An ecomorphological framework for the coexistence of two cyprinid fish and their hybrids in a novel environment

Authors

  • BENJAMIN J. TOSCANO,

    1. Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, Connecticut 06269-3043, USA
    2. UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
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    • These authors contributed equally to this work.

    • Present address: Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.

  • DOMITILLA PULCINI,

    1. Laboratory of Experimental Ecology and Aquaculture, Department of Biology, University of Rome ‘Tor Vergata’, via della Ricerca Scientifica s.n.c, 00133 Rome, Italy
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    • These authors contributed equally to this work.

  • BRIAN HAYDEN,

    1. UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
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  • TOMMASO RUSSO,

    1. Laboratory of Experimental Ecology and Aquaculture, Department of Biology, University of Rome ‘Tor Vergata’, via della Ricerca Scientifica s.n.c, 00133 Rome, Italy
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  • MARY KELLY-QUINN,

    1. UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
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  • STEFANO MARIANI

    Corresponding author
    1. UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
      E-mail: stefano.mariani@ucd.ie
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E-mail: stefano.mariani@ucd.ie

Abstract

Niche variation between hybrid taxa and their parental species has been deemed imperative to the persistence of hybrid populations in nature. However, the ecological factors promoting hybrid establishment remain poorly understood. Through the application of a multidisciplinary approach integrating genetics, morphometry, life-history, and trophic ecology, we studied the hybrids of roach (Rutilus rutilus L.) and bream (Abramis brama L.), and their parental species inhabiting an Irish lake. The roach × bream hybrid exhibited a body shape intermediate of that of the parental species. Diet analyses depicted the hybrid as a generalist, feeding on all prey items consumed by either parental species. Stable isotope data confirm the trophic niche breadth of hybrids. A significant correlation between body shape and diet was detected, suggesting that the intermediate phenotype of hybrids might play a role in their feeding abilities, resulting in the utilization of a broader trophic spectrum than the parental species. Growth and age class structure analyses also yielded a scenario that is consistent with the ecological success of hybrids. Genetic analyses suggest that the majority of hybrids result from first-generation crosses between the parental species; however, a potentially significant proportion of back-crosses with bream were also detected. The recent introduction of roach and bream into Irish waters, as well as the climatic and ecological features of the colonized habitats, can explain the remarkable success of the roach × bream hybrid in Ireland. The adaptive significance of hybridization and its demographic consequences for the parental species are discussed. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 768–783.

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