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Show 226 MR. E. U. POULTON ON THE PROTECTIVE [Mar. 1, Such an education would be somewhat dearly bought; it would be unpleasant to the insect-eater and destructive to the insect. But if, as I shall endeavour to show, there is a superficial resemblance between the colours employed by very different insects, and frequently even a similarity of pattern, we see that a comparatively few unpleasant experiences would be sufficient to create a prejudice against any insect with colours and patterns at all resembling the nauseous forms which have already produced so indelible an impression upon the memory. And thus it is most probable that the conspicuous appearance which astonishes one sense becomes associated in the mind of the Vertebrate insect-eater with the well-remembered effect of other qualities upon other senses. Different Vertebrates vary much in their rates of education. Thus my Frogs were much more stupid in this respect than tbe Lizards ; but then the imperfect memory or limited power of generalization in Frogs is less fatal to insects than it would be in the case of the other Vertebrates; for I do not think that the larvse were ever injured in the least after having been tasted by these animals. It is therefore probable that the gradual development of warning colours by natural selection was due to the fatalities which followed the experimental tasting of other Vertebrate enemies (especially Birds and Lizards), which inflict incidental injuries during the process of tasting. But the warning appearance having been acquired by such means, the Frogs have certainly taken the opportunity (thus offered to them ready-made and without having themselves contributed towards its existence) to acquire a somewhat limited education. This was seen in the case of the queen wasp (see Appendix II.), which on being placed in the case was tasted by three Frogs out of twelve, but afterwards was untouched for rr.any hours (as far as I was able to observe). A proof of the limited extent of the education is given by Butler, who speaks as if his Frogs repeatedly tried to eat the two species of nauseous larvse (A. grossulariata and U. wavaria), seeming only to become suspicious when they had actually made a trial of the insects on each separate occasion. It also seemed to me that my Frogs generally, if not always, ate bees from want of memory or deficient discrimination; for in nearly all cases they were finally rejected. But the experience did not seem to make any difference to the readiness with which the next bee would be seized and again rejected. On the other band I did not see a ladybird tasted on any occasion. Tbe slight power of discrimination possessed by Frogs was also shown by tbe fact that they frequently jumped at and seized the dark-coloured ends of the forceps with which I used to introduce insects into their case. For the tolerably complete demonstration of tbe principle which I believe has been at work, a far larger number of observations are necessary, while complete confirmation requires experimental evidence with young Vertebrates which have been reared in confinement, so that the whole <f their education is under observation. As conducing towards this end, I publish the suggestion with its foundation on the resemblances indicated by the tables given below, which have this |