

TEMPEKATURE OF THE HONEYBEE CLUSTER IN WINTER. 5 



only after the day's records are made) and only when absolutely 

 necessary. It is found that entering the constant-temperature room 

 may under some conditions influence the behavior of the bees in a 

 marked manner. 



Other colonies are kept on the roof of the same laboratory, where 

 they are left untouched from the beginning to the end of a series 

 of readings. The wires of the thermometers are led to the room 

 below through rubber tubes, and all the temperature readings are 

 made at a distance, as is absolutely necessary to eliminate disturbance. 

 Disturbances of outside colonies have also been found to influence 

 their behavior in a pronounced manner, especially in cold weather. 



By studying the temperature of various fixed points within each 

 hive it has been found possible to use the temperature readings as a 

 substitute for direct observations. After becoming familiar with 

 the normal temperature and the temperatures incident to various 

 activities one can tell the shape, location, and various activities of 

 the cluster by a study of the temperature of different points within 

 the hive and can, in fact, form an opinion as to the welfare of the 

 colony. It has therefore been possible to folloAv closely the activities 

 of each cluster without opening the hives and even without going 

 near them. 



THE INFLUENCE OF EXTERNAL TEMPERATURE ON HEAT 



PRODUCTION. 



The colony (A) to be discussed under this heading was wintered 

 out of doors (1912-13) on the roof, where the bees were free to fly 

 whenever the weather permitted. It was in a 10- frame Langstroth 

 hive, with the entrance reduced to f inch deep and 8 inches wide, and 

 was not packed or given additional protection. This hive contained 

 19 of the electrical thermometers — 12 among the combs, 4 in the cor- 

 ners of the hive, and 3 on the bottom board. Readings were made 

 hourly from 9 a. m. to 4 p. m. through the winter (Sept. 26 to Mar. 

 28), except Sundays and holidays, and at intervals additional read- 

 ings were made every 15 minutes (or sometimes every 30 minutes) 

 during the night (5 p. m. to 8.45 a. m.) for periods of several days 

 each. In all, 41,413 temperature records were made for colony A. 



The reaction of the cluster in heat production, as induced by 

 changes in external temperature, is well shown by the records made 

 from noon November 13 to 2 p. m., November 15 (1912), when read- 

 ings were made hourly from 9 a. m. to 4 p. m. and every 15 minutes 

 at night. From noon on November 13 the outside temperature 

 dropped slowly until 6 a. m., November 15, and the weather was 

 cloudy, so that the bees did not fly. It will be seen from the accom- 

 panying diagram (fig. 1) that at noon on the 13th the outside tem- 

 perature was about 69.2° F. and all the points within the hive were 



