534 The Animal Kingdom 



In the tropical regions of the world, many other interesting ants 

 are common. One of the most astonishing of these is the army ant 

 of the New World which periodically goes on raids in search of insect 

 prey. They scour the forest floor, destroying everything that comes 

 in their line of march. The umbrella ants gather leaves on which a 

 fungus is grown deep in their nesting sites. This fungus is used for the 

 nutrition of the colony. One ant, Polyergus, has its workers make 

 periodic slave raids on colonies of another genus. The workers of 

 Polyergus die if deprived of their slaves. One slave is able to keep 

 ten slavemakers. Through many parts of the world, aphids and other 

 insects are reared by the ants for their secretions. 



Probably the most familiar of the social insects is the honey bee 

 {Apis mellijera). Much is known of its life and habits for it has been 

 reared since early times for its honey and wax. In the honeybee col- 

 onies, combs of wax are produced ; some of these are used for the de- 

 velopment of the larvae, while others are used for the storage of honey 

 to be eaten during cold weather. By metabolizing this stored food, the 

 workers are able to keep the colony warm during periods of freezing. 



The organization of the honeybee colony varies somewhat from 

 those described above. There are three different types of individuals 

 in the colony : the workers, the drones or males, and the queen. The 

 drones or males develop from unfertilized eggs. They have the func- 

 tion of building the colony, caring for the young, protecting the colony, 

 and obtaining food. The queen is the fertilized female which produces 

 the eggs. While both the queen and the workers are produced from 

 fertilized eggs, those eggs destined to be queens are placed in special 

 cells and the larvae are fed "royal jelly" during their development. 

 Royal jelly is a secretion from the glands of the worker's heads. 

 Those eggs destined to become workers are placed in smaller cells, and 

 the larvae are fed royal jelly at first, and later receive nectar. This 

 represents a very striking example of nutritional control of sexual de- 

 velopment. Queens can be produced at will by the workers, but are 

 produced more often as the present queen ages and the colony becomes 

 crowded. Usually the old queen accompanied by many workers swarms 

 out of the hive and moves to a new location. The new queen left 

 behind has a nuptial flight in which she is fertilized by a drone. This 

 single fertilization lasts through the life of the queen bee. Upon re- 

 turning to the hive, she stings any other queen bees to death and starts 

 producing new young. It should be noted here that the queen does not 



