Understanding adaptation involves establishing connections between selective agents and beneficial population responses. However, relatively little attention has been paid to seasonal adaptation, in part, because it requires complex and integrative knowledge about seasonally fluctuating environmental factors, the effects of variable phenology on exposure to those factors, and evidence for temporal specialization. In the European corn borer moth, Ostrinia nubilalis, sympatric pheromone strains exploit the same host plant (Zea mays) but may genetically differ in phenology and be reproductively “isolated by time.” Z strain populations in eastern North America have been shown to have a prolonged larval diapause and produce one annual mating flight (July), whereas E strain populations complete an earlier (June) and a later (August) mating flight by shortening diapause duration. Here, we find evidence consistent with seasonal “adaptation by time” between these ecotypes. We use 12 years of field observation of adult seasonal abundance to estimate phenology of ecotype life cycles and to quantify life-stage specific climatic conditions. We find that the observed reduction of diapause duration in the E strain leads their non-diapausing, active life stages to experience a ~ 4 °C colder environment compared to the equivalent life stages in the Z strain. For a representative pair of populations under controlled laboratory conditions, we compare life-stage specific cold tolerance and find non-diapausing, active life stages in the E strain have as much as a 60% greater capacity to survive rapid cold shock. Enhanced cold hardiness appears unrelated to life-stage specific changes in the temperature at which tissues freeze. Our results suggest that isolation by time and adaptation by time may both contribute to population divergence, and they argue for expanded study in this species of allochronic populations in nature experiencing the full spectrum of seasonal environments. Cyclical selective pressures are inherent properties of seasonal habitats. Diverse fluctuating selective agents across each year (temperature, predation, competition, precipitation, etc.) may therefore be underappreciated drivers of biological diversity.

中文翻译：

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依赖于物候学的冷暴露和Nostrinia nubilalis生态型的热性能。

理解适应性涉及在选择因子和有益人群反应之间建立联系。但是，对季节适应的关注相对较少，部分原因是因为它需要有关季节波动的环境因素，可变物候对这些因素的影响以及时间专业化证据的复杂和综合的知识。在欧洲玉米bore蛾（Ostrinia nubilalis）中，同胞信息素菌株利用相同的寄主植物（Zea mays），但在物候学上可能具有遗传差异，并且在繁殖上“被时间隔离”。研究表明，北美东部的Z菌株种群幼虫滞育时间延长，每年会产生一次交配飞行（7月），而E株种群通过缩短滞育时间来完成较早的（6月）和较晚的（8月）交配飞行。在这里，我们发现了与这些生态型之间的季节性“时间适应”相一致的证据。我们使用12年的成年季节丰度实地观察，以估算生态型生命周期的物候状态，并量化生命阶段的特定气候条件。我们发现，与Z菌株的等效生命阶段相比，E菌株的滞育持续时间减少导致其非停滞的活跃生命阶段经历了约4°C的低温环境。对于在受控实验室条件下的一对有代表性的种群，我们比较了生命周期的特定耐寒性，发现E品系的非渗血性，活跃生命期具有高达60％的快速抗寒能力。增强的抗寒性似乎与组织冻结温度的生命周期特定变化无关。我们的研究结果表明，时间隔离和时间适应都可能导致种群分化，并且他们主张对经历了整个季节环境的自然界中的同种异时种群进行进一步的研究。周期性选择压力是季节性生境的固有特性。因此，全年中各种波动的选择剂（温度，捕食，竞争，降水等）可能是生物多样性被低估的驱动力。他们主张对经历了整个季节环境的自然界中的同种异时种群进行进一步的研究。周期性选择压力是季节性生境的固有特性。因此，每年波动的选择剂（温度，捕食，竞争，降水等）可能是生物多样性被低估的驱动力。他们主张对经历了整个季节环境的自然界中的同种异时种群进行进一步的研究。周期性选择压力是季节性生境的固有特性。因此，每年波动的选择剂（温度，捕食，竞争，降水等）可能是生物多样性被低估的驱动力。