Abstract:

Abstract: In anuran species with short breeding seasons, an extension of diel activity to the night hours could be favoured to maximize mating opportunities but individuals must deal with physiological and behavioural constraints. We tested this hypothesis in the Yungas red-belly toad, Melanophryniscus rubriventris (Vellard, 1947). We registered diel pattern of male callingactivity in two localities using automated recording systems, and related it to abiotic factors as temperature, relative air humidity and precipitation. The diel pattern of vocalization was mainly diurnal. Interestingly, though, nocturnal calling activity was a common feature, representingbetween 40% and 43% of call records in both localities. Vocal activity was significantly influenced by time of the day and presence of rainfall. Calling males showed high plasticity, with activity in the entire environmental range of relative air humidity and temperature. Nocturnal calling seems to play an important role in the mating strategy of males, and it is probably morefrequent in the genus Melanophryniscus than currently assumed. We discuss the implications of our findings in relation to different aspects of ecology of the species and suggest that bright coloration in M. rubriventris might result from a compromise between several non-conflicting functions (e.g. aposematism and thermoregulation).

Author affiliation: Pereyra, Laura Cecilia. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET - Salta. San Salvador de Jujuy; Argentina

Author affiliation: Akmentins, Mauricio Sebastián. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET - Salta. San Salvador de Jujuy; Argentina

Author affiliation: Sanabria, Eduardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan. Facultad de Filosofía, Humanidades y Artes; Argentina

Author affiliation: Vaira, Marcos. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET - Salta. San Salvador de Jujuy; Argentina

Abstract:

We study the variation in thermal parameters in two contrasting populations Yungas Redbelly Toads (Melanophryniscus rubriventris) with different discrete color phenotypes comparing field body temperatures, critical thermal maximum and heating rates. We found significant differences in field body temperatures of the different morphs. Temperatures were higher in toads with a high extent of dorsal melanization. No variation was registered in operative temperatures between the study locations at the moment of capture and processing. Critical thermal maximum of toads was positively related with the extent of dorsal melanization. Furthermore, we founded significant differences in heating rates between morphs, where individuals with a high extent of dorsal melanization showed greater heating rates than toads with lower dorsal melanization.The color pattern-thermal parameter relationship observed may influence the activity patterns and body size of individuals. Body temperature is a modulator of physiological and behavioral functions in amphibians, influencing daily and seasonal activity, locomotor performance, digestion rate and growth rate. It is possible that some growth constraints may arise due to the relationship of colorpattern-metabolism allowing different morphs to attain similar sizes at different locations instead of body-size clines.

Author affiliation: Sanabria, Eduardo Alfredo. Universidad Nacional de San Juan. Facultad de Filosofía, Humanidades y Artes. Instituto de Ciencias Básicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Vaira, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina

Author affiliation: Quiroga, Lorena Beatriz. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Akmentins, Mauricio Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina

Author affiliation: Pereyra, Laura Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina