Mechanical defenses in leaves eaten by Costa Rican howling monkeys (Alouatta palliata)

Mark F. Teaford, P. W. Lucas, P. S. Ungar, K. E. Glander

Research output: Contribution to journalArticle

Abstract

Primate species often eat foods of different physical properties. This may have implications for tooth structure and wear in those species. The purpose of this study was to examine the mechanical defenses of leaves eaten by Alouatta palliata from different social groups at Hacienda La Pacifica in Costa Rica. Leaves were sampled from the home-ranges of groups living in different microhabitats. Specimens were collected during the wet and dry seasons from the same tree, same plant part, and same degree of development as those eaten by the monkeys. The toughness of over 300 leaves was estimated using a scissors test on a Darvell mechanical tester. Toughness values were compared between social groups, seasons, and locations on the leaves using ANOVA. Representative samples of leaves were also sun-dried for subsequent scanning electron microscopy and energy dispersive x-ray (EDX) analyses in an attempt to locate silica on the leaves. Both forms of mechanical defense (toughness and silica) were found to be at work in the plants at La Pacifica. Fracture toughness varied significantly by location within single leaves, indicating that measures of fracture toughness must be standardized by location on food items. Monkeys made some food choices based on fracture toughness by avoiding the toughest parts of leaves and consuming the least tough portions. Intergroup and seasonal differences in the toughness of foods suggest that subtle differences in resource availability can have a significant impact on diet and feeding in Alouatta palliata. Intergroup differences in the incidence of silica on leaves raise the possibility of matching differences in the rates and patterns of tooth wear.

Original languageEnglish (US)
Pages (from-to)99-104
Number of pages6
JournalAmerican Journal of Physical Anthropology
Volume129
Issue number1
DOIs
StatePublished - Jan 2006

Fingerprint

Alouatta
Haplorhini
monkeys
Tooth Wear
Silicon Dioxide
food
Food
leaves
Homing Behavior
Costa Rica
silica
Solar System
Electron Scanning Microscopy
Primates
Analysis of Variance
incidence
X-Rays
Diet
energy
Alouatta palliata

Keywords

  • Alouatta
  • Diet
  • Fracture toughness
  • Silica

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Anthropology

Cite this

Mechanical defenses in leaves eaten by Costa Rican howling monkeys (Alouatta palliata). / Teaford, Mark F.; Lucas, P. W.; Ungar, P. S.; Glander, K. E.

In: American Journal of Physical Anthropology, Vol. 129, No. 1, 01.2006, p. 99-104.

Research output: Contribution to journalArticle

Teaford, Mark F. ; Lucas, P. W. ; Ungar, P. S. ; Glander, K. E. / Mechanical defenses in leaves eaten by Costa Rican howling monkeys (Alouatta palliata). In: American Journal of Physical Anthropology. 2006 ; Vol. 129, No. 1. pp. 99-104.
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