Ecological and chemical correlates of cutaneous resistance to evaporative water loss for hylid frogs from the wet-dry tropics of Australia

  • Jeanne Elise Young

    Student thesis: Doctor of Philosophy (PhD) - CDU


    Most frog species show little resistance to evaporative water loss (EWL), but some arboreal species are known to have very high resistances. We measured EWL and cutaneous resistance to evaporation (Rc) in 25 species of frogs from northern Australia, including 17 species in the family Hylidae, six species in the Myobatrachidae, one each in the Bufonidae and the Microhylidae. These species display a variety of ecological habits, including aquatic, terrestrial and arboreal specialisations, with the complete range of habits displayed within just the one hylid genus, Litoria. The 25 species measured in this study have resistances that range from Rc = 0 to 63.1. These include low values indistinguishable from a free water surface to high values typical of ‘waterproof’ anuran species. There was a strong correlation between ecological habit and Rc, even taking phylogenetic relationships into account; arboreal species had the highest resistance, aquatic species tended to have little or no resistance, and terrestrial species tended to have resistance between those of arboreal and aquatic frogs. For one species, Litoria rubella, we found no significant changes in EWL along a 1500 km aridity gradient. This study represents the strongest evidence to date of a link between ecological habits and cutaneous resistance to water loss among species of frogs.

    Note: Please note that Appendix 1 is available in hard copy only.
    Date of AwardDec 2006
    Original languageEnglish
    SupervisorKeith Christian (Supervisor) & David Parry (Supervisor)

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