72 



FOURTEENTH ANNUAL REPORT OF- THE 



abnormal, due to disturbance, the chief 

 difficulty in understanding the phe- 

 nomena which take place is due to in- 

 sufficient observations. For example, 

 if between noon November 13 and 2 

 p. m. November 15 only a half dozen 

 temperature records had been made for 

 the cluster (and perhaps without find- 

 ing the warmest part of it) and the 

 outside air, it would have been im- 

 possible to determine the limits of 

 heat production. Most observers have 

 been satisfied with a few observations. 

 and seemingly every one who has in- 

 serted a thermometer in a hive has 

 felt called upon to publish the results, 

 thereby only confusing the problem. 



The Effect of Confinement and the 

 Accumulation of Feces. Before begin- 

 ning a discussion of the effect of con- 

 finement and the accumulation of feces 

 it may be recalled that during the ac- 

 tive summer season 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 we have evidence to prove that 

 this applies to the winter also, and this 

 belief is entirely supported by the ex- 

 perience of bee-keepers everywhere. 

 That bees may come out of winter 

 quarters strong in numbers and vital- 

 ity 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 there- 

 fore to find the conditions under w'hich 

 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 incident to flying on warm 

 days (if free to fly), and therefore the 

 problem, so far as it is under the con-- 

 trol of the bee-keeper, is primarily to 

 obviate the necessity for the produc- 

 tion of heat. If brood is reared the 

 work of the bees is necessarily enor- 

 mously increased, and their vitality is 

 correspondingly decreased. So far as. 

 evidence is available in our work, the ' 

 colony is not fully recompensed for 

 this expenditure of energy by an in- 

 crease in the strength of the colony by 

 bees thus reared. 



The colonies to be discussed under 

 this heading (Nos. 1 and 3) were 

 wintered in a constant-temperature 

 room at the University of Pennsyl- 



vania, Philadelphia, Pennsylvania, in 

 special 6 frame hives (to economize 

 space and concentrate the colony so 

 that fewer thermometers would be re- 

 quired) with full entrances and were 

 not propolized or sealed at the top. 

 During the regular series of readings 

 the room was kept at a temperature 

 which rarely dropped below 40°F. or 

 went above 4.5 °F., and the average 

 temperature from October 14 to March 

 6 was 42.67 OF. This temperature was 

 chosen as being nearly the one usually 

 considered best by bee-keepers. 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. On this colony, 24,- 

 077 temperature readings were taken. 



According to what has been said in 

 the previous section, we should expect 

 bees at such a temperature to main- 

 tain 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 OF. 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. It was then removed for a 

 flight and put back the same even-' 

 ing, where it remained until March 28. 

 From March 7 at 9 a. m. until March 

 28 at 4 p. m. readings were made on 

 this colony every 15 minutes night and 

 day, wit^i the exception of the period 

 between 9 a. m. and 7 p. m. on the 24th, 

 when it was out of doors. During this 

 period of three weeks the temperature 

 of the room was changed slowly, being 

 raised as high as 640F. and cooled to 

 130F. 



When this colony was first placed in 

 the room for the regular series of read- 

 ings, after a preliminary confinement, 

 October 12 (the readings were begun 

 Monday, October 14), it maintained a 

 cluster temperature which usually lay 

 between 64° and 680F., the daily aver- 

 age temperature departing from these 

 rather narrow limits only four times 

 up to November 22. The average 

 temperature is 66.50F. During the first 

 five weeks the temperature of the room 

 was less regular than later (due to 

 faulty working of the regulating ap- 

 paratus), and this doubtless accounts 

 for some irregularities in the cluster 

 temperature. At first the three ther- 



