The quality and quantity of light changes significantly over the course of the day. The effect of light intensity on physiological and behavioural responses of animals has been well documented, particularly during the scotophase, but the effect of the wavelength of light, particularly during the photophase, less so. We assessed the daily responses in urine production, urinary 6-sulfatoxymelatonin (6-SMT) and glucocorticoid metabolite (uGCM) concentrations in the nocturnal Namaqua rock mouse (Micaelamys namaquensis) and diurnal four striped field mouse (Rhabdomys pumilio) under varying wavelengths of near monochromatic photophase (daytime) lighting. Animals were exposed to a short-wavelength light cycle (SWLC; ∼465–470 nm), a medium-wavelength light cycle (MWLC; ∼515–520 nm) and a long-wavelength light cycle (LWLC; ∼625–630 nm). The SWLC significantly attenuated mean daily urine production rates and the mean daily levels of urinary 6-SMT and of uGCM were inversely correlated with wavelength in both species. The presence of the SWLC greatly augmented overall daily 6-SMT levels, and simultaneously led to the highest uGCM concentrations in both species. In M. namaquensis, the urine production rate and urinary 6-SMT concentrations were significantly higher during the scotophase compared to the photophase under the SWLC and MWLC, whereas the uGCM concentrations were significantly higher during the scotophase under all WLCs. In R. pumilio, the urine production rate and uGCM were significantly higher during the scotophase of the SWLC, not the MWLC and LWLC. Our results illustrate that wavelength in the photophase plays a central role in the entrainment of rhythms in diurnal and nocturnal African rodent species.

光的质量和数量在一天中会发生显着变化。光强度对动物生理和行为反应的影响已得到充分证明，特别是在暗相期间，但光波长的影响，特别是在光相期间，则较少。我们评估了夜间活动的 Namaqua 岩鼠（Micaelamys namaquensis）和昼夜四条纹田鼠（Rhabdomys pumilio) 在不同波长的近单色光相（白天）照明下。动物暴露于短波长光循环（SWLC；~465-470 nm）、中波长光循环（MWLC；~515-520 nm）和长波长光循环（LWLC；~625-630 nm） ）。SWLC 显着降低了平均每日尿液产生率，并且尿液 6-SMT 和 uGCM 的平均每日水平与两种物种的波长呈负相关。SWLC 的存在极大地增加了总体每日 6-SMT 水平，同时导致两个物种的 uGCM 浓度最高。在M. namaquensis，与 SWLC 和 MWLC 下的光相相比，在暗相期间尿液产生率和尿 6-SMT 浓度显着更高，而在所有 WLC 下，在暗相期间 uGCM 浓度显着更高。在R. pumilio 中，在 SWLC 的暗相期间，尿液产生率和 uGCM 显着更高，而不是 MWLC 和 LWLC。我们的研究结果表明，光相位中的波长在昼夜活动的非洲啮齿动物物种的节律夹带中起着核心作用。