Seasonal variations in thermogenesis and energy requirements of plateau pikas Ochotona curzoniae and root voles Microtus oeconomus

Abstract

. 1996. Seasonal variations in thermogenesis and energy requirements of plateau pikas Ochotona curzoniae and root voles Microtus oeconomus. Acta Theriologica 41: 225-236.The seasonal patterns of nonshivering thermogeneis (NST), resting metabolic rate (RMR) at 15°C and 25°C in plateau pikas Ochotona curzoniae (Hodgson, 1858) and root voles Microtus oeconomus (Pallas, 1776), from the Qinghai-Tibetan plateau, were determined and thermal conductance was calculated. NST tended to increase during cold season for both species. No significant seasonal variations in NST were found in pikas (mean maximum in winter: 3.46 ± 0.19 ml 02/g'h; minimum in spring: 3.07 ± 0.16 ml O^g'h). Voles increased NST significantly as the ambient temperature decreased, from the lowest, mean 8.00 ± 0.42 ml 02/g'h, in summer to the peak in winter, mean 11.29 ± 0.44 ml 02/g'h. RMR and thermal conductance were lower in winter than those in summer for both species (mean in summer at 25°C: 4.96 + 0.35 ml 0 2 /g-h and 0.509 ± 0.027 ml 0 2 /g-h-°C for voles and 2.11 ± 0.09 ml 02/g'h and 0.179 ± 0.003 ml 02/g-h-°C for pikas, respectivly; mean in winter at 25°C: 4.22 ± 0.26 ml02/g-h and 0.379 ± 0.012 ml02/g-h-°C for voles and 1.55 ± 0.06 ml 02/g-h and 0.123 ± 0.003 ml 0 2 /g*h-°C for pikas, respectively). Voles lost body weights in winter whereas pikas kept their body weights. This suggests that alpine small mammals, which have high levels of metabolism and thermal conductance, mainly depend on increasing thermogenic capacities and insulation, decreasing energy expenditure per individual, augmented by behavoral adjustments to cope with cold temperatres of winter.

Effect of photoperiod on body mass, food intake and body composition in the field vole,Microtus agrestis

“…Similar seasonal changes (i.e. SD-induced decreases in body mass and adiposity) have also been demonstrated in the European hamster (Cricetus cricetus; Canguilhem et al, 1988), montane vole (Microtus montanus; Petterborg, 1978), meadow vole (Microtus pennsylvanicus; Dark and Zucker, 1984), tundra vole (Microtus oeconomus; Wang and Wang, 1996) and bank vole (Clethrionomys glareolus; Peacock et al, 2004).…”

Effect of Repeated Cold Water Swimming Exercise on Adaptive Changes in Body Weight in Older Rats

“…The response of small mammals to cold stress differs, as is the case of Dicrostonyx groenlandicus and Mesocricetus auratus, the body weight of which increased during cold acclimation (Nagy, Negus, 1993;Janský, Haddad, Pospísilová, Dvorák, 1986). However, the body weight of Apodemus sylvaticus and Acomys cahirinus was not affected by cold acclimation (Klaus, Heldmaier, Ricquier, 1988;Khokhlova, Krasnov, Shenbrot, Degen, 2000;Gunduz, 2002); on the contrary, the body weight of Phodopussungorus, Microtusochrogaster, M. pennslvanicus and Clethrionomysglareolus decreased during cold acclimation (Klaus et al, 1988;Wiesinger, Heldmaier, Buchberger, 1989;Voltura, Wunder, 1998;Wang, Wang, 1990). In the study by Arnold, Richard (1987), cold exposure had no additional effect on body composition in physically active rats.…”

Effects of photoperiod and temperature on the body mass, thermogenesis, and serum leptin levels of Apodemus draco (Rodentia: Muridae) in the Hengduan Mountain region, China

“…It was shown that the NST capacity of Phodopus sungorus in winter increased by 70% compared to that in summer (Heldmaier et al 1982). The plateau pika (Ochotona curzoniae) and root vole (Microtus oeconomus) which live on the Qinghai-Tibet Plateau (Wang and Wang 1996) and Brandt's voles (M. brandti) that live in grasses of Inner Mongolia (Li and Wang 2005b) also showed similar patterns of adaptation. The increased energy expenditure in the cold can be compensated for by increasing energy intake and mobilizing body fat.…”