Sperm Storage and Sperm Competition Across Ovarian Cycles in the Dragon Lizard, Ctenophorus fordi

Authors

  • TOBIAS ULLER,

    Corresponding author
    1. School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
    • Department of Zoology, Edward Grey Institute, University of Oxford, Oxford, United Kingdom
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  • TONIA SCHWARTZ,

    1. School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
    2. Office of Energetics, School of Public Health, University of Alabama at Birmingham, Alabama
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  • TROY KOGLIN,

    1. School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
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  • MATS OLSSON

    1. School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
    2. School of Biological Sciences, Heydon-Laurence Building, The University of Sydney, Sydney, NSW, Australia
    3. Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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  • Conflicts of interest: None.

Correspondence to: Tobias Uller, Department of Zoology, Edward Grey Institute, University of Oxford, OX1 3PS Oxford, United Kingdom.

E-mail: tobias.uller@zoo.ox.ac.uk

ABSTRACT

Female sperm storage can influence male reproductive success and may favour males that produce sperm that remain viable across several ovarian cycles. Here we show that sperm are viable in the female reproductive tract across ovarian cycles in the mallee dragon, Ctenophorus fordi. Based on experimental mating trials, we show that stored sperm were generally less likely to fertilize eggs than recently inseminated sperm. The fertilization success of stored sperm increased with male body size relative to rivals. This may be due to differences in ejaculate volume or sperm number transferred by males of different sizes. However, there was no evidence that copulation time, which is correlated with ejaculate volume, contributed to fertilization success. We suggest that sperm storage across ovarian cycles may be common in small, multi-clutched lizards and that its impact on selection on male phenotypes could contribute to the evolution of lizard mating systems. J. Exp. Zool. 319A: 404–408, 2013. © 2013 Wiley Periodicals, Inc.

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