Letter | Published:

Aggression by polyembryonic wasp soldiers correlates with kinship but not resource competition

Nature volume 430, pages 676679 (05 August 2004) | Download Citation



Kin selection theory predicts that individuals will show less aggression and more altruism towards relatives1,2. However, recent theoretical developments suggest that with limited dispersal, competition between relatives can override the effects of relatedness3,4,5,6,7,8,9. The predicted and opposing influences of relatedness and competition are difficult to approach experimentally because conditions that increase average relatedness among individuals also tend to increase competition. Polyembryonic wasps in the family Encyrtidae are parasites whose eggs undergo clonal division to produce large broods10. These insects have also evolved a caste system: some embryos in a clone develop into reproductive larvae that mature into adults, whereas others develop into sterile soldier larvae that defend siblings from competitors11,12,13,14. In a brood from a single egg, reproductive altruism by soldiers reflects clone-level allocation to defence at the cost of reproduction, with no conflict between individuals. When multiple eggs are laid into a host, inter-clone conflicts of interest arise. Here we report that soldier aggression in Copidosoma floridanum is inversely related to the genetic relatedness of competitors but shows no correlation with the level of resource competition.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    The evolution of altruistic behaviour. Am. Nat. 97, 354–356 (1963)

  2. 2.

    The genetical evolution of social behaviour, I & II. J. Theor. Biol. 7, 1–52 (1964)

  3. 3.

    , & Can altruism evolve in a purely viscous population? Evol. Ecol. 6, 331–341 (1992)

  4. 4.

    Altruism in viscous populations—an inclusive fitness model. Evol. Ecol. 6, 352–356 (1992)

  5. 5.

    Inclusive fitness in a homogeneous environment. Proc. R. Soc. Lond. B 249, 299–302 (1992)

  6. 6.

    Genetic relatedness in viscous populations. Evol. Ecol. 8, 70–73 (1994)

  7. 7.

    in Behavioural Ecology: An Evolutionary Approach (eds Krebs, J. R. & Davies, N. B.) 62–84 (Blackwell Scientific, Oxford, 1984)

  8. 8.

    , , , & Testing Hamilton's rule with competition between relatives. Nature 409, 510–513 (2001)

  9. 9.

    , & Cooperation and competition between relatives. Science 296, 72–75 (2002)

  10. 10.

    in Encyclopedia of Insects (eds Carde, R. & Resch, V.) 928–932 (Academic, San Diego, 2003)

  11. 11.

    & The development and evolution of polyembryonic insects. Curr. Top. Dev. Biol. 35, 121–160 (1997)

  12. 12.

    , , & Caste determination in a polyembryonic wasp involves inheritance of germ cells. Proc. Natl Acad. Sci. USA (in the press)

  13. 13.

    A sterile defender morph in a polyembryonic hymenopterous parasite. Nature 294, 446–447 (1981)

  14. 14.

    , & Competition induces adaptive shifts in caste ratios of a polyembryonic wasp. Nature 406, 183–186 (2000)

  15. 15.

    Oviposition behavior and progeny allocation by the polyembryonic wasp Copidosoma floridanum. J. Insect Behav. 2, 355–369 (1989)

  16. 16.

    , & Sibling rivalry and brood sex ratios in polyembryonic wasps. Nature 360, 254–256 (1992)

  17. 17.

    & Progeny and sex allocation decisions of the polyembryonic wasp Copidosoma floridanum. J. Anim. Ecol. 64, 213–224 (1995)

  18. 18.

    , , & Development and pattern formation in the polyembryonic wasp, Copidosoma floridanum. Development 122, 795–804 (1996)

  19. 19.

    & in Sex ratios: Concepts and Research Methods (ed. Hardy, I. C. W.) 218–234 (Cambridge Univ. Press, Cambridge, 2002)

  20. 20.

    & Host resistance and the evolution of kin recognition in polyembryonic wasps. Proc. R. Soc. Lond. (Suppl.) Biol. Lett. published online 17 June 2004 (DOI:10.1098/rsb1/2004.0205)

  21. 21.

    Relatedness and the fraternal major transitions. Phil. Trans. R. Soc. Lond. B 355, 1647–1655 (2000)

  22. 22.

    Genetic clonal recognition abilities in marine invertebrates must be maintained by selection for something else. Evolution 40, 1100–1101 (1986)

  23. 23.

    The Evolution of Individuality (Princeton Univ. Press, Princeton, 1987)

  24. 24.

    The evolution of allorecognition specificity in clonal invertebrates. Q. Rev. Biol. 63, 377–412 (1988)

  25. 25.

    , & Altruism and social cheating in the social amoeba Dictyostelium discoideum. Nature 408, 965–967 (2000)

  26. 26.

    , & Genetic conflict and conditional altruism in social aphid colonies. Proc. Natl Acad. Sci. USA 98, 12068–12071 (2001)

  27. 27.

    Development of the polyembryonic parasitoid Copidosoma floridanum in Trichoplusia ni. Entomol. Exp. Appl. 50, 37–46 (1989)

Download references


This work was supported in part by the Natural Environment Research Council (UK), the National Science Foundation (US), the University of Georgia Experiment Station, and the Conseil General de la Region (France).

Author information


  1. Department of Entomology, University of Georgia, Athens, Georgia 30602, USA

    • David Giron
    •  & Michael R. Strand
  2. School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK

    • Derek W. Dunn
    •  & Ian C. W. Hardy


  1. Search for David Giron in:

  2. Search for Derek W. Dunn in:

  3. Search for Ian C. W. Hardy in:

  4. Search for Michael R. Strand in:

Competing interests

The authors declare that they have no competing financial interests.

Corresponding author

Correspondence to Michael R. Strand.

About this article

Publication history






Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.