Many animals exhibit dramatic responses when subjected to a stressor. A classic marker of the stress response is an increase in plasma glucocorticoids, but this constitutes only one step in the cascade from experience of a stressor to wider organismal changes, including behavior. The behavioral sensitivity to glucocorticoids would determine the consequences of the stress-related alteration of behavior for the organism. In this study we explored, under laboratory conditions, the prenatal and postnatal effects of corticosterone on activity and thermoregulation of juveniles of the common lizard, Lacerta vivipara. Activity was measured as the time spent moving and the time spent scratching the wall in an empty terrarium. Thermoregulatory behavior was measured as the time spent motionless under a light bulb. Activity and thermoregulation of juveniles of the common lizard showed a different sensitivity to prenatal and postnatal corticosterone treatment, modulated by juvenile sex and maternal condition. Prenatal corticosterone manipulation influenced the time spent moving in both sexes. By contrast, only juvenile females increased the time spent scratching the walls of the terrarium when corticosterone was delivered both at the prenatal and postnatal stage. Prenatal hormone manipulation increased the time spent basking by juveniles issued from large females. These results suggest that, in addition to influencing a variety of behavioral and morphological traits, corticosterone may also play an important role in the regulation of activity and thermoregulation of juvenile lizards, modulated by individual sex and maternal condition.
Copyright 2004 Wiley-Liss, Inc.