Those of you reluctant to babysit your sister’s kids or play wingman for your twin brother may appreciate this criticism of the inclusive-fitness theory of eusociality. Favoured by the Oxford school of evolutionary biologists (J.B.S. Haldane, W.D. Hamilton, John Maynard Smith and Richard Dawkins), inclusive fitness and kin selection have since the 1960s been the popular explanations of brood care for offspring, foregone reproduction by some individuals, and other cooperative, self-sacrificing behaviour by ants, wasps, bees (and other social species including humans). Hamilton gives a crude explanation below.
More exactly, Hamilton’s inequality says that altruism is favoured when the coefficient of genetic relatedness exceeds the reproductive cost-benefit ratio (for donor and recipient together) of the cooperative act. Hence Haldane’s famous answer, when asked if he would sacrifice his life for that of his brother: “No, but I would to save two brothers or eight cousins”. (The high proportion of shared alleles among some insects explains, so the story goes, why a worker bee should sacrifice her reproductive potential for just 1.5 sisters.)
Nature and ScienceDaily have discussions of the new paper. Because one of the authors is E.O. Wilson, and the targets of criticism are confrères from the 1970s like Dawkins and Robert Trivers, some people are treating this as part of a late-career volte-face against orthodoxy and towards group selection. In truth, as Razib Khan shows, Wilson has been quietly at this since the Sociobiology days. Not surprisingly, few people – enemies or friends – noticed.