New evidences for the evolution of eusociality by kin selection?

by Benoit Guenard Fri May 30, 2008 9:23 am

An article by William O. H. Hughes, Benjamin P. Oldroyd, Madeleine Beekman and Francis L. W. Ratnieks is published in Science 320 p 1213-1216, under the title:
Ancestral Monogamy Shows Kin Selection Is Key to the Evolution of Eusociality

Here is the abstract:
Close relatedness has long been considered crucial to the evolution of eusociality. However, it has recently been suggested that close relatedness may be a consequence, rather than a cause, of eusociality. We tested this idea with a comparative analysis of female mating frequencies in 267 species of eusocial bees, wasps, and ants. We found that mating with a single male, which maximizes relatedness, is ancestral for all eight independent eusocial lineages that we investigated. Mating with multiple males is always derived. Furthermore, we found that high polyandry (>2 effective mates) occurs only in lineages whose workers have lost reproductive totipotency. These results provide the first evidence that monogamy was critical in the evolution of eusociality, strongly supporting the prediction of inclusive fitness theory.

The results of the articles support 3 main ideas:
While eusociality has evolved separately at least 9 times in Hymenopterans, the ancestral states were monandrous. The totipotence of workers (reproductive capacity) is found in monandrous species and not in polyandrous species. And finally, functionnal polygyny is a derived state that appear after the formation of societies. It seems that the model of evolution of eusociality through group selection as explained by Wilson won't fit with those results.