Evol Ecol Res 7: 23-35 (2005)     Full PDF if your library subscribes.

Balancing the thermal costs and benefits of refuge use to cope with persistent attacks from predators: a model and an experiment with an alpine lizard

Vicente Polo, Pilar López and José Martín*

Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain

Author to whom all correspondence should be addressed.
e-mail: jose.martin@mncn.csic.es


When prey take refuge to reduce predation risk, they forfeit time for other activities. They may also pay a physiological cost. In particular, optimal regulation of body temperature is essential for ectotherms. Qualitative models predict that lizards have to balance anti-predatory decisions in relation to thermal conditions of the refuge and predation risk when deciding when to resume activity. However, these models are not general and empirical tests of their assumptions are scarce. We modified previous models to include the case of a high and maintained level of predation risk. The predictions of the model were further investigated in a laboratory experiment using male Iberian rock lizards. The same level of predation risk was displayed in two treatments in which temperature inside the refuge was high or low, and in the mating or the post-reproductive season. As predicted, lizards increased successive emergence times – an increase that was not linear but accelerating – and they had shorter emergence times when thermal costs of refuge use were higher. Nevertheless, body size of lizards and the season of the experiment had no effect on these decision rules. Our results are in line with an economical balance between costs and benefits in the decision rules controlling active versus inactive periods.

Keywords: costs of refuge use, Lacerta monticola, lizards, predation risk.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2005 José Martín. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.