vi THE DOMESTIC LIFE OF ANIMALS 



107 



as to be in full view of the female during courtship, but the atti- 

 tudes and antics of the male spider at that time are actually such 

 as to display them to the fullest extent possible. The fact that in 

 the Attidae the males vie with each other in making an elaborate 

 display, not only of their grace and agility, but also of their beauty, 

 before the females, and that the females, after attentively watching 

 the dances and tournaments which have been executed for their 

 gratification, select for their mates the males that they find most 

 pleasing, points strongly to the conclusion that the great differences 

 in colour and in ornament between these spiders are the result of 

 sexual selection." 



These conclusions support Darwin's position that the female's 

 choice is a great factor in evolving attractiveness, and are against 



FIG. 29. Two MALE SPIDERS (Habrocestum splendens TO THE LEFT, AND 

 Astia viltata TO THE RIGHT) DISPLAYING THEMSELVES BEFORE THEIR 

 MATES. 



(After G. W. and E. G. Peckham.) 



Wallace's contention that bright colours express greater vitality, 

 and that the females are less brilliant because enemies eliminate 

 the conspicuous. It is quite likely that Darwin's view is true in 

 some cases (e.g. these spiders), and Wallace's conclusion true in 

 others (e.g. birds and butterflies), or that both may be true in many 

 cases ; while the fact that the males of these spiders are always 

 more brilliant than their mates suggests again that the brilliancy 

 is wrapped up along with the mystery of maleness, which it is 

 not sufficient to define merely as superabundant vitality, or as 

 greater activity, but rather as a tendency towards a relative in- 

 crease of destructive or disruptive vital changes over those which 

 are constructive or conservative. But the problem is very com- 

 plex, and dogmatic conclusions are premature. We need to know 

 the chemical nature and history of the pigments to which the 

 colour is due ; we need to have an approximate balance-sheet of 

 the income and expenditure of the two sexes. Enough of this, 



