CONICET | Buscador de Institutos y Recursos Humanos

We studied the variation of thermal parameters of Odontophrynus occidentalis between season (wet and dry) in the Monte desert (Argentina). We measured body temperatures, micro-habitat temperatures and operative temperatures; while in the laboratory we measured the selected body temperatures. Our results show a change in the thermal parameters of O. occidentalis that is related to environmental constraints of their thermal niche. Environmental thermal constraints are present in both seasons (dry and wet), showing variations in thermal parameters studied. Apparently imposed environmental restrictions the toads in nature always show body temperatures below the set point. As acclimatization an advantage for toads as allows them to bring more frequent body temperatures to the set point. The selected body temperature has seasonal intra-individual variability. These variations can be due to thermo-sensitivity of toads and life histories of individuals by limiting their allocation and acquisition of resources. Possibly the range of variation found in selected body temperature is consequence of the thermal environmental variation along the year. These variations of thermal parameters are common in deserts environmental and thermal bodies of nocturnal ecthoterms. The plasticity of selected body temperature gives to O. occidentales longer periods of activity for foraging and reproduction, while maintaining reasonable high performance at different temperatures. The plasticity in seasonal variation of the thermal parameters has been poorly studied, and is greatly advantageous to desert species during changes in both seasonal and daily temperature, since these environments are known for their high environmental variability.