WEATHER AND CHANGE IN" WEIGHT OE BEE COLONY 11 



thus making the diurnal and nocturnal periods of approximately 

 equal length for all days studied for that year. This change was 

 necessitated by the errors in weight due to water standing on the 

 hives that year, as previously explained. In calculating the data 

 for 1923 such a shifting of D was unnecessary, since the two hives 

 used that year were under cover and no water stood on them. 

 When rain interfered with flight during midday, and flight was later 

 resumed, the point D takes its natural place at the close of flight 

 activity for the day. 



A graphic representation of changes in weight for a period of 24 

 hours is given in Figure 3. Either of two methods may be employed, 

 both being shown in this graph. The heavy dark line represents 

 cumulative gains and losses m weight, while the shaded portion 

 shows differences in weight from hour to hour. In case of the 

 shaded portion that part above the base line (shown as AF'm fig. 2) 

 is increase in weight and that below is decrease. It is readily seen 

 that the shaded portion of the graph is more important than the 

 line showing cumulative gain, since it magnifies small changes in the 

 rate of gain or loss which might otherwise not be observed. For this 

 reason the method showing differences in weight from hour to hour 

 has been used in all graphs except those showing the net gain. In 

 certain graphs both methods are used for greater clearness of differ- 

 ences. The effects of the various weather factors upon the hive- 

 weight changes in the spring and fall are so different that these two 

 periods must be considered separately. 



COMPARISON OF CHANGES IN WEIGHT OF TWO COLONIES OF BEES 



Beekeepers often assume great differences in the gathering ability 

 of colonies of bees in the same apiary and under exactly similar ex- 

 ternal conditions. In the interpretation of the data obtained in this 

 investigation it might be assumed that the colonies used were either 

 unusually good or unusually poor at gathering nectar and pollen. In 

 order to show that in the following calculations the individual char- 

 acteristics of the colonies play a very minor role, it seems best at this 

 point to insert a correlation of the changes in weight of the two col- 

 onies used in 1923. There is, in fact, little reason to believe that 

 such differences in colonies as have been assumed by many beekeepers 

 actually are important in considering the differences in honey crops 

 obtained by various colonies in an apiary, and this is especially the 

 case when observations are confined to a single race of bees, as was 

 true in this experiment. When differences in the total acquisition 

 of adjacent colonies of bees are noted, they must in most cases be 

 attributed to differences in manipulation or care of the colonies, or 

 to tendencies to retard gathering ill certain cases because of crowd- 

 ing, or to a dominance of the swarming instinct, rather than to propen- 

 sities for heavy" or light gathering by the individual bees. Obviously, 

 in the case of poor queens which are unable to keep up the population 

 of their colonies there will be a reduction in the accumulation of stores 



