THE IMPORTANCE OF SOCIAL LIFE 8l 



thick-walled cell from an egg which the queen lays after 

 having closed off the duct through which spermatozoa 

 would pass. Nurse workers produce from special glands the 

 "royal jelly," which is the basis of the nutritive control; and 

 these workers seem to appear in large numbers when the 

 queen cells are built. Just how this situation is controlled is 

 not clearly known. It is known, however, that if the queen 

 dies or is removed by an observer, the workers will start 

 enlarging one or more cells of developing larvae and will 

 change the food treatment to produce a queen. Perhaps 

 there is here a sort of "social hormone" which is controlling 

 the situation, as in the termites. Temperature and crowding 

 are factors in determining the time of swarming when the 

 new queens and a great number of workers and a few 

 drones fly off to found new colonies. For this nuptial flight 

 the queen is impregnated with a supply of spermatozoa 

 which she retains the rest of her life, using or not using it 

 as the conditions of the colony dictate. The state of the 

 colony controls the production of the castes, but the actual 

 means of supervision has so far escaped observers. The bee- 

 hive with its clever structure and division of labor of the 

 individuals within it (cell workers, nurse workers, honey 

 and pollen collectors) is the product of an evolution toward 

 a high-order control over the environment. Only in recent 

 years have we come to realize how very special and extraor- 

 dinary are the structural and behavioral patterns of these 

 insect societies. In Chapter 11 on instinct, it will be important 

 to examine the almost unbelievable talents of some of these 

 organisms. 



Among ants, sterile females are divided into soldiers and 

 workers, the latter being subdivided on the basis of size. 

 W. M. Wheeler believed that both ants and bees evolved 

 from ancestral wasps, and that each developed the caste 

 system independently. He also thought that the castes in 

 ants are the result of heredity and not of special care and 

 feeding, as in bees and wasps. Ants are very highly social, 



