Abstract: Comparing the foraging behavior of sibling species can reveal similarity in behavioral plasticity and adaptability.White-headed langur(Trachypithecus leucocephalus) and François'langurs(T.francoisi) are sibling species sharing similar body size, social structure and habitat environment.They are neighboring primates distributed in the karst seasonal rain forest of the white-headed Langur National Nature Reserve in Chongzuo, Guangxi.In order to explore whether the two langurs have similar foraging strategies in response to karst habitat, we studied their foraging behavior from January to December 2012 using instantaneous scanning sampling.The results revealed that the feeding habits of the white-headed langur and the François'langur did not vary across day time.Leaves were the main food items for these two species, which accounted for 77.0%±4.4% of annual diet for the white-headed langurs and 68.9%±8.3% of annual diet for the François'langurs.There was no significant change in the eating time of leaves for both langurs(white-headed langur:χ²=6.602, df=11, P=0.830;François'langurs:χ²=11.393, df=11, P=0.411).Foraging behaviors of both species occurred frequently after leaving the sleeping cave in the early morning and before entering the sleeping cave in the later afternoon.Specifically, at 09:00-10:59 and 16:00-17:59, white-headed langur spent 41.7% and 46.3% of day time on feeding, whereas François'langurs devoted 31.3% and 38.0% of day time to feeding at 09:00-10:59 and 16:00-17:59, respectively.In addition, there was no significant difference in foraging time between the two langurs.Our result suggests that the white-headed langur and François'langurs share similar foraging strategy in the limestone forest, implying that the similar conservation efforts based on feeding ecology should be considered for both langurs.

Key words: Trachypithecus leucocephalus, T.francoisi, Dietary composition, Foraging, Behavioral similarity

摘要： 开展近缘物种觅食行为比较对理解动物的行为可塑性及适应性具有重要意义。白头叶猴（Trachypithecus leucocephalus）和黑叶猴（T.francoisi）是近缘物种，体形大小相近，社会结构和栖息环境相似，是广西崇左白头叶猴国家级自然保护区喀斯特季节性雨林中邻域分布的灵长类。为了探索两个物种在喀斯特生境中是否有相似的觅食策略，我们于2012年1-12月采用瞬时扫描取样法对两种叶猴的觅食行为进行研究。结果表明，白头叶猴与黑叶猴在不同时段均为叶食性，树叶是两种叶猴各个时段主要食物，其中白头叶猴日均取食树叶77.0%±4.4%，黑叶猴日均取食68.9%±8.3%，两者对树叶的采食比例均没有显著的日时段差异（白头叶猴：χ²=6.602，df=11，P=0.830；黑叶猴：χ²=11.393，df=11，P=0.411）。两种叶猴的觅食行为都在猴群清晨离开夜宿石洞后和进入过夜山洞前的时段中频繁发生。白头叶猴在09：00-10：59和16：00-17：59出现觅食高峰，时间占比分别为41.7%和46.3%；黑叶猴同样在09：00-10：59和16：00-17：59的时间段内发生高频率的觅食行为，时间占比分别为31.3%和38.0%。此外，两种叶猴的觅食时间在大部分时段中的差异并不明显。白头叶猴和黑叶猴在石灰岩生境中具有相似的觅食策略，这意味着两种叶猴在取食生态学上可能采取相似的保护措施。

关键词: 白头叶猴, 黑叶猴, 食物组成, 觅食行为, 行为相似性