Protecting embryos from stress: corticosterone effects and the corticosterone response to capture and confinement during pregnancy in a live-bearing lizard (Hoplodactylus maculatus)

Adrenal and white cell count responses to chronic stress in gestating and postpartum females of the viviparous skink Egernia whitii (Scincidae)

“…These results suggest that, as discussed extensively by Cree et al (2003), there has been no selection for a reduced corticosterone response to stressors such as captivity during gestation in viviparous reptiles, imp lying that the stress of chronic confinement does not pose a threat to reproductive investment in these animals. We are currently exploring this hypothesis further, via experimental manipulations of the hypothalamo -pituitary-adrenal axis and examination of acute stress responses in female E. whitii (Cartledge and Jones, unpublished results).…”

“…Hoplodactylus maculatus exhibited no suppression of the stress response to captivity relative to vitellogenic females, with both groups having greater responses than male s of that species (Cree et al, 2003). These results suggest that, as discussed extensively by Cree et al (2003), there has been no selection for a reduced corticosterone response to stressors such as captivity during gestation in viviparous reptiles, imp lying that the stress of chronic confinement does not pose a threat to reproductive investment in these animals.…”

How much stress do researchers inflict on their study animals? A case study using a scincid lizard, Eulamprus heatwolei

“…Activities such as mate-searching, courtship, mating and male-male combat may require elevated levels of energy expenditure, thus favouring increased plasma corticosterone levels in males rather than females . Additionally, high levels of corticosterone in pregnant females of a viviparous species (such as Eulamprus heatwolei) might have negative effects on the developing offspring (Cree et al, 2003). Neither of these ideas accords with our own data, in that it was females not males that exhibited high levels of plasma corticosterone; and many of the females that we used were pregnant during the trials.…”

“…Thus, our working definition of stress is 'the physiological response of an animal to an experimental stimulus, as measured by elevated circulating glucocorticoid levels'. Changes in plasma corticosterone levels have been used to assess the impact of capture, handling, restraint and confinement on reptilian species (Moore et al, 1991;Cree et al, 2003;Cree et al, 2000;Mathies et al, 2001;Kreger and Mench, 1993;Cash et al, 1997), but the amount of stress induced by alternative commonly used research procedures beyond initial capture and housing has not been previously assessed. The present paper describes a study that set out to quantify the ways in which plasma corticosterone levels in lizards are affected by a variety of methods that are commonly used in fields of research such as behavioural ecology and microevolution.…”

Stress Ecology of the Pacific Rattlesnakes (Crotalus Oreganus and Crotalus Helleri)

“…This trend is well supported in the literature, as secretion of CORT by ectotherms is correlated with metabolic rate (Landys et al 2006) and this secretion increases with temperature in many reptiles (Cree et al 2003;Tyrrell & Cree 1998;Jones & Bell 2004;Romero & Wikelski 2006). In some snakes, CORT release appears to be thermally independent (Sykes & Klukowski 2009) or is increased at colder Tb (Dupoué et al 2013), but this does not appear to be the case in C.…”