The Red Queen_ Sex and the Evolution of Human Nature - Matt Ridley [64]
Laws are passed to enforce the collective interest at the expense of the individual, just as crossing over was invented to foil outlaw genes. If gender selection were cheap, a fifty-fifty sex ratio would be imposed by parliaments on people as surely as equitable meiosis was imposed by the parliament of the genes.
CHAPTER FIVE
The Peacock’s Tale
Tut, you saw her fair, none else being by,
Herself poised with herself in either eye.
But in that crystal scales let there be weighed
Your lady’s love against some other maid
That I will show you shining at this feast,
And she shall scant show well that now seems best.
Shakespeare, Romeo and Juliet, Act I, Scene 1
The Australian brush turkey builds the best compost heaps in the world. Each male constructs a layered mound of two tonnes of leaves, twigs, earth and sand. The mound is just the right size and shape to heat up to the perfect temperature to cook an egg slowly into a chick. Female brush turkeys visit the males’ mounds, lay eggs in them and depart. When the eggs hatch the young struggle slowly to the surface of the mound, emerging ready to fend for themselves.
To paraphrase Samuel Butler (‘a hen is only an egg’s way of making another egg’), if the eggs are just the female’s way of making another brush turkey, then the mound is just the male’s way of making another brush turkey. It is almost as precisely a product of his genes as the egg is of hers. Unlike the female, though, the male has a residual uncertainty. How does he know that he is the father of the eggs in the mound? The answer, discovered recently by Australian scientists, is that he does not know, and in fact, is often not the father. So why does he build vast mounds to raise other males’ offspring, when the whole point of sexual reproduction is for his genes to find a way into the next generation? It turns out that the female is not allowed to lay an egg in the mound until she has agreed to mate with the male: that is his price for the use of his mound. Her price is that he must then accept an egg. It is a fair bargain.
But this puts the mound in an entirely different light. From the male’s point of view the mound is not after all his way of making young brush turkeys. It is his way of attracting female brush turkeys to mate with him. Sure enough, the females select the best mounds, and therefore the best mound makers, when deciding where to lay their eggs. The males sometimes usurp each other’s mounds so the best mound owner may actually be the best mound stealer.
Even if a mediocre mound would do, a female is wise to pick the best so that her sons inherit the mound-building, mound-stealing and female-attracting qualities of their father. The male brush turkey’s mound is both his contribution to child-rearing and a solid expression of his courtship.1
The story of the brush turkey’s mound is a story from the theory of sexual selection, an intricate and surprising collection of insights about the evolution of seduction in animals: the subject of this chapter. And, as will become clear in later chapters, much of human nature can be explained by sexual selection.
Is Love Rational?
It is sometimes hard even for biologists to remember that sex is merely a genetic joint venture. The process of choosing somebody to have sex with (sometimes known as falling in love) is mysterious, cerebral and highly selective. We do not regard any and all members of the opposite sex as adequate partners for a genetic joint venture. We consciously decide whether to consider people; we fall in love despite ourselves; we entirely