WEATHER AND CHANGE IN WEIGHT OP BEE COLONY 27 



TEMPERATURE AND CHANGES IN THE COLONY WEIGHT 



In the vast literature of beekeeping few data are found to be useful 

 in throwing light on the relation of external temperature to the 

 changes in colony weight. Many experiments, however, have been 

 conducted to ascertain the relation of temperature to nectar secretion. 

 Of the latter, the work of Bonnier stands out most prominently. 

 Unfortunately, he published but few of the actual data upon which 

 his conclusions were based, so that it is difficult to make mathemati- 

 cal comparisons with the data herein presented or with the data of 

 other investigators. Broadly speaking, the correlation between plant 

 or animal activity and temperature is positive within, of course, cer- 

 tain limits. Most reactions, whether organic or inorganic in nature, 

 are retarded by low temperatures, and increased by higher tempera- 

 tures, although there are many examples to the contrary. 



TEMPERATURE AND NET GAIN 



During the spring period temperature has a marked effect upon net 

 gain, the correlation between these factors being .7529 ±.0473. 

 This is a higher correlation than was found between net gain and any 

 of the other weather factors, from which it appears that among those 

 considered, temperature is the most important single factor influenc- 

 ing changes in the colony weight. Bonnier (1, p. 163), in referring 

 to nectar secretion, states that the volume of nectar varies inversely 

 as the temperature. Kenoyer (20) also says that the accumulation 

 of sugar in the flower and its vicinity varies inversely as the temper- 

 ature. In referring to honey production, however, Kenoyer (19) states 

 that good honey months average slightly higher in temperature than 

 poor ones, this being especially true of the fall and spring months, 

 and that the yield is best on days having a maximum of 80° to 90° F. 

 (.26.7° to 32.2 6 C.) . Ono (26, p. 15) , in studying the secretion of extra- 

 floral nectaries, does not lay much stress on temperature. He found 

 that within the range of 15° to 25° C. (59° to 77° F.) the influence 

 of temperature upon secretion is not remarkable; and that tempera- 

 ture seems to have merely an indirect influence in so far as it affects 

 the plant itself. Harrault (15) states that for a given plant placed 

 in suitable vegetative conditions the production of nectar increases 

 with the increase in temperature and the quantity of sunlight, the 

 production following general botanical laws. The writer's calculation 

 of Ilarrault's rather scanty data gives a correlation of .5258 ±.0639 

 between net gain and temperature. A negligible correlation of 

 .0065 ±.1079 was likewise calculated from data presented by Mau- 

 jean (28). 



Bonnier reached his conclusion by removing the nectar from vari- 

 ous species of plants from hour to hour by means of a small pipette, 

 and noting the temperature. The writer's calculations of Bonnier's 

 data gave a correlation of — .6581 ±.0901 between temperature and 

 nectar secretion. Coefficients of correlations were also calculated from 

 the same data between humidity and gain and between humidity 

 and temperature, with the following results, where T= temperature, 

 H= humidity, and iV= volume of nectar: 



r Nr = -.6581 ±.0901 

 r KU = .8040 ±.0562 

 r TB = - -9202 ± .0243 



