Marhold S, Nagel A
Zoologisches Institut, J.W. Goethe Universität, Frankfurt am Main.
J Comp Physiol B. 1995;164(8):636-45. doi: 10.1007/BF00389805.
Body temperature, oxygen consumption, respiratory and cardiac activity and body mass loss were measured in six females and four males of the subterranean Zambian mole rat Cryptomys sp. (karyotype 2 n = 68), at ambient temperatures between 10 and 35 degrees C. Mean body temperature ranged between 36.1 and 33.2 degrees C at ambient temperatures of 32.5-10 degrees C and was lower in females (32.7 degrees C) than in males (33.9 degrees C) at ambient temperatures of 10 degrees C but did not differ at thermoneutrality (32.5 degrees C). Except for body temperature, mean values of all other parameters were lowest at thermoneutrality. Mean basal oxygen consumption of 0.76 ml O2.g-1.h-1 was significantly lower than expected according to allometric equations and was different in the two sexes (females: 0.82 ml O2.g-1.h-1, males: 0.68 ml O2.g1.h-1) but was not correlated with body mass within the sexes. Basal respiratory rate of 74.min-1 (females: 66.min1, males: 87.min-1) and basal heart rate of 200.min-1 (females: 190.min-1, males: 216.min-1) were almost 30% lower than predicted, and the calculated thermal conductance of 0.144 ml O2.g-1.h1.degrees C-1 (females: 0.153 ml O2.g-1.h-1.degrees C-1, males: 0.131 ml O2.g-1.h-1.degrees C-1) was significantly higher than expected. The body mass loss in resting mole rats of 8.6-14.1%.day-1 was high and in percentages higher in females than in males. Oxygen consumption and body mass loss as well as respiratory and cardiac activity increased at higher and lower than thermoneutral temperatures. The regulatory increase in O2 demand below thermoneutrality was mainly saturated by increasing tidal volume but at ambient temperatures < or = 15 degrees C, the additional oxygen consumption was regulated by increasing frequency with slightly decreasing tidal volume. Likewise, the additional blood transport capacity was mainly effected by an increasing stroke volume while there was only a slight increase of heart frequency. In an additional field study, temperatures and humidity in different burrow systems have been determined and compared to environmental conditions above ground. Constant temperatures in the nest area 70 cm below ground between 26 and 28 degrees C facilitate low resting metabolic rates, and high relative humidity minimizes evaporative water loss but both cause thermoregulatory problems such as overheating while digging. In 13-16 cm deep foraging tunnels, temperature fluctuations were higher following the above ground fluctuations with a time lag.(ABSTRACT TRUNCATED AT 400 WORDS)
在10至35摄氏度的环境温度下，对6只雌性和4只雄性赞比亚地下鼹形鼠（Cryptomys sp.，核型2n = 68）进行了体温、耗氧量、呼吸和心脏活动以及体重损失的测量。在32.5至10摄氏度的环境温度下，平均体温在36.1至33.2摄氏度之间，在10摄氏度的环境温度下，雌性（32.7摄氏度）低于雄性（33.9摄氏度），但在热中性温度（32.5摄氏度）下没有差异。除体温外，所有其他参数的平均值在热中性温度下最低。平均基础耗氧量为0.76 ml O2·g-1·h-1，根据异速生长方程，该值显著低于预期，且两性之间存在差异（雌性：0.82 ml O2·g-1·h-1，雄性：0.68 ml O2·g-1·h-1），但在两性内部与体重均无相关性。基础呼吸频率为74次/分钟（雌性：66次/分钟，雄性：87次/分钟），基础心率为200次/分钟（雌性：190次/分钟，雄性：216次/分钟），几乎比预测值低30%，计算得出的热传导率为0.144 ml O2·g-1·h-1·℃-1（雌性：0.153 ml O2·g-1·h-1·℃-1，雄性：0.131 ml O2·g-1·h-1·℃-1），显著高于预期。静息鼹形鼠的体重损失为8.6 - 14.1%·天-1，且损失率较高，雌性高于雄性。在高于和低于热中性温度时，耗氧量、体重损失以及呼吸和心脏活动都会增加。低于热中性温度时，对氧气需求的调节性增加主要通过增加潮气量来满足，但在环境温度≤15摄氏度时，额外的耗氧量通过增加频率并略微降低潮气量来调节。同样，额外的血液运输能力主要通过增加每搏输出量来实现，而心率仅略有增加。在另一项野外研究中，测定了不同洞穴系统中的温度和湿度，并与地面环境条件进行了比较。地下70厘米处巢穴区域的恒定温度在26至28摄氏度之间，有利于低静息代谢率，高相对湿度可使蒸发水分损失最小化，但两者都会导致体温调节问题，如挖掘时过热。在13 - 16厘米深的觅食隧道中，温度波动随地面波动而变化，存在时间滞后。（摘要截取自400字）
