中文摘要：

日食性变化和活动节律是动物行为的重要方面，通过对日食性变化与活动节律的研究，可以了解食物、温度和光照时间等环境因素的变化对动物行为的影响，以及动物在行为上的应对策略。2009年1—12月，在广西靖西县邦亮东部黑冠长臂猿自治区级自然保护区内，采用瞬时扫描取样法对2群东黑冠长臂猿觅食行为和活动节律进行了研究。结果显示，东黑冠长臂猿的活动和食性在旱季和雨季都具有明显的节律。鸣叫只发生在12：00之前，但旱季的鸣叫时间偏晚。在日节律上，东黑冠长臂猿在离开过夜树后和进入过夜树前各有一个取食高峰，07：00喜欢取食果实和无花果，16：00也选择更多的果实，但无花果较少，13：00—15：00取食更多的叶和芽。在10：00—12：00，其用于休息和社会活动的时间增加。在雨季，东黑冠长臂猿以果实和无花果为主要食物，并且花大量时间觅食无脊椎动物；但在旱季，其食物以叶和芽为主。与之相适应，东黑冠长臂猿在旱季通过减少移动增加休息来节约能量开支和应对低温，同时它们增加取食的时间以获得等价的能量和营养。雨季时社会行为的比例明显高于旱季，而且其高峰出现在08：00—10：00，但旱季社会行为主要出现在11：00—14：00。在雨季东黑冠长臂猿没有出现休息高峰，相反在旱季10：00左右出现一个明显的休息高峰。上述行为节律体现了东黑冠长臂猿对环境季节性变化的良好适应，使其能够在寒冷并且退化的喀斯特森林中生存繁衍。

英文摘要：

Diet and activity rhythms are important aspects of animal behavior. Studying these topics provides valuable insights into how variations of food, temperature and illumination time impact animal behavior and behavioral adaptations. To better understand how these variables affect the endangered eao vit gibbon, we collected behavioral and dietary data using instantaneous scan sampling at 5 - min intervals on two groups in Bangliang Nature Reserve in Guangxi, China from January 2009 to December 2009. Both activity and diet showed an obvious rhythm in rainy and dry seasons. Gibbons sang only before 12：00 in both rainy and dry seasons, but later in dry season. There were two feeding peaks each day, one in the early morning after leaving sleeping trees and the other in the afternoon before entering sleeping trees. Gibbons fed primarily on fruit and figs in the early morning （07： 00） , and ate more fruit but less figs in the late afternoon （16： 00）. They consumed more leaves and buds between 13 ： 00 and 15 ： 00. Gibbons spent more time resting and exhibiting social behaviors between 10 ： 00 and 12 ： 00. Seasonality in diet corresponded with availability of preferred foods. In the warm rainy season when fruit and figs were most abundant, gibbons＇ diet consisted mainly of fruit and figs, as well as more invertebrates. In the cold dry season, their diet mainly comprised leaves and buds. In response to variations of temperature and lower fruit abundance in the dry season, the gibbons spent more time feeding, and decreased their time spent traveling, but increased their resting time, presumably as a mechanism to conserve energy and cope with lower temperatures. In the rainy season, gibbons spent more time exhibiting social behavior, which peaked between 08 ： 00 and 10 ： 00, whereas in the dry season social behavior was predominantly observed between 11 ： 00 and 14 ： 00. There was no obvious resting behavior peak in the rainy season, whereas resting behavior clearly peaked at 10：00 in dry seas