Feeding adaptation ofFrançois’ langurs (Trachypithecus francoisi) to thefragmented limestone habitats in Southwest ChinaWei Yaoa,1, Cheng-Ming Huanga,b,1, Jia-Xin Zhaob, Rong Huangb, Wen-Hua Lib,Peng-Lai Fan a,*, Qi-Hai Zhou a,*aKey Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Key Laboratory of Rare and Endangered Animal Ecology, Guangxi Normal University, Guilin, Chinab Institute of Zoology, Chinese Academy of Sciences, Beijing, China.c Encheng National Nature Reserve, Chongzuo, China∗Corresponding authorRunning Title: Feeding adaptation of François’ langurs to the fragmented limestone habitatsCorresponding author:Prof. Qi-Hai Zhou, Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, 1# Yanshan Zhong Road, Guiling, Guangxi 541006, China. E-mail:[email protected] Prof. Pen-Lai Fan, Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, 1# Yanshan Zhong Road, Guiling, Guangxi 541006, China. E-mail:[email protected] Yao and Cheng-Ming Huang are co-first authorsAbstract: Limestone forests are an unusual habitat for primates, especially fragmented limestone habitats. However, limited research has been conducted on François’ langurs (Trachypithecus francois ) in these habitats, and there is a need to understand their behavioral adaptations to the fragmented limestone habitat. We collected data on the diet of François’ langurs in a fragmented limestone habitat in Encheng National Nature Reserve, southwestern Guangxi, China, and their feeding adaptations to the fragmented forest were examined. The results indicated that a total of 101 species of plants were consumed by the langurs. The langurs ate a higher number of food species throughout the year when compared with other species, maintained a high level of food diversity, and ate more vines. Moreover, they were highly selective in their use of vegetation in their home range, and fewer plants provided a high-quality food source. During the season when food resources were scarce, similar to monkey populations in other geographic populations, the consumption of fruits and young leaves decreased as their availability decreased. This led to the use of other species, such as mature leaves and seeds. Overall, François’ langurs in Encheng National Nature Reserve are generally considered to employ energy minimization strategies. The findings support that François’ langurs adjust their feeding behavior to cope with seasonal and micro-variations in their dietary requirements and to adapt to their particular environment.Key words: François’ langurs, Feeding adaptation, Limestone habitat, Fragmentation

The interaction between plants and frugivores plays a critical role in sustaining ecosystem function and community diversity, but little is known about the structure of interaction networks between fruit plants and frugivore birds in urban green spaces. We observed the interactions between plants and birds throughout the year in the Guilin Botanical Garden and assessed the characteristics of the total plant-frugivore and seasonal networks. We also analyzed the relationship between the network roles of species and ecological traits to explore the structure and characteristics of the plant-frugivore network. The interactions between a total of 14 frugivore birds and 13 fruit plant species were analyzed in the study area, the autumn and winter interaction connections contributed 38.79% and 33.15% to the total network, respectively. The specialization (H2´), and interaction evenness (E2) of the network were higher in spring and summer than that in autumn and winter. However, connectance (C), nestedness, and interaction diversity (H2) were contrary to the specialization and interaction evenness of the network. Compared to the networks (N=1000) generated by the null model, the observed network exhibited lower connectance (C), interaction diversity(H2), interaction evenness (E2), and higher nestedness and specialization (H2´). A correlation analysis combining ecological traits and network roles showed that plants with black fruit had higher species strength, whereas the other traits of plants and birds were not significantly correlated with their network parameters.