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Proc Biol Sci. Jun 7, 2002; 269(1496): 1125–1128.
PMCID: PMC1691004

Evolution of larger sperm in response to experimentally increased sperm competition in Caenorhabditis elegans.


Sperm morphology evolves rapidly, resulting in an exceptional diversity of sperm size and shape across animal phyla. This swift evolution has been thought to prevent fertilizations between closely related species. Alternatively, recent correlative analyses suggest that competition among sperm from more than one male may cause sperm diversity, but these hypotheses have not been tested. Here, we test experimentally the effect of sperm competition on sperm-size evolution using the nematode Caenorhabditis elegans. This worm has a three day generation time, which allowed the study to cover many generations. Sperm volume increased nearly 20% over 60 generations in lines genetically induced to have high levels of sperm competition compared with those of control lines. These results show that sperm competition can and does cause morphological evolution of sperm and, therefore, can explain much of the diversity in sperm morphology.

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Selected References

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  • Brenner S. The genetics of Caenorhabditis elegans. Genetics. 1974 May;77(1):71–94. [PMC free article] [PubMed]
  • Gomendio M, Roldan ER. Sperm competition influences sperm size in mammals. Proc Biol Sci. 1991 Mar 22;243(1308):181–185. [PubMed]
  • Hodgkin J. Male Phenotypes and Mating Efficiency in CAENORHABDITIS ELEGANS. Genetics. 1983 Jan;103(1):43–64. [PMC free article] [PubMed]
  • Hosken DJ. Sperm competition in bats. Proc Biol Sci. 1997 Mar 22;264(1380):385–392. [PMC free article] [PubMed]
  • Hosken DJ, Garner TW, Ward PI. Sexual conflict selects for male and female reproductive characters. Curr Biol. 2001 Apr 3;11(7):489–493. [PubMed]
  • LaMunyon CW, Ward S. Assessing the viability of mutant and manipulated sperm by artificial insemination of Caenorhabditis elegans. Genetics. 1994 Nov;138(3):689–692. [PMC free article] [PubMed]
  • LaMunyon CW, Ward S. Larger sperm outcompete smaller sperm in the nematode Caenorhabditis elegans. Proc Biol Sci. 1998 Oct 22;265(1409):1997–2002. [PMC free article] [PubMed]
  • LaMunyon CW, Ward S. Evolution of sperm size in nematodes: sperm competition favours larger sperm. Proc Biol Sci. 1999 Feb 7;266(1416):263–267. [PMC free article] [PubMed]
  • Morrow EH, Gage MJ. The evolution of sperm length in moths. Proc Biol Sci. 2000 Feb 7;267(1440):307–313. [PMC free article] [PubMed]
  • Parker GA. Why are there so many tiny sperm? Sperm competition and the maintenance of two sexes. J Theor Biol. 1982 May 21;96(2):281–294. [PubMed]
  • Pitnick S, Spicer GS, Markow TA. How long is a giant sperm? Nature. 1995 May 11;375(6527):109–109. [PubMed]
  • Presgraves DC, Baker RH, Wilkinson GS. Coevolution of sperm and female reproductive tract morphology in stalk-eyed flies. Proc Biol Sci. 1999 May 22;266(1423):1041–1041. [PMC free article]
  • Prout T, Clark AG. Seminal fluid causes temporarily reduced egg hatch in previously mated females. Proc Biol Sci. 2000 Jan 22;267(1439):201–203. [PMC free article] [PubMed]
  • Rice WR. Sexually antagonistic male adaptation triggered by experimental arrest of female evolution. Nature. 1996 May 16;381(6579):232–234. [PubMed]
  • Roberts TM, Pavalko FM, Ward S. Membrane and cytoplasmic proteins are transported in the same organelle complex during nematode spermatogenesis. J Cell Biol. 1986 May;102(5):1787–1796. [PMC free article] [PubMed]
  • Shakes DC, Ward S. Initiation of spermiogenesis in C. elegans: a pharmacological and genetic analysis. Dev Biol. 1989 Jul;134(1):189–200. [PubMed]
  • McGory RW, Ishitani MB, Oliveira WM, Stevenson WC, McCullough CS, Dickson RC, Caldwell SH, Pruett TL. Improved outcome of orthotopic liver transplantation for chronic hepatitis B cirrhosis with aggressive passive immunization. Transplantation. 1996 May 15;61(9):1358–1364. [PubMed]

Articles from Proceedings of the Royal Society B: Biological Sciences are provided here courtesy of The Royal Society


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