Lu Shiyi, Lin Nanxin, Huang Anshu, Tong Dewen, Liang Yongyan, Li Youbang, Lu Changhu
College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China.
Guangxi Forest Resources and Environment Monitoring Center, Nanning 530028, China.
Animals (Basel). 2024 Feb 8;14(4):565. doi: 10.3390/ani14040565.
The feeding posture of a group of François' langurs in Fusui County, Guangxi, was studied using instantaneous scan sampling from January to December 2016 to explore how the species adapts to karst limestone forests by collecting data on feeding posture, forest strata height, and substrate use. The results showed that leaves were the main food type of the François' langurs, with young leaves accounting for 64.97% ± 19.08% of the food composition, mature leaves accounting for 11.88% ± 12.09%, fruits accounting for 12.96% ± 12.89%, flowers accounting for 4.16% ± 4.06%, and other food types, including stems, petioles, and other unknown parts of the tree, accounting for a total of 6.03% ± 9.09%. The François' langurs had four main postures during feeding, of which sitting and bipedal standing feeding accounted for the largest proportions, at 85.99% ± 5.97% and 12.33% ± 6.08% of the total records, respectively. Quadrupedal standing and suspending were rarely observed and only appeared occasionally during feeding activities at the peak resting period, the two postures together accounting for 1.39% ± 1.59% of the total records. The feeding postures of the langurs had marked seasonal variation, as evidenced by the fact that seated feeding accounted for a significantly higher proportion of the total behavioral records in the rainy season than in the dry season, whereas feeding while standing bipedally was significantly more frequent during the dry season. Correlation analyses showed that feeding posture was correlated with food composition, showing a positive correlation between the proportion of bipedal standing feeding and mature leaf consumption. François' langurs preferred to forage in the lower and middle forest layers, with the lower forest layer accounting for 55.93% ± 16.50% of the total number of recordings and the middle forest layer accounting for 33.63% ± 18.33%. Langurs were less likely to forage on the ground (rocks), accounting for only 6.79% ± 4.78% of the records. The frequency of langurs feeding in the upper part of the forest layer was the lowest at 3.65% ± 2.73%. Additionally, in the dry season, langurs utilized the lower forest layer more but used the middle forest layer less than in the rainy season. This study demonstrates that the spatial distribution of foods in the limestone forest has an important effect on the feeding posture of François' langurs and their forest layer utilization.
2016年1月至12月，采用瞬时扫描取样法对广西扶绥县一群黑叶猴的取食姿势进行了研究，通过收集取食姿势、森林层次高度和基质利用等数据，探讨该物种如何适应喀斯特石灰岩森林。结果表明，树叶是黑叶猴的主要食物类型，其中嫩叶占食物组成的64.97%±19.08%，成熟叶占11.88%±12.09%，果实占12.96%±12.89%，花占4.16%±4.06%，其他食物类型（包括茎、叶柄和树的其他未知部分）总共占6.03%±9.09%。黑叶猴在取食时有四种主要姿势，其中坐着取食和双脚站立取食所占比例最大，分别占总记录的85.99%±5.97%和12.33%±6.08%。四足站立和悬吊姿势很少观察到，仅在休息高峰期的取食活动中偶尔出现，这两种姿势合起来占总记录的1.39%±1.59%。黑叶猴的取食姿势有明显的季节性变化，表现为雨季坐着取食在总行为记录中所占比例显著高于旱季，而旱季双脚站立取食则明显更频繁。相关性分析表明，取食姿势与食物组成相关，双脚站立取食比例与成熟叶消耗量呈正相关。黑叶猴更喜欢在森林的中下层觅食，下层占总记录数的55.93%±16.50%，中层占33.63%±18.33%。黑叶猴在地面（岩石）上觅食的可能性较小，仅占记录的6.79%±4.78%。黑叶猴在森林上层觅食的频率最低，为3.65%±2.73%。此外，在旱季，黑叶猴更多地利用森林下层，但与雨季相比，对中层的利用较少。本研究表明，石灰岩森林中食物的空间分布对黑叶猴的取食姿势及其对森林层次的利用有重要影响。
