HEAT PRODUCTION OF HONEYBEES IN WINTER. 5 



DISCUSSION OF THE TEMPERATURE RESPONSES IN THIS 



EXPERIMENT. 



The colony used in the experiment here reported was taken to 

 Washington from the suburbs some time prior to the beginning of 

 the experiment. The bees were placed in the calorimeter and then 

 it was found that the apparatus was defective and it was necessary 

 to remove them. During the interval before the experiment here 

 recorded was begun, they were placed outside where they were 

 free to fly when the weather permitted, and they had several flights 

 and carried out the dead bees. They were therefore in good condi- 

 tion at the beginning of the experiment. 



For several hours after the hive was again placed in the respira- 

 tion chamber, the temperatures of the hive and bees were high, 

 chiefly as a result of the disturbance arising from the handling 

 necessary at this time. They were put in place at 3 p. m. on Decem- 

 ber 11, and during the night the temperature of the bees on one 

 occasion, and in one point only, rose to 35° C. During the night 

 the temperature of both the chamber and the bees drifted down, 

 until shortly after noon on the 12th, when they may be considered 

 as having reached normal quiescence. Just when the bees definitely 

 formed a winter cluster is not clear from the data, but certainly 

 when they had reached quiescence they were clustered. 



In the graphic charts of temperatures of this colony, records are 

 included for thermocouples 6, 7, and 12, these being the ones which 

 were in the center of the cluster, which was located near the top 

 and slightly to one side of the hive. For comparison with these 

 the record for thermocouple 15 giving the temperature of the air 

 of the chamber at one point outside the hive is also included. 



It will be observed that on several occasions the temperature of the 

 center of the cluster (which shifted between thermocouples 12 and 7, 

 according to the movement of the cluster during the experiment) 

 rose somewhat abruptly but temporarily, not, however, reaching the 

 temperatures observed at the time that the bees were placed in the 

 chamber. While some of the rises may be attributed to mechanical 

 disturbances, it was not always possible to determine the exciting 

 cause. This is in accordance with numerous observations made in the 

 work on the behavior of bees in confinement to which reference has 

 already been made. Throughout the experiment, of course, heat 

 production never ceased, and with the bees in this condition of 

 activity it took but a small disturbance to induce them to generate 

 slightly more heat. This is comparable with the periods of activity 

 that have long been observed in bees wintered in cellars. 



It is more important to note that during the 12 days that the 

 bees were in the respiration chamber the temperature of the cen- 



