达乌尔黄鼠冬眠期间体温的变化和冬眠模式

摘要

用植入式半导体温度记录元件iButton记录了达乌尔黄鼠冬眠季节及其前后的体温,分析了其冬眠模式和体温调节特点.结果显示:1)实验室条件下,达乌尔黄鼠冬眠季节长短的个体差异较大,可以分成深冬眠型、少冬眠型和不冬眠型三种类型；2)达乌尔黄鼠在冬季表现出深冬眠阵(最低体温Tbmin＜ 20℃,冬眠阵的持续时间BD＞24 h)、短冬眠阵(Tbmin＜20℃,BD≤24h)和日眠阵(Tbmin≥20℃,BD≤24 h)3种类型,最低体温分别为2.54℃ ±0.35℃、10.05℃±1.97℃和23.09℃±0.40℃,彼此之间差异显著.日眠阵阵间产热阶段的最高体温为38.09℃±0.17℃,高于深冬眠阵(37.31℃±0.15℃)和短冬眠阵(37.22℃±0.31℃)；3)深冬眠阵和日眠阵中最低体温均与环境温度显著相关,冬眠过程中的最低体温为-2.43℃；4)深冬眠过程中,多数个体可以短时(≤3h)耐受-2℃～0℃的低温,激醒或继续维持深冬眠,无致死效应,但长时间(15 h)或过度低温(-5℃以下)的条件下,深冬眠的达乌尔黄鼠被激醒(70％)或死亡(30％),不能持续冬眠；5)入眠前10 d的体温日波动幅度显著增加,高于出眠后的日体温波动,且多数个体入眠前出现体温的“试降”.表明,冬眠前入眠的准备阶段,动物的体温调节已开始发生变化；冬季日眠的调节机制可能与冬眠不同；短时-2℃～0℃的低体温对深冬眠的达乌尔黄鼠无致死效应.%In order to understand the patterns of body temperature changes and hibernation, we used iButtons to monitor body temperatures (Tb) in a typical hibernator, the Daurian ground squirrel (Spermophilus dauricus) , before, during, and after their hibernation period. Hibernation patterns and thermoregulation characteristics were analyzed. In the laboratory, there were great individual differences in the length of the hibernation time. Three types of torpor were distinguished, deep hibernation, short hibernation, and no hibernation. Three different kinds of torpor bouts could also be distinguished during the hibernation season, deep hibernation bouts (the minimal body temperature, Tbmin <20℃, the duration of the hibernation bout, BD＞24 h), short hibernation bouts (Tbmin＜20℃, BD≤24 h) , and daily torpor bouts (Tbmin≥20℃ , BD≤ 24 h). The Tbmin in deep hibernation bouts (2. 54t ±0. 351) was lower than in short hibernation bouts (10. 051 ± 1. 97℃) , but the Tbmin in daily torpor bouts (38. 09℃ ± 0.17℃) was higher than in either of the other conditions (37. 31℃ ±0. 15℃ and 37. 22℃ ±0. 31℃). These results suggest that the regulation mechanism for daily torpor may be different from the other two kinds. Tbmin, in deep hibernation bouts and daily torpor bouts was significantly correlated with ambient temperature (Ta). The lowest Tb we recorded was -2.431. In deep hibernation bouts, most individuals were a-ble to tolerate temperatures as low as -2℃ to 0℃. The fluctuation amplitude of Tb within 10 days before hibernation was greater than after hibernation. Most animals displayed very "careful" body temperature reductions before entering hibernation, which imply that the thermoregulatory mechanism is schanged to a new state before hibernation starts.