Surviving winter on the Qinghai-Tibetan Plateau: Pikas suppress energy demands and exploit yak feces to survive winter
| Autor: | Liangzhi Zhang, Jianguo Cui, Xinghao Wang, Catherine Hambly, Gang-Bin Tang, Peter Thomson, Xin-Yu Liu, Zengli Wang, Haibo Fu, Quinn E. Fletcher, Yanming Zhang, Lu Wang, Olivia C. Robertson, Stuart B. Piertney, De-Hua Wang, Qing-Sheng Chi, Paula Glover, Łukasz Ołdakowski, Paula Redman, John R. Speakman, Yongguo Li, Jacques Togo |
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| Rok vydání: | 2021 |
| Předmět: |
0106 biological sciences
0301 basic medicine Hibernation Acclimatization Ochotona curzoniae Fauna Zoology Doubly labeled water Tibet 010603 evolutionary biology 01 natural sciences Feces 03 medical and health sciences Animals Pika geography Multidisciplinary Plateau geography.geographical_feature_category biology Altitude Lagomorpha Interspecific competition Biological Sciences biology.organism_classification 030104 developmental biology Basal metabolic rate Basal Metabolism Seasons Energy Metabolism |
| Zdroj: | Proc Natl Acad Sci U S A |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.2100707118 |
| Popis: | The Qinghai-Tibetan Plateau, with low precipitation, low oxygen partial pressure, and temperatures routinely dropping below −30 °C in winter, presents several physiological challenges to its fauna. Yet it is home to many endemic mammalian species, including the plateau pika (Ochotona curzoniae). How these small animals that are incapable of hibernation survive the winter is an enigma. Measurements of daily energy expenditure (DEE) using the doubly labeled water method show that pikas suppress their DEE during winter. At the same body weight, pikas in winter expend 29.7% less than in summer, despite ambient temperatures being approximately 25 °C lower. Combined with resting metabolic rates (RMRs), this gives them an exceptionally low metabolic scope in winter (DEE/RMRt = 1.60 ± 0.30; RMRt is resting metabolic rate at thermoneutrality). Using implanted body temperature loggers and filming in the wild, we show that this is achieved by reducing body temperature and physical activity. Thyroid hormone (T(3) and T(4)) measurements indicate this metabolic suppression is probably mediated via the thyroid axis. Winter activity was lower at sites where domestic yak (Bos grunniens) densities were higher. Pikas supplement their food intake at these sites by eating yak feces, demonstrated by direct observation, identification of yak DNA in pika stomach contents, and greater convergence in the yak/pika microbiotas in winter. This interspecific coprophagy allows pikas to thrive where yak are abundant and partially explains why pika densities are higher where domestic yak, their supposed direct competitors for food, are more abundant. |
| Databáze: | OpenAIRE |
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