370 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1955 



moreover, that at the same time many of the bees at the entrance of 

 the hive were rapidly beating their wings (this action is known as 

 "fanning") and standing in a characteristic attitude — with the tip 

 of the abdomen raised so as to expose a portion of the membrane 

 that connects the fifth and sixth segments of its dorsal surface. 

 Sladen then took several newly killed worker bees, dissected off this 

 membrane, and showed that this material was capable of attracting 

 other bees. He thus established that the bee's scent was associated with 

 this membrane, and proceeded to his final conclusion, which was that 

 the scent ( and not the noise of the vibrating wings, as had hitherto been 

 supposed) is the means of allurement that enables a fanning bee to 

 attract its companions and encourage them to enter the hive. 



The scent organ is exposed in other circumstances when it would 

 be useful for a bee to attract its friends. It has been noted, for 

 example, that bees which are collecting from a dish of strong sugar 

 solution usually scent in this way, and the frequency of this scenting 

 tends to be proportional to both the concentration of the syrup and 

 the ease with which it is obtainable. As often happens when one 

 studies other aspects of bee behavior, one finds that there is much varia- 

 tion between different individuals; when one watches a number of 

 bees collecting from the same dish, he sees some bees that do not scent 

 even when collecting very rich syrup, whereas other individuals scent 

 even when the syrup is much diluted. The extent to which bees expose 

 their scent organ when they are working on flowers has not been 

 settled ; some observers have seen them perform this action, and the 

 Indian honey bee is said to do it frequently while collecting nectar 

 from flowers. 



As one might expect, honey bees can use the scent they give out as a 

 guide to themselves on a return visit to a source of sugar or nectar, 

 as well as to attract their companions. Moreover, recent experi- 

 ments have shown that this scent has other surprising and important 

 properties — the bees of each colony produce a distinctive scent, which 

 is different from that of other colonies. 



RECOGNITION OF COMPANIONS 



Some experiments that shed light on the bee's ability to recognize 

 members of its own hive have been carried out at Rothamsted. The ap- 

 paratus used in these experiments is shown in figure 1; it includes 

 two small dishes which are set down in a field about 30 inches apart ; 

 each dish is surrounded by an open box which serves as a windshield. 

 The box in the center does service as a partition and also as an extra 

 windshield. 



Two colonies of bees, A and B, are placed 50 yards or so away from 

 the pair of feeding dishes, and the stage is now set for our first 

 experiment. The experimental procedure is as follows : On the first 



