STATES DEPARTMENT OF AGRICULTU1 



DEPARTMENT BULLETIN No. 1339 



Washington, D. C. V October, 1925 



THE EFFECT OF WEATHER UPON THE CHANGE IN WEIGHT OF A 

 COLONY OF BEES DURING THE HONEY FLOW 



By James I. Hambleton, Apiculturist, in Charge of Bee Culture Investigations, 



Bureau of Entomology 



CONTENTS 



Introduction — - 1 



Method 0/ obtaining data 5 



Method of presenting data .... 3 



Comparison of changes in weight of two colo- 

 nies of bees 11 



The spring period 15 



The fall period 22 



Correlations between external factors and the 



changes in colony weight 25 



Page 

 The effect of unknown factors on changes in 



colony weight 38 



Theoretically changing weather factors and pre- 

 dicting resulting gains 44 



Conclusions 48 



Literature cited 50 



INTRODUCTION 



The annual honey crop of a colony of honeybees is dependent upon 

 a considerable number of factors, part dealing with the activities of 

 the bees and part resulting from the various external factors influ- 

 encing the secretion of nectar by the honey plants of the locality. 

 Demuth (8, p. 18) 1 has shown this interrelationship by pointing out 

 that there are four factors which combine to make the honey crop : 

 A surplus population in the colony over and above the bees neces- 

 sary for colony maintenance, a predominance of the storing instinct 

 and the control of swarming, honey plants growing under opti- 

 mum conditions, and weather suitable for the secretion of nectar and 

 the gathering of it by the bees. If any one of these factors is reduced 

 to zero, the crop is zero, and if any one factor is reduced one-half, 

 the crop is one-half the maximum. Naturally, so long as the factors 

 do not rest on a mathematical expression, it is impossible to inter- 

 pret them with exactness, but every experienced beekeeper realizes 

 this interrelationship; it is therefore safe, as a working hypothesis, 

 to accept these factors as real and fundamental. 



Most of the work done on beekeeping subjects has dealt either 

 with methods of obtaining for the colony a surplus population at the 

 right time for the gathering of the crop, or with the management of 



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