Urbanization is gaining force globally, which challenges biodiversity, and it has recently also emerged as an agent of evolutionary change. Seasonal phenology and life cycle regulation are essential processes that urbanization is likely to alter through both the urban heat island effect (UHI) and artificial light at night (ALAN). However, how UHI and ALAN affect the evolution of seasonal adaptations has received little attention. Here, we test for the urban evolution of seasonal life-history plasticity, specifically changes in the photoperiodic induction of diapause in two lepidopterans, Pieris napi (Pieridae) and Chiasmia clathrata (Geometridae). We used long-term data from standardized monitoring and citizen science observation schemes to compare yearly phenological flight curves in six cities in Finland and Sweden to those of adjacent rural populations. This analysis showed for both species that flight seasons are longer and end later in most cities, suggesting a difference in the timing of diapause induction. Then, we used common garden experiments to test whether the evolution of the photoperiodic reaction norm for diapause could explain these phenological changes for a subset of these cities. These experiments demonstrated a genetic shift for both species in urban areas toward a lower daylength threshold for direct development, consistent with predictions based on the UHI but not ALAN. The correspondence of this genetic change to the results of our larger-scale observational analysis of in situ flight phenology indicates that it may be widespread. These findings suggest that seasonal life cycle regulation evolves in urban ectotherms and may contribute to ecoevolutionary dynamics in cities.

城市化正在全球范围内获得力量，这对生物多样性提出了挑战，并且最近它也成为了进化变化的推动者。季节性物候和生命周期调节是城市化可能通过城市热岛效应 (UHI) 和夜间人造光 (ALAN) 改变的基本过程。然而，UHI 和 ALAN 如何影响季节性适应的演变却很少受到关注。在这里，我们测试了季节性生活史可塑性的城市演变，特别是两种鳞翅目Pieris napi (Pieridae) 和Chiasmia clathrata 中光周期诱导滞育的变化（几何科）。我们使用来自标准化监测和公民科学观察计划的长期数据，将芬兰和瑞典六个城市的年度物候飞行曲线与邻近农村人口的年度物候飞行曲线进行比较。该分析表明，对于这两种物种，大多数城市的飞行季节较长且结束较晚，这表明滞育诱导的时间存在差异。然后，我们使用常见的花园实验来测试滞育的光周期反应规范的演变是否可以解释这些城市子集的这些物候变化。这些实验表明，城市地区的两个物种都朝着较低的日长阈值进行了直接发育，这与基于 UHI 而非 ALAN 的预测一致。这种遗传变化与我们对原位飞行物候的更大规模观察分析结果的对应关系表明它可能是普遍存在的。这些发现表明，季节性生命周期调节在城市变温动物中进化，可能有助于城市的生态进化动态。