CHAPTER IX 



WARNING COLOURS AND MIMICRY 



We have seen that vast numbers of insects are protected 

 from hostile attack by a close resemblance to their habit- 

 ual surroundings, and that this resemblance is due mainly 

 to colour adjustment. But the veriest tyro in nature 

 study must have noticed that many insects are not dis- 

 guised in this way. On the contrary, their colours are 

 crude in tone and boldly contrasted. This is the case 

 with the common wasp (Vespa vulgaris), the ladybird 

 beetle (Cocchiella), and the caterpillar of the cinnabar 

 moth (Euchelia jacobcece) — to cite only three well-known 

 examples. Such insects seem to court attention. Clearly 

 they are not coloured to be hidden, but in order that they 

 may readily be seen. How are we to account for this ? 

 There is reason to think that such showily coloured insects 

 almost always possess some offensive or hurtful character 

 which renders them unpalatable, and that their showy 

 liveries act as warning advertisements to insect-eating 

 animals. All insects are relatively frail creatures. The 

 hard armour of a beetle avails little against the beak of a 

 hawk or the teetli of a monkey, while one peck from a bird 

 bent upon testing the edibility of a moth or caterpillar is 

 likely to prove fatal. Thus the mere fact that an insect 

 is unsuitable for food will not suffice to save it from 

 destruction. But if a noxious or unpalatable insect is 

 coloured in a manner so striking that its appearance 

 becomes firmly fixed in the mind of its assailant, a distinct 

 advantage to the species is likely to result. For the 



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