Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, NSW, 2351, Australia.
J Comp Physiol B. 2010 Aug;180(6):869-76. doi: 10.1007/s00360-010-0459-9. Epub 2010 Mar 9.
Many small desert dasyurids employ torpor almost daily during winter, because cold nights and low food availability impose high energetic costs. However, in Western Australia the arid zone extends into tropical, coastal regions, where winter temperature conditions are far less severe. We studied the thermal biology and activity patterns of free-ranging kaluta (approximately 27 g), a dasyurid restricted to these tropical spinifex deserts, during the Austral winter (June-July) and in addition quantified activity patterns in captivity. Unlike most dasyurids, wild and captive kalutas were almost exclusively diurnal and retreated into underground burrows during the night. Despite being active during the warmer part of the day, kalutas entered torpor daily. However, torpor patterns differed remarkably between males and females. While females spent most of the night torpid at body temperatures (T (b)) as low as 21 degrees C, close to soil temperature, males entered multiple short and shallow bouts (T (b) > 25 degrees C) during the night. Males also maintained higher T (b)s during the early morning when active, occupied larger home ranges and covered greater distances while foraging than females. Hence, males appear to expend more energy than the similar-sized females both while foraging and during the rest phase. We propose that physiological as well as behavioural preparations for the September mating season that culminate in a complete male die-off might already impose energetic costs on males during winter.
许多小型沙漠袋鼩科动物在冬季几乎每天都会进入休眠状态，因为寒冷的夜晚和食物供应不足会带来很高的能量成本。然而，在澳大利亚西部，干旱地区延伸到了热带沿海地区，那里的冬季温度条件要温和得多。我们研究了自由活动的 kaluta（约 27 克）的热生物学和活动模式，kaluta 是一种仅限于这些热带针茅草沙漠的袋鼩科动物，研究时间是澳大利亚的冬季（6 月至 7 月），此外还在圈养条件下量化了它们的活动模式。与大多数袋鼩科动物不同，野生和圈养的 kalutas 几乎都是昼行性的，晚上会退回到地下洞穴中。尽管在白天的温暖时段活动，但 kalutas 每天都会进入休眠状态。然而，雄性和雌性的休眠模式差异非常显著。虽然雌性在夜间大部分时间都处于休眠状态，体温（T(b)）低至 21 摄氏度，接近土壤温度，但雄性在夜间会多次进入短暂而浅的休眠状态（T(b)>25 摄氏度）。雄性在清晨活跃时也保持着更高的 T(b)，活动时占据的家园范围更大，觅食时覆盖的距离也更大。因此，雄性在觅食和休息阶段消耗的能量似乎比类似大小的雌性多。我们提出，为 9 月的交配季节做生理和行为上的准备，最终导致雄性完全死亡，这可能已经在冬季对雄性造成了能量成本。
