The Herpetological Journal

pp. 110-116

Authors: Annaïs Carbajal, Oriol Tallo-Parra1, Laura Monclús, Manel Aresté, Hugo Fernández-Bellon, Vanessa Almagro & Manel Lopez-Bejar

Abstract: The analysis of corticosterone (CORT), the main glucocorticoid in reptiles, via blood or faeces provides an index of hormone concentrations over a relatively short time period. Unlike these conventional matrices, snake shed skin is supposed to incorporate circulating CORT over the period of skin growth, thus reflecting long-term retrospective levels of the hormone. The present study aimed to assess the feasibility to extract CORT from shed skin of Komodo dragon and biochemically validate the quantification of the hormone by enzyme immunoassay (EIA). Additionally, possible sources of variation in shed skin CORT that could reflect biological variation were examined (sex, age, body region and season of ecdysis). Results of the biochemical validation showed that CORT can be reliably measured in shed skin of Komodo dragon by EIA through the presented methodology. Males presented statistically higher levels of CORT than females, and when accounting for males’ seasonal differences, concentrations decreased significantly from spring to summer. Juveniles showed higher CORT values than adults, however, results should be interpreted with caution since the model revealed that date of ecdysis was significantly influencing CORT levels. Besides that, concentrations of CORT were not influenced by body region. Overall, the present study demonstrates a potential biological source of variation in shed skin CORT concentrations due to sex, age and season of skin ecdysis. Combined with other indicators, detection of CORT concentrations in shed skin could allow a systematic control of Komodo dragon’s physiology, offering a useful tool for zoo management and providing key data for the species conservation.

Key words: Chronic stress; Ecdysis; Glucocorticoid; Saurian