Heat production and evaporative water loss of dune larks from the Namib Desert
Heat production and evaporative water loss of dune larks from the Namib Desert
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DOI：
10.2307/1370011
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Joseph B. Williams
中科院分区：
文献类型：
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作者：
Joseph B. Williams
沙丘云雀Miafra erythrocephalus是唯一生活在纳米布沙海的永久居民，纳米布沙海是地球上最干燥的地区之一。对于沙丘云雀与平均体重为27.3 F 1.8 g（n = 12），基础代谢率（BMR）等于36.0千焦天-'，一个值附近的异速生长预测。因此，我没有发现任何证据表明这些鸟类的BMR降低。我认为，因为它们在冬季生活在相对凉爽的环境中，这要求重要Meta机制用于产热，所以此时云雀的BMR升高。在30 ℃以下，总蒸发失水量（TEWL）随环境温度（T_1）变化不大，平均为66.0mgH_2O·hr ~（-1）或1.58g·d ~（-1）。后一个值比异速生长预测值低21-44%，支持云雀TEWL降低的观点，这可能归因于皮肤水分流失减少。考虑到在17.0 ℃以下的T，s时，蒸发损失的水分被补充，代谢产水可能在云雀的水分经济中起重要作用。
Dune Larks Miafra erythrocephalus are the only permanent residents living in the Namib Sand Sea, one of the driest regions on earth. For Dune Larks with an average body mass of 27.3 F 1.8 g (n = 12), basal metabolic rate (BMR) equaled 36.0 kJ day-', a value near allometric predictions. Hence, I found no evidence that these birds have a reduced BMR. I sug- gest that because they live in a relatively cool cnvi- ronment in winter, which mandates significant meta- bolic machinery for thermogenesis, larks have an el- evated BMR at this time. Below 3O"C, total evapora- tive water loss (TEWL) varied little with ambient temperature (T,), and averaged 66.0 mg H,O hrr', or 1.58 g day-'. The latter value was 21-44% lower than allometric predictions, supporting the idea that larks have a reduced TEWL, attributable, perhaps, to re- duced cutaneous water loss. Metabolic water produc- tion may play a significant role in the water economy of larks in view of the fact that evaporative water loss- es are replaced at T,s below 17.O"C.