INSECT SOCIETIES 



and the worker minor, are often very marked and quite^as 

 big as the differences between species of solitary insects. 



If workers have a uniform structure, then at different times 

 they contribute to all the activities of the colony. The castes 

 of social wasps are feebly differentiated, and in them per- 

 manent division of labour, except between the queen and her 

 workers in the mature colony, scarcely exists. In the termites, 

 by way of contrast, we find the worker and the soldier often 

 with a strikingly different appearance and with quite distinct 

 functions. Even more curious is the example of the amazon 

 ants, in which the amazons are in effect the soldiers and the 

 worker caste is represented by slaves of another species. It 

 seems that the essential nature of an insect society must be 

 looked for in the physiology of the individuals. 



Before pursuing this point further, we may notice how 

 different has been the evolution of social vertebrates. Structural 

 and physiological differences within the species are relatively 

 trivial apart from the differences between the sexes. Perhaps 

 because of this, only man has been able to build societies 

 of a complexity even approaching that of the ant or termite 

 colony. Without physiological differentiation, it is very 

 difficult to organise a society until there are elaborate means 

 of communication and a brain capable of understanding 

 what is conveyed. 



There are a few exceptional animals like the beaver about 

 which one would like to know much more, but in general 

 the non-human social mammals combine only in a rather 

 rudimentary way, either for hunting or for defence. Any 

 division of labour depends either on age or on sex ; for 

 example, bulls defending the cows and young amongst wild 

 oxen. It might be argued that in man there is a division of 

 labour based on innate differences in abilities, but there is 

 very little physiological differentiation. The superficial 



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