Modulation of corticosterone secretion in tuatara (Sphenodon punctatus): Evidence of a dampened stress response in gravid females.
Baseline and stress response glucocorticoid (GC) secretion can be modulated by individuals to support activities and physiological functions connected with reproduction (migration, mating, oviposition and/or parturition, care of young). Corticosterone (CORT) is the primary GC in reptiles and, in accordance with other vertebrates, an adrenocortical stress response is observed. Modulation of CORT secretion occurs in several reptile species, such that elevated baseline CORT concentration and/or a dampened CORT response are common during reproductive life-history events. We investigated CORT secretion after 24 h capture-restraint in the oviparous tuatara (Sphenodon punctatus), the last living rhynchocephalian, and tested whether gravid females have a dampened CORT response compared with non-gravid females. We also included males as a comparison. We confirmed that gravid females have significantly higher baseline plasma CORT concentrations than non-gravid females, suggesting increased CORT secretion during nesting. Furthermore, we found that gravid females exhibit a dampened CORT response compared to non-gravid females and males. Our results demonstrate that female reproductive condition influences CORT secretion in tuatara, and suggest that gravid females modulate CORT secretion during nesting to maintain homeostasis, effectively increasing chances of reproductive success and promoting overall fitness.
Allan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand. Electronic address: anderson.lindsay.erin@gmail.com.
Lindsay
L
Anderson
Department of Zoology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand. Electronic address: alison.cree@otago.ac.nz.
Alison
A
Cree
Ecosystem Development Team, Science and Technical Group, Department of Conservation, Private Bag 68-908 Newton, Auckland 1145, New Zealand. Electronic address: dtowns@doc.govt.nz.
David
D
Towns
Allan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand. Electronic address: nicola.nelson@vuw.ac.nz.
Nicola
N
Nelson
D000818:Animals; D001831:Body Temperature; D003345:Corticosterone / Q000097:blood*; D005260:Female; D008297:Male; D012098:Reproduction / Q000502:physiology; D012104:Reptiles / Q000097:blood*; D012149:Restraint, Physical / Q000502:physiology; D013312:Stress, Physiological
D003345:Corticosterone
Corticosterone; Modulation; Nesting; Oviparous; Reptile; Stress response