HOW BEES RECOGNIZE EACH OTHER 



THAT bees recognize each other 

 principally by the sense of smell 

 is the conclusion of N. E. 

 Mclndoo, of the Bureau of 

 Entomology, who discussed the subject 

 at the last annual meeting of the 

 American Society of Zoologists. Most 

 of his conclusions are confirmed by the 

 work of other students. 



" It is certain," he says, "that a queen 

 gives of? an odor, and it seems reason- 

 able that the odors from any two queens 

 would be slightly different. All the off- 

 spring of the same queen seem to in- 

 herit a particular odor from her. This 

 odor, called the family odor, perhaps 

 plays little or no part in the lives of bees, 

 for it is certainly masked by the other 

 odors. Drones seem to emit an odor 

 peculiar to their sex, but little can be 

 said about it. It seems certain that 

 each worker emits an individual odor 

 which is different from that of any other 

 worker. It is also probable that the 

 wax generators and nurse bees emit 

 odors slightly different from those of 

 the field bees. 



"Of all the odors produced by bees, 

 the hive odor is probably the most im- 

 portant. It seems to be the funda- 

 mental factor or principle upon which 

 the social life of a colony of bees depends, 

 and perhaps upon which the social 

 habit was acquired; without it a colony 

 of bees could not exist. The hive 

 odor is composed chiefly of the indi- 

 vidual odors from all the workers in a 

 hive, and is supplemented by the odors 

 from the queen, drones, combs, frames 

 and walls of the hive, etc. From this 

 definition it is easily understood why no 

 two colonies have the same hive odor. 

 The hive odor of a queenless colony is 

 perhaps considerably different from that 

 of a colony which has a queen. The 

 absence of a queen odor in the hive odor 

 probably explains why the workers in a 

 queenless colony are irritable and never 

 work normally. All the bees — workers, 

 queens and drones — of a colony carry 

 the hive odor of that colony on their 



bodies among the hairs. This odor 

 serves as a sign or mark by which all 

 the occupants of a hive 'know' one 

 another. vSince the queen and drones 

 are 'aristocrats' they seem to disregard 

 the sign that has been thrust upon them, 

 but whenever a queen enters the wrong 

 hive, she soon 'realizes' that she wears 

 the wrong badge. Worker bees re- 

 turning to the hive from the fields pass 

 the guards unmolested, because they 

 carry the proper sign, although the 

 hive odor that they carry is fainter than 

 when they left the hive, and it is also 

 partly masked by the odors from the 

 nectar and pollen carried by these bees. 



ODORS MAY CHANGE 



"Bees kept in the open air for three 

 days lose all the hive odor carried on 

 their bodies, but each bee still emits its 

 individual odor. When a colony is 

 divided the hive odor in each half soon 

 changes so that by the end of the third 

 day the original colony possesses a hive 

 odor so different from that of the other 

 half of the colony, that when the workers 

 are removed from the two new colonies 

 and are placed together in observation 

 cages, they fight one another as though 

 the}^ had been separated all their lives. 



"While a foreign hive odor calls forth 

 the fighting spirit in workers, the queen 

 odor always seems pleasant to workers 

 regardless of whether the queen belongs 

 to their hive or to another hive. Even 

 though the queen odor forms a part of 

 the hive odor, it is probable that this 

 odor to the workers stands out quite 

 prominently from the hive odor. That 

 workers do not miss their queen for 

 some time after she has left the hive, 

 indicates that her odor thoroughly per- 

 meates the hive odor and that whenever 

 this odor grows faint the workers 

 'know' she is not among them. 



"There has been much speculation 

 concerning the ruling spirit or power in 

 a colony of bees. The writer is in- 

 clined to believe that a normal hive 

 odor serves such a purpose. The hive 



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