THE SOCIAL INSECTS 



stimulates raiding and that when raiding is active the bivouac 

 is frequently shifted. On each occasion all the brood have 

 to be carried to the new site. 



GATHERERS OF MIXED FOODS 



Just as most ants do at least a little hunting, so most of 

 them will collect other foods of various types, especially the 

 sweet excreta of aphides, scale-insects, mealy-bugs and leaf- 

 hoppers. Some ants, like the common red stinging ants of 

 the genus Myrmica, are hunters as well as collecting some 

 nectar from flowers and some excreta from various insects. 

 At the other extreme, the common yellow mound-building 

 Lasius flavus subsists almost entirely on the excreta of root- 

 aphides, but also takes some dead caterpillars, etc. I once saw 

 on top of an ant mound a large dead caterpillar completely 

 surrounded by fifty or sixty ants dismembering it. From the 

 great excitement which this ant exhibits if given animal food 

 in an artificial nest it seems certain that this is an important 

 supplement to its sugary diet. The relative importance of 

 different articles of diet to the various kinds of ant is very 

 little known, but it is clear that the balance is different from 

 genus to genus. 



None of the British ants builds elaborate shelters above 

 ground to shelter aphides or mealy-bugs, though they may 

 build up earth round the base of a plant which these insects 

 inhabit. Many exotic ants, however, build elaborate structures 

 around the suppliers of their sweet food and seem, at least 

 to some extent, to protect them from their enemies No 

 doubt the shelters are usually built round a natural colony 

 of insects which the ants happen to have discovered, but 

 there is a little evidence that they sometimes drive insects 

 into their sheds and prevent them from escaping from them. 

 Hingston describes an Indian ant, Polyrhachis, which builds 



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