Sexual signals serve as an honest indicator of individual quality, reflecting either developmental and/or maintenance costs. A possible underlying physiological mechanism is oxidative stress, which could mediate energy trade-offs between sexual signals and other quality traits. In ectotherms, thermal performance acts as a key indicator of individual quality and influence signal intensity. We investigated how oxidative state is reflected in visual signals of lizards from different thermal habitats. According to our hypothesis, efficient thermoregulation requires different strategies in different thermal environments. In a habitat with predictable temperature changes, animals are less exposed to suboptimal temperature ranges and selection will, therefore, be stronger on the maximum oxidative damage at optimal body temperature. Contrarily, in a habitat with rather stochastic thermal shifts, individuals are often constricted by suboptimal thermal conditions, and oxidative damage can be limiting on a wide temperature range. We used Iberolacerta cyreni and Psammodromus algirus inhabiting stochastic and predictable thermal environments respectively. We examined two aspects of oxidative stress: the level of reactive oxygen metabolites at the preferred temperature (maximal ROM) and the temperature range in which animals produce at least 80% of the maximum level of reactive oxygen metabolites (effective ROM range). In I. cyreni, we found that duller coloration was related to a wider effective ROM range, while expression of coloration in P. algirus was negatively correlated with the maximal ROM. Our results suggest that different thermal constraints affect different aspects of oxidative damage which can indicate individual quality and are, therefore, represented in sexual ornaments.

中文翻译：

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氧化应激与蜥蜴的性着色之间的关系取决于栖息地

性信号可作为个体质量的真实指标，反映了开发和/或维护成本。潜在的潜在生理机制是氧化应激，它可以介导性信号与其他质量性状之间的能量权衡。在等温线中，热性能是单个质量和影响信号强度的关键指标。我们研究了氧化态如何在来自不同热生境的蜥蜴的视觉信号中反映出来。根据我们的假设，有效的温度调节在不同的热环境中需要采取不同的策略。在温度变化可预测的栖息地中，动物较少暴露于次优温度范围，因此在最佳体温下对最大氧化损伤的选择会更强。相反，在热变化相当随机的栖息地中，个体通常会受到次佳的热条件的束缚，氧化损伤可能会限制在较宽的温度范围内。我们用了cyberi cyreni和Psammodromus algirus分别居住在随机和可预测的热环境中。我们研究了氧化应激的两个方面：优选温度下的活性氧代谢物水平（最大ROM）和动物产生至少80％的活性氧代谢物最大水平的温度范围（有效ROM范围）。在cyren cyreni中，我们发现暗沉的着色与更宽的有效ROM范围有关，而在阿尔及利亚疟原虫中表达着色与最大ROM负相关。我们的结果表明，不同的热约束影响氧化损伤的不同方面，这可以表明个体的素质，因此表现为性装饰品。