ECOLOGICAL STUDY FOR CIRCADIAN CLOCK-ANALYSIS OF ADAPTIVE SIGNIFICANCE OF ECLOSION TIMING AND LOCOMOTOR ACTIVITY RHYTHMS

对于在土壤中化蛹的昆虫来说，昼夜温度循环可能为成虫在一天中适当的时间发生羽化提供了一个主要的时间线索（授时因子）。而在土壤中，由于土壤导热系数较低，温度循环阶段随深度的变化而延迟。因此，位于土壤深处的蛹可能会补偿授时虫的深度相关相位延迟，以避免不合时宜的羽化。我们在实验室里研究了洋葱蝇（Delia antiqua）在不同土壤深度和不同温度下化蛹的成虫羽化时间，以确定这种补偿是否确实发生。我们发现，D.antiqua能够通过提前闭合时间来补偿随深度变化的Zeitgeber相位延迟，以响应随深度减小的温度周期幅度。许多双翅目昆虫在清晨以成虫的形式出现。这一趋势可能与环境条件的急剧变化有关。解释这一现象的一个著名的假说是，早晨相对潮湿和凉爽的空气有利于新出的成虫的翅膀伸长（Pitendrigh 1954）。然而，目前对干燥和高温如何干扰新羽化蝇的翅伸长知之甚少。为了验证这一假设，研究了湿度和温度对古翅龙葵翅伸长的影响。在20 ~ 35℃的温度范围内，干燥对机翼伸长率无不利影响；即使相对湿度低于10%，大多数被检查的个体都成功地拉长了翅膀。与湿度相比，高温对翅伸长的影响较大。因此，避免正午的高温至少在一定程度上参与了清晨成虫羽化的适应性意义。

For the insects pupating in the soil, the day-night temperature cycle may provide a primary time cue (Zeitgeber) for adult eclosion to occur at an appropriate time of the day. In the soil, however, the phase of temperature cycle is delayed with depth because of the low heat conductivity of soil. Therefore pupae located deeper in the soil might compensate for the depth-dependent phase delay of Zeitgeber to avoid mistimed emergence. We examined the adult eclosion timing of the onion fly, Delia antiqua, pupating at different depths in soil and under various thermoperiods in the laboratory to determine if such compensation indeed occurs. We found that D.antiqua is able to compensate for the depth-dependent phase delay of the Zeitgeber by advancing the eclosion timing in response to the amplitude of the temperature cycle decreasing with depth.Many dipteran insect emerge as adults in early morning. This trend would be associated with diel change in environmental conditions. One of the well-known hypothesis explaining this phenomenon is that relatively humid and cool air in the morning would favor the wing elongation of newly emerged adults (Pitendrigh 1954). At oresent, however, little is known how desiccation and high temperature disturb the wing elongation of newly emerged flies. To test this hypothesis, influence of humidity and temperature on wing-elongation of D.antiqua was examined. In the temperature range from 20C to 35C, desiccation has no harmful effect on the wing elongation; even if RH fell below 10%, most individuals examined elongated their wings successfully. Contrast to humidity, high temperature disturbed the wing-elongation considerably. Thus, avoidance of mid-day high temperature would be at least in part involved in the adaptive significane of early morning adult eclosion.