DEPARTMENT BULLETIN No. 1349 



Washington, D. C. ▼ September, 1925 



THE BROOD-REARING CYCLE OF THE HONEYBEE 



By W. J. Nolan, Associate Apiculturist, Division of Bee Culture Investigations, 



Bureau of Entomolgy 



CONTENTS 



Introduction 1 



Method 4 



Annual brood-rearing cycle 6 



Description of the colonics used in 1921 12 



Seasonal characteristics of 1921 13 



Brood rearing of a typical colony for two suc- 

 cessive seasons 14 



General observations on the remaining colonies, 16 



General discussion of the records for 1921 25 



Observations in 1920 27 



Migrations of the queen within the hive. 30 



Compactness of brood nest 32 



Time relation of brood rearing to nectar gath- 

 ered 33 



Egg laying 35 



Conclusions 36 



Literature cited 37 



Tables 38 



Graphs _ 44 



INTRODUCTION 



In previous work of the Bureau of Entomology emphasis has been 

 placed on the conditions necessary for the proper wintering of bees, 

 in order that colony population and energy may be conserved to the 

 utmost during the period when no brood is reared by normal colonies. 

 It is evident, however, that merely wintering the bees in the best 

 possible condition will not in itself guarantee that the colony will at 

 the right moment have the proper strength and composition for 

 gathering a maximum honey crop. Nevertheless, if, through proper 

 wintering, the strength of the colony has been adequately conserved, 

 the resumption of brood rearing in the spring may take place at the 

 proper time and the amount of brood reared may increase at a remark- 

 able rate, since the ability of the colony will not have been impaired 

 through excessive work during the winter. It is appropriate, there- 

 fore, tliat the investigation of wintering conditions should be followed 

 by ji d in vestigation of the factors which modify brood-rearing activity, 

 more especially those which are under the control of the beekeeper. 



Since normally a worker bee, before going to the field, spends the 

 first two or three weeks of its life in duties within the hive, the quantity 

 of nectar gathered by any colony depends not merely on the total 

 Dumber 01 bees in the colony during a honey flow, but on the number 

 included within that total which represents bees of proper age to serve 

 nectar gatherers. In order- bo have the largest possible number of 

 field bees at the proper moment, therefore, the highest daily rate of 

 bees emerging from bhi brood cells during any given season should 



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