16 BULLETIN 93, U. S. DEPARTMENT OF AGRICULTURE. 



excessive activity this bee stood in the same place for a time. Rapid 

 respiration may play a more important part in heat production than 

 at first appears. One bee was observed to breathe 21 times in 14 

 seconds and then cease the rapid respiration. On other occasions 

 50 or more bees would begin shaking their bodies from side to side. 



It has been shown in earlier sections that feces in the rectum cause 

 irritation, which induces increased activity and causes greater heat 

 production. It has also been found that other kinds of irritation 

 bring about the same result, but a discussion of these points can not 

 be undertaken here. It is at least evident from the records obtained 

 in this work that colonies of bees in winter, either in cellars or out of 

 doors, should be disturbed as little as possible. This appears to apply 

 especially to cold weather out of doors or in the cellar, especially 

 after the colony has been confined for some time. 



The facts mentioned concerning the ability of the bees to conserve 

 the heat generated will perhaps raise the question as to the tempera- 

 ture of the hive outside the cluster in cold weather, when the cluster 

 is compact. In the case of Colony A the temperature of the hive 

 outside the cluster was often practically as low as the outside tem- 

 perature. This colony was not packed and had a rather large en- 

 trance. If the cluster forms such an efficient insulator in itself it 

 might be presumed that packing about the hive is of little value and 

 that it might even be harmful, in that it would not serve to conserve 

 heat and would prevent the heat from the sun from penetrating to 

 the cluster. This line of reasoning, however, does not follow, and 

 in any case it is unsafe to speculate about these things without more 

 facts. The effects of various forms of packing are being studied. 



In closing it may be desirable again to state that too hasty con- 

 clusions must not be drawn from the facts here presented. For 

 example, the records on heat production might be interpreted as indi- 

 cating the desirability of a cellar temperature higher than beekeepers 

 usually believe to be best. Experiments to test such a theory are now 

 being carried on. and it is found that a broad statement as to the 

 best cellar temperature can not yet be given. Under most conditions 

 colonies can not be brought to the critical temperature, 57° F., with- 

 out disturbance. It is hoped that more work will throw some much- 

 needed light on this important subject. 



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