1886 



GLEANINGS IN BEE CULTURE. 



91 



WINTER TEMPERATURE OF BEES. 



A UEPLY TO G. M. DOOLITTLE'S AHTICI.E, I'AOK 1!I0, 

 MARCH 15, 1885. 



R. DOOLITTLE has laid his fellow bce-kcfp- 

 ers under an oblijration of griititude liy his 

 thermometrical observations in regard to 

 the degree of heat maintained inside a clus- 

 ter of bees during the winter, as reported 

 on page 193. Though his e.\periments have con- 

 ducted him to a conclusion unfavorable to my 

 views coucerniug hibernation, he has ray thanks 

 none the less; and I hope to show him, before I 

 have done, lliat he has decided against hibernation 

 on Insufficient evidence. At any rate, 1 shall ti-y 

 to do so. 



At the outset, however, let me say that the Amcr- 

 icait Apiculturint is in error when it states, concern- 

 ing entomologists, that "not one of this class can 

 tell us any thing reliable about the winter tempera- 

 ture of the bee-hive." Huber, Reaumer, Newport, 

 and others, have given nsHnformation, which, con- 

 sidering the sources of it, must sui-elj' be regarded 

 as " reliable." Mr. Newport especially, made nu- 

 merous experiments to ascertain the temperature 

 of the interior of bee hives in winter, which he re- 

 corded in a valuable paper published in the Philo- 

 sophical Transaction::, entitled "On the Tempera- 

 ture of Insects." 



Huber tells us, as the result of his observations, 

 that "the heat in a well-peopled hive continues 86 

 or 88 Fahrenheit, when it is several degrees below 

 zero in the open air." He also says, that bees 

 "then cluster together and keep themselves ))( mo- 

 tion in order to preserve their heat;" and that, " in 

 the depth of winter, they do not cease to ventilate 

 the hive by the singular pi'ocess of agitating their 

 wings before described." Mr. Newport was of the 

 opinion that Huber was altogether in error in as- 

 signing a heat of 80 or 88 Fahrenheit to a populous 

 hive, which, he contends, has its temperature some- 

 times (thougli rarely) lower than that of the freez- 

 ing-point, and in the winter months does not aver- 

 age moi-e than from 7 to 9 degrees above that of the 

 atmosphere, or about 52, though merely tapping on 

 the outside of the hive, by exciting the bees, will, 

 at any time, greatly increase the heat: in one in- 

 stance, Feb. 3, to 102% when the temperature of an 

 adjoining hive was only 48. .5° ; and it is from this 

 eii-cumstance that he supposes Huber's error to 

 have arisen, as the mere excitement caused bj' in- 

 troducing a thermometei" is sufficient, to raise the 

 heat to the point (£6° or 88°) which that observer 

 mentions. Mr. Newport admits that hive-bees are 

 never strictly torpid, but pa»>< the winter in a state 

 of hihernatino sleep, linhle to constant interruption 

 by considerable variations of external temperature 

 or accidental excitement. 



Mr. Doolittle's experiments prove the extreme 

 ilifficulty, if not utter impossibility, of ascertaining 

 the normal temperature of the interior of a bee- 

 cluster; for the moment the bees ai-e disturbed and 

 excited, the heat begins to increase. It is natural 

 to suppose that the bees at or near the outside of 

 the cluster will be cooler than those at the center 

 of it; yet they may be, and no doubt are, warmer 

 than the air outside the cluster, owing to the trans- 

 mission of heat from their companions who occupy 

 an inside berth. 



If Mr. Doolittle had noticed my article in the 

 An^rrican Iice JouDKtl of .lanuary U, I8S5, headed. 



"Chilled Bees are Not Hibernating," he would 

 hardly have made the remark that I call " stiffened " 

 bees "hibernating" bees. I there said, "Chilled 

 bees are not hibernating bees, but bees undergoing 

 the process of being frozen to death. In the early 

 stages of this process they may be restored by 

 warmth; but unless thus restored they will die. 

 They are not on the road to death when they hlbei-- 

 nate. This is nature's expedient for preserving 

 them alive." I must ask Mr. Doolittle to read the 

 whole article, from which the above is a brief ex- 

 tract. 



My belief is, that bees, in a climate like ours, 

 "pass the winter in a state of hibernating sleep," 

 as Newport expresses it. Unable, before going in- 

 to this state, to take food enough to last them any 

 great length of time, they must necessarily rouse 

 up at intervals to feed. I think they usually do 

 this when spells of mild weather come. But, if the 

 demands of hunger compel them to wake up and 

 eat when the surrounding atmosphere is cold, they 

 have recourse to that faculty of generating heat 

 which Huber mentions, and with which all bee- 

 keepers are familiar. During the present winter 

 (1884-5) we have had scarcely any warm spells; but 

 I have noticed that whenever we did have one there 

 was a hum of activity in my supposed-to-be hiber- 

 nating hives. This hum 1 have taken to be the 

 sound of the dinner-gong. 



"A well-peopled hive," as Huber calls it, is, no 

 doubt, much warmer than the outer air, even when 

 the bees have fallen into their hibernating sleep. 

 How much 1 do not know, nor is it easy to find out, 

 because the least disturbance of the bees raises the 

 heat. But 1 am inclined to think there must be ex- 

 citement before the temperature becomes 86 or 88°, 

 as noted by Huber. T have observed the phenom- 

 enon of warmth under the cushion and just over 

 the cluster of bees, mentioned in the editorial 

 notes to Mr. Doolittle's letter, and so, doubtless, 

 have most bee-keepers. We want to find out, if we 

 can, what that degree of heat should be to enable 

 bees to hibernate comfortably. Then we must try 

 to ascei-tain the size of cluster, and dimensions of 

 hive, necessary to secui-e that degree of heat. 



I suppose if we could investigate a hibernating 

 bear we should find the outer fur pretty cool; but 

 the roots of the hair imbedded in the hide, would be 

 warmer. Then if we could sink the bulb of a ther- 

 mometer down to the region of the heart we should, 

 no doubt, find blood-heat there. A cluster of bees, 

 when balled and knotted up as tightly as possible, 

 may perhaps be of the nature of one living entity, 

 the outer bees in a state similar to that of the 

 bear's fur, and the central ones warm as Bruin's 

 heart, and, like that, diffusing heat and life to the 

 whole cluster. 



Mr. Doolittle thinks it "impossible for bees to hi- 

 bernate when they must burn honey enough to 

 warm a temperature of 10 below zero to 6'5 above." 

 To which I reply: 1. When it is 16 below zero out of 

 doors, it will not be so cold as that inside a chaff- 

 packed hive with sawdust cushion on top, irrespec- 

 tive of heat generated by the bees. When it is 10 

 below zero in the open air, as it has often been this 

 winter, 1 have fouud that it was not nearly st) cold 

 inside my wood-shed, which is only a single-boarded 

 building. 2. It would not take much of a lamp to 

 raise the temperature inside a hive, such as Mr. 

 Doolittle experimented upon, to 63 above zero. Is 

 It too much to believe that the respiration of 2 i.Odll 



