Abstract # 2561 Poster # 42:

Scheduled for Saturday, September 19, 2009 06:30 PM-09:00 PM: Session 5 (Mission Bay Ballroom CDE) Poster Presentation


MANTLED HOWLER MONKEY (ALOUATTA PALLIATA) MATURE LEAF CHOICE IN RELATION TO CONDENSED TANNIN CONTENT AT SANTA ROSA, COSTA RICA

B. J. Welker
SUNY Geneseo, Anthropology, 1 College Circle, Geneseo, NY 14454, USA
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The importance of the protein-to-fiber ratio (PFR) in primate leaf choice has been amply demonstrated. Using a sample of twelve food species (seven used for both young (YL) and mature leaves (ML) and five for YL only), I have previously shown [Welker, 2008] that a group of free-ranging mantled howler monkeys fed only on ML from those species for which the PFR was above 0.32. Condensed tannins (CT) are also known to play a role in howler monkey leaf choice. This next phase of the study examines the CT content of ML from the aforementioned food species. ML specimens were collected in January 2007 at the study site of Sector Santa Rosa, Costa Rica. Leaves were ground and mixed with a combination acid butanol and iron reagent and absorbance (indicative of CT content) was read using a spectrophotometer at 550nm. Absorbance values >3.0 did not register as absolute values. Results indicate that ML from species used for both YL and ML [mean=1.14±0.45, values=0.15, 0.17, 0.21, 0.80, 1.09, 2.57, >3.0] had significantly lower values [t(10)=4.15, p=0.006] than those from species used for YL only [all means>3.0]. Other than the one species with a value >3.0, all species used for ML were <=2.57. Thus the monkeys’ leaf choice is complex and involves a balancing act between avoiding multiple digestion-inhibiting compounds while obtaining enough protein.