Ancestral Monogamy Shows Kin Selection Is Key to the Evolution of Eusociality
William O. H. Hughes,1* Benjamin P. Oldroyd,2 Madeleine Beekman,2 Francis L. W. Ratnieks3
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. [Bold mine, Ed.] 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.
1 Institute of Integrative and Comparative Biology, University of Leeds, Leeds, LS2 9JT, UK.
2 School of Biological Sciences, University of Sydney, Sydney, New South Wales 2006, Australia.
3 Department of Biological and Environmental Science, University of Sussex, Falmer, Brighton, BN1 9QG, UK.
NB: Mash up with paradic design and the meaning of "normal."