Journal
AMERICAN JOURNAL OF PRIMATOLOGY
Volume 77, Issue 5, Pages 479-491Publisher
WILEY
DOI: 10.1002/ajp.22361
Keywords
group size; food competition; ecological constraints model; Indo-Chinese gray langur; Wuliangshan
Categories
Funding
- State Key Laboratory of Genetic Resources and Evolution
- Kunming Institute of Zoology
- Chinese Academy of Sciences [GREKF12-06]
- National Natural Science Foundation of China [31372216]
- Programe of The Ministry of Education for New Century Excellent Talents [NCET-13-0700]
- Major Research Projects of The Ministry of Education Department in Yunnan
- Wuliangshan National Nature Reserve
Ask authors/readers for more resources
Identifying ecological factors underlying primate group size has been a central theme in primate behavioral ecology. The ecological constraints model proposes that increased group size leads to enhanced within-group feeding competition, necessitating increased travel to encounter additional or more productive feeding sites. Over the course of three years, we studied the largest known group (>80 individuals) of Trachypithecus crepusculus (Indo-Chinese gray langur) for 1738 hours during 213 days (including 96 full day follows) in Wuliangshan, China. During this period, group size increased from 81 individuals to over 90 individuals. The group consumed plant parts from 27 +/- 8 (range: 15-51) species per month, and a total 148 plant species during the study. Based on time spent feeding, the diet was similar (54.2% leaves and 32.1% fruit and seeds) to that reported for other colobines. Despite occupying a home range several times larger than other groups of Trachypithecus, we found no evidence of an increase in daily path length with increasing group size, and the group's time budget and daily path length remained relatively constant despite marked monthly changes in dietary pattern (e.g. time spent exploiting fruit and seeds vs. buds and young leaves, vs. mature leaves). These results are inconsistent with many of the predictions of the ecological constraints model. Rather, our data suggest that high dietary diversity and the ability to exploit difficult to digest foods enabled Indo-Chinese gray langurs to reduce opportunities for feeding competition associated with increased group size. Am. J. Primatol. 77:479-491, 2015. (c) 2014 Wiley Periodicals, Inc.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available