12 BULLETIN" 93, U. S. DEPARTMENT OF AGRICULTURE. 



recorded 61.5° F. These thermometers showed about the same tem- 

 peratures for about 10 days, and then these two and thermometer 16 

 showed a cooling, since the bees were dying so fast that there were 

 no longer enough to warm up these thermometers away from the 

 center of activity. It was to be expected that this colony would die, 

 and the experiment was performed to learn the phenomena incident 

 to the loss. 



Before summing up the results of these two colonies, Nos. 1 and 3, 

 it may be stated that, so far as the evidence here presented is con- 

 cerned, the results as far as here discussed are confirmed by records 

 from 10 other colonies kept in the constant-temperature room, but 

 fed other foods and otherwise different. There is in all of the records 

 no evidence which the authors can interpret as at all contrary to the 

 views here stated. A discussion of these other colonies is reserved. 



It is evident from the behavior of colony No. 1 that at least one 

 factor entered which gradually caused the bees in the cluster to 

 generate more and more heat until at the beginning of the special 

 series, March 7, the cluster temperature was about 20° warmer than 

 it was at the same room temperature at the beginning of the confine- 

 ment. It is also seen that during the special series, March 7-24, the 

 cluster temperature always remained at least 20° above the room 

 temperature, whereas from the discussion of bees unconfined 

 (Colony A) we might expect them to cease heat generation when 

 above the lower critical temperature (57° F.). In the case of colony 

 3, fed on honeydew honey stores, the factor which caused more heat 

 to be produced evidently increased much more rapidly. As stated 

 previously, honeydew honey is a poor food for winter and is so 

 recognized. It contains the same sugars as honey, but contains in 

 addition a considerable amount of dextrin, the particular lot fed to 

 colony 3 containing 4.55 per cent while good honeys contain only a 

 fraction of 1 per cent. From the evidence at hand it appears that 

 dextrin can not be digested by bees and, whether or not this is the 

 explanation, honeydew honey causes a rapid accumulation of feces 

 which usually results in the condition known as dysentery, in bad 

 cases of which the feces are voided in the hive. In the case of colony 

 3 the whole hive inside and out, as well as the frames and combs, were 

 spotted badly, the inside of the hive being practically covered. Even 

 with fine honey stores such a spotting is usually noticed after a pro- 

 longed confinement, especially in severe weather (or during brood 

 rearing). It therefore appears that the accumulation of feces acts 

 as an irritant, causing the bees to become more active and conse- 

 quently (see later section) to maintain a higher temperature. We 

 are therefore justified in believing that the cause of poor wintering 

 on honeydew honey is due to excessive activity, resulting in the bees 

 wearing themselves out and ultimately in the death of the colony. 



