Operational sex ratio affects nest tending and aggression in male flagfish Jordanella floridae Goode & Bean

Authors

  • H. Klug,

    Corresponding author
    1. Department of Zoology, University of Florida, 223 Bartram Hall, Gainesville, FL 32611, U.S.A.
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  • C. I. Kontax,

    1. Department of Zoology, University of Florida, 223 Bartram Hall, Gainesville, FL 32611, U.S.A.
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    • Present address: 3521 SW 30th Way Apartment 101, Gainesville, FL 32608, U.S.A.

  • S. Annis,

    1. Department of Zoology, University of Florida, 223 Bartram Hall, Gainesville, FL 32611, U.S.A.
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    • Present address: 1449 Myakka Road, Sarasota, FL 34240, U.S.A. and

  • N. Vasudevan

    1. Department of Zoology, University of Florida, 223 Bartram Hall, Gainesville, FL 32611, U.S.A.
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    • §

      Present address: 3510 SW 24th Avenue Road, Ocala, FL 34474, U.S.A.


*Department of Biological and Environmental Science, P. O. Box 65, University of Helsinki, 00014, Helsinki, Finland. Tel.: +358 9 1915 7713; fax: +358 9 1915 7694; email: hklug@zoo.ufl.edu

Abstract

Operational sex ratio (OSR, the ratio of sexually active males to fertilizable females at a given time and location) affected male behaviour in the flagfish Jordanella floridae. When OSR was male biased, males spent (1) more time at their nests and (2) more time fanning prior to receiving eggs. Pre-mating fanning has previously been correlated with male mating success and is hypothesized to be used in female choice in this population. Thus, these results suggest that on average, male flagfish invest more time in behaviour associated with female choice when there are relatively more male competitors. The OSR also affected the frequency of male aggression, and specifically male aggression towards females was more frequent at female-biased OSR treatments. The observed patterns were dependent upon the direction of OSR bias (i.e. unbiased, male biased and female biased), and in some cases the intensity of the OSR bias affected the patterns of behaviour. These findings suggest that experimentally detecting effects of OSR is sensitive to the specific OSR values considered, and highlight the importance of considering a range of OSR values in future studies.

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