VARIETIES OF WASP SOCIETY 



honey. The store of honey may well have one of the same 

 uses as it does in the honey bee, namely that of allowing the 

 wasps to get through a period (either dry or cold) when food 

 is scarce. 



It was stated earlier that Polybia workers could as a rule 

 hardly be separated from the queens. A curious fact which 

 we discovered was that in several species careful measurement 

 showed that the workers and queens differed somewhat in 

 their proportions. The queens are a little larger and the base 

 of the abdomen is often relatively broader. These differences 

 could not arise after the wasps are adult, so that it seems that, 

 as in Polistes and the common wasp, the difference between 

 queens and workers is determined earlier in life. There may 

 well be some difference in feeding, though there is as yet 

 no evidence for it. We found that the number of workers 

 available to look after each grub increased with the age of the 

 colony. This is a simple consequence of the fact that a worker 

 lives longer than the time it takes for an egg to turn into an 

 adult, so that the number of workers relative to grubs gradu- 

 ally increases. It may be that the very slight differences 

 between queens and workers are produced by the increased 

 care which the grubs receive during the last part of the life 

 of the colony. This would be the simplest way of differentia- 

 ting queen and worker castes and would be automatic, with- 

 out any demand for special behaviour. 



It seems clear that there must be some balance between 

 egg-laying and the construction of cells since either the queens 

 would lay below the rate of which they were capable or else 

 many cells would be built for which eggs could not be pro- 

 vided. We found that in Polybia nests on the average about 

 one-fifth of the cells at any time are empty. It was possible 

 to show that the rate of egg-production is probably the 

 limiting factor in the growth of the colony. The age of the 



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