Forest seasonality shapes diet of limestone-living rhesus macaques at Nonggang, China.

Limestone forests are an unusual habitat for primates, but little information is available for the genus Macaca in such habitats, making a comparative understanding of extant limestone primates' behavioral adaptation incomplete. We collected data on the diet of rhesus macaques (Macaca mulatta) in a limestone habitat at Nonggang Nature Reserve, southwestern Guangxi, China, and examined the effects of forest seasonality on their diet. Our results indicated that a total of 114 species of plants are consumed by macaques. Young leaves are a preferred food, accounting for 48.9 and 56.9% of the overall diets. One group significantly increased young leaf consumption in response to availability. Fruits contributed to only 27.3 and 28.7% of overall diet. The macaque diet varied according to season. They fed on more fruits in the rainy season. Consumption of mature leaves increased when the availability of young leaves and fruits declined in the dry season, indicating that mature leaves are a fallback food for macaques in a limestone habitat. Similar to sympatric Assamese macaques, Bonia saxatilis, a shrubby, karst-endemic bamboo was consumed by rhesus macaques throughout the year, and was the top food species through most of the year, suggesting that bamboo consumption represents a key factor in the macaque's dietary adaptation to limestone habitat.