SOLITARY AND SOCIAL BEES 



Few insects are more familiar than the honey bee, one of the 

 very few insect species which has been domesticated and 

 which is consequently the subject of a large literature. Never- 

 theless the vast majority of bees are solitary species and 

 rarely noticed except by the specialist. There are two hundred 

 species of bees found in Great Britain, but less than one- 

 quarter of these are social. In most of them, such as the 

 Anthophora and the mason bee shown on Plates 27—30 (facing 

 p. 81), a single female constructs a nest in the soil, in rotten 

 wood, or in some crevice, quite in the manner of a solitary 

 wasp. Sometimes, as in the mason bee, many cells may 

 eventually be constructed side by side. There are good 

 grounds for thinking that in the remote past the bees evolved 

 from the same stem as the sand wasps, the beginning of the 

 divergence being a change in habit from hunting to collecting 

 vegetable food. Many wasps make considerable use of fruit- 

 juices or of the nectar of flowers and one curious group of 

 solitary wasps (Masaridae), found in warmer climates, lives 

 entirely on pollen and nectar in all stages. The bees made a 

 similar change and developed, gradually, a series of new 

 bodily structures which especially fit them for this mode of 

 life. Many of the hairs, which are usually numerous all over 

 the body, are branched. This helps the pollen grains to adhere 

 to them and enables a large load to be carried on each 

 journey. Often the hairs are grouped on special areas of the 



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