Abstract
Theory predicts that mate choice can lead to an increase in female fecundity if the secondary sexual traits used by females to assess male quality covary with the number of sperm transferred during copulation. Where females mate multiply, such a relationship between male attractiveness and ejaculate size may, additionally (or alternatively), serve to augment the effect of indirect selection by biasing paternity in favour of preferred males. In either case, a positive correlation between male attractiveness and the size of ejaculates delivered at copulation is predicted. To date, some of the most convincing (indirect) evidence for this prediction comes from the guppy, a species of fish exhibiting a resource-free mating system in which attractive males tend to have larger sperm reserves. We show that, during solicited copulations, male guppies with preferred phenotypes actually transfer more sperm to females than their less-ornamented counterparts, irrespective of the size of their initial sperm stores. Our results also reveal that, during coercive copulations, the relationship between ejaculate size and the male's phenotype breaks down. This latter result, in conjunction with our finding that mating speed--a factor under the female's control-is a significant predictor of ejaculate size, leads us to speculate that females may exert at least partial control over the number of sperm inseminated during cooperative matings.
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Selected References
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- Birkhead T. R., Fletcher F. Male phenotype and ejaculate quality in the zebra finch Taeniopygia guttata. Proc Biol Sci. 1995 Dec 22;262(1365):329–334. doi: 10.1098/rspb.1995.0213. [DOI] [PubMed] [Google Scholar]
- Brooks R., Endler J. A. Direct and indirect sexual selection and quantitative genetics of male traits in guppies (Poecilia reticulata). Evolution. 2001 May;55(5):1002–1015. doi: 10.1554/0014-3820(2001)055[1002:daissa]2.0.co;2. [DOI] [PubMed] [Google Scholar]
- Brooks R. Negative genetic correlation between male sexual attractiveness and survival. Nature. 2000 Jul 6;406(6791):67–70. doi: 10.1038/35017552. [DOI] [PubMed] [Google Scholar]
- Elgar M. A., Schneider J. M., Herberstein M. E. Female control of paternity in the sexually cannibalistic spider Argiope keyserlingi. Proc Biol Sci. 2000 Dec 7;267(1460):2439–2443. doi: 10.1098/rspb.2000.1303. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Evans J. P., Magurran A. E. Patterns of sperm precedence and predictors of paternity in the Trinidadian guppy. Proc Biol Sci. 2001 Apr 7;268(1468):719–724. doi: 10.1098/rspb.2000.1577. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gomendio M., Cassinello J., Roldan E. R. A comparative study of ejaculate traits in three endangered ungulates with different levels of inbreeding: fluctuating asymmetry as an indicator of reproductive and genetic stress. Proc Biol Sci. 2000 May 7;267(1446):875–882. doi: 10.1098/rspb.2000.1084. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jennions M. D., Petrie M. Why do females mate multiply? A review of the genetic benefits. Biol Rev Camb Philos Soc. 2000 Feb;75(1):21–64. doi: 10.1017/s0006323199005423. [DOI] [PubMed] [Google Scholar]
- doi: 10.1098/rspb.1997.0099. [DOI] [PMC free article] [Google Scholar]
- doi: 10.1098/rspb.1997.0155. [DOI] [PMC free article] [Google Scholar]
- doi: 10.1098/rspb.1999.0862. [DOI] [PMC free article] [Google Scholar]
- doi: 10.1098/rspb.1999.0938. [DOI] [PMC free article] [Google Scholar]
- Pizzari T., Birkhead T. R. Female feral fowl eject sperm of subdominant males. Nature. 2000 Jun 15;405(6788):787–789. doi: 10.1038/35015558. [DOI] [PubMed] [Google Scholar]
- Warner R. R., Shapiro D. Y., Marcanato A., Petersen C. W. Sexual conflict: males with highest mating success convey the lowest fertilization benefits to females. Proc Biol Sci. 1995 Nov 22;262(1364):135–139. doi: 10.1098/rspb.1995.0187. [DOI] [PubMed] [Google Scholar]