TEMPERATURE OF THE HONEYBEE CLUSTER IN WINTER. 7 



mined 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. The authors believe that they have evidence to prove that 

 this applies to the winter also, and this belief is entirely supported 

 by the experience of beekeepers everywhere. That bees may come 

 out of winter quarters strong in numbers and vitality it follows that 

 the work 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 broodless bees do the least work. 

 The work which broodless bees do in winter consists, so far as has 

 been determined, solely in the production of heat or in activity inci- 

 dent to flying on warm days (if free to fly), and therefore the prob- 

 lem, so far as it is under the control of the beekeeper, is primarily 

 to obviate the necessity for the production of heat. If brood is 

 reared the work of the bees is necessarily enormously increased, and 

 their vitality is correspondingly decreased. So far as evidence is 

 available in this work, the colony is not fully recompensed for this 

 expenditure of energy by an increase in the strength of the colony 

 by bees thus reared. 



The colonies 1 to be discussed under this heading (Nos. 1 and 3) 

 were wintered in the constant-temperature room in special 6-frame 

 hives (to economize space and concentrate the colony so that fewer 

 thermometers would be required) with full entrances and were not 

 propolized or sealed at the top. During the regular series of read- 

 ings the room was kept at a temperature which rarely dropped below 

 40° F. or went above 45° F., and the average temperature from 

 October 14 to March 6 was 42.67° F. This temperature was chosen 

 as being nearly the one usually considered best by beekeepers. The 

 foods given these colonies were stored in the combs, just as placed 

 by the bees. There was some pollen available in colony No. 1. 

 (Fig. 2.) 



According to what has been said in the previous section, we should 

 expect bees at such a temperature to maintain a compact cluster and 

 to generate some heat at all times. This was actually the case, the 

 temperature of the interior of the clusters dropping below 64° F. 

 only a few times in either colony. 



Colony No. 1, on honey stores, was in the constant-temperature 

 room from October 12, 1912, to March 24, 1913, or 163 days. 2 It 



1 In order that the young bees might all get a flight before the winter confinement, the 

 two colonies here discussed were placed in the constant-temperature room after the brood 

 had been removed. They were kept here several days, removed for a flight, and then 

 returned to the room for the regular series. The significance of this manipulation must 

 be reserved for a later discussion. This explanation is made to show how it was possible 

 to put these colonies in the room so early in a climate as mild as that at Philadelphia. 

 The object was, of course, to increase the time available for observation. Bees are 

 usually not wintered in cellars in climates as mild as that of Philadelphia. 



2 In all, 24,077 temperature records were made for this colony. 



