12 BULLETIN 1349, TJ. S. DEPARTMENT OF AGRICULTURE 



DESCRIPTION OF THE COLONIES USED IN 1921 



The brood-rearing investigation in 1921, as originally planned, 

 was to be carried out along lines which would tend to show the effects 

 of insulation, of stores, and of the age of the queen. Accordingly, 

 each of the 16 colonies used in 1921 had been wintered in two 10-frame 

 Langstroth hive bodies, eight colonies having been left all winter 

 without packing and eight having been wintered in quadruple 

 packing cases. The colonies were not in any way manipulated 

 for the purpose of changing their brood-rearing rate, except that 

 the addition of frames or supers had some influence in this respect. 

 The record is, therefore, largely a presentation of what bees do 

 without the interference of the beekeeper. The colonies without 

 packing comprised two groups of four, and it was the original in- 

 tention that the packed colonies should comprise the colonies in 

 two packing cases. Since, however, one of the packed colonies 

 became queenless during the winter, a colony packed in another 

 group was used in its place. The group containing three colonies 

 was unpacked on March 8, while the substituted colony (No. 10) 

 was unpacked on March 21; but the group containing four colonies 

 was not unpacked until May 5. Three of the colonies without 

 packing had queens bred in 1919, whereas all the others, including 

 both those with and without packing, had 1920 queens. Lack of 

 stores was not during 1921 a factor in the brood-rearing activity of 

 the eight unprotected colonies, as each colony proved to have more 

 than sufficient stores for all purposes. Of the colonies packed all 

 winter, four had heavy stores of honey, whereas the other four had 

 light stores, all in. the second hive body. The early spring was so 

 favorable for incoming nectar and pollen, however, that each colony 

 except No. 15 had sufficient stores for spring brood-rearing purposes. 

 All the 16 colonies used were located at the Bee Culture Laboratory, 

 Bureau of Entomology, at Somerset, Md., near Washington, D. C. 



In an endeavor to determine some of the factors which influence 

 brood-rearing activity during the three phases of the active season, 

 it is of interest to study the seasonal brood records of these 16 indi- 

 vidual colonie's. For this purpose the general features of the brood- 

 rearing activity in 1921 of 15 colonies are presented here, as well as a 

 somewhat more detailed study of the brood record of an additional 

 colony for two successive seasons. For each of these colonies a 

 seasonal curve (figs. 1 to 16) has been constructed, based on counts 

 (Tables 1 to 16) of sealed brood made from photographic records 

 taken in 1921, as well as an additional curve (fig. 17) for one of these 

 colonies, based on data (Table 17) from 1922. Although at first 

 glance the 17 curves seem to show little correlation, they reveal 

 definite relationships on closer study. The apparent differences 

 result from abnormal conditions within individual colonies, which 

 caused modifications in the brood-rearing responses. On the whole, 

 the 17 curves point to certain more or less definite and constant 

 seasonal variations in brood-rearing activity, due to normal, seasonal 

 stimuli, but subject to modifications by the presence of any abnormal 

 factors. This fact becomes apparent upon an examination of the 

 two successive seasonal curves presented for colony No. 4. 



It may be noted in passing that, even before unpacking colonies 

 wintered in two hive bodies in quadruple packing cases, removal of 

 frames from the lower hive bodies can be accomplished readily by 



