140 Mr. G. A. K. Marshall on Diaposemo.tism, villi reference 



I very much regret that here likewise I am quite unable 

 to agree to this sweeping rejection of the whole of the 

 evidence that tells in favour of palatability, merely on an 

 d 'priori assumption. In the carrying out of these experi- 

 ments the importance of maintaining a natural diet was 

 fully recognised, and although there will be no doubt a 

 certain percentage of error, yet I am w 7 ell satisfied that the 

 results may be taken as giving a very fair idea as to the 

 general likes and dislikes of these animals in regard to 

 both butterflies and Coleoptera. Surely it must be some- 

 thing more than a mere coincidence that in every case 

 where the flight or habits of a butterfly indicated the 

 probable existence of an unpleasant taste, the baboons 

 arrived at a similar conclusion from actual experiment. 

 Moreover it is not quite clear why acceptance should be 

 admitted as evidence of edibility in Coleoptera, but not in 

 Lepidoptera. 



Later on in the same paper the question of experimental 

 evidence is summarised in the following terms: "It has 

 already been pointed out that the refusal or evident dislike 

 of insect food by captive animals is trustworthy evidence 

 of unpalatability, while acceptance is not proof of palata- 

 bility " (/. c. p. 436). This statement seems open to serious 

 objection on two grounds. In the first place, there is too 

 emphatic an insistence upon the possibility of error where 

 an insect is accepted ; for it practically casts suspicion upon 

 every such case. On the other hand, the possibility of 

 error in the other direction is not indicated. I agree that 

 where an insect is tasted and rejected with signs of dislike, 

 such is good evidence of distastefulness. But where an 

 insect is merely disregarded or refused without tasting, 

 this is not of itself reliable evidence; it may, or may not, 

 indicate the existence of nauseous qualities. Everything 

 depends upon the conditions of the experiment. To take 

 a few examples. The refusal by one of my baboons of 

 the first specimen of Precis sesamus (wet) cannot be inter- 

 preted as a sign of unpalatability, for this is negatived 

 by their subsequent behaviour towards this species; the 

 refusal was almost certainly due to either a mimetic 

 misapprehension, or that general distrust of brightly 

 coloured insects usually exhibited by these animals. Care 

 also had to be exercised that too many distasteful things 

 were not presented at once, otherwise they became very 

 suspicious of everything offered to them. 



