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Mating system does not predict permanent sperm depletion in black widow spiders

Authors

  • Maria Modanu,

    Corresponding author
    1. Department of Biological Sciences, Integrative Behaviour and Neuroscience Group, University of Toronto Scarborough, 1265 Military Trail, Toronto ON M1C1A4, Canada
    • Department of Neurobiology and Behavior, Cornell University, 215 Tower Road, Ithaca, NY 14853, USA
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  • Peter Michalik,

    1. Department of General and Systematic Zoology, Zoological Institute and Museum, Ernst-Moritz-Arndt-University, Johann-Sebastian-Bach-Str. 11/12, Greifswald D-17489, Germany
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  • Maydianne C. B. Andrade

    1. Department of Biological Sciences, Integrative Behaviour and Neuroscience Group, University of Toronto Scarborough, 1265 Military Trail, Toronto ON M1C1A4, Canada
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Author for correspondence (e-mail: mm2474@cornell.edu)

SUMMARY

Variation in sperm production is strongly influenced by mating system across taxa. Recent work in spiders suggests that males of some species show termination of spermatogenesis before their adult molt and thus an inability to produce sperm after maturation. This permanent sperm depletion (PSD) has been hypothesized to co-occur with monogyny, genital mutilation, or sexual cannibalism because the maintenance of continual sperm supplies is not necessary for species where males can expect only one mating opportunity. Here we test this hypothesis in two congeners exhibiting genital mutilation: the sexually cannibalistic, monogynous Australian redback spider Latrodectus hasselti and the polygynous Western black widow Latrodectus hesperus. We report that PSD does not occur in adult males of either species, and show that males transfer sperm into their copulatory organs multiple times as adults. These data suggest evolutionary links between mating system and investment in sperm production may be more complex than currently appreciated.

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