Summary: Feeding Selectivity by Mantled Howler Monkeys
(Alouatta palliata) in Relation to Leaf Secondary Chemistry
in Hymenaea courbaril
B. J. Welker & W. König & M. Pietsch & R. P. Adams
Received: 22 November 2006 /Revised: 9 March 2007 /Accepted: 20 March 2007 /
Published online: 14 April 2007
# Springer Science + Business Media, LLC 2007
Abstract This study is a quantitative examination of primate feeding selectivity in relation
to secondary chemistry within a single plant species, Hymenaea courbaril. It provides the
first evidence that sesquiterpenes may act as feeding deterrents in mantled howler monkeys.
A free-ranging group of mantled howler monkeys at the study site of Sector Santa Rosa,
Area de Conservacion Guanacaste, Costa Rica were observed for the 2-month period of H.
courbaril leaf flush in 1999. Tree characteristic data and leaf specimens were collected from
22 focal trees. Gas chromatography and mass spectrometry were used to estimate relative
percentages of sesquiterpenes in leaf specimens. The monkeys fed only on the youngest
leaves and only from particular trees. Whereas leaf stage selectivity was likely governed by
tannin content and structural carbohydrates in younger and older leaf stages, respectively,
differential tree use may be related to variability in sesquiterpene content. There is evidence
that -copaene may have played a role in interindividual tree use, and that cyperene may also
be implicated. However, there is no reported evidence of antiherbivore activity for cyperene.