ILLINOIS STATE BEE-KEEPERS' ASSOCIATION 



55 



Conservation of Heat and Reduction of 

 Expenditure of Energy. 



In outside wintering the heat pro- 

 duced by the bees is conserved by the 

 insulation of the cluster itself and aisu 

 by the insulation of the hive and pack- 

 ing. In the cellar there is less insula- 

 tion near the cluster, but the cellar it- 

 self — i^places the packing, and is in 

 reality simply an insulation. The in- 

 sulation of the individual hive, of sev- 

 eral hives packed together, or of bees 

 in a cellar, serves solely to reduce the 

 loss of heat generated by the bees. 



The amount of packing that should 

 be used, obviously, varies with the cli- 

 mate and it is impossible to make def- 

 inite general statements in a Bulletin 

 intended for all parts of the United 

 States. There' is one general state- 

 ment which can be made with safety: 

 The majority of bee-keepers do not 

 give sufficient insulation and no bee- 

 keeper ever gave a colony too much. 

 The aim of the bee-keeper should be 

 to keep the air about the bees at about 

 57° F., at which temperature there is 

 no condensation of moisture within the 

 hive, even on the inside of the cover, 

 where it first appears. It might be in- 

 ferred that if double the amount of 

 packing had been used the temperature 

 of the air about the bees w^ould have 

 been too high. This is not the case, for 

 bees cease heat-generation when the 

 temperature reaches 57° F., (or even 

 sooner when the surrounding temper- 

 ature is rising) and the temperature 

 will not exceed 57° F. unless that of 

 the outer air remains higher than that 

 for a considerable period. 



Bees well protected and with good 

 stores do not fly from the hive because 

 of the warmth within when the outer 

 air is too cold for them to do so safely. 

 If bees fly at low temperatures (45° to 

 50° F.), it is an indication that they 

 need a flight because of an accumula- 

 tion of feces from poor wintering, and 

 does not at all indicate too high an 

 inside temperature because of too much 

 packing. In conclusion, the bee-keeper 

 can not apply too much insulating ma- 

 terial to a hive. 



It has been found that, even with 

 abundant insulation, the temperature 

 within the hive and outside the cluster 

 is greatly reduced if the packing case 

 is exposed to wind. During the winter 

 1914-15 a record was kept of wind ve- 

 locity directly over a heavily packed 



case (with entrances % inch by 8 

 inches), and it was found that a wind 

 with a velocity of 20 miles per hour 

 directly on the case reduces the tem- 

 perature within the hives practically to 

 that observed in an unprotected hive. 

 The beneficial effects of the insulation 

 were therefore nullified, and the proper 

 temperature within the hive was not 

 regained for several days unless the 

 outer temperature rose considerably. 

 Bee-keepers have long emphasized the 

 importance of protection from wind, 

 but the results observed were much 

 more pronounced than was anticipated 

 or than has ever been suspected by 

 practical bee-keepers. The ideal to- 

 ward which the bee-keeper should 

 work is to keep his colonies during cold 

 weather absolutely protected from 

 wind, for here again the protection can 

 not be too great. It is entirelj' erron- 

 eous to assume, as some have done, 

 that such protection is not essential in 

 well -packed hives. 



There are several types of hives on 

 the market in which the insulation is 

 built in, to be retained throughout the 

 j'ear. There is no objection to the 

 packing in the summer, except that 

 such hives are not convenient for mov- 

 ing and in some other manipulations. 

 Insulation in commercial double-walled 

 hives is by means of air spaces or In- 

 sulation, such as sawdust, chaff, broken 

 cork, or shavings. These hives are bet- 

 ter for outside wintering than single- 

 walled hives in any part of the United 

 States, but they do not provide ade- 

 quate insulation at temperatures below 

 40° F. Such hives must, of course, be 

 protected from wind, or they are for 

 the time being no better than single- 

 walled hives. 



Types of Insulation. — Various mate- 

 rials are used for insulation. Beside 

 those named above, paper, dry leaves, 

 and many other substances are in use. 

 Most of the common insulating ma- 

 terials depend on small confined dead- 

 air spaces for their insulating value, 

 and, in general, the more finely divided 

 the air spaces the more efficient the 

 material. Sawdust is usually con- 

 demned, because if moisture escapes 

 from the hive into the packing it is 

 retained and the insulatins: value is re- 

 duced. However, if a colony is suffi- 

 ciently packed, moisture does not con- 

 dense, except possibly at extremelv low 

 external temperatures, and this objec- 



