Abstract # 141:

Scheduled for Sunday, September 20, 2009 06:30 PM-09:00 PM: Session 14 (Mission Bay Ballroom CDE) Poster Presentation


FEEDING SITES AND AGONISM: PATTERNS AMONG ASSOCIATING CALLIMICO GOELDII, SAGUINUS LABIATUS, AND S. FUSCICOLLIS IN ACRE, BRAZIL

J. A. Rehg
Southern Illinois University Edwardsville, Department of Anthropology, Edwardsville, IL 62026, USA
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Possible costs of group-living include reduced access to resources through scramble and contest competition, and resource characteristics themselves can influence accessibility and competitive interactions. I investigated evidence of competition among associating C. goeldii (callimico), S. labiatus (saddle-backed tamarin), and S. fuscicollis (red-bellied tamarin) in Amazonian Brazil, based on use of feeding sites of varying accessibility (“patch” size) and agonism. Observations focused on a polyspecific group during periods in 1999-2000, 2002, and 2003 [~420 hrs]. Data included all occurrences feeding records and ad libitum notes on agonism. Feeding sites were categorized into 3 classes (small, medium, large) by CBH (circumference at breast height), and frequency of use of classes was calculated. Mean site CBH was 95 cm [n=72, range 11-485 cm]. Of 178 sites, 50% were visited by 2 or more species; 20% by 3 species. More than 1 species used a site during the same visit on 28% of visits [n=268]. Sites used by 3 species were primarily large [50%] and least often small [13%]. Number of species visiting sites was not independent of patch size [n=144, Χ2=12.14; p=0.005]. Food-related agonism occurred once/13 hrs [n=14], and nearly all involved S. labiatus displacing heterospecifics. Low agonism rates suggest contest competition is not a major component of these associations. Feeding site use suggests scramble competition may be more important, and supports niche differentiation as limiting dietary overlap.