This time I gave the main hall a miss (Noel Power on Swarming Scenarios) and, instead, headed for Video Room 1 where Dan Basterfield was due to talk on Bee Nutrition. This was a much better presentation than the earlier ones: lighter and brighter with more interaction with the audience. There weren’t many there, about 30 I think.
The three important nutritional sources are: water (without which they wouldn’t be able to dilute honey (hard tack!) for use or to work their air conditioning system); pollen, their protein source for body building, and nectar/honey as a source of sugar for energy. Nectar varies between 5% and 80% sugar but is usually around 30% – 40%-ish, whereas honey is between 77% and 88%.The bees assess the quality/ strength during collection and concentrate on the best sources.
The bees need water to dilute the honey, roughly 50:50. They tend to choose what we would regard as ‘dirty’ water but we don’t know why. Maybe it is a source of extra vitamins/minerals or perhaps it is merely simpler to locate, although they can mark a source with their footprint pheromone. Bees originate from a drier environment and are built to consider water important.
Pollen provides protein, amino acids, fats, illegible, and vitamins but the bees aren’t able to assess the quality while collecting. Nutrient levels and the balance between types vary significantly. Amino acids are found in good quantities in oilseed rape, viper’s bugloss, clover, gorse and beans. Sunflower, buckwheat and maize are relatively poor sources.
A colony uses about 30kg (getting on for 5 stones in English!) of pollen a year, gathered in over a million foraging trips, and between 2 and 3 times that weight of honey gathered in 4 million trips.
Water gathering is variable: often at dawn and evening, and, of course, there is usually quite a lot in nectar. Larval nutrition is at about 100mg (I don’t know what that is in English!) per larva per day and progresses through the brood food produced by the young workers’ hypopharyngeal glands to a mixture of honey and pollen as they near the capping stage of their development. During their larval phase, bees multiply their weight by 1,000 times. The bees feed about 2 larvae per cell full of pollen. The queen lays, very roughly, 1,000 eggs per day so a lot of pollen is consumed!
The workers’ work is age related: they start by eating lots of pollen which their hypopharyngeal glands convert to brood food with which, after a few days, they feed their baby sisters until they are about 10 days old and move on to other duties.
Bees’ use of trophyllaxis: food sharing, mouth to mouth, spreads information and nutrients.
If you want to feed pollen to your bees, it can be preserved by freezing.
Recommended books: The Biology of the Honey Bee by Mark Winston; ‘Fat bees, skinny bees’ which is a pdf document that you can download for free; Colour Guide to the Pollen Loads of Bees by William Kirk .