Ellison G T, Skinner J D, Ferguson J W
Mammal Research Institute, University of Pretoria, Republic of South Africa.
J Comp Physiol B. 1994;164(1):62-8. doi: 10.1007/BF00714572.
The daily activity and energy metabolism of pouched mice (Saccostomus compestris) from two localities in southern Africa was examined following warm (25 degrees C) and cold (10 degrees C) acclimation under long (LD 14:10) and short (LD 10:14) photoperiod. There was no differential effect of photoperiod on the daily activity or metabolism of pouched mice from the two localities examined, which suggests that reported differences in photoresponsivity between these two populations were not the result of differences in daily organisation. Nevertheless, there was a significant increase in metabolism at 10 degrees C, irrespective of photoperiod, even though seven cold-acclimatized animals displayed bouts of spontaneous torpor and saved 16.4-36.2% of their daily energy expenditure. All but one of these bouts occurred under short photoperiod, which suggests that short photoperiod facilitated the expression of torpor and influenced the daily energy metabolism of these individuals. As expected for a nocturnal species, the amount of time spent active increased following acclimation to short photoperiod at 25 degrees C. However, there was a reduction in mean activity levels under short photoperiod at 10 degrees C, possibly because the stimulation of activity by short photoperiod was masked by a reduction in activity during bouts of spontaneous torpor. Cold temperature clearly had an overriding effect on the daily activity and metabolism of this species by necessitating an increase in metabolic heat production and eliciting spontaneous torpor which over-rode the effect of short photoperiod on activity at an ambient temperature of 10 degrees C.
在长光照周期（LD 14:10）和短光照周期（LD 10:14）条件下，对来自非洲南部两个地区的袋鼩（南非囊鼠）进行温暖（25摄氏度）和寒冷（10摄氏度）驯化后，检测了它们的日常活动和能量代谢情况。光照周期对所检测的来自两个地区的袋鼩的日常活动或代谢没有差异影响，这表明报道的这两个种群在光反应性上的差异并非日常活动模式差异的结果。然而，无论光照周期如何，在10摄氏度时代谢都显著增加，尽管7只冷驯化的动物出现了自发的蛰伏期，并节省了其每日能量消耗的16.4%至36.2%。这些蛰伏期除一次外均发生在短光照周期下，这表明短光照周期促进了蛰伏的表现，并影响了这些个体的日常能量代谢。正如对夜行性物种的预期，在25摄氏度下适应短光照周期后，活动时间增加。然而，在10摄氏度的短光照周期下，平均活动水平有所降低，这可能是因为短光照周期对活动的刺激被自发蛰伏期活动的减少所掩盖。低温显然对该物种的日常活动和代谢具有首要影响，因为它需要增加代谢产热并引发自发蛰伏，从而在10摄氏度的环境温度下，短光照周期对活动的影响被其掩盖。
