FIFTEENTH ANNUAL YEAR BOOK— PART VIII. 509 



therefore, that the temperature within the cluster is far from being uni- 

 form in winter, as has been, in a sense, assumed among practical bee- 

 keepers. At the temperature at which other insects become less active 

 (begin hibernation), the honey bee becomes more active and generates 

 heat in some cases until the temperature within the cluster is as high as 

 that 'of the brood nest in summer. To sum up, wh§n the temperature of 

 a colony of undisturbed broodless bees is above 57° F. and below 69° F. 

 the bees are quiet and their temperature drifts with the outer tempera- 

 ture; at lower temperatures they form a compact cluster, and the tem- 

 perature within it is raised by heat generated by the bees. 



We desire to state that while the lower critical point, 57° F., appears 

 rather well established, the observations up to the present do not justify 

 too definite a statement concerning the upper limit of quiescence. It 

 must be emphasized that these conditions do not apply when the colony 

 has brood. The rearing of brood in winter causes a marked -increase in 

 heat production and constitutes a condition which may become one of the 

 most disastrous that can befall a confined colony. 



When the heat production of the colony is explained, we are able to 

 understand to some extent the divergence in the records obtained by other 

 observers. It has, of course, long been known that bees generate heat, 

 and it has been pointed out that during cold weather the temperature of 

 the cluster is often higher than during ^>armer weather. While the tem- 

 peratures previously recorded are in most cases abnormal, due to d'is- 

 turbance, the chief difficulty in understanding the phenomena which takes 

 place is due to insufficient observations. For example, if between noon 

 November 13 and 2 p. m. November 15 only a half dozen temperature rec- 

 ords had been made for the cluster (and perhaps without finding the 

 warmest part of it) and the outside air, it would have been impossible to 

 determine the limits of heat production. Most observers have been satis- 

 fied with a few observations, and seemingly everyone who has inserted a 

 thermometer in a hive has felt called upon to publish the results, thereby 

 only confusing the problem. 



THE EFFECT OF CONFINEMENT AND THE ACCUMtJLATION OF FECES. 



Before beginning a discussion of the effect of confinement and the accu- 

 mulation of feces, it may be recalled that during the active summer sea- 

 son the length of life of worker bees is in a sense determined by the work 

 done by them rather than by days or weeks. The greater the necessity for 

 excessive activity the shorter the term of life. We believe that they haVe 

 evidence to prove that this applies to the winter also, and this belief is en- 

 tirely supported by the experience of beekeepers everywhere. That bees 

 may come out of winter quarters strong in numbers and vitality, it fol- 

 lows that the vvork to be done by the bees in the winter should be reduced 

 to a minimum; and the winter problem, as thus interpreted, is therefore 

 to find the conditions under which broodlees bees do the least work. The 

 work which broodless bees do in winter consists, so far as has been deter- 

 mined, solely in the production of heat or in activity incident to flying 



