1026 LIFE : OUTLINES OF GENERAL BIOLOGY 



"Any one who reads these most interesting chapters will admit that 

 the fact of display is demonstrated ; and it may also be admitted, as 

 highly probable, that the female is pleased or excited by the display. 

 But it by no means follows that slight differences in the shape, 

 pattern, or colours of the ornamental plumes are what lead a female 

 to give the preference to one male over another; still less that all 

 the females of a species, or the great majority of them, over a wide 

 area of country, and for many successive generations, prefer exactly 

 the same modification of the colour or ornament." [Darwinism, 1899, 

 p. 285.) 



But the edge has been taken off this objection by Lloyd Morgan 

 and others, who point out the gratuitousness of crediting the hen 

 bird with a standard of taste or capacity for esthetic valuation. 

 "The chick selects the worm that excites the strongest impulse to 

 pick it up and eat it. So, too, the hen selects that mate which by his 

 song or otherwise excites in greatest degree the mating impulse. 

 Stripped of all its unnecessary esthetic surplusage, the hypothesis 

 of sexual selection suggests that the accepted mate is the one that 

 most strongly evokes the pairing instinct." (Habit and Instinct, 

 1896, p. 217.) 



It may be insisted, however, that if individual excellence in 

 attractive characters (such as plumes, singing power, dancing 

 agility) does not as such appeal to the female, it cannot be deter- 

 minative in preferential mating, and therefore its establishment 

 cannot be effected by any process of sexual selection. Unless the 

 female is somehow aware of the individual variation in question, 

 the theory breaks down ; and yet it is difficult to believe that the 

 female is so meticulous in fastidiousness, so detailed in her pre- 

 ferential excitability. 



The answer, probably sound, is that the details count, not as 

 such, but as contributory to a general impression. Each has its effect, 

 but synthetically, not analytically. "Even when the female seems 

 to choose some slight improvement in colour or song or dance, the 

 probability is that she is simply surrendering herself to the male 

 whose tout ensemble has most successfully excited her sexual interest.' 

 (Geddes and Thomson, Evolution, 1911, p. 172.) 



UTILITY OF COURTSHIP.— If we provisionally accept the theory 

 that a secondary sex-character may have been established and 

 augmented because it contributed to a decision in preferential 

 mating, we have to face the further question of the significance or 

 racial justification of the courtship-habits — often so prolonged, 

 elaborate, and exhausting. The sifting probably works well in keeping 

 up a standard of racial fitness, for the most persuasive male is 

 likely to be, among animals, the fittest all round. But there is surely 

 more than this. 



