IT IS just about the greatest sacrifice possible, and in evolutionary terms it looks like madness. Forgoing reproduction in order to help raise another’s offspring is a supreme act of altruism. It happens routinely in hundreds of ant, bee and wasp species, where sterile workers toil for the benefit of the queen.
For the last 40 years, the evolution of such altruism has been explained by kin selection: the idea that helping your relatives – and therefore helping spread the genes you share with them – outweighs the cost of not having offspring of your own. It’s the genes that matter, not the individuals in…
