Abstract # 102:

Scheduled for Friday, August 19, 2005 10:45 AM-11:00 AM: Session 7 (Parliament Room) Oral Presentation

Inter-matrilineal Feeding Competition in Taiwanese Macaques (Macaca cyclopis) at Fushan, Taiwan

H. Su1, L. Lee1 and S. Cachel2
1Institute of Ecology and Evolutionary Biology, National Taiwan University, Institute of Ecology and Evolutionary Biology, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, 106, Taiwan, 2Department of Anthropology, Rutgers University, New Brunswick, New Jersey
     Feeding behavior of a Taiwanese macaque group on the fruit of Machilus pseudolongifolia was investigated at Fushan Experimental Forest to examine whether inter-matriline feeding competition existed. This study was conducted from June 12 through July 8 of 2000, during which the fruiting phase of M. pseudolongifolia peaked. The tree crown of M. pseudolongifolia could be divided into two feeding zones of differential feeding efficiency. The upper zone of the tree crown had higher fruit density and was considered a better feeding site than the lower zone. Data on feeding activities and agonistic interactions were collected by scan sampling and all-occurrence observation, respectively, when the macaques fed in the tree crown of M. pseudolongifolia. Frequencies of agonistic interactions involving members in the same matriline were significantly lower than the expected frequency, whereas agonism between individuals of different matrilines occurred more frequently than expected (Goodness of fit test, χ2 = 4.57, df = 1, P = 0.03). The adult male and members of high-ranking matrilines spent higher percentages of feeding time in the upper zone of the tree crown than did those of low-ranking matrilines (Mann-Whitney test, nh = 9, nl = 9, z = -2.25, P = 0.024). The monkeys fed in the upper zone of the tree crown significantly more frequently when their kin were present (Fisher’s exact test, P = 0.01). Results indicated that inter-matrilineal feeding competition existed in these Taiwanese macaques. Individual monkeys benefited from being associated with direct kin when feeding.