COURTSHIP AND MATING 77 



the female accepting the sex rather than the individual." 8 Mont- 

 gomery did not subscribe to Wallace's belief that the males ex- 

 hibited a higher degree of vitality, but argued instead that the need 

 of greater protection by the females was the reason for their less 

 conspicuous coloration, as in birds. 



It has remained for W. S. Bristowe to take up the problem where 

 Montgomery left off, and to extend and elaborate his thesis on the 

 basis of a much vaster literature and innumerable observations of 

 European spiders. Bristowe's views were presented in convincing 

 fashion in 1929, in a long paper entitled "The Mating Habits of 

 Spiders, with special reference to the Problems surrounding Sex 

 Dimorphism." In this treatise he pointed out that the complicated 

 visual displays of the jumping spiders probably arose by ordinary 

 natural selection. 



Primitive spiders were short-sighted hunters that groped their 

 way as they walked and stretched out their front legs to test the 

 substratum. Perception of the environment was accomplished by a 

 chemotactic sense largely confined to the extremities of the append- 

 ages. Since sight was limited, it was necessary for the male to touch 

 the spoor, the threads, or the body of the female to discover her 

 presence. Since the males were able to detect the presence of a 

 mate often before she was touched, those males that started to ad- 

 vertise their identity early by means of their front legs were more 

 likely to survive the assault of their larger, predaceous mates. 

 Aiovement of the appendages and parts of the body enhanced the 

 chances of survival and also increased the possibility of finding a 

 mate. All these advances in posturing were accompanied by a 

 gradual improvement in the acuity of the eyes, likewise arrived at 

 by selection. Males tend to produce more pigment than females, so 

 those that were able to develop strikingly colored spots in front, 

 visible to the female, were able to survive more often. The various 

 antics and decorations worked hand in hand. 



The most generalized types of courtship are exhibited by those 

 spiders in which distance perception is feebly developed, the ma- 

 jority being short-sighted hunters. More specialized displays have 

 arisen in two ways: By improvement in the acuity of the eyes, as 

 in the long-sighted hunters; and by development of expansive webs 

 that enlarge the limits of perception by touch, as in the web build- 

 ers. These divisions approximate in a general way the systematic 

 position of the species. 

 ., p. 173. 



Ibid. 



