Skip to main content
Log in

Modelling the Evolution of Traits in a Two-Sex Population, with an Application to Grandmothering

  • Original Article
  • Published:
Bulletin of Mathematical Biology Aims and scope Submit manuscript

Abstract

We present a mathematical simplification for the evolutionary dynamics of a heritable trait within a two-sex population. This trait is assumed to control the timing of sex-specific life-history events, such as the age of sexual maturity and end of female fertility, and each sex has a distinct fitness trade-off associated with the trait. We provide a formula for the fitness landscape of the population and show a natural extension of the result to an arbitrary number of heritable traits. Our method can be viewed as a dynamical systems generalisation of the Price equation to include two sexes, age structure and multiple traits. We use this formula to examine the effect of grandmothering, whereby post-fertile females subsidise their daughter’s fertility by provisioning grandchildren. Grandmothering can drive a shift towards increasingly male-biased mating sex ratios due to a post-fertile life stage in females, while male fertility continues to older ages. Our fitness landscapes show a net increase in fitness for both males and females at longer lifespans, and as a result, we find that grandmothering alone provides an evolutionary trajectory to higher longevities.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4

Similar content being viewed by others

References

  • Batty CJ, Crewe P, Grafen A, Gratwick R (2014) Foundations of a mathematical theory of darwinism. J Math Biol 69(2):295–334

    Article  MathSciNet  MATH  Google Scholar 

  • Chan MH, Hawkes K, Kim PS (2016) Evolution of longevity, age at last birth and sexual conflict with grandmothering. J Theor Biol 393:145–157

    Article  MATH  Google Scholar 

  • Chapman T, Arnqvist G, Bangham J, Rowe L (2003) Sexual conflict. Trends Ecol Evol 18(1):41–47

    Article  Google Scholar 

  • Charnov EL (1993) Life history invariants: some explorations of symmetry in evolutionary ecology. Oxford University Press, Oxford

    Google Scholar 

  • Coxworth JE, Kim PS, McQueen JS, Hawkes K (2015) Grandmothering life histories and human pair bonding. Proc Natl Acad Sci 112(38):11806–11811

    Article  Google Scholar 

  • Frank SA (2012) Natural selection. IV. The Price equation. J Evol Biol 25(6):1002–1019

    Article  Google Scholar 

  • Grafen A (2015) Biological fitness and the Price Equation in class-structured populations. J Theor Biol 373:62–72

    Article  MathSciNet  MATH  Google Scholar 

  • Hawkes K, Coxworth JE (2013) Grandmothers and the evolution of human longevity: a review of findings and future directions. Evol Anthropol 22(6):294–302

    Article  Google Scholar 

  • Hawkes K, Kim PS, Kennedy B, Bohlender R, Hawks J (2011) A reappraisal of grandmothering and natural selection. Proc R Soc Lond B Biol Sci 278(1714):1936–1938

    Article  Google Scholar 

  • Hawkes K, O’Connell JF, Blurton Jones NG, Alvarez H, Charnov EL (1998) Grandmothering, menopause, and the evolution of human life histories. Proc Natl Acad Sci 95(3):1336–1339

    Article  Google Scholar 

  • Hawkes K, Smith KR, Robson SL (2009) Mortality and fertility rates in humans and chimpanzees: how within-species variation complicates cross-species comparisons. Am J Hum Biol 21(4):578–586

    Article  Google Scholar 

  • Kachel AF, Premo LS, Hublin JJ (2011) Grandmothering and natural selection. Proc Biol Sci 278(1704):384–391

    Article  Google Scholar 

  • Kim PS, Coxworth JE, Hawkes K (2012) Increased longevity evolves from grandmothering. Proc Biol Sci 279(1749):4880–4884

    Article  Google Scholar 

  • Kim PS, McQueen JS, Coxworth JE, Hawkes K (2014) Grandmothering drives the evolution of longevity in a probabilistic model. J Theor Biol 353:84–94

    Article  Google Scholar 

  • Loo SL, Chan MH, Hawkes K, Kim PS (2017) Further mathematical modelling of mating sex ratios & male strategies with special relevance to human life history. Bull Math Biol. doi:10.1007/s11538-017-0313-2

    MathSciNet  Google Scholar 

  • Mineau G, Bean L, Skolnick M (1979) Mormon demographic history II: the family life cycle and natural fertility. Population Studies 33(3):429–446

    Article  Google Scholar 

  • Parker GA (2006) Sexual conflict over mating and fertilization: an overview. Philos Trans R Soc B Biol Sci 361(1466):235–259

    Article  Google Scholar 

  • Pavard S, Branger F (2012) Effect of maternal and grandmaternal care on population dynamics and human life-history evolution: a matrix projection model. Theor Popul Biol 82(4):364–376

    Article  MATH  Google Scholar 

  • Price GR (1970) Selection and covariance. Nature 227(5257):520–521

    Article  Google Scholar 

  • Price GR (1972) Extension of covariance selection mathematics. Ann Hum Genet 35(4):485–490

    Article  MATH  Google Scholar 

  • Schacht R, Bell AV (2016) The evolution of monogamy in response to partner scarcity. Sci Rep 6:32472

    Article  Google Scholar 

  • Süli E, Mayers DF (2003) An introduction to numerical analysis. Cambridge University Press, Cambridge

    Book  MATH  Google Scholar 

  • te Velde ER, Pearson PL (2002) The variability of female reproductive ageing. Hum Reprod Update 8(2):141–154

    Article  Google Scholar 

Download references

Acknowledgements

MHC and PSK were supported by the Australian Research Council, Discovery Project (DP160101597).

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Matthew H. Chan.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Chan, M.H., Hawkes, K. & Kim, P.S. Modelling the Evolution of Traits in a Two-Sex Population, with an Application to Grandmothering. Bull Math Biol 79, 2132–2148 (2017). https://doi.org/10.1007/s11538-017-0323-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11538-017-0323-0

Keywords

Navigation