Why we love the union of a coy female and an alpha male

The world's fascination with the royal wedding tells us many things. One is that we are still living in Victorian times, scientifically speaking. The focus is on the alpha male and his coy female: her mate choice is so laudable - so enviable - because of what he has to offer in physical protection and good genes for her progeny. Most of the world watches with a warm glow. All is as it should be.

It was Charles Darwin who gave scientific validity to the idea that the natural world is populated by passive females who are secured by courageous, pugnacious, dynamic males. Clearly the notion was a product of his time, and Darwin was the first to admit that it was only meant to be a working hypothesis. "I am aware that much remains doubtful," he wrote in The Descent of Man. Somehow, though, the notion has survived - despite a lack of convincing evidence in its favour.

There is some support for the idea - elephant seals provide the classic example. The gradual increase in the average weight of the population shows that the bigger, stronger males get to sire the next generation. But things are more complicated than is generally appreciated.

The late John Maynard Smith took red deer as an example of where things go wrong. While the powerful males are busy rutting, many of the females slope off to have sex with the less macho males of the herd (Maynard Smith labelled them the "sneaky fuckers").

It makes sense: it is hard to believe that there are so few good genes out there that the females are willing to focus all their attention on just one or
two males. After all, if the theory holds together, all the males are the progeny of strong, fit males from the previous generation. So there couldn't be such a marked difference that females would be so discerning.

Then there are the experiments that show females deliberately eschewing the strongest, fittest males. In an experiment with Goby fish, where males had to fight each other for the best site to lay eggs, females often chose the loser. It turned out that this loser was much more vigilant when protecting the developing eggs from predators.

Tight society

There are alternatives to the standard story. One of the most promising is social selection.

This idea, put forward by Joan Roughgarden of Stanford University, is an attempt to answer the question of why animals would be co-operative and social if their only aim is to reproduce - especially when only a few get that chance.

Put simply, social selection posits that animals live in social groups, where a variety of traits and benefits are in play - and sex is only one of them. Not everyone is driven solely by the desire to propagate their genes. Grooming, hunting and foraging, nest-building, protection and the chance to reproduce are all thrown into a barter system which ensures that everyone has something to contribute towards the central goal: group cohesion, a prerequisite for survival.

There's an irony here, because the unquestioning acceptance of the fairy tale of Victorian sexual selection theory also provides cohesion. Whether you're among the carping cynics or naive romantics, it seems that nothing brings a group together like a royal wedding.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 02 May 2011 issue of the New Statesman, The Firm