pollen not concentrated feed Wolfgang Ritter
June, pollen variety is extremely good, because most flowering plants are blooming during long daylight hours. From July onwards (when daytime is getting shorter) variety begins to decrease. It can then be necessary to migrate colonies to nectar plants known to be also good pollen providers. American goldenrod Solidago is an important plant that flowers in summer and during harvest. Himalayan balsam Impatiens glandulifera also supplies a late pollen source. However the spreading of these non-native plant species should be avoided because beekeepers are committed to environmental protection. It is much better to use late flowering indigenous plants such as cornflower, mustards and trefoil.
Keywords: balanced nutrition, bee forage, pollen supplement In an intact environment with a variety of flowers, swarms of wild honey bees settle in nesting places offering everything that they need. Today this is more difficult and beekeepers have to care for the survival of their bee colonies. While lack of carbohydrate can be met to some extent, very little is known about proteins. Honey bees are strict vegetarians and balanced nutrition facilitates optimal development of the bee colony. Important food components are proteins, minerals, fats, vitamins, carbohydrates and water. If one or more of these are missing, colony strength decreases and each bees’ life is shortened – suffering more because of diseases, and this often ends in death of the whole colony.
The value of a pollen source is often judged by the frequency of bee visits. However, this is not a firm indicator of good provision for a colony. How much pollen needs to be gathered depends more on the content of crude proteins. Rape pollen contains 25% crude protein, while maize pollen contains 15%.
Proteins consist of amino acids, ten of which are classified as essential for bees. Bees need different quantities of all of these. If one or several of the amino acids are absent, or present only in small quantity, the bee colony tries to balance this by an increased frequency of pollen flights. Pollen with low crude protein content, yet with a small amount of the most important amino acids, may be critical for a colony. Fat content seems to be adequate in all kinds of pollen. It is mainly the fatty acids that are important for bees. Little is known about bees’ vitamin requirements. It is possible that they need B complex vitamins as do other insects. Vitamins do not persist in stored pollen, and so the value of pollen stocks is often overestimated. If pollen is infested by bacteria or mildew it becomes harmful for bees. Best for the bee colony is freshly harvested pollen – from as many different plant species as possible.
In spring in temperate climates bees use their first foraging flights to gather hazelnut and willow pollen All photos © J Schwenkel
As beekeepers we should constantly survey our colonies’ food stocks. Within a flight radius of up to three kilometres, a large variety of forage should be available throughout the season. Some beekeepers take care only that bees gather enough nectar and/ or honeydew with the aim of taking a good honey harvest, and they do not pay attention to pollen supply. Pollen is the only source of protein and it provides also other important nutrients. Depending on colony strength and the season, a colony needs 20–55 kg of pollen every year. Due to seasonal variation in vegetation, pollen supply varies considerably during the year.
Quantity and quality of pollen
The real value of a certain pollen for the bee colony is defined not only by its crude protein content, but also by its composition.
Fluctuating pollen supply The pollen supply in Germany (temperate climate with a forage break in winter) shows a critical phase in spring, between cleansing flights and the beginning of fruit tree blossoming, when older winter bees are replaced by newly reared young summer bees within a short time, and a sufficient supply of pollen is crucial. Hazelnut is often too early but some willow species such as the sallow are important sources of pollen. From April to 3
