NOVEMBKR 1. 1915 



ity. Examination of the hives where hees 

 have died, in '.)9 oases out of 100, if not 999 

 out of 1000, shows hives to be soiled by 

 liijiiid feces. 



hi;at gknekatiox by a cluster op bkes. 

 While the authors do not make this state- 

 ment, we believe it to be in harmony Avilh 

 their teachings. ]n order that the reader 

 rcav better understand the subject of heat 

 generation, if he has not already read pase 

 789 of our volume for last year, and pages 

 49 and 93 of this year, we quote all that is 

 said in the bulletin on this subject. 



EXCESSIVE HEAT. GKNERATIOX. 



Tt was first shown by the authors in the bulletin 

 to which reference has been made that at hive tem- 

 pivatures between about 57° and 69' F. a normal 

 bvoodless colony of bees does not form a cluster, 

 but the bees remain inactive on the combs. When 

 the temperature of the air immediately surrounding 

 the bees fnot the teraperaUire of the air outside thq 

 hivel falls to 57" F. or lower, they form a cluster, 

 and those in the center beprin to generate heat by 

 muscular activity, while those in the outer portioi; 

 s'-rve as insulators by crowding close together, usu- 

 ally with their heads toward the center of the clus- 

 ter. The innermost portion rapidly acquires a tem- 

 perature considerably hig-her than that of the aii- 

 .ibout the bees before clustering was necessary, often 

 going to 90° F. in :iormal colonies and higher in 

 abnormal ones. The number of bees engaged in 

 heat prodiiction increases as the outer temperature 

 falls, and the insulriting zone is consequently de- 

 crcMsed in thickness, but becomes more compact. 

 The entire cluster becomes smaller as the outer tem- 

 perature falls. 



If bees can be kept in an environment such that 

 the temperature of the air immediately surroundin;^ 

 them is 57° F. or slightly above, they are saved 

 much unnecessary and unprofitable labor. To the 

 theoretical objection that bees need exercise, it is nec- 

 essary only to state tbat the authors have so wintered 

 hees in a cellar as well as outdoors with wonderfnlly 

 successful results. If bees are kept in a cellar un- 

 der the best conditions the results are excellent ; but 

 it is not proposed to discuss this more complicated 

 phase of the subject here. If wintered outside in 

 a packing-case, with abundant insulation, any heat 

 generated escapes slowly and the temperature of the 

 air in the hive rarely falls below 55° F. If inade- 

 quately protected, the temperature of the hive can 

 not be kept so high, and the bees must generate 

 much more heat. In single-walled hives it is corn- 

 iron for the temperature of the air around the 

 duster to fall to freez-ing or lower, in which event 

 the bees generate an o-cessive amount of heat, arid 

 perhaps die when they are no longer capable of the 

 necessary muscular activity. The necessity of pack- 

 ing is thus made clear, and in any locality in which 

 the outer temperiiture often falls to 40° F. or belov/ 

 it is desirable to protect bees to conserve their vital- 

 ity. If the temperature shoald fall to 40° F. only 

 a few times during the winter, this would not be 

 serious enough to make insulation necessary. It is 

 obvious, however, that winter protection is benefi<'ial 

 ihroughout practi"ally the entire United States. 



If the reader will peruse the foregoin.g 

 very carefully he will be able better to 

 understand why "excessive heat production" 

 is the direct cause of the death of the bees. 

 Of course it cannot be denied that cold is 

 the real cau.se of e.\ce.ssive heat crnneratiou : 

 hut cold as alieady pointed out is not wir.ii 



usually kills the bees. If the beekeeper can 

 keep the proper temperature in his hives by 

 m'^aus of adequate protection, either out- 

 doors or in cellars, there will be no exces- 

 sive heat generation. 



The authors very properly call attention 

 to the importance of young bees in the fall. 

 Old ones soon succumb to the work of heat 

 generation as soon as cold- weather comes 

 on. 



WE.-VK COLONIES AND WHY THEY DIE SOON. 



AA^eak colonies cannot stand cold even 

 relatively as well as the strong ones. "Since," 

 say the au.thors, " the sui'face of a spherical 

 cluster is proportionate to the square of 

 the diameter, while the volume is propor- 

 tionate to the cube of the diameter, it fol- 

 lows that a large 'colony cluster has a rela- 

 tively smaller surface for radiation of heat 

 than does a small one." Tt follows, tliere- 

 fore, that the weak cluster must do m.ore 

 work in proportion to its size to keep up 

 the proi'jer temperature, and hence it is 

 plain Avhy they are more inclined to have 

 dysentery than the big colonies. 



THE ACCUMCLATION OF FECES. 



On the question of the effects of the ac- 

 cumulation of feces, the authors say that 

 " Dysentery causes death of bees in winter, 

 so far as has been seen, solely by undue 

 activity and excessive heat production. This 

 detrimental effect is reduced by good stores, 

 but obviously the proi^er method is to pre- 

 vent an unnecessary' accumulation of feces 

 by preventing a heavy consumption of 

 stores, chiefly by providing a sufficiently 

 high surrounding temperature." 



A good queen will better prepare a colony 

 for Avinter by supplying it with a large 

 force of young bees. She will also furnish 

 plentv' of brood in the sj^ring provided the 

 colony is strong enough and ihe stores good. 



METHODS OF PACKING. 



On the subject of the conservation of 

 heat and the reduction of expenditure of 

 energy, we feel that we must quote the 

 authors in full; for this question of pack- 

 ing for outdoor wintering is often misun- 

 derstood. Here is Avhat they saj-. 



CONSEKV-^TION OP HEAT AND REDUCTION OF EX 

 PENDITURE OF ENERGY. 



In outside wintering, the heat produced by the 

 bees is conserved by the insulation of the cluster it- 

 self, and also by the insulation of the hive and pack- 

 ing. In the cellar there is less insulation near the 

 cluster, but the cellar itself replaces the pac!:ing, 

 and it is in reality simply an insulation. The insu- 

 lation of the individual hive, of several hives packed 

 liiscther, or of bees in a cell.Tr, serves solely to re- 

 dure the loss of heat eenerated by the bees. 



The amount of jiacking that should be used obvi- 

 ou>;ly varies with the climate ; and it is ilnpossible to 

 iii'ikc difinite general statements in a bulletin intend- 

 id fvv all p:»rt-s of the United States. There is otio 



