432 



POPULATIONS 



remains in one place. The moving pupae 

 within the cocoons stimulate the workers to 

 open the cocoons, and the restless move- 

 ments of the callows excite the workers 

 tactually and perhaps chemically. When the 

 level of raiding activity is raised, the 

 nomadic change of the bivouac site is re- 

 sumed. The day-night rhythm is based upon 

 excitation by light. Approximately seven 

 days after a given statary period, a new 



tiun between infant and mother during 

 breast feeding. He points out that the 

 "social outcome of insect trophallaxis is 

 largely set by hereditary factors; the social 

 outcome of human trophallaxis is highly 

 variable and plastic, in dependence upon 

 a given cultural setting." 



We accept the significance of Schneirla's 

 discussion of the analogous trophallaxis in 

 the social integration of ants and man, but 



Fig. 153. Army ants (Eciton hamatum) transporting their larvae slung under their bodies 

 during a change of the bivouac site. Note the different sizes of the workers. (Photograph by 

 Ralph Buchsbaum.) 



batch of eggs is produced by the queen, 

 who develops a physogastric condition only 

 during the short egg-producing period. 



Schneirla has thus shown that intra- 

 societal factors, such as the reproductive 

 cycle of the queen and the brood cycle, 

 are basic in determining the pattern of army 

 ant behavior, and that factors external to 

 the colony impart diel rhythms and other 

 special characteristics. 



Schneirla (1946) not only accepts 

 trophallaxis (including exchange of nourish- 

 ment, chemicals, and tactile stimuli) as an 

 important mechanism for the stimulation of 

 social response among the insects, but he 

 applies the theory to human social processes 

 and cites as an example the mutual stimula- 



in the same paper he concludes that the 

 analogy between organism and supra-or- 

 ganism, and also the comparison of domi- 

 nance hierarchies found in various verte- 

 brates, are inadequate for the study of 

 comparative social behavior. Instead of dis- 

 missing the concepts of the supra-organism 

 and social hierarchy as insignificant, we 

 think that they are significant in both the 

 analysis and synthesis of convergently 

 evolved social systems. Circular eflFects are 

 doubtless involved in explaining the inter- 

 actions within an organism or within a 

 social insect colony. The survival of the 

 whole is the mechanism that brings about 

 the evolution of the parts adapted to each 



