The timing of organisms' senescence is developmentally programmed but also shaped by the interaction between environmental inputs and life-history traits. In ectotherms, ageing dynamics are still poorly understood even though their body temperature, metabolism, or growth trajectory are very sensitive to environmental changes. Here, we investigated the role of life-history traits such as age, sex, body size, body condition, and tail autotomy (i.e self-amputation) in shaping telomere length in six populations of the Algerian sand lizard (Psammodromus algirus) distributed along an elevational gradient from 300 to 2500 m above the sea level. Additionally, we compiled the available information on reptiles' telomere length in a review table. Our cross-sectional study shows that older lizards have longer telomeres, which might be mostly linked to the selective disappearance of individuals with shorter telomeres or, alternatively, mediated by a higher expression of telomerase across their life. In fact, variation in telomere length across elevation was explained by age structure of lizards; thus, in contrast to our predictions, altitude had no effect on telomere length in this study system. Telomere length was unaffected by tail regeneration and was sex-independent, but positively correlated with body condition, which might be linked to high somatic investment. Hence, our results suggest that life-history traits such as age or body condition can be major drivers of telomere dynamics for this species, whereas environmental conditions apparently had scarce or no effects on lizard telomeres. Our findings emphasize the relevance of understanding species' life histories for fully disentangling the causes and consequences of differences in ageing in ectotherms.

生物衰老的时机是经过编程设定的，但也受环境投入和生活史特征之间相互作用的影响。在等温线中，对衰老动态的了解仍然很少，尽管它们的体温，新陈代谢或生长轨迹对环境变化非常敏感。在这里，我们调查了生活史特征（例如年龄，性别，体型，身体状况和尾部自动截肢术（即自我截肢））在塑造阿尔及利亚沙蜥蜴（Psammodromus algirus）六个种群的端粒长度中的作用。）沿海拔300至2500 m的海拔梯度分布。此外，我们在复查表中汇总了有关爬行动物端粒长度的可用信息。我们的横断面研究表明，年龄较大的蜥蜴的端粒更长，这可能与端粒较短的个体的选择性消失有关，或者端粒酶在其一生中的表达较高。实际上，蜥蜴的年龄结构可以解释端粒长度随海拔的变化。因此，与我们的预测相反，在该研究系统中，海拔高度对端粒长度没有影响。端粒的长度不受尾巴再生的影响，并且不受性别的影响，但与身体状况呈正相关，这可能与较高的体细胞投入有关。因此，我们的结果表明，该物种的生命历史特征（例如年龄或身体状况）可能是端粒动力学的主要驱动力，而环境条件显然对蜥蜴端粒几乎没有影响。我们的发现强调了了解物种的生活史对于充分区分等温线老化差异的原因和后果的相关性。