Data from: Temperature-induced colour change varies seasonally in bearded dragon lizards

The benefits of colour change are expected to vary seasonally due to changes in reproductive activity, temperature and potentially predation risk; yet temporal variation in colour change has seldom been examined. We measured colour change in spring and autumn using captive individuals from two differently coloured populations of the central bearded dragon lizard, Pogona vitticeps. We predicted that colour change should be greater in spring than autumn due to added requirements of reproductive and territorial activity. To elicit colour change in a standardised way, we placed lizards inside temperature controlled chambers and measured colour at 15, 25, 35 and 40°C, repeating experiments in spring and autumn. Lizards from both populations changed from dark grey to light yellowish or orange-brown (increasing luminance and saturation) with increasing temperature in both seasons, and both populations changed colour to a similar extent. As predicted, the maximum extent of temperature-induced colour change (in particular luminance change) was greater in spring than autumn. Our results confirm that temperature-induced colour change is greater in the peak activity season, likely an adaptation to the greater thermal and/or signalling needs of that time of year.

由于繁殖活动、温度以及潜在捕食风险的季节波动，体色改变的生态益处预计会随季节发生变化；但迄今为止，体色改变的时间动态却极少被系统研究。本研究以两种体色存在差异的圈养中部鬃狮蜥（Pogona vitticeps）种群个体为实验对象，分别在春季与秋季开展体色变化测定。我们预先预测，鉴于繁殖与领地防御活动的额外需求，春季的体色改变幅度应大于秋季。为以标准化流程诱导体色改变，我们将蜥蜴置于温控箱内，分别在15、25、35与40℃条件下测定其体色参数，并于春季和秋季重复该实验。实验结果显示，两个种群的蜥蜴在两个季节中均随温度升高从深灰色转变为浅黄或橙棕色（亮度与饱和度均显著提升），且二者的体色改变幅度相近。正如预测，温度诱导的体色改变最大幅度（尤其是亮度变化）在春季显著高于秋季。本研究结果证实，温度诱导的体色改变在动物活动高峰期（春季）更为显著，这大概率是为适应该时段更高的热需求和/或信号传递需求而演化出的适应性特征。