Data_Sheet_1_Energetics and Water Flux in the Subterranean Rodent Family Bathyergidae.PDF

The doubly labeled water (DLW) technique and indirect calorimetry enable measurement of an animal’s daily energy expenditure (DEE, kJ/day), resting metabolic rate (RMR, kJ/d), sustained metabolic scope (SusMS), body fat content (BF, %) as well as water turnover (WTO, ml/day), and water economy index (ml/kJ). Small mammals have been the primary focus of many of the DLW studies to date. From large multi-species analyses of the energetics and water flux of aboveground small mammals, well-defined trends have been observed. These trends mainly refer to an adaptive advantage for lower RMR, DEE, SusMS, WTO and WEI in more ariddwelling animals to increase water and energy savings under low and unpredictable resource availability. The study of the subterranean rodent family Bathyergidae (African mole-rats) has been of particular interest with regards to field metabolic rate and metabolic studies. Although a great deal of research has been conducted on the Bathyergidae, a complete overview and multi-species analysis of the energetics and water flux of this family is lacking. Consequently, we assessed DEE, RMR, SusMS, BF, WTO and WEI across several different species of bathyergids from various climatic regions, and compared these to the established patterns of energetics and water flux for aboveground rodents. There was notable variation across the Bathyergidae inhabiting areas with different aridities, often contrary to the variations observed in above-ground species. These include increased DEE and WEI in arid-dwelling bathyergid species. While the climate was not a clear factor when predicting the SusMS of a bathyergid species, rather the degree of group living was a strong driver of SusMS, with solitary species possessing the highest SusMS compared to the socially living species. We conclude that the constraints of the underground lifestyle and the consequent spectrum of social behaviors possessed by the family Bathyergidae are most likely to be more crucial to their energetics and water flux than their habitat; however other important unstudied factors may still be at play. More so, this study provides evidence that often unreported parameters, measured through use of the DLW technique (such as BF and WEI) can enable species to be identified that might be at particular risk to climate change.

双重标记水（DLW）技术和间接量热法使得能够测量动物每日能量消耗（DEE，千焦/日）、基础代谢率（RMR，千焦/日）、持续代谢范围（SusMS）、体脂含量（BF，百分比）以及水周转率（WTO，毫升/日）和水经济指数（毫升/千焦）。迄今为止，小型哺乳动物一直是许多DLW研究的焦点。通过对地面小型哺乳动物能量代谢和水通量的多物种大型分析，已观察到明确趋势。这些趋势主要涉及在更干旱栖息地中，具有较低RMR、DEE、SusMS、WTO和WEI的动物在资源稀缺且不可预测的情况下，具有增加水分和能量节约的适应性优势。对地下啮齿动物家族Bathyergidae（非洲鼹鼠）的研究，特别是在现场代谢率和代谢研究方面，特别引人注目。尽管对Bathyergidae进行了大量研究，但对该家族能量代谢和水通量的全面概述和多物种分析仍显不足。因此，我们对来自不同气候区域的不同种类Bathyergidae的DEE、RMR、SusMS、BF、WTO和WEI进行了评估，并将这些结果与地面啮齿动物的已确立的能量代谢和水通量模式进行了比较。在栖息地干旱程度不同的Bathyergidae中观察到显著的变异，往往与地面物种观察到的变异相反。这包括干旱栖息地Bathyergidae物种中DEE和WEI的增加。虽然气候并不是预测Bathyergidae物种SusMS的明显因素，相反，群居程度是SusMS的强大驱动力，与群居物种相比，独居物种具有最高的SusMS。我们得出结论，地下生活方式的约束以及Bathyergidae家族所拥有的社会行为谱系，很可能对其能量代谢和水通量比其栖息地更为关键；然而，其他重要的未研究因素可能仍在发挥作用。更重要的是，本研究提供了证据，表明通过DLW技术测量的通常未报告的参数（如BF和WEI）可以使物种被识别，这些物种可能特别容易受到气候变化的影响。