Influence of temperature on the corticosterone stress-response: An experiment in the Children's python (Antaresia childreni)
Résumé
To cope with environmental challenges, organisms have to adjust their behaviours and their physiology 28 to the environmental conditions they face (i.e. allostasis). In vertebrates, such adjustments are often 29 mediated through the secretion of glucocorticoids (GCs) that are well-known to activate and/or inhibit 30 specific physiological and behavioural traits. In ectothermic species, most processes are temperature- 31 dependent and according to previous studies, low external temperatures should be associated with 32 low GC concentrations (both baseline and stress-induced concentrations). In this study, we experimen- 33 tally tested this hypothesis by investigating the short term influence of temperature on the GC stress 34 response in a reptile species, the Children's python (Antaresia childreni). Snakes were maintained in 35 contrasting conditions (warm and cold groups), and their corticosterone (CORT) stress response was 36 measured (baseline and stress-induced CORT concentrations), within 48 h of treatment. Contrary to 37 our prediction, baseline and stress-induced CORT concentrations were higher in the cold versus the warm 38 treatment. In addition, we found a strong negative relationship between CORT concentrations (baseline 39 and stress-induced) and temperature within the cold treatment. Although it remains unclear how cold 40 temperatures can mechanistically result in increased CORT concentrations, we suggest that, at subopti- 41 mal temperature, high CORT concentrations may help the organism to maintain an alert state.