Calling behaviour under climate change: geographical and seasonal variation of calling temperatures in ectotherms |
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Authors: | Diego Llusia Rafael Márquez Juan F. Beltrán Maribel Benítez José P. do Amaral |
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Affiliation: | 1. Fonoteca Zoológica, Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), , Madrid, 28006 Spain;2. Departamento de Zoología, Facultad de Biología, Universidad de Sevilla, , Sevilla, 41012 Spain;3. Grupo de Biología y Conservación de Vertebrados Mediterráneos, Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, , Granada, 18071 Spain;4. Science & Health Department, University of Cincinnati Clermont College, , Batavia, OH, 45103–1785 USA |
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Abstract: | Calling behaviour is strongly temperature‐dependent and critical for sexual selection and reproduction in a variety of ectothermic taxa, including anuran amphibians, which are the most globally threatened vertebrates. However, few studies have explored how species respond to distinct thermal environments at time of displaying calling behaviour, and thus it is still unknown whether ongoing climate change might compromise the performance of calling activity in ectotherms. Here, we used new audio‐trapping techniques (automated sound recording and detection systems) between 2006 and 2009 to examine annual calling temperatures of five temperate anurans and their patterns of geographical and seasonal variation at the thermal extremes of species ranges, providing insights into the thermal breadths of calling activity of species, and the mechanisms that enable ectotherms to adjust to changing thermal environments. All species showed wide thermal breadths during calling behaviour (above 15 °C) and increases in calling temperatures in extremely warm populations and seasons. Thereby, calling temperatures differed both geographically and seasonally, both in terrestrial and aquatic species, and were 8–22 °C below the specific upper critical thermal limits (CTmax) and strongly associated with the potential temperatures of each thermal environment (operative temperatures during the potential period of breeding). This suggests that calling behaviour in ectotherms may take place at population‐specific thermal ranges, diverging when species are subjected to distinct thermal environments, and might imply plasticity of thermal adjustment mechanisms (seasonal and developmental acclimation) that supply species with means of coping with climate change. Furthermore, the thermal thresholds of calling at the onset of the breeding season were dissimilar between conspecific populations, suggesting that other factors besides temperature are needed to trigger the onset of reproduction. Our findings imply that global warming would not directly inhibit calling behaviour in the study species, although might affect other temperature‐dependent features of their acoustic communication system. |
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Keywords: | acoustic communication
Alytes
amphibian decline audio‐trapping global warming
Hyla
thermal breadth |
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