Variations in diet composition of sympatric Trachypithecus francoisi and Macaca assamensis in the limestone habitats of Nonggang, China

Comparative studies of sympatric species are essential for understanding behavioral and ecological adaptation as well as the mechanisms that can reduce resource competition to allow coexistence. Francois＇ langurs （Trachypithecus francoisi） and Assamese macaques （Macaca assamensis） are sympatric primate species found in the limestone seasonal rainforests of Nonggang Nature Reserve, southwestern Guangxi, China. To explore their different adaptation strategies, we collected data on diet using scan sampling at 15-min intervals. Our results revealed that Francois＇ langurs showed a more flexible diet composition than Assamese macaques Francois＇ langurs increased dietary diversity and mature leaf consumption in response to seasonal scarcity of preferred young leaves and fruits, whereas Assamese macaques relied heavily on young bamboo leaves （Indocalamus calcicolus） in most months These variations reflect the differences in digestive physiology, morphology, and the temporal and spatial distribution of food resources.

Habitat use and locomotion of the François’langur(Trachypithecus francoisi)in limestone habitats of Nonggang,China

We collected data on habitat use and locomotion of the François’langur(Trachypithecus francoisi)between August 2003 and July 2004 at Nonggang Nature Reserve,China.A total of 739 h of behavioral data were collected during this study.We tested 2 predictions:(1)that the langurs may have special patterns of habitat use and locomotion adaptive to the limestone habitat,and(2)the langurs may exhibit different patterns of habitat use and locomotion among different zones of limestone hill.Our results indicated that François’langurs spent more time in the low-risk,relatively food-poor cliff-hilltop areas.When young leaves and fruit were scarce in the dry season,the langurs increased their time in the high-risk,food-rich valley basin.François’langurs were semi-terrestrial,and leaping and climbing were their main locomotor modes.These behavioral patterns are considered to be related to characteristics of topography and vegetation in limestone habitat,such as large areas of cliff and discontinuous canopy.Our results also supported Prediction 2.The langurs confined locomotion to the main canopy and frequently adopted leaping while traveling in the hillside and valley basin.While traveling in cliff-hilltop areas,they tended to stay in the lower stratus(≤5 m)or move on the ground,and walking and climbing were their dominant traveling modes.

Ranging behavior of the François’langur(Trachypithecus francoisi)in limestone habitats of Nonggang,China

Ranging behavior is an important aspect of animal behavior that researchers use to investigate ecological influences on individual behavior.We collected data on the ranging behavior of one group of François’langurs(Trachypithecus francoisi)between August 2003 and July 2004 in a limestone habitat within Nonggang Nature Reserve,China.We evaluated the influences of food availability,water resources and sleeping sites on ranging behavior.During the study period,the total home range size for the study group was 64.5 or(69.3 ha if the lacunae within the borders in which langurs were not observed were included),and the mean daily path length was 541 m.These are well within the range of variation reported in Trachypithecus species.The monthly range size was between 9.8 and 23.3 ha,and monthly range size correlated negatively with young leaf availability.The langurs tended to use a larger range size during young leaf-lean periods.The langurs did not use their home range uniformly,and 74%of their activities occurred within 35%of their home range.The most heavily used quadrats in the home range were located near the most frequently used sleeping sites,suggesting that sleeping sites have a significant influence on the ranging behavior of François’langurs in limestone habitats.

Diet of the Assamese macaque Macaca assamensis in lime- stone habitats of Nonggang, China

To enhance our understanding of dietary adaptations in macaques we studied the diet of the Assamese macaque Macaca assamensis in limestone seasonal rain forests at Nonggang Nature Reserve, China from September 2005 to August 2006. Our results show that although macaques fed on many plant species, 85.2% of the diet came from only 12 species, of which a bamboo species, Indocalamus calcicolus contributed to 62% of the diet. Young leaves were staple food items （74.1% of the diet） for Assamese macaques at Nonggang, and constituted the bulk of monthly diets almost year-round, ranging from 44.9% （July） to 92.9% （May）. Young parts of Indocalamus calcicolus unexpanded leaves contributed to a large proportion of the young leaf diet in most months. Fruit accounted for only 17.4% of the diet, with a peak of consumption in July. We suggest that this highly fo- livorous diet may be related to the long lean season of fruit availability in limestone habitats as well as the utilization of cliffs of low fruit availability

Sleeping site use of the white-headed langur Trachypithecus leucocephalus： The role of predation risk, territorial defense, and proximity to feeding sites

We collected data on sleeping site use from two groups of white-headed langurs Trachypithecus leucocephalus living in Fusui Nature Reserve, China between August 2007 and July 2008. This information was used to test several hypotheses regarding ultimate causes of sleeping site use in this primate. White-headed langurs slept either in caves （17 sites） or on a cliffledge （one site）. They used all sleeping sites repeatedly, and reused some of them on consecutive nights; three nights was the longest consecutive use of any one sleep site. We suggest that langurs use sleeping sites to make approach and attack by predators difficult, and to increase their own familiarity with a location so as to improve chances for escape. Langurs＇ cryptic behaviors with an increased level of vigilance before entering sleeping sites may also help in decreasing the possibility of detection by predators. Group 1 spent more sleeping nights in the central area of their territory than expected; in contrast, group 2 spent more sleeping nights in the periphery of their territory, which overlaps with that of another groups, than expected. The position of sleeping site relative to the last feeding site of the day and the first feeding site of the subsequent morning indicated a strategy closer to that of a multiple central place forager than of a central place forager. These results suggest that territory defense and food access may play an important role in sleeping site use of white-headed langurs [Current Zoology 57 （3）： 260-268, 2011].