THE SOCIAL INSECTS 



marked with coloured paints, so that their field routine can 

 be recorded. 



From the point of view of the bee, there seem to be two 

 different ways of collecting food efficiently. One arrange- 

 ment, seen in some British solitary bees and in a very large 

 number of species in North America, is to specialise on a 

 single species of flower. This involves synchronising the 

 flight period with the flowering time of the plant and has 

 often led to the development of a special structure, of the 

 tongue for instance, adapted to deal with the particular 

 shape of the flower. As in a human population which depends 

 on a single industry, the arrangement may be extremely 

 effective as long as conditions do not change. In the long 

 run, however, it is very risky. 



The alternative is to eschew specialisation and to obtain 

 food from whatever flowers are available at the moment. 

 Perhaps most solitary bees behave in an intermediate way : 

 they visit more than one kind of flower but by no means all, 

 and usually have a favourite one. Social bees, on the other 

 hand, are very rarely at all particular, and visit almost any 

 flower which is providing a good flow of nectar or has plenty 

 of pollen. This is seen in humble bees almost as much as in 

 the honey bee. A large colony can find enough food near 

 the nest-site only if it is willing to take what it can find. 



SOLITARY ORIGINS OF SOCIAL SPECIES 



It is thought that social life in bees developed from the 

 more usual solitary type of behaviour in much the same way 

 as it did in wasps. Females must have acquired the habit 

 of progressive-provisioning, so that they made contact 

 with their grubs, and as they became longer-lived their life- 

 span overlapped that of their daughters. Later still some of 

 these daughters became more concerned with running the 



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