摘  要  【目的】 明确草地贪夜蛾Spodoptera frugiperda羽化昼夜节律对不同光周期线索的响应，探究建立以其羽化昼夜节律为表型的生物钟机制的研究方法。【方法】 持续黑暗（Dark-Dark，DD）、持续光照（Light-Light，LL）、DD延长1日（DD+1）及LL延长1日（LL+1）光周期设置之前，试虫均饲养于L14∶D10（LD）光周期下，且LD处理组中LD光周期设置贯穿整个世代周期。将蛹龄为9 d（针对DD+1与LL+1）或10 d（针对LD、DD和LL）的蛹转移至自主建立的“基于时间生物学的小型动物生物节律表型全时监测装置”中，结合不同光周期线索设置监测蛹历期、成虫羽化历时及羽化昼夜节律。【结果】 LD、DD、DD+1与LL光周期设置下成虫羽化主要发生于暗期或LD导引过程中暗期对应的相位，LD下成虫羽化最高峰出现于授时因子时间（Zeitgeber time，ZT）15-16（24%），且在暗期开始前存在成虫羽化的光暗转换预期现象（Light-to-dark anticipation），DD与DD+1下羽化最高峰进一步后移，分别出现于昼夜节律时间（Circadian time，CT）17-18（24%）和CT21-22（22%）。虽然LL下仍存在较弱的成虫羽化昼夜节律，但额外1日的LL处理（即LL+1）完全扰乱了成虫羽化昼夜节律。【结论】 草地贪夜蛾存在受光暗循环线索导引（Entrain）及生物钟协同调控的羽化昼夜节律，其羽化高峰在LD下发生于暗期，羽化昼夜节律自由运转生物钟周期τ大于24 h，足够时长的持续光照处理可扰乱该昼夜节律。综上，草地贪夜蛾羽化昼夜节律可作为其生物钟机制研究的可靠表型。

Abstract  [Objectives]  To determine the circadian eclosion rhythm of Spodoptera frugiperda in response to photoperiod cues and establish an eclosion behavior-based assay to explore the endogenous circadian clock of this pest. [Methods]  S. frugiperda were kept under a L14︰D10 (LD) photoperiod before being randomly subdivided into one of four treatment groups; constant darkness (dark-dark, DD), constant light (light-light, LL), and two groups with an extra day of exposure to either constant darkness (DD+1) or constant light (LL+1). The control group was kept under the original LD photoperiod for an entire generation. Nine-day-old (for DD+1 and LL+1 groups) or 10-day-old (for LD, DD, and LL) pupae were transferred to a purpose built, chronobiology-based, full-time monitoring device for determining the biological rhythm phenotype of small animals. Pupal duration, eclosion duration, and circadian eclosion rhythm were monitored and determined by combining different photoperiod cues. [Results]  Adult eclosion mainly occurred in the dark phase, or the corresponding phase of the dark phase, during LD entrainment under the LD, DD, DD+1, and LL photoperiods. The adult emergence peak occurred at Zeitgeber Time ZT15-16 (24%) under LD. Moreover, anticipation of the light-to-dark transition for eclosion was found during the light phase under LD. Adult emergence peaks in the DD and DD+1 groups were delayed, occurring at Circadian Time CT17-18 (24%) and CT21-22 (22%), respectively. Although poor eclosion rhythm was still evident under LL, an extra day of exposure to LL (i.e., LL+1) completely disrupted the circadian eclosion rhythm of S. frugiperda. [Conclusion]  A circadian eclosion rhythm exists in S. frugiperda that is regulated by both light-dark cycle entrainment and an endogenous circadian clock. The adult eclosion peak occurs during the dark phase of a long day photoperiod, and the free-running circadian period underlying the circadian eclosion rhythm of S. frugiperda is longer than 24 hours. Overall, adult circadian eclosion rhythms appear to be a reliable phenotype that can help reveal circadian clockwork mechanisms in S. frugiperda.