THE ORGANIZATION OF INSECT SOCIETIES 



427 



Table 29. Temporal Division of Labor Often Found in the Life of an Individual Adult Worker 

 Honeybee (From Rosch, 1927, 1930; Morland, 1930) 



having complete information concerning 

 all the details. For that matter we are in 

 an early stage of comprehension of func- 

 tions and integration that make any organ- 

 ism an organism. But we know enough to 

 see that the social insect colony has a pat- 

 tern significantly similar to that of a lowly 

 multicellular organism such as a sponge. 

 The correlations may be synthesized under 

 the concept of a social supra-organism (p. 

 435). We shall review here a few of the 

 mechanisms of social integration among the 

 insects. 



GENETIC INTEGRATION 



The primary link between individuals of 

 an intraspecies population is hereditary 

 continuity. Autocatalytic gene patterns are 

 passed along from generation to generation. 

 They initiate ontogenetic patterns of de- 

 velopment and fimction. Wright (1934) 

 concisely summarizes the relation of 

 genetic and physiological systems in the 

 development of the organism. 



It is true that "the different offspring of 

 a single queen cannot be genetically iden- 

 tical, for the factors in which their mother 

 is heterozygous must segregate. . . . Such 

 genetic variability, however, . . . seems 

 not to be utilized in producing polymor- 

 phism" (Fisher, 1930, p. 181). With the 

 exception of sex differentiation, the differ- 

 ent castes of most social insects seem to 

 develop from genetically similar eggs. 



Physiological agents acting at certain 



thresholds of development determine the 

 direction the individual will take. This sit- 

 uation parallels the genetic capacity of the 

 fertilized egg cell under appropriate phys- 

 iological conditions to produce any type 

 of differentiated cell characteristic of the 

 particular organism. Thus the analogy of 

 somatic tissues with the sterile castes of 

 social insects is founded upon fundamental 

 biological similarities, and the sterile castes 

 may be properly referred to as somatic in- 

 dividuals in the social supra-organism. 



Sex determination among the social in- 

 sects follows the same systems as are found 

 in their solitary ancestors. A discussion 

 of some of the evolutionary implications of 

 the haploid male and diploid female in the 

 Hymenoptera will be found later (pages 

 687 and 688; also see Flanders, 1939, 

 1946). It is well to point out here, however, 

 that convergent social systems have evolved 

 with many astonishing parallelisms in the 

 ants and termites (p. 435), one with hap- 

 lodiploidy, the other probably with sex 

 chromosomes. The fact that sexually and 

 therefore genetically different individuals 

 can be incorporated into a social supra- 

 organism is proof that the population repre- 

 sents a different level of integration com- 

 pared with a multicellular individual, and 

 that the similarities between these systems 

 are strictly analogous and not homologous, 

 even though some of the mechanisms of 

 differentiation and integration may be re- 

 markably similar. 



