Causes of Deficiency of Soybean Flour as a Pollen Substitute for Honeybees1

Publisher Website
Google Scholar
Abstract
Colonies consisting of newly emerged bees which have never eaten pollen were kept in isolated cages and fed candy made of soybean flour alone and that fortified with riboflavin, niacin, both riboflavin and niacin, and dried brewers'' yeast. Mortality of bees was noted. Brood rearing activity was followed for 4 consecutive 10-day periods. All colonies reared brood. However, in the colonies fed soybean flour alone or soybean flour fortified with only riboflavin there was an abrupt impairment in the brood rearing activity beginning with the 3d period. The decrease in the brood rearing activity in the colonies fed soybean flour supplemented with niacin was more gradual. That in colonies offered soybean flour fortified with both niacin and riboflavin or dried brewers'' yeast, although gradually decreasing, was the closest to the normal brood rearing. The best results were obtained when the food was fortified with 20% of dry brewers'' yeast. Niacin is probably the main limiting factor in soybean flour. The amt. of riboflavin in the latter is also inadequate since an addition of riboflavin to the niacin-fortified diet increased the nutritive value of the food still further. There seem to be some other factors in which soybean flour is deficient and which are supplied by dried brewers'' yeast. The calculated amt. of N used in rearing one bee was equal to 4.96, 4.66, and 4.36 mg. for the colonies fortified with niacin, with both niacin and riboflavin and with dried brewers'' yeast, respectively. That amt. in the colonies fed soybean flour alone or that supplemented with riboflavin was greater being 5.36 and 6.16 mg., respectively. It appears that the amt. of N used in rearing one bee is inversely correlated with the index of food efficiency.

This publication has 4 references indexed in Scilit: