Just as man, largely because of his reasoning ability, is classed at the head 

 of the vertebrates, so the insects, largely because of their extreme development 

 of instinct, are regarded as the highest of the invertebrates. As the final tri' 

 umph of instinct we find some of the insects organized into complicated com' 

 munities where each individual plays some definite part in the affairs of the 

 group and specialization and division of labor have reached remarkable heights. 

 In the hive of the honey bee one female, called the queen, does all the egg' 

 laying, while some fifty thousand others carry on all the other activities. The 

 males are known as drones and the females, other than the queen, are called 

 workers. Certain ones act as nurses for the young grubs, others build cells, 

 others act as guards at the hive door, and so on. During the active season each 

 worker serves at some one of these tasks for about two weeks and then devotes 

 the rest of its short life to the main purpose of the hive, the gathering of honey. 

 Only the queen lives for any length of time. If a new egg-laying female is 

 raised, the old queen must fight to the death or leave with her attendants to 

 establish a new home, a procedure known as swarming. Even more complicated 

 but less fully known is the community life of the ant. The ants' use of plant'lice 

 or aphids as '"'cows" and their constant attendance upon them has been noticed 

 by many a gardener. He may be unaware, however, that the ants commonly 

 take the female aphids into their own nests for the winter, care for their eggs, 

 and establish more aphid colonies each spring. In warmer climates some kinds 

 of ants cut leaves and build mushroom beds upon which they cultivate fungi 

 for food. Certain of the ants regularly keep other species as slaves and may 

 sometimes be seen making furious attacks upon the nests of other species in 

 order to carry off larvae or pupae which may be reared to serve them. Even 

 more elaborate is the community life of the termites, miscalled white ants. In 

 their nests may be found several distinct forms, each serving a different pur- 

 pose in the activity of the group. There are usually four or more of these 

 "castes". Unlike the bees and the ants, each caste of termites contains both 

 males and females. The harmonious adjustments of these social insects have 

 long excited the attention, admiration and even the envy of man. The reader 

 will find some of the popular accounts of insect life as entertaining as any books 

 of adventure. 



Insects in general are considered to be terrestrial animals, but a great 

 many of them are secondarily adapted for the water, especially in the immature 

 stages. Because of their very great numbers, wide distribution and diversity 

 of form they provide excellent material for the study of ecology. In fact 

 many ecology courses deal almost exclusively with insect distribution, abund' 

 ance and adaptation. Insects are so sensitive to changes in environment, such as 

 light, temperature and the like, that many serve as ecological indicators. The 

 rapidity of chirping of the cricket, for example, is said to be directly correlated 

 with temperature. 



226 



