Evolutionary Ecology

, Volume 10, Issue 3, pp 265–284 | Cite as

Assortative mating by size: A meta-analysis of mating patterns in water striders

  • Göran Arnqvist
  • Locke Rowe
  • James J. Krupa
  • Andy Sih


Assortative mating by size is a common mating pattern that can be generated by several different behavioural mechanisms, with different evolutionary implications. Assortative mating is typically associated with sexual selection and has been regarded as an attribute of populations, species, mating systems or even higher order taxa. In most animal groups, however, appropriate analyses of assortative mating at these different levels are lacking and the causes and forms of assortative mating are poorly understood. Here, we analyse 45 different population level estimates of assortative mating and non-random mating by size in seven confamiliar species of water striders that share a common mating system. A hierarchical comparative analysis shows that virtually all the variance within the clade occurs among samples within species. We then employ meta-analysis to estimate the overall strength of assortative mating, to determine the form of assortative mating and to further assess potential differences among species as well as the probable causes of assortative mating in this group of insects. We found overall weak but highly significant positive assortative mating. We show that analyses of the degree of heteroscedasticity in plots of male versus female size are critical, since the evolutionary implications of ‘true’ and ‘apparent’ assortative mating differ widely and conclude that the positive assortative mating observed in water striders was of the ‘true’ rather than the ‘apparent’ form. Further, within samples, mating individuals were significantly larger than non-mating individuals in both males and females. All of these non-random mating patterns were consistent among species and we conclude that weak positive assortative mating by size is a general characteristic of those water strider species that share this mating system. We use our results to illustrate the importance of distinguishing between different forms of assortative mating, to discriminate between various behavioural causes of assortative mating and to assess potential sources of interpopulational variance in estimates of assortative mating. Finally, we discuss the value of using meta-analytic techniques for detecting overall patterns in multiple studies of non-random mating.


assortative mating sexual selection meta-analysis genetic variation non-random mating Gerridae 


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  1. Arak, A. (1983) Male-male competition and mate choice in anuran amphibians. InMate choice (P. Bateson, ed.) pp. 181–210. Cambridge University Press, Cambridge, UK.Google Scholar
  2. Arnqvist, G. (1989) Sexual selection in a water strider: the function, nature of selection and heritability of a male grasping apparatus.Oikos 56 344–50.Google Scholar
  3. Arnqvist, G. (1990) Heritability estimates of morphological traits inGerris odontogaster (Zett.) (Heteroptera; Gerridae).Hereditas 112 89–91.Google Scholar
  4. Arnqvist, G. (1992a) Precopulatory fighting in a water strider: intersexual conflict or mate assessment?Anim. Behav. 43 559–67.Google Scholar
  5. Arnqvist, G. (1992b) The effects of operational sex ratio on the relative mating success of extreme male phenotypes in the water striderGerris odontogaster (Zett.) (Heteroptera: Gerridae).Anim. Behav. 43 681–3.Google Scholar
  6. Arnqvist, G. (1992c) Spatial variation in selective regimes: sexual selection in the water strider,Gerris odontogaster.Evolution 46 914–29.Google Scholar
  7. Arnqvist, G. (1995) The evolution of water strider mating systems: causes and consequences of sexual conflicts. InSocial competition and cooperation in insects and arachnids: Vol. I. Evolution of mating systems (J.C. Choe and B.J. Crespi, eds), in press. Princeton University Press, Princeton, NJ.Google Scholar
  8. Arnqvist, G. and Wooster, D. (1995). Meta-analysis: synthesizing research findings in ecology and evolution.Trends in Ecol. Evol.,10 236–40.Google Scholar
  9. Brown, W.D. (1993) The cause of size-assortative mating in the leaf beetleTrirhabda canadensis (Coleoptera: Chrysomelidae).Behav. Ecol. Sociobiol. 33 151–7.Google Scholar
  10. Christy, J.H. (1983) Female choice in the resource-defence mating system of the sand fiddler crab,Uca pugilator.Behav. Ecol. Sociobiol. 12 169–80.Google Scholar
  11. Cohen, J. (1988)Statistical Power Analysis for the Behavioral Sciences. Lawrence Erlbaum, Hillsdale.Google Scholar
  12. Cooper, H.M. and Hedges, L.V. (1994)The Handbook of Research Synthesis. Russel Sage Foundation, New York.Google Scholar
  13. Crespi, B.J. (1989) Causes of assortative mating in arthropods.Anim. Behav. 38 980–1000.Google Scholar
  14. Crow, J. and Felsenstein, J. (1968) The effect of assortative mating on the genetic composition of a population.Eugen. Qt. 15 85–97.Google Scholar
  15. Dick, J.T.A. and Elwood, R.W. (1993) The mating system ofGammarus pulex: a negligible role for microhabitat segregation.Anim. Behav. 45 188–90.Google Scholar
  16. Fairbairn, D.J. (1988) Sexual selection for homogamy in the Gerridae: an extension of Ridley's comparative approach.Evolution 42 1212–22.Google Scholar
  17. Falconer, D.S. (1981)Introduction to Quantitative Genetics. John Wiley, New York.Google Scholar
  18. Foster, W.A. and Treherne, J.E. (1982) Reproductive behavior of the ocean skaterHalobates robustus (Hemiptera: Gerridae) in the Galapagos Islands.Oecologia 55 202–7.Google Scholar
  19. Gurevitch, J. and Hedges, L.V. (1993) Meta-analysis: combining the results of independent experiments. InDesign and analysis of ecological experiments (S.M. Scheiner and J. Gurevitch, eds), pp. 378–98. Chapman & Hall, New York.Google Scholar
  20. Gurevitch, J., Morrow, L.L., Wallace, A. and Walsh, J.S. (1992) A meta-analysis of competition in field experiments.Am. Nat. 140 539–72.Google Scholar
  21. Harvey, P.H. and Pagel, M.D. (1991)The Comparative Method in Evolutionary Biology. Oxford University Press, Oxford.Google Scholar
  22. Hedges, L.V. and Olkin, I. (1985)Statistical Methods for Meta-analysis. Academic Press, Orlando, FL.Google Scholar
  23. Hunter, J.E. and Schmidt, F.L. (1990)Methods of Meta-analysis: Correcting Error and Bias in Research Findings. Sage Publications, Newbury Park, CA.Google Scholar
  24. Hurlbert, S.H. (1984) Pseudoreplication and the design of ecological field experiments.Ecol. Monogr. 54 187–211.Google Scholar
  25. Jormalainen, V., Tuomi, J. and Merilaita, S. (1994) Effect of female resistance on size-dependent precopula duration in mate-guarding Crustacea.Anim. Behav. 47 1471–4.Google Scholar
  26. Järvinen, A. (1991) A meta-analytic study of the effects of female age on laying-date and clutch-size in the Great TitParus major and the Pied FlycatcherFicedula hypoleuca.Ibis 133 62–7.Google Scholar
  27. Kirby, K.N. (1993)Advanced Data Analysis with SYSTAT. Van Nostrand Reinhold, New York.Google Scholar
  28. Krupa, J.J. and Sih, A. (1993) Experimental studies on water strider mating dynamics: spatial variation in density and sex ratio.Behav. Ecol. Sociobiol. 33 107–20.Google Scholar
  29. Nummelin, M., Vepsäläinen, K. and Spence, J.R. (1984) Habitat partitioning among developmental stages of waterstriders (Heteroptera: Gerridae).Oikos 42 267–75.Google Scholar
  30. Partridge, L. (1983) Non-random mating and offspring fitness. InMate choice (P. Bateson, ed.), pp. 227–56. Cambridge University Press, Cambridge, UK.Google Scholar
  31. Poulin, R. (1994) Meta-analysis of parasite-induced behavioural changes.Anim. Behav. 48 137–46.Google Scholar
  32. Reid, D.G., Abello, P., Warman, C.G. and Naylor, E. (1994) Size-related mating success in the shore crabCarcinus maenas (Crustacea: Brachyura).J. Zool. (Lond.)232 397–407.Google Scholar
  33. Ridley, M. (1983)The Explanation of Organic Diversity: The Comparative Method and Adaptations for Mating. Clarendon Press, Oxford.Google Scholar
  34. Rosenthal, R. (1991)Meta-analytic Procedures for Social Reserach. Sage Publications, Newbury Park, CA.Google Scholar
  35. Rosenthal, R. and Rosnow, R.L. (1991)Essentials of Behavioural Research: Methods and Data Analysis. McGraw-Hill, New York.Google Scholar
  36. Rowe, L. (1992) Conveniance polyandry in a water strider: foraging conflicts and female control of copulation frequency and guarding duration.Anim. Behav. 44 189–202.Google Scholar
  37. Rowe, L. and Arnqvist, G. (1995) Analysis of the causal components of assortative mating in water striders. (manuscript)Google Scholar
  38. Rowe, L., Arnqvist, G., Sih, A. and Krupa, J.J. (1994) Sexual conflict and the evolutionary ecology of mating patterns: water striders as a model system.Trends Ecol. Evol. 9 289–93.Google Scholar
  39. Rubenstein, D.I. (1984) Resource acquisition and alternative mating strategies in water striders.Am. Zool. 24 345–53.Google Scholar
  40. Shradish, W.R. and Haddock, C.K. (1994) Combining estimates of effect size. InThe handbook of research synthesis (H.M. Cooper and L.V. Hedges, eds), pp. 215–30. Russel Sage Foundation, New York.Google Scholar
  41. Sih, A. and Krupa, J.J. (1992) Predation risk, food deprivation and non-random mating by size in the stream water strider,Aquarius remigis.Behav. Ecol. Sociobiol. 31 51–6.Google Scholar
  42. Sih, A. and Krupa, J.J. (1995) Interacting effects of predation risk, sex ratio and density on male-female conflicts and mating dynamics of the stream-dwelling water strider,Aquarius remigis. Behav. Ecol. (in press)Google Scholar
  43. Snead, J.S. and Alcock, J. (1985) Aggregation formation and assortative mating in two meloid beetles.Evolution 39 1123–31.Google Scholar
  44. Sokal, R.R. and Rohlf, F.J. (1981)Biometry. W.H. Freeman, San Fransisco.Google Scholar
  45. Spence, J.R. (1981) Experimental analysis of microhabitat selection in water-striders (Heteroptera: Gerridae).Ecology 62 1505–14.Google Scholar
  46. Spence, J.R. and Andersen, N.M. (1994) Biology of water striders: interactions between systematics and ecology.Ann. Rev. Entomol. 39 97–124.Google Scholar
  47. Tonhasca, A. and Byrne, D.N. (1994) The effects of crop diversification on herbivorous insects: a metaanalysis approach.Ecol. Entomol. 19 239–44.Google Scholar
  48. VanderWerf, E. (1992) Lack's clutch size hypothesis: an examination of the evidence using meta-analysis.Ecology 73 1699–705.Google Scholar
  49. Ward, P.I. (1993) Micro-habitat segregation and the mating system ofGammarus pulex.Anim. Behav. 45 191–2.Google Scholar
  50. Ward, P.I. and Porter, A.H. (1993) The relative roles of habitat structure and male-male competition in the mating system ofGammarus pulex (Crustacea; Amphipoda): a simulation study.Anim. Behav. 45 119–33.Google Scholar
  51. Wilkinson, L. (1987)SYSTAT: The System for Statistics. SYSTAT Inc., Evanston, IL.Google Scholar
  52. Williams, S.M. and Sarkar, S. (1994) Assortative mating and the adaptive landscape.Evolution 48 868–75.Google Scholar
  53. Zar, J.H. (1984)Biostatistical Analysis. Prentice-Hall, Englewood Cliffs, NJ.Google Scholar

Copyright information

© Chapman & Hall 1996

Authors and Affiliations

  • Göran Arnqvist
    • 1
  • Locke Rowe
    • 2
  • James J. Krupa
    • 3
  • Andy Sih
    • 3
  1. 1.Department of BiologyUniversity of New MexicoAlbuquerqueUSA
  2. 2.Department of ZoologyUniversity of TorontoTorontoCanada
  3. 3.Center for Evolutionary Ecology, School of Biological SciencesUniversity of KentuckyLexingtonUSA

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