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Philosophical Transactions of the Royal Society B: Biological Sciences logoLink to Philosophical Transactions of the Royal Society B: Biological Sciences
. 2002 Mar 29;357(1419):319–330. doi: 10.1098/rstb.2001.0926

Why is mutual mate choice not the norm? Operational sex ratios, sex roles and the evolution of sexually dimorphic and monomorphic signalling.

Hanna Kokko 1, Rufus A Johnstone 1
PMCID: PMC1692955  PMID: 11958700

Abstract

Biases in the operational sex ratio (OSR) are seen as the fundamental reason behind differential competition for mates in the two sexes, and as a strong determinant behind differences in choosiness. This view has been challenged by Kokko and Monaghan, who argue that sex-specific parental investment, mortalities, mate-encounter rates and quality variation determine the mating system in a way that is not reducible to the OSR. We develop a game-theoretic model of choosiness, signalling and parental care, to examine (i) whether the results of Kokko and Monaghan remain robust when its simplifying assumptions are relaxed, (ii) how parental care coevolves with mating strategies and the OSR and (iii) why mutual mate choice is observed relatively rarely even when both sexes vary in quality. We find qualitative agreement with the simpler approach: parental investment is the primary determinant of sex roles instead of the OSR, and factors promoting choosiness are high species-specific mate-encounter rate, high sex-specific mate-encounter rate, high cost of breeding (parental investment), low cost of mate searching and highly variable quality of the opposite sex. The coevolution of parental care and mating strategies hinders mutual mate choice if one parent can compensate for reduced care by the other, but promotes it if offspring survival depends greatly on biparental care. We argue that the relative rarity of mutual mate choice is not due to biases in the OSR. Instead, we describe processes by which sexual strategies tend to diverge. This divergence is prevented, and mutual mate choice maintained, if synergistic benefits of biparental care render parental investment both high and not too different in the two sexes.

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Selected References

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  1. Amundsen T. Why are female birds ornamented? Trends Ecol Evol. 2000 Apr;15(4):149–155. doi: 10.1016/s0169-5347(99)01800-5. [DOI] [PubMed] [Google Scholar]
  2. Clutton-Brock T. H., Vincent A. C. Sexual selection and the potential reproductive rates of males and females. Nature. 1991 May 2;351(6321):58–60. doi: 10.1038/351058a0. [DOI] [PubMed] [Google Scholar]
  3. Cunningham EJA, Birkhead TR. Sex roles and sexual selection. Anim Behav. 1998 Dec;56(6):1311–1321. doi: 10.1006/anbe.1998.0953. [DOI] [PubMed] [Google Scholar]
  4. Eens M, Pinxten R. Sex-role reversal in vertebrates: behavioural and endocrinological accounts. Behav Processes. 2000 Oct 5;51(1-3):135–147. doi: 10.1016/s0376-6357(00)00124-8. [DOI] [PubMed] [Google Scholar]
  5. Emlen S. T., Oring L. W. Ecology, sexual selection, and the evolution of mating systems. Science. 1977 Jul 15;197(4300):215–223. doi: 10.1126/science.327542. [DOI] [PubMed] [Google Scholar]
  6. Engqvist L., Sauer K. P. Strategic male mating effort and cryptic male choice in a scorpionfly. Proc Biol Sci. 2001 Apr 7;268(1468):729–735. doi: 10.1098/rspb.2000.1423. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Iwasa Y., Pomiankowski A. Good parent and good genes models of handicap evolution. J Theor Biol. 1999 Sep 7;200(1):97–109. doi: 10.1006/jtbi.1999.0979. [DOI] [PubMed] [Google Scholar]
  8. Kraak SBM, Bakker TCM. Mutual mate choice in sticklebacks: attractive males choose big females, which lay big eggs. Anim Behav. 1998 Oct;56(4):859–866. doi: 10.1006/anbe.1998.0822. [DOI] [PubMed] [Google Scholar]
  9. Kvarnemo C, Simmons LW. Male potential reproductive rate influences mate choice in a bushcricket. Anim Behav. 1998 Jun;55(6):1499–1506. doi: 10.1006/anbe.1998.0732. [DOI] [PubMed] [Google Scholar]
  10. McNamara J. M., Webb J. N., Collins E. J., Székely T., Houston A. I. A general technique for computing evolutionarily stable strategies based on errors in decision-making. J Theor Biol. 1997 Nov 21;189(2):211–225. doi: 10.1006/jtbi.1997.0511. [DOI] [PubMed] [Google Scholar]
  11. Mcnamara J. M., Székely T., Webb J. N., Houston A. I. A dynamic game-theoretic model of parental care. J Theor Biol. 2000 Aug 21;205(4):605–623. doi: 10.1006/jtbi.2000.2093. [DOI] [PubMed] [Google Scholar]
  12. Owens I. P., Thompson D. B. Sex differences, sex ratios and sex roles. Proc Biol Sci. 1994 Nov 22;258(1352):93–99. doi: 10.1098/rspb.1994.0148. [DOI] [PubMed] [Google Scholar]
  13. doi: 10.1098/rspb.1997.0216. [DOI] [PMC free article] [Google Scholar]
  14. doi: 10.1098/rspb.1998.0515. [DOI] [PMC free article] [Google Scholar]
  15. Rhen T. Sex-limited mutations and the evolution of sexual dimorphism. Evolution. 2000 Feb;54(1):37–43. doi: 10.1111/j.0014-3820.2000.tb00005.x. [DOI] [PubMed] [Google Scholar]
  16. Sheldon BC. Differential allocation: tests, mechanisms and implications. Trends Ecol Evol. 2000 Oct 1;15(10):397–402. doi: 10.1016/s0169-5347(00)01953-4. [DOI] [PubMed] [Google Scholar]

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