Whole-animal experiments devised to investigate possible association between photoperiodic time measurement and the circadian system (Bünning's hypothesis) are compared with more recent molecular investigations of circadian clock genes. In Sarcophaga argyrostoma and some other species, experimental cycles of light and darkness revealed a photoperiodic oscillator, set to constant phase at dusk and measuring night length repeatedly during extended periods of darkness. In some species, however, extreme dampening revealed an unrepetitive (i.e., hourglass-like) response. Rhythms of clock gene transcript abundance may also show similar phase relationships to the light cycle, and gene silencing of important clock genes indicates that they play a crucial role in photoperiodism either alone or in concert. However, the multiplicity of peripheral oscillators in the insect circadian system indicates that more complex mechanisms might also be important.

中文翻译：

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休眠，滞育和昼夜节律系统在昆虫光周期中的作用。

旨在研究光周期时间测量与昼夜节律系统之间可能联系的全动物实验（Bünning的假设）与最近进行的昼夜节律基因的分子研究进行了比较。在Sarcophaga argyrostoma和其他一些物种中，光与暗的实验周期显示出一个光周期振荡器，该振荡器在黄昏时设置为恒定相位，并在较长的黑暗时间内重复测量夜间长度。但是，在某些物种中，极度阻尼显示出不重复的（即类似沙漏的）响应。时钟基因转录本丰度的节律也可能显示与光循环相似的相位关系，重要时钟基因的基因沉默表明它们在光周期异常中起着至关重要的作用，无论是单独还是协同作用。然而，