A ‘green-beard’ gene is defined as a gene that causes a phenotypic effect (such as the presence of a green beard or any other conspicuous feature), allows the bearer of this feature to recognize it in other individuals, and causes the bearer to behave differently towards other individuals depending on whether or not they possess the feature1,2,3. Such genes have been proposed on theoretical grounds to be agents mediating both altruism and intragenomic conflicts1,2, but until now few, if any, of these genes have been identified4,5. Here we provide evidence of a green-beard gene in the red imported fire ant, Solenopsis invicta. In polygyne (multiple-queen) colonies, all egg-laying queens are Bb heterozygotes at the locus Gp-9 (ref. 6). Previous studies suggested that bb females die prematurely from intrinsic causes6; we now show that BB queens initiating reproduction are killed by workers, and that it is primarily Bb rather than BB workers that are responsible for these executions. This implies that allele Gp-9b is linked to a green-beard allele that preferentially induces workers bearing the allele to kill all queens that do not bear it. Workers appear to distinguish BB from Bb queens on the basis of a transferable odour cue.
Access optionsAccess options
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Hamilton, W. D. The genetical evolution of social behavior. 2. J. Theor. Biol. 7, 17–52 (1964).
Dawkins, R. The Selfish Gene (Oxford University Press, New York, (1976)).
Haig, D. in Behavioural Ecology. An Evolutionary Approach (eds Krebs, J. R. & Davies, N. B.) 4th edn 284–304 (Blackwell, Oxford, (1997)).
Queller, D. J. C. Kin selection and frequency dependence: a game theoretical approach. Biol. J. Linn. Soc. 23, 133–143 (1984).
Haig, D. Gestational drive and the green-bearded placenta. Proc. Natl Acad. Sci. USA 93, 6547–6551 (1996).
Ross, K. G. Multilocus evolution in fire ants—effects of selection, gene flow and recombination. Genetics 145, 961–974 (1997).
Keller, L. & Ross, K. G. Phenotypic basis of reproductive success in a social insect: genetic and social determinants. Science 260, 1107–1110 (1993).
Willer, D. E. & Fletcher, D. J. C. Differences in inhibitory capability among queens of the ant Solenopsis invicta. Physiol. Entomol. 11, 475–482 (1986).
Fletcher, D. J. C. & Blum, M. S. Regulation of queen number by workers in colonies of social insects. Science 219, 312–314 (1983).
Ross, K. G. Strong selection on a gene that influences reproductive competition in a social insect. Nature 355, 347–349 (1992).
Ross, K. G., Vargo, E. L. & Keller, L. Simple genetic basis for important social traits in the fire ant Solenopsis invicta. Evolution 50, 2387–2399 (1996).
Vargo, E. L. & Fletcher, D. J. C. On the relationship between queen number and fecundity in polygynous colonies of the fire ant, Solenopsis invicta. Physiol. Entomol. 14, 223–232 (1989).
Ridley, M. & Grafen, A. Are green beard genes outlaws? Anim. Behav. 29, 954–955 (1981).
Wade, M. J. & Beeman, R. W. The population dynamics of maternal-effect selfish genes. Genetics 138, 1309–1314 (1994).
Wilson, D. S. & Dugatkin, L. Nepotism vs TFT or why should you be nice to your rotten brother? Evol. Ecol. 5, 291–299 (1991).
Durand, D., Ardlie, K., Buttel, L., Levin, S. A. & Silver, L. M. Impact of migration and fitness on the stability of lethal t-haplotype polymorphism in Mus musculus: a computer study. Genetics 145, 1093–1108 (1997).
Silver, L. M. The peculiar journey of a selfish chromosome: mouse t haplotypes and meiotic drive. Genetics 9, 250–254 (1993).
Sokal, R. R. & Rohlf, F. J. Biometry. The Principles and Practice of Statistics in Biological Research3rd edn (Freeman, San Francisco, (1995)).
Glancey, B. M., Vandenburgh, M. K. & St Romain, M. K. Testis degeneration in the imported fire ant, Solenopsis invicta. J. Georgia Entomol. Soc. 2, 83–88 (1976).
Keller, L. & Ross, K. G. Phenotypic plasticity and cultural transmission of alternative reproductive strategies in the fire ant Solenopsis invicta. Behav. Ecol. Sociobiol. 33, 121–129 (1993).
We thank A. Bourke, C. DeHeer, J. Evans, M. Goodisman, D. Haig, L. Hurst and D.Queller for comments on the manuscript. This work was funded by grants from the Swiss and US National Science Foundations and the National Geographic Society.
About this article
Behavioral Ecology and Sociobiology (2019)
Unexpected patterns of segregation distortion at a selfish supergene in the fire ant Solenopsis invicta
BMC Genetics (2018)
Nature Communications (2017)
Evolutionary Biology (2017)