THE TEMPERATURE OF THE BEE COLONY 



15 





synchronous variation. Without doubt of these three factors the 

 loss of heat from the cluster by convection is sufficient to counteract 

 the hypothesis of the lag. Coupled with this the other factors would 

 be expected to participate. The convection is also modified by the 

 generally known contraction and relaxation of the cluster, referred 

 to elsewhere. 



These physical phenomena are evidently unsatisfactory as an inter- 

 pretation from this standpoint of the lag. Thorough comparison of 

 the charts fails to provide suitable material for conclusions as to the 

 cause. 



Table III shows the relative increase of temperature in the cluster 

 corresponding to the progress of the winter season, while Table IV 

 shows the monthly maximum and minimum temperature of the center 

 of the cluster during the period from November 9 to March 9. 



Table III. — Relative increase of temperature in the bee cluster corresponding to the 

 progress of the winter season. 



Month. 



Range of temperature. 



November, beginning of winter conditions 



December 



Jan. 1 to 18 



Jan. 19 to 31 



February 



Mar. 1 to 9 



When brood rearing is established 



°C. 



20 to 24 

 20 to 22 



22 to 25 



23 to 28 



24 to 30 

 27 to 32 

 34 to 35 



"F. 



68. to 75. 2 

 68. to 71. 6 

 71. 6 to 77. 

 73. 4 to 82. 4 

 75. 2 to 86. 

 80. 6 to 89. 6 

 93. 2 to 95. 



Table IV. — Monthly maximum and minimum temperature of the center of the bee cluster 

 during the winter period, Nov. 9 to Mar. 9. 





Month. 



Temperature of cluster. 





Maximum. 



Minimum. 





27° C 



17° to 18.2° C. 







80.60° F 



62.60° to 64.76° F. 





18.5° and 31.3° C.i 

 65.30° and 88.34° F.... 

 30.2°C2 



18.1° C. 





64.58° F. 

 19° C. 







86.36° F 



66.20° F. 





32° C.3 



21° C. 







89.60° F 



69.80° F. 



Mar. 1-9 



33.2° C.4... 



27° C. 







91.76° F 



80.60° F. 









i On a very warm day, Dec. 28. 



2 This occurred on two occasions, Jan. 14 and 30, at 8 a.m., when the outside temperature was 4° C. or 

 more below freezing. 



3 Approximated several times when outside temperature was below freezing. 



4 Occurred after a warm day; approaches summer conditions 



EFFECTS OF MANIPULATION ON THE CLUSTER. 



Good beekeepers know that it is not well to open a hive in winter, 

 but perhaps few realize the resulting effects on the colony. In 

 Washington there are days in every winter month which are suf- 

 ficiently warm to permit opening a hive without chilling the bees. 

 It was necessary, partially in order to observe the effects on the 



