Corticosterone and pace of life in two life-history ecotypes of the garter snake thamnophis elegans

• Autores: Palacios, María Gabriela; Sparkman, Amanda M.; Bronikowski, Anne M.
• Año de publicación: 2012
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Corticosterone; Life-History; Physiological Mechanism; Reptile; Stress; Trade-Off
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Glucocorticoids are main candidates for mediating life-history trade-offs by regulating the balance between current reproduction and survival. It has been proposed that slow-living organisms should show higher stress-induced glucocorticoid levels that favor self-maintenance rather than current reproduction when compared to fast-living organisms. We tested this hypothesis in replicate populations of two ecotypes of the garter snake (Thamnophis elegans) that exhibit slow and fast pace of life strategies. We subjected free-ranging snakes to a capture-restraint protocol and compared the stress-induced corticosterone levels between slow- and fast-living snakes. We also used a five-year dataset to assess whether baseline corticosterone levels followed the same pattern as stress-induced levels in relation to pace of life. In accordance with the hypothesis, slow-living snakes showed higher stress-induced corticosterone levels than fast-living snakes. Baseline corticosterone levels showed a similar pattern with ecotype, although differences depended on the year of study. Overall, however, levels of glucocorticoids are higher in slow-living than fast-living snakes, which should favor self-maintenance and survival at the expense of current reproduction. The results of the present study are the first to relate glucocorticoid levels and pace of life in a reptilian system and contribute to our understanding of the physiological mechanisms involved in life-history evolution.
Fil: Palacios, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina. University of Iowa; Estados Unidos
Fil: Sparkman, Amanda M.. University of Iowa; Estados Unidos
Fil: Bronikowski, Anne M.. University of Iowa; Estados Unidos