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Length of activity season drives geographic variation in body size of a widely distributed lizard

Authors

  • Terézia Horváthová,

    1. Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
    2. Edward Grey Institute, Department of Zoology, University of Oxford, Oxford, U.K
    Current affiliation:
    1. Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
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    • These authors contributed equally to this work.
  • Christopher R. Cooney,

    1. Edward Grey Institute, Department of Zoology, University of Oxford, Oxford, U.K
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    • These authors contributed equally to this work.
  • Patrick S. Fitze,

    1. Department of Ecology and Evolution (DEE), Biophore, Université de Lausanne, Lausanne, Switzerland
    2. Department of Biodiversity & Evolutionary Biology, Museo Nacional de Ciencias Naturales (MNCN–CSIC), Madrid, Spain
    3. Instituto Pirenaico de Ecología (IPE-CSIC), Jaca, Spain
    4. Fundación Araid, Zaragoza, Spain
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  • Tuula A. Oksanen,

    1. Department of Biological & Environmental Science, Centre of Excellence in Evolutionary Research, University of Jyväskylä, Jyväskylä, Finland
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  • Dušan Jelić,

    1. Croatian Institute for Biodiversity, Croatian Herpetological Society HYLA, Zagreb, Croatia
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  • Ioan Ghira,

    1. Faculty of Biology & Geology, Babes-Bolyai University Cluj-Napoca, Cluj, Romania
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  • Tobias Uller,

    Corresponding author
    1. Edward Grey Institute, Department of Zoology, University of Oxford, Oxford, U.K
    • Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
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    • These authors contributed equally to this work.
  • David Jandzik

    Corresponding author
    1. Department of Ecology & Evolutionary Biology (EBIO), University of Colorado, Boulder, CO, USA
    • Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
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    • These authors contributed equally to this work.

Correspondence

David Jandzik, Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina B-1, 842 15 Bratislava, Slovakia. Tel: +421-2-60296249; Fax: +421-2-60296333; E-mail: davidjandzik@gmail.com

Tobias Uller, Edward Grey Institute, Department of Zoology, University of Oxford, OX1 3PS, Oxford, U.K. E-mail: tobias.uller@zoo.ox.ac.uk

Abstract

Understanding the factors that drive geographic variation in life history is an important challenge in evolutionary ecology. Here, we analyze what predicts geographic variation in life-history traits of the common lizard, Zootoca vivipara, which has the globally largest distribution range of all terrestrial reptile species. Variation in body size was predicted by differences in the length of activity season, while we found no effects of environmental temperature per se. Females experiencing relatively short activity season mature at a larger size and remain larger on average than females in populations with relatively long activity seasons. Interpopulation variation in fecundity was largely explained by mean body size of females and reproductive mode, with viviparous populations having larger clutch size than oviparous populations. Finally, body size-fecundity relationship differs between viviparous and oviparous populations, with relatively lower reproductive investment for a given body size in oviparous populations. While the phylogenetic signal was weak overall, the patterns of variation showed spatial effects, perhaps reflecting genetic divergence or geographic variation in additional biotic and abiotic factors. Our findings emphasize that time constraints imposed by the environment rather than ambient temperature play a major role in shaping life histories in the common lizard. This might be attributed to the fact that lizards can attain their preferred body temperature via behavioral thermoregulation across different thermal environments. Length of activity season, defining the maximum time available for lizards to maintain optimal performance, is thus the main environmental factor constraining growth rate and annual rates of mortality. Our results suggest that this factor may partly explain variation in the extent to which different taxa follow ecogeographic rules.

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