Data from: The Urban Heat Island and its spatial scale dependent impact on survival and development in butterflies of different thermal sensitivity

Climate alteration is one of the most cited ecological consequences of urbanization. However, the magnitude of this impact is likely to vary with spatial scale. We investigated how this alteration affects the biological fitness of insects, which are especially sensitive to ambient conditions and well-suited organisms to study urbanization-related changes in phenotypic traits. We monitored temperature and relative air humidity in wooded sites characterized by different levels of urbanization in the surroundings. Using a split-brood design experiment, we investigated the effect of urbanization at the local (i.e., 200 × 200 m) and landscape (i.e., 3 × 3 km) scale on two key traits of biological fitness in two closely related butterfly species that differ in thermal sensitivity. In line with the Urban Heat Island concept, urbanization led to a 1°C increase in daytime temperature and an 8% decrease in daytime relative humidity at the local scale. The thermophilous species Lasiommata megera responded at the local scale: larval survival increased twofold in urban compared to rural sites. Urbanized sites tended to produce bigger adults, although this was the case for males only. In the woodland species Pararge aegeria, which has recently expanded its ecological niche, we did not observe such a response, neither at the local, nor at the landscape scale. These results demonstrate interspecific differences in urbanization-related phenotypic plasticity and larval survival. We discuss larval pre-adaptations in species of different ecological profiles to urban conditions. Our results also highlight the significance of considering fine-grained spatial scales in urban ecology.气候改变（climate alteration）是城市化（urbanization）最常被提及的生态后果之一。然而，该影响的强度大概率随空间尺度（spatial scale）发生变化。本研究探究了此类气候改变如何影响昆虫的生物学适合度（biological fitness）——昆虫对环境条件（ambient conditions）尤为敏感，是研究城市化相关表型性状（phenotypic traits）变化的理想模式生物。我们对周边城市化水平各异的林地样地的气温与空气相对湿度进行了监测。本研究采用分群设计（split-brood design）实验，探究了局部（即200×200米）与景观（即3×3千米）尺度下的城市化对两种亲缘关系相近、热敏感性（thermal sensitivity）存在差异的蝴蝶物种的两项核心生物学适合度性状的影响。结合城市热岛（Urban Heat Island）效应理论，局部尺度下的城市化致使日间气温升高1℃，日间空气相对湿度下降8%。嗜热（thermophilous）物种*Lasiommata megera*仅在局部尺度呈现响应：相较于乡村样地，城市化样地的幼虫存活率（larval survival）提升了一倍。城市化样地羽化的成虫体型更大，但该现象仅见于雄性个体。对于近期拓展了生态位（ecological niche）的林地物种*Pararge aegeria*，无论在局部还是景观尺度下，均未观测到此类响应。上述结果表明，与城市化相关的表型可塑性（phenotypic plasticity）及幼虫存活率存在种间差异（interspecific differences）。本研究还讨论了不同生态特征（ecological profiles）物种的幼虫对城市环境的预适应（pre-adaptations）现象。本研究结果同时强调了在城市生态学（urban ecology）研究中考虑精细空间尺度（fine-grained spatial scales）的重要性。