Abstract
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.
| Original language | English |
|---|---|
| Article number | 867350 |
| Number of pages | 17 |
| Journal | Frontiers in Ecology and Evolution |
| Volume | 10 |
| DOIs | |
| Publication status | Published - 2 Jun 2022 |
Bibliographical note
Funding Information:We thank all the funding agencies that made this research possible, namely, the SARChI Chair of Mammal Behavioral Ecology and Physiology (GUN 64756), National Research Foundation RSA (Grants 2053801 and 2053514), the British Ecological Society (SEPG), and the National Science Foundation, United States no. 0130600.
Acknowledgments
We would like to thank the Duckitt Family (Darling) and the Stone Family (Kamieskroon) for allowing us to conduct research on their farms Waylands and Kardou, respectively. We want to thank the Northern Cape Department of Agriculture, Land Reform and Environment, and Goegap Nature Reserve staff for their assistance. Furthermore, we would like to thank Glengarry golf estate for access to their property for animal capture and KwaZulu-Natal Nature Conservation Service. We would like to thank all the field assistants that contributed to this large data set.
Data Availability Statement
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fevo.2022.867350/full#supplementary-materialKeywords
- African mole-rats
- aridity
- body fat (BF)
- daily energy expenditure (DEE)
- resting metabolic rate (RMR)
- sustained metabolic scope (SusMS)
- water economy index (WEI)
- water turnover (WTO)
Access to Document
- Hart_etal_FEE_EnergeticsandWaterFlow
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