Center for Biological Rhythm Research, Ahmednagar College, Ahmednagar 414001, M.S., India.
Chronobiol Int. 2010 Jan;27(1):83-94. doi: 10.3109/07420520903398567.
The effects of nocturnal irradiance tenfold dimmer than starlight intensity on the locomotor activity rhythm of Drosophila jambulina were investigated in two types of light-dark (12 h:12 h) cycles, in which light intensity of the photophase was 10 lux while that of the scotophase was either 0 lux for control flies or 0.0006 lux for experimental flies. Activity onset in the experimental flies was approximately 5.4 h prior to lights-on, so it occurred around midnight. However, activity onset of the control flies coincided almost with the lights-on. Nevertheless, activity offset was the same in both groups, occurring at lights-off. Duration of the active phase (alpha) and activity passes/fly/cycle (APC) in the experimental flies was far greater than in controls. After-effects of the nocturnal illumination of the light-dark cycles when the flies were transferred to constant darkness were evident as the period of the free-running rhythm was shortened, alpha was lengthened, and APC was enhanced in the experimental compared to control flies. Thus, very low photic sensitivity of these flies appears to be a physiological adaptation to dim-light ambiance in its natural breeding site in the field.
我们研究了夜间光照强度比星光强度低十倍对果蝇运动活动节律的影响，这种夜间光照强度分别在两种明暗（12 小时：12 小时）周期中进行，其中光相的光强度为 10 勒克斯，而暗相的光强度对对照果蝇为 0 勒克斯，对实验果蝇为 0.0006 勒克斯。实验果蝇的活动起始时间大约比光照时间提前 5.4 小时，因此发生在午夜左右。然而，对照果蝇的活动起始时间几乎与光照时间一致。然而，两组的活动结束时间相同，都发生在光照时间。实验组果蝇的活跃期（alpha）和活动次数/只/周期（APC）比对照组的要长得多。当这些果蝇被转移到持续黑暗中时，光暗周期的夜间照明的后效明显，因为自由运行节律的周期缩短，alpha 延长，而 APC 在实验组中比对照组增强。因此，这些果蝇对低光的非常低的光敏性似乎是对其在野外自然繁殖地的暗淡光环境的生理适应。
