Lovegrove B G, Raman J, Perrin M R
School of Botany and Zoology, University of Natal, Scottsville, South Africa.
J Comp Physiol B. 2001 Feb;171(1):11-21. doi: 10.1007/s003600000140.
Patterns of daily torpor were measured in response to photoperiod and food restriction at a constant temperature (18 degrees C) in two species of elephant shrew (Macroscelidea), Elephantulus rozeti (from Morocco) and Elephantulus myurus (from southern Africa). Body temperature was monitored continuously for ca. 3 months using temperature-sensitive telemeters. Under short photoperiods (8:16 L:D), both species entered spontaneous torpor on an ad libitum diet, but showed a higher frequency of induced torpor when food was restricted. Under long photoperiods (16:8 L:D), E. myurus could be induced to enter daily 'summer' torpor. A total of 378 torpor bouts were measured, none of which were longer in duration than 18 h. Under short photoperiods, arousal from torpor was associated with the onset of the photoperiod, whereas the time of entry was variable throughout the scotophase. However, E. myurus tended to phase shift torpor from the photophase to the scotophase under long photoperiods, despite displaying weak circadian amplitudes of body temperature indicative of a photophase rest phase. Both species lacked well-defined circadian amplitudes of body temperature, a pattern thought to be associated with polyphasic activity cycles characteristic of several Elephantuluis species. It was concluded that these and other patterns of torpor shown by Elephantulus show similarities with other small Afrotropical insectivores inhabiting semi-arid habitats or unpredictable environments.
在恒定温度（18摄氏度）下，研究了两种象鼩（象鼩目）——罗氏象鼩（来自摩洛哥）和南非洲象鼩——对光周期和食物限制的每日蛰伏模式。使用温度敏感遥测仪连续监测体温约3个月。在短光周期（8:16光:暗）下，两种象鼩在自由采食时都会自发进入蛰伏状态，但在食物受限情况下，诱导蛰伏的频率更高。在长光周期（16:8光:暗）下，南非洲象鼩可被诱导进入每日的“夏季”蛰伏状态。共测量到378次蛰伏发作，持续时间均不超过18小时。在短光周期下，从蛰伏中苏醒与光周期开始有关，而进入蛰伏的时间在整个暗期是可变的。然而，尽管南非洲象鼩体温的昼夜振幅较弱，表明光期为休息期，但在长光周期下，它倾向于将蛰伏从光期转移到暗期。两种象鼩都缺乏明确的体温昼夜振幅，这种模式被认为与几种象鼩属物种的多相活动周期有关。得出的结论是，象鼩所表现出的这些以及其他蛰伏模式与栖息在半干旱栖息地或不可预测环境中的其他小型非洲食虫动物相似。
