The Red Queen_ Sex and the Evolution of Human Nature - Matt Ridley [67]
To Win or to Woo
It took more than this to establish the fact of female choice. There were plenty of diehards who followed Huxley in thinking it was all a matter of competition between males. ‘Where female choice has been described, it plays an ancillary, and probably less significant, role than competition between males,’ wrote the British biologist Tim Halliday as late as 1983. Just as a female red deer accepts her harem master, who has fought for the harem, so perhaps a peahen accepts that she will mate with the champion male.10
In one sense, the distinction does not matter much. Peahens that all pick the same cock and red deer hinds that indifferently submit to the same harem-master both end up ‘choosing’ one male from among many. In any case, the peahens’ ‘choice’ may be no more voluntary or conscious than the hinds’. The peahens have merely been seduced rather than won. They may have been seduced by the display of the best male without ever having given the matter a conscious thought – let alone realized that what they are doing is ‘choosing’. People have repeatedly made the mistake of thinking choice must be conscious and active, and thinking that it was therefore unreasonable to expect female animals to choose their mates using ‘rational’ criteria.11 Think of human analogies. Two caricatured cavemen who fight to the death so that the winner can sling the loser’s wife over his shoulder and take her away are at one extreme; Cyrano de Bergerac is at the other, hoping to seduce Roxanne with words alone. But in between there are thousands of permutations. A man can ‘win’ a woman by competing with other men, or he can woo her, or both.
The two techniques – wooing or winning – are equally likely to sieve out the ‘best’ male. The difference is that whereas the first technique will select dandies, the second will select bruisers. Thus bull elephant seals and red deer stags are big, armed and dangerous. Peacocks and nightingales are aesthetic show-offs.
By the mid 1980s, the evidence had begun to accumulate that, in many species, females had a large say in the matter of their mating partner. Where males gather on communal display arenas, a male’s success owes more to his ability to dance and strut than to his ability to fight other males.12
It took a series of ingenious Scandinavians to establish that female birds really do pay attention to male plumes when choosing a mate. Anders Møller, a Danish scientist whose experiments are famously clever and thorough, found that male swallows with tails made artificially longer acquired mates more quickly, reared more young and had more adulterous affairs than males with tails of normal length.13 Jakob Höglund proved that male great snipe, which display by flashing their white tail feathers at passing females, could be made to lure more females by the simple expedient of having white typing-correction fluid painted on to their tails.14 The first of these manipulation experiments was by Malte Andersson, who studied the widow bird of Africa. Widow birds have thick, black tails many times the length of their bodies, which they flaunt while flying above the grass. Andersson caught thirty-six of these males, cut their tails and either spliced on a longer set of tail feathers, or left them shortened. Those with elongated tails won more mates than those with shortened tails or tails of unchanged length.15 Similar tail-lengthening experiments in other species that have unusually long tails have similarly boosted male success.16
So females choose. Definitive evidence that the female preference itself is heritable has so far been hard to come by, but it would be odd if it were not. A suggestive hint comes from Trinidad, where small fish called guppies vary in colour according to the stretch of water they inhabit. Two American scientists proved that in those races of guppy in which the males are brightest orange the