200 ANIMAL BEHAVIOUR 



infrequent in the more complex instincts, namely, the serial 

 nature of the adaptation. There is a sequence of activities, 

 and the whole sequence is adaptive in its nature." 



What are the general characteristics of instinctive be- 

 haviour as exhibited by animals like ants, bees, and wasps, 

 of the little brain type? 



(1) Instinctive behaviour in its typical form is always 

 specific or particulate. The garden-spider's web is not like 

 the hedge-spider's web; the nest of one wild-bee is not like 

 another's; each wasp has its own victims which it deals with 

 in its own way; the female butterfly lays eggs on specific 

 food-plants which are appreciated not by her but by the 

 future caterpillars; and so on. Another aspect of the par- 

 ticulateness is a certain wooden lack of plasticity. 



(2) The routine of instinctive behaviour has often a con- 

 siderable degree of perfection the very first time, and while 

 it may be improved by practice, it certainly does not require 

 learning or experimenting. In other words, the instinctive 

 behaviour depends upon a hereditary predisposition of the 

 nervous system. Professor Driesch has defined instinctive 

 behaviour as " a complicated reaction that is perfect the 

 very first time ", but this inclines to be too hard and fast, 

 for there is a certain amount of individual development in 

 some instincts. None the less Paley expressed one of the 

 characteristics of instinct when he spoke of it as ^^ a pro- 

 pensity prior to experience and independent of instruction ". 

 Instinctive behaviour ^ just comes ' when the organism is 

 exposed to the appropriate stimulation. 



(3) The capacity for a particular piece of instinctive be- 

 haviour is shared with approximate equality by all like mem- 

 bers of the species. All the female spiders of a given species 

 make an equally fine web; all the males an equally inferior 



