Modulation of corticosterone secretion in tuatara (Sphenodon punctatus): Evidence of a dampened stress response in gravid females

Moving house: long-term dynamics of corticosterone secretion are unaltered in translocated populations of a rare reptile (the tuatara,Sphenodon punctatus)

“…Nevertheless, a significant CORT response was observed throughout all stages of the translocation process, and at no point did CORT returned to baseline concentrations. This observation is consistent with results from our previous study examining the acute CORT response to capture restraint in tuatara, in which a return to baseline CORT concentrations was not observed over 24 h ( Anderson et al ., 2014 ). Therefore, we recommend that animal disturbance, holding time, transport duration and post-translocation disturbance be minimized in tuatara to mitigate potentially harmful effects of sustained CORT secretion in individuals directly following translocation.…”

“…Depending on field conditions (i.e. electricity available or not), blood samples were separated either by centrifuge (5 min at 480 g ) or under normal gravity for 6–8 h at 4°C ( Reimers et al ., 1983 ; Sheriff et al ., 2011 ; Anderson et al ., 2014 ). Plasma was transferred into cryogenic vials with a micropipette, stored in a cryogenic dry shipper (Thermo ScientificTM, Arctic ExpressTM Dual 10) or in a freezer at −20°C until return to the laboratory, and then stored at −80°C until assayed.…”

“…Plasma was transferred into cryogenic vials with a micropipette, stored in a cryogenic dry shipper (Thermo ScientificTM, Arctic ExpressTM Dual 10) or in a freezer at −20°C until return to the laboratory, and then stored at −80°C until assayed. Corticosterone was analysed with commercial enzyme immunoassay kits (Cayman Chemical Co., Ann Arbor, MI, USA) using a previously described method validated for tuatara ( Anderson et al ., 2014 ). Briefly, CORT was extracted from plasma samples with redistilled dichloromethane, and each sample was assayed in duplicate.…”

“…In 2012, wild tuatara were translocated to six island and mainland sanctuaries from two source populations (Lady Alice Island and Stephens Island/Takapourewa, New Zealand; Cree, 2014 ), which presented an excellent opportunity to examine the CORT response to translocation in multiple populations. Previous studies have examined patterns of CORT secretion in tuatara; in general, baseline CORT in tuatara is fairly low (with plasma concentrations typically 2–5 ng/ml), a significant CORT response to capture restraint is observed, and female reproductive condition, body temperature and season (but not time of day) are influential factors ( Tyrrell and Cree, 1998 ; Tyrrell et al ., 2000 ; Anderson et al ., 2014 ). In a recent study examining CORT secretion in four populations of tuatara, we found that baseline CORT was similar among all populations; however, the CORT response varied with latitude, seabird density, sex ratio and genetic diversity (L. Anderson, N. Nelson, D. Towns and A. Cree, unpublished data).…”

Stress hormone levels in a freshwater turtle from sites differing in human activity

“…However, females exhibited a dampened CORT stress response during the nesting season, whereas males exhibited a heightened stress response during the nesting season. Furthermore, previous studies in other vertebrates and in some reptiles have shown a dampened stress response in all females during the nesting season ( Astheimer et al ., 1995 ; Breuner et al ., 2003 ) or specific to gravid females during the same period ( Jessop et al ., 2000 ; Anderson et al ., 2014 ).…”