Data from: Natural Zeitgebers under temperate conditions cannot compensate for the loss of a functional circadian clock in timing of a vital behavior in Drosophila

The adaptive significance of adjusting behavioral activities to the right time of the day seems obvious but is under debate. Our data provides evidence that proper timing of eclosion, a vital behavior of the fruit fly Drosophila melanogaster, requires a functional molecular clock under quasi-natural conditions. We compared eclosion profiles and assessed eclosion rhythmicity in wildtype flies (CS) and clock-related mutant strains (per01, pdf01, han5304) under laboratory and outdoor conditions. In the laboratory, flies were entrained in either light-dark cycle (LD12:12) or warm (25°C)-cold (16°C) cycle (WC12:12), and tested under entrainment or constant conditions using TriKinetics Drosophila Eclosion Monitors. For outdoor assays, a WEclMon system was used and experiments were performed between July-Octobre 2014 and July-Octobre 2016. Flies with a defective molecular clock showed impaired rhythmicity and gating under natural temperate conditions in Würzburg/Germany even in the presence of a full complement of abiotic Zeitgebers. We also found that eclosion rhythmicity cannot be entrained by daily cycles in relative humidity. Low relative humidity also did not or only weakly affect the ability of the flies to eclose and unfold their wings. Our results suggest that the presence of natural Zeitgebers is not sufficient, and a functional molecular clock is required to induce stable temporal eclosion patterns in flies under temperate conditions with considerable day-today variation in light intensity and temperature. Temperate Zeitgebers are, however, sufficient to functionally rescue a loss of PDF-signalling. The data set belongs to the publication: Ruf F, Mitesser O, Mungwa ST, Horn M, Rieger D, Hovestadt T, and Wegener C (2021) Natural Zeitgebers Under Temperate Conditions Cannot Compensate for the Loss of a Functional Circadian Clock in Timing of a Vital Behavior in Drosophila. Journal of Biological Rhythms 36: 271–285. DOI: 10.1177/0748730421998112.

将行为活动调整至当日适宜时段的适应性意义看似不言而喻，却仍存在学术争议。本数据集提供证据表明，黑腹果蝇（Drosophila melanogaster）的关键生存行为——羽化的精准时序调控，在准自然条件下依赖于功能完整的分子钟（molecular clock）。我们分别在实验室与室外环境中，对比了野生型果蝇（CS品系）与三类时钟相关突变株系（per01、pdf01、han5304）的羽化谱，并评估了其羽化节律性。实验室实验阶段，果蝇分别在光暗循环（LD12:12，即12小时光照/12小时黑暗）或温度循环（25℃暖温/16℃冷温，WC12:12）下完成节律同步，随后分别在同步状态与恒定条件下，使用TriKinetics果蝇羽化监测仪（TriKinetics Drosophila Eclosion Monitors）开展测试。室外实验采用WEclMon系统完成，实验时段覆盖2014年7月至10月，以及2016年7月至10月。在德国维尔茨堡的自然温带环境中，即便存在全套非生物授时因子（Zeitgeber），分子钟功能缺陷的果蝇仍出现了节律性与羽化门控受损的表型。本研究同时发现，每日相对湿度循环无法对果蝇的羽化节律起到同步驯化作用；低相对湿度既不会，也仅会微弱影响果蝇的羽化与翅膀展开能力。本研究结果显示，仅依靠自然授时因子并不足以维持果蝇的羽化节律；在光照强度与温度存在显著逐日波动的温带环境中，果蝇要形成稳定的羽化时间模式，必须依赖功能完整的分子钟。不过，温带环境下的授时因子足以在功能上弥补PDF信号通路缺失的缺陷。本数据集关联的发表论文为：Ruf F、Mitesser O、Mungwa ST、Horn M、Rieger D、Hovestadt T及Wegener C（2021）《温带环境下的自然授时因子无法弥补黑腹果蝇关键行为时序调控中功能昼夜钟的缺失》，刊载于《生物节律期刊》（Journal of Biological Rhythms）第36卷，第271–285页。DOI: 10.1177/0748730421998112。