Lack of consistent hormonal responses to capture during the breeding season of the bearded dragon, Pogona barbata

The bearded dragon (Pogona barbata: Agamidae) is a diurnal, oviparous, multi-clutching lizard from Australia. We examined plasma hormonal responses to capture in males and females during the spring breeding season. Corticosterone concentrations at capture (0 h; less than or equal to 3 min after capture) were low (males: 1.81 +/- 0.63 ng/ml; females 2.23 +/- 0.47 ng/ml) and within sexes were unrelated to the time of the day, snout-vent length or, in females, reproductive condition (vitellogenic, gravid, assumed spent). Corticosterone concentrations at capture were significantly and inversely correlated with body condition in males, but not in females. Unexpectedly, neither sex showed significant changes in mean concentrations of corticosterone at 3.5 or 24 h after capture compared with 0 h values. Corticosterone concentrations at 3.5 h after capture did not differ between dragons bled at capture or not. Concentrations of progesterone in both the sexes did not change between 0 h and 3.5 or 24 h after capture. Testosterone concentrations in males at capture were moderate (10.1 +/- 2.2 ng/ml), and unchanged at 3.5 h after capture. The adrenocortical axis of adult bearded dragons in the breeding season seems remarkably unresponsive to capture compared with many other reptiles. Low adrenocortical responses to capture may be a feature of reptiles known to adjust well to captivity. (C) 2000 Elsevier Science Inc. All rights reserved.