Bethge Janina, Wist Bianca, Stalenberg Eleanor, Dausmann Kathrin
Zoological Institute, Functional Ecology, Biocenter Grindel, University Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany.
Division of Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT, Australia.
J Comp Physiol B. 2017 Jul;187(5-6):827-834. doi: 10.1007/s00360-017-1082-9. Epub 2017 Mar 17.
The spiny forest of South Madagascar is one of the driest and most unpredictable habitats in Africa. The small-bodied, nocturnal primate Lepilemur leucopus lives in this harsh habitat with high diurnal and seasonal changes in ambient temperature. In this study, we investigated seasonal adaptions in energy budgeting of L. leucopus, which allow it to live under these conditions by measuring resting metabolic rate using open-flow respirometry. No signs of heterothermy were detected, and resting metabolic rate was significantly lower in the warmer wet season than in the colder dry season. In fact, L. leucopus possesses one of the lowest mass-specific metabolic rates measured so far for an endotherm, probably the result of adaptations to its habitat and folivorous and potentially toxic diet. Surprisingly, we identified a shift of the thermoneutral zone from between 25 and 30 °C in the wet season to between 29 and 32 °C in the cool dry season. L. leucopus seems to be more affected by the hot daytime temperatures during the dry season and thermoregulation seems to be more costly during this time, which makes this shift of the thermoneutral zone advantageous. Our findings suggest that L. leucopus has a very small scope to unfavorable conditions, making it highly vulnerable, e.g., to changing conditions due to climate change.
马达加斯加岛南部的多刺森林是非洲最干旱、最不可预测的栖息地之一。小型夜行性灵长类动物白脚鼬狐猴生活在这种恶劣的栖息地中，这里昼夜和季节的环境温度变化很大。在这项研究中，我们通过使用开放式流动呼吸测定法测量静息代谢率，研究了白脚鼬狐猴在能量预算方面的季节性适应，这些适应使其能够在这些条件下生存。未检测到异温性迹象，温暖的湿季静息代谢率显著低于寒冷的干季。事实上，白脚鼬狐猴拥有迄今为止测量到的恒温动物中最低的质量特异性代谢率之一，这可能是其对栖息地以及食叶和潜在有毒饮食适应的结果。令人惊讶的是，我们发现热中性区从湿季的25至30°C转移到凉爽干季的29至32°C。白脚鼬狐猴似乎在干季更容易受到白天高温的影响，并且在此期间体温调节的成本似乎更高，这使得热中性区的这种转移具有优势。我们的研究结果表明，白脚鼬狐猴应对不利条件的空间非常小，这使其极易受到影响，例如受到气候变化导致的条件变化的影响。
