THE INSECT WORLD 



The evidence for insight learning is based on more 

 elaborate behaviour of this type. A solitary spider-hunting 

 wasp, Anoplius fuscus, has been much studied. When it has 

 stung and paralysed its prey, it hides it in a tuft of vegetation 

 and, after making a short locality-study on foot, searches for 

 a place to dig its nest. Once when the nest was several feet 

 away from the spider, the Swedish entomologist Adlerz put 

 a white towel, of a size 2 x 3 J feet, on the ground between the 

 wasp's nest and the spider. The wasp normally visits the 

 spider several times while the nest is being constructed. On 

 such a visit, when she came to the towel she was completely 

 nonplussed. She would only walk an inch or two on to 

 it and, eventually, after casting round for half an hour, 

 she found her way round the edge of the towel and ran 

 to the spider. Coming back to the nest, she took a bee- 

 line across the towel and later the spider was dragged to 

 the nest by the same path. This suggests that the wasp 

 appreciates the relative positions of the spider and the nest 

 and that once the intruding object has been studied she 

 can pass from one to the other without using detailed land 

 marks. 



Still clearer evidence for insight learning has been found by 

 Thorpe in the solitary wasp, Ammophila pubescens, which, 

 as we shall see, is known to be highly endowed in other 

 respects. This wasp catches caterpillars and drags them back 

 to her nest. When metal screens were put in her path she 

 merely made a detour round them and then went straight 

 on in the right direction. Even if the wasp was caught and 

 carried some distance in a dark box, she was usually able, 

 when released, to set off straight for her nest. She gave the 

 impression of knowing all the landmarks on a considerable 

 area of rough ground so well that she could quickly find her 

 nest from any starting point. 



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