树麻雀代谢率和器官重量在季节驯化中表型的可塑性变化

动物能量代谢的生理生态特征与物种的分布和丰富度密切相关,基础代谢率(BMR)是内温动物能量预算的重要组成部分。北温带的小型鸟类,通过增加产热来适应低温环境。增加BMR的基础之一是中心器官(代谢机器)发生明显的变化。本研究中我们测定了树麻雀(Passermontanus)的BMR、体重和各器官的重量,分析了麻雀各器官的季节性变化及与BMR的关系。方差分析表明:麻雀的BMR存在明显的季节性变化,在冬季和秋季较高。麻雀内部器官的变化同样有明显的季节性,冬季和秋季麻雀的肝脏、心脏、肌胃、小肠、直肠和整体消化道的重量,都有明显的增加。相关分析表明:麻雀的BMR与肝脏、心脏和消化道等内部器官存在明显的相关性。我们的结果验证了“中心限制假说”,即麻雀体内存在着与BMR相关的“代谢机器”,中心器官是提高麻雀BMR的基础之一。

Phenotypic flexibility of metabolic rate and organ masses among tree sparrows Passer montanus in seasonal acclimatization

Acclimatization to winter conditions is an essential prerequisite for survival of small passerines of the northern temperate zone. In this study, we measured seasonal changes in basal metabolic rate (BMR) and organ mass, and evaluated the relationship between BMR, organ mass in tree sparrows Passer montanus. The results were used to test the 'energy demand' hypothesis for adjustments in metabolic rate. The energy demand hypothesis posits that birds adjust the size of their internal organs relative to food intake, a correlate of energy demand. Winter and autumn sparrows demonstrated significantly higher BMR than their spring and summer counterparts. Winter and autumn birds also had higher liver, heart, gizzard, small intestine, rectum and total digestive tract than spring and summer birds. These data support the view that prominent winter increases in BMR are components of winter acclimatization in tree sparrows and that seasonal changes in metabolism in sparrows are similar to those for other small temperate-wintering birds. Meanwhile, these data test the hypothesis that central organs have a significant positive relationship with BMR. The relationship between BMR and internal organs could be due to either (or both) increased energy demand or seasonal shifts in dietActa Zoologica Sinica 52(3):469-477,2006].