APIS Volume 5, Number 4, April, 1987
In this issue
- Pollen: The Other Side of the Nutritional Coin
POLLEN: THE OTHER SIDE OF THE NUTRITIONAL COIN
It now appears more and more certain that the widespread bee kill phenomena seen this spring throughout the southeast was due in large measure to pollen shortage in colonies (see February and March 1987 APIS). This unusual lack of pollen appears to have been the result of drought conditions. I have heard "old timers" say that sporadically over the years they have seen these same conditions, and that colonies fed pollen supplement/substitute recovered quickly.
This situation has led to a petitioning of the Agriculture Stabilization and Conservation Service (ASCS) to extend the deadline for last summer's drought disaster relief, allowing beekeepers to take advantage of that program in the near future. Those interested in the progress of this issue should contact their beekeeping associations, urging support on this issue.
Reports from the Northeast of large winter losses have suggested that the bee kill extended into that area. Pollen shortage was ruled out by many there, because there was no drought. However, at least some beekeepers agree that pollen dearth in that region in the fall has occurred for two years running. Bees transported from the Northeast and fed pollen supplement/substitute in Florida have done well through the winter.
There will continue to be arguments about the situation and its root causes. Evidence suggests and many beekeepers believe that perhaps parasites, pathogens or pesticides were involved, but it is not known if these may have precipitated colony decline or simply contributed to an already existent stress situation.
Let's again examine the symptoms of the die off. The bees appeared to go into the fall and winter in good shape. Then in early spring colonies rapidly declined in size. What the beekeeper saw upon opening a colony was a double handful of bees that appeared to be starving, yet the hive was full of honey! Bees were also seen that were unable to coordinate their movements; it has been suggested this was because the bees were using the protein in their own bodies to try to raise brood. Finally, smaller-than-normal bees were visible, suggesting malnutrition during developmental stages. Another twist to the story; incidence of chalkbrood has declined when an increase might be expected due to a high degree of stress. It takes brood rearing, however, fueled by pollen, in order for chalkbrood to develop.
There are two sides of the nutritional coin, both must be taken into consideration during colony inspection. Generally beekeepers most concern themselves with the carbohydrate side. They look at a colony to see if it has enough honey stores. Many don't open the top, but simply "heft" or weigh a colony. It's relatively easy to estimate the amount of honey a colony has and will use.
Honey only represents energy for a colony. Pollen provides important protein building blocks and must be present to produce spring replacement bees each year when large numbers of winter bees are dying off. During brood rearing, bees can use a large amount of pollen in a hurry. Estimating the amount needed can be difficult, because some is very often available in the field when most needed.
The quality of the pollen collected is also important, some plants produce more nutritious pollen than others. Like the diet of any organism, a good mixture is probably required. Even the bees themselves have trouble discriminating protein sources; at times they may be seen collecting everything from cattle feed to sawdust when natural pollen is not available.
I've heard the Australians have developed a sophisticated method for determining the pollen requirements of colonies during nectar flows. The protein level of the bees is monitored chemically while colonies are collecting nectar from eucalyptus, for example, notorious for its poor pollen production. When the protein level reaches a certain threshold level, colonies are moved out to areas where pollen is readily available.
This technology is not practiced in the United States where pollen appears to be more readily available. But estimating a colony's protein needs remains a guessing game. In order to ensure a supply of pollen, the best alternative is to feed pollen supplement/substitute.
Traditionally, there has been a semantic separation between pollen supplement and substitute. The former was mixed with perhaps 10 to 20 percent pollen, while the latter was supposed to take the place of pollen. The line blurs between the two because some pollen is probably present at most times in the field, making the substitute in reality a supplement. Bases for supplement/substitute include several products, expeller-processed soybean flower (fat content must be low--5 to 7 percent) and brewers yeast; Wheast and a derivative product, Wheast Bee Bread ©, a registered trademark of Merrick's Inc.; and the Beltsville Bee Diet ©, a registered trademark of Bio-Serv Inc. In addition to these products, bee supply outlets may also sell various formulations of bee diets.
A general problem encountered is that bees will often not eat pollen substitute, preferring instead to throw it out of a colony. Research has shown that certain chemicals present in pollen, called phagostimulants, are necessary to stimulate consumption. Incorporating sugar and/or adding natural pollen will make the supplement/substitute more attractive. Be careful purchasing natural pollen; it losses nutritional value over time, even when dried or frozen. Research in the west indicates that pollen is an excellent biomagnifier, that is it collects and concentrates various air pollutants which can include heavy metals.
As a general rule, mix the base material with sugar syrup and/or water and confectioner's sugar into a patty, stiff enough to place over the top bars. Then wrap the patty in wax paper to confine it and keep moisture from building up which might cause it to slide down between frames. Feed 1 pound patties a quarter to one-half inch thick; invert the inner cover or provide a ring to provide space above the top bars.
Sincerely,
Malcolm T. Sanford
Bldg 970, Box 110620
University of Florida
Gainesville, FL 32611-0620
Phone (352) 392-1801, Ext. 143 FAX: (352)-392-0190
http://www.ifas.ufl.edu/~mts/apishtm/apis.htm
INTERNET Address: MTS@GNV.IFAS.UFL.EDU
©1987 M.T. Sanford "All Rights Reserved
