426 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1938 



purposes, but there is no food in it. The bees fly to the boxes, smelling 

 around the holes, but they only enter the scent box. It is therefore 

 clear that they can smell this scent, and that they use it as a guide to 

 the food place. 



The sense of taste is a very closely allied sense. It is also a chemical 

 sense. But for taste it is necessary that the mouth parts should come 

 in contact with a solution. If it is a sweet solution, the bees suck it up. 

 Indeed, the bees are rather fastidious about sweetness. If it is a solu- 

 tion containing 20 percent saccharose, they suck it up. If it contains 

 10 percent we can see that in bees as in men there is an individual 

 difference in taste. Some bees drink, others hesitate, and others refuse 

 it. If it contains 5 percent, they taste it and refuse to accept it. In 

 this connection it is interesting that nectar in bee-blossoms is always a 

 solution with a high content of sugar; on an average nectar contains 

 about 40 percent sugar. 



Training to taste is impossible. Either they drink the solution, 

 or they refuse it. Nevertheless, it is possible to find out something 

 about the quality of their sense of taste. But I cannot explain 

 the methods in a few words. Let me only say that bees can dis- 

 tinguish the same qualities as we can — sweet, bitter, sour, salty. 

 But not all substances we consider sweet are sweet for bees. Many 

 sugars very sweet for us are tasteless to bees, e. g., lactose, cellobiose, 

 raflinose, etc. And the artificial sugars saccharin and dulcin are 

 not sweet but are tasteless to bees. 



It is much easier to find out more facts about the quality of 

 the sense of smell in bees, because we can train to a certain scent. 

 Thus, for example, we provide all the boxes with different scents. 

 The bees trained to a certain scent are able to pick out the training 

 scent from 30 to 40 different scents. Furthermore, we can dilute 

 the training scent more and more, and the result is that for the 

 sense of smell in bees the limit is quite the same as for human beings. 

 The scent of most flowers, therefore, cannot attract from a great 

 distance. The color of flowers has the advantage of attracting bees 

 from a greater distance. Scent has the advantage of being perfectly 

 distinct for each species of flower. And so the scent permits the 

 definite recognition of flowers from nearby. 



In earlier times biologists thought that the function of the scent 

 of flowers was to attract insects and to enable them to find the 

 flowers. I think this is true of such bees as fly out to seek new 

 feeding-places; for scout bees. Another function of scent is to enable 

 the collecting bees to recognize certain flowers to which they are 

 true and to distinguish them from other kinds of flowers. But 

 there is one more function of scent — perhaps the most important. 

 To explain it I must speak about the language of bees. 



