A rapidly changing climate has the potential to interfere with the timing of environmental cues that ectothermic organisms rely on to initiate and regulate life history events. Short-lived ectotherms that exhibit plasticity in their life history could increase the number of generations per year under warming climate. If many individuals successfully complete an additional generation, the population experiences an additional opportunity to grow, and a warming climate could lead to a demographic bonanza. However, these plastic responses could become maladaptive in temperate regions, where a warmer climate could trigger a developmental pathway that cannot be completed within the growing season, referred to as a developmental trap. Here we incorporated detailed demography into commonly used photothermal models to evaluate these demographic consequences of phenological shifts due to a warming climate on the formerly widespread, multivoltine butterfly (Pieris oleracea). Using species-specific temperature- and photoperiod-sensitive vital rates, we estimated the number of generations per year and population growth rate over the set of climate conditions experienced during the past 38 years. We predicted that populations in the southern portion of its range have added a fourth generation in recent years, resulting in higher annual population growth rates (demographic bonanzas). We predicted that populations in the Northeast United States have experienced developmental traps, where increases in the thermal window initially caused mortality of the final generation and reduced growth rates. These populations may recover if more growing degree days are added to the year. Our framework for incorporating detailed demography into commonly used photothermal models demonstrates the importance of using both demography and phenology to predict consequences of phenological shifts.

中文翻译：

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发展陷阱还是人口富矿？早期物候在多变蝴蝶气候变化中的相反结果。

快速变化的气候有可能干扰变温生物赖以启动和调节生命史事件的环境线索的时间安排。在其生活史中表现出可塑性的短命外温动物可以在气候变暖的情况下增加每年的世代数。如果许多人成功地完成了额外的一代，人口就会有更多的增长机会，而气候变暖可能会导致人口繁荣。然而，这些塑性反应在温带地区可能会变得不适应，那里气候变暖可能会触发无法在生长季节内完成的发育途径，称为发育陷阱。在这里，我们将详细的人口统计学纳入常用的光热模型，以评估气候变暖导致的物候变化对以前分布广泛的多变蝴蝶 (Pieris oleracea) 的这些人口统计结果。使用特定物种的温度和光周期敏感的生命率，我们估计了过去 38 年经历的一系列气候条件下每年的世代数和人口增长率。我们预测其范围南部的人口近年来增加了第四代，导致更高的年人口增长率（人口富矿）。我们预测美国东北部的人口经历了发展陷阱，其中热窗口的增加最初导致最后一代的死亡率和增长率降低。如果一年中增加更多的生长度日，这些种群数量可能会恢复。我们将详细的人口统计学纳入常用光热模型的框架证明了使用人口统计学和物候学来预测物候变化后果的重要性。