The folowing may help explain the complexity of bee nutrition.
http://maarec.cas.psu.edu/bkCD/HBBio...upplements.htm

Pollen
Pollen is eaten by adult bees and fed (via the mixture of glandular secretions, honey, and pollen supplied by nurse bees) to worker and drone larvae after they are 3 days old. Unlike young house bees, field bees do not require pollen in their diet. Stored pollen (bee bread) is consumed by nurse bees (fig. 2). Under natural conditions, pollen collected by bees is usually stored on the periphery of the brood area (fig. 3). In a colony rearing brood, pollen placed next to a comb full of eggs is con sumed in 2 or 3 days; if placed on the periphery of larvae, it is used by nurse bees within 1 or 2 days but it may be stored for much longer periods of time. A normal-sized colony may consume 100 pounds or more pollen a year. Not all pollens are nutritionally alike; bees generally collect and utilize a mixture, and many individual pollens are nutritionally inadequate.
The protein content of pollens varies from 10 to 36 percent. Some pollens contain proteins that are deficient in certain amino acids required by bees. All the amino acids listed in table 1, except threonine, are essential for normal growth of the
young adult bee. With the exception of histidine and perhaps arginine, they cannot be synthesized by bees and must be obtained from the consumed pollens or from some other appropriate protein source.
An average pollen mixture contains lipids (fats) and the following minerals: calcium, chlorine, copper, iron, magnesium, phosphorus, potassium, silicon, and sulfur. Vitamins include ascorbic acid, biotin, vitamins D and E, folic acid, mositol, nicotinic acid, pantothenic acid, pyridoxine, riboflavin, and thiamine. Amino acid content is listed in table 1.
Table 1. Amino acid content of average pollen expressed as percent of crude protein
CONSTITUENT Average pollen(crude protein, 26.3%)
īpercent
Arginine 5.3
Histidine 2.5
Isoleucine 5.1
Leucine 7.1
Lysine 6.4
Methionine 1.9
Phenyalalamine 4.1
Threomine 4.1
Trypotophane 1.4
Valine 5.8


Protein Supplemental Foods for Bees
Numerous kinds of plant and animal products have been fed to bees in attempts to find a sub stitute to replace pollen in their natural diet.
None has been found that is a complete replacement for natural pollen. Certain protein foodstuffs, however, will improve nutrition and ensure continued colony development in places and times of shortage of natural pollen.


Regards,
Ernie
Lucas Apiaries