It may be awkward for those with a philosophical prejudice against the ‘selfish gene’ school of thinking in evolutionary biology, but recent work by researchers in the UK and Australia has cast doubt on at least one aspect of the group natural selection theory of Harvard biologist Edward O Wilson.
Kin selection is the theory that individuals pass on their genes by assisting close relatives to reproduce. To give an extreme example, eusocial insects such as bees, wasps and ants sacrifice their own reproduction to help raise the offspring of the hive queen. This is altruism at a biological level.
Wilson argued that altruism evolved because it benefits groups, not individual genes. For what Wilson termed ‘group natural selection’ to work, organisms need not be closely related. Close relatedness would follow from animals sticking together and cooperating.
In a recent paper in Science magazine, William Hughes at Leeds University, Ben Oldroyd and Madeleine Beekman in Sydney, and Francis Ratnieks in Brighton, show convincingly that genetic relatedness is ancestral, and does not evolve after eusociality, as Wilson claimed.
Using a statistical technique known as ancestral state reconstruction, Hughes and his colleagues reconstructed female mating behaviour in 267 species of eusocial bees, wasps and ants. The researchers found that mating with a single male – monandry – is ancestral for all the independent eusocial lineages studied. Polyandry, on the other hand, is always derived.
Hughes discusses the experiment in a fascinating and easily comprehensible podcast, which is available to non-subscribers on the Science website.
So far there is little in the way of online discussion of the work. Other researchers will no doubt be mulling over the results, and I’m sure we haven’t heard the last of this, despite Hughes’ assertion that “It’s pretty cut and dry, really.”
Be warned that much of the public discussion on kin versus group selection is driven by philosophical and political prejudices. And few are immune to this. I incline toward group natural selection, if only out of reaction against the often naively social-reductionist interpretations heaped on the ‘selfish gene’ theory by non-scientists*. It will be interesting to see how this plays out.
* I should qualify “non-scientists” in the light of an argument between friends over at Obscene Desserts. The problem is due mostly to non-scientists abusing science for ideological ends, but scientists themselves are not entirely blameless. Even senior players such as Steven Pinker (e.g., The Blank Slate) have contributed to the debasement of scientific debate with polemics that rely more on demonising rhetorical devices than honest argument and a willingness to listen and learn from others.