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Hanya G, Kiyono M, Takafumi H, Tsujino R & Agetsuma N (2007) Mature leaf selection of Japanese macaques: effects of availability and chemical content. Journal of Zoology 273: 140-147.

Abstract
Mature leaf food selection of Japanese macaques was studied in two different altitudinal zones of Yakushima: in the coniferous (1000-1200 m) and coastal forests (0-200 m). Logistic regression analysis was conducted to reveal the effect of chemical (neutral detergent fiber (NDF), crude protein, crude ash, crude lipid, condensed tannin, hydrolysable tannin and crude protein/NDF ratio) and availability properties (density of trees and total basal area) on the macaques’ choice between the major food leaves and the rarely eaten or non-food leaves. In both forests, macaques selected leaves with high crude ash and crude protein content, or high crude protein/NDF ratio, as major foods. In the coniferous forest, macaques selected leaves with less condensed tannin, but the tendency was absent in the coastal forest. This was because macaques in the coniferous forest suffer from a larger risk of ingesting large amounts of condensed tannins, since their feeding time on mature leaves were seven times as long as that in the coastal forest. Among the chemical and availability properties, stepwise multiple regression analysis revealed that the number of trees (/ha) was the only significant factor explaining the variations in feeding time among major food leaves, both in the coniferous and coastal forests. The present results suggest that the effect of traveling cost, which can be saved by selecting common trees, exceeds the benefits gained by selecting high-quality foods.

Keywords: folivory; leaf chemistry; mature leaf; optimal foraging strategy; Yakushima

<Written by: Goro Hanya (hanya<atmark>pri.kyoto-u.ac.jp)>
<Contact: Goro Hanya (hanya<atmark>pri.kyoto-u.ac.jp)>
<Last update: September 25, 2007>