Daily Torpor in Free‐Ranging Rock Elephant Shrews, Elephantulus myurus: A Year‐Long Study
Daily Torpor in Free‐Ranging Rock Elephant Shrews, Elephantulus myurus: A Year‐Long Study
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自由放养的岩象鼩每天的麻木状态：一项为期一年的研究
DOI：
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发表时间：
2004
影响因子：
1.6
通讯作者：
B. G. Lovegrove
中科院分区：
文献类型：
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作者：
N. Mzilikazi;B. G. Lovegrove
在实验室条件下，岩象鼩，Elephantulus myurus，使用每天的麻痹在短和长的光周期驯化。然而，在野外和实验室条件下，异温性的使用往往不同。我们调查了2001年5月至2002年5月在自由放养的象鼩中使用麻痹。象鼩全年每天都能麻痹，而麻痹在冬季最为普遍。我们记录了两个麻痹发作在初夏（11月）。年内，我们共录得467次麻痹发作。全年平均最低体温（Tbmin）为15.3° ± 4.4°C，平均滞育时间为8.6 ± 3.5h。这些值在每日异温动物的预期范围内。然而，与冬眠特征有一些边缘重叠;少数麻痹发作的持续时间超过24小时，Tbmin下降到10°C以下。休眠与低环境温度和光周期高度相关。在控制光周期效应后，休眠也与无脊椎动物丰度相关。在进行这项研究的那一年，降雨量比长期平均水平低14%。历史降雨记录显示，强厄尔尼诺年夏季降雨量比长期平均水平低40%。在这些干旱年份，夏季麻痹的频率可能更高，这突出了对自由放养动物长期生理数据的需求。
Under laboratory conditions, rock elephant shrews, Elephantulus myurus, use daily torpor under both short and long photoperiod acclimation. However, use of heterothermy often differs under field and laboratory conditions. We investigated the use of torpor in free‐ranging elephant shrews from May 2001 to May 2002. The elephant shrews were capable of daily torpor throughout the year, with torpor most prevalent during winter. We recorded two torpor bouts during early summer (November). We recorded a total of 467 torpor bouts during the year. The mean torpor minimum body temperature (Tbmin) for the whole year was 15.3° ± 4.4°C, and the mean bout length was 8.6 ± 3.5 h. These values were in the range expected for daily heterotherms. However, there was some marginal overlap with hibernation characteristics; a few torpor bouts were longer than 24 h in duration, and Tbmin decreased below 10°C. Torpor was highly correlated with low ambient temperature and photoperiod. Torpor was also correlated with invertebrate abundance after controlling for photoperiod effects. During the year in which this study was conducted, the rainfall was 14% below long‐term average. Historical rainfall records show that summer rainfall during strong El Niño years is up to 40% below the long‐term average. During these drought years, the frequency of summer torpor may be higher, highlighting the need for long‐term physiological data in free‐ranging animals.