温度与光周期是环境季节性变化的最直接表现因子及时间变化指示标志,对动物的形态、生理及行为产生重要的影响.本文以白头鹎为研究对象,探讨了不同温度与光周期对其体质量、能量收支和消化道形态的影响,分析了能量收支与消化道形态特征的关系.将28只白头鹎(12雄16雌)分为4组:暖温长光组(30℃,16 L8 D;3雄4雌)、暖温短光组(30℃,8L16 D;3雄4雌)、低温长光组(10℃,16 L8 D;3雄4雌)和低温短光组(10℃,8 L16D;3雄4雌).结果表明:低温与短光照可促进白头鹎的体质量、摄入能及同化能明显增加,同时温度与光周期的交互作用对白头鹎的摄入能及同化能影响显著.低温条件下,胃、小肠、直肠及总消化道的湿质量及干质量明显增加.残差分析表明,小肠与总消化道的长度及干质量与摄入能和同化能显著相关.表明低温与短光照下白头鹎通过增加体质量、能量摄入和改变消化道形态来应对严酷的环境条件.
Temperature and photoperiod are proximate environmental factors that have an important influence on the morphological,physiological and behavioral adjustments animals performance during seasonal acclimatization. In this study,the effects of temperature and photoperiod on phenotypic flexibility in body mass,energy budget and digestive tract morphology in the Chinese bulbul( Pycnonotus sinensis) were examined,and the relationship between energy budget and digestive tract morphology was analyzed. Twelve male and sixteen female Chinese bulbuls were randomly assigned into 4 experimental groups so that each group was comprised of three males and four females. The groups were: 1) a warm and long photoperiod( 30 ℃,16 light: 8 dark) group,2) a warm and short photoperiod( 30 ℃,8 light: 16 dark) group,3) a cold and long photoperiod( 10 ℃,16light: 8 dark) group,and 4) a cold and short photoperiod( 10 ℃,8 light: 16 dark) group. Each group was acclimated to its respective temperature and photoperiod for 4 weeks. Birds in the cold temperature and short photoperiod group underwent a significant increase in body mass,gross energy intake( GEI) and digestible energy intake( DEI) compared to the other three groups,and there was a significant interaction between temperature and photoperiod on gross energy intake and digestible energy intake. The mass of the stomach,small intestine,rectum,and total digestive tract,all increased significantly in cold temperature treatment groups compared to those acclimated to a relatively warm temperature. There was a significant,positive correlation between GEI and DEI residuals and those of the length and dry mass of the small intestine and total digestive tract. These results suggested that the Chinese bulbul met the increased energy demands of winter( colder tempe-ratures and reduced foraging time due to shorter day-length) by increasing its body mass,digestible energy intake and digestive tract size.