WEATHER AND CHANGE IN WEIGHT OF BEE COLONY 



of the two working together as one, and recorded as "colony weight 

 changes," have been studied in their relation to the prevailing 

 weather conditions. 



It is a very common practice among the best beekeepers to main- 

 tain what is known as a scale colony. A colony of average strength 

 is usually chosen for this purpose and is placed on scales in the 

 apiary. This colony is weigned once or twice a day, usually in early 

 morning and after the bees have stopped flying in the evening. Such 

 weighings however, are usually made in a haphazard manner, with- 

 out much care that the weighings are recorded at an exact time each 

 day. Such records give little information except that they indicate 

 in a rough manner the 

 trend of the honey 

 flow. Unfortunately, 

 even such records as 

 these are not available 

 for most localities. 



Records of careful 

 hourly weighings of 

 colonies are scarce. 

 Dufour (10) pointed 

 out the value of hourly 

 weighings and showed 

 how enormously the 

 hourly changes in 

 weights throughout the ft 

 day may vary on days | 



- 4-00 



- 800 



-/zoo 



-/600 



showing the same net 

 gain. Figure 1, taken 

 from data used in the 

 present investigation, 

 illustrates graphically 

 the activities on two 

 days when the net 

 gains were approxi- 

 mately the same. The 

 times of regaining the 

 original weights are 

 shown at the intersec- 

 tions of the curves with 

 the zero line. Dufour 

 (10) gives information 

 on the weather condi- 

 tions only in a general 

 way, during the time when he carried on his experiments, and it is 

 therefore impossible to calculate the exact relationship in his investi- 

 gation between the changes of colony weight and the weather. 



In any discussion of changes in colony weight it is important to> 

 keep in mind the fact that these changes are brought about by two 

 factors working jointly, both influenced by weather conditions. 

 These factors are the secretion of nectar by the plants and its collec- 

 tion by the bees. Of the two factors, investigatory have given more 

 attention to nectar secretion than they have to bee behavior. Even 

 in the field of nectar seer"! ion there is no general agreement as to the 



Fig. 1.— Graphs of hourly changes in the weight of a colony of bees on* 

 two clays when the net gains were approximately the same. The 

 solid line presents the changes on May 9, the other those on Sep- 

 tember 28, 1922 



