The importance of protein in leaf selection of folivorous primates.
Protein limitation has been considered a key factor in hypotheses on the evolution of life history and animal communities, suggesting that animals should prioritize protein in their food choice. This contrasts with the limited support that food selection studies have provided for such a priority in nonhuman primates, particularly for folivores. Here, we suggest that this discrepancy can be resolved if folivores only need to select for high protein leaves when average protein concentration in the habitat is low. To test the prediction, we applied meta-analyses to analyze published and unpublished results of food selection for protein and fiber concentrations from 24 studies (some with multiple species) of folivorous primates. To counter potential methodological flaws, we differentiated between methods analyzing total nitrogen and soluble protein concentrations. We used a meta-analysis to test for the effect of protein on food selection by primates and found a significant effect of soluble protein concentrations, but a non-significant effect for total nitrogen. Furthermore, selection for soluble protein was reinforced in forests where protein was less available. Selection for low fiber content was significant but unrelated to the fiber concentrations in representative leaf samples of a given forest. There was no relationship (either negative or positive) between the concentration of protein and fiber in the food or in representative samples of leaves. Overall our study suggests that protein selection is influenced by the protein availability in the environment, explaining the sometimes contradictory results in previous studies on protein selection. Am. J. Primatol. 79:e22550, 2017. © 2016 Wiley Periodicals, Inc.
Animal Ecology and Conservation, University of Hamburg, Hamburg, Germany.
Joerg U
JU
Ganzhorn
Department of Biological and Environmental Science, California University of Pennsylvania, California, Pennsylvania.
Summer J
SJ
Arrigo-Nelson
Department of Biology, Zoology and Anthropology Unit, Pisa, Italy.
Valentina
V
Carrai
Central Department of Zoology, Tribhuvan University, Kirtipur, Nepal.
Mukesh K
MK
Chalise
Nocturnal Primate Research Group, Department of Social Sciences, Oxford Brookes University, Gipsy Lane, OX3 0BP, Oxford, UK.
Giuseppe
G
Donati
Behavioral Ecology and Sociobiology, German Primate Center, Göttingen, Germany.
Iris
I
Droescher
Animal Ecology and Conservation, University of Hamburg, Hamburg, Germany.
Timothy M
TM
Eppley
Department of Anthropology, Northern Illinois University, DeKalb, Illinois.
Mitchell T
MT
Irwin
Behavioral Ecology and Sociobiology, German Primate Center, Göttingen, Germany.
Flávia
F
Koch
Department of Anthropology, Stony Brook University, and Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, New York.
Andreas
A
Koenig
Estación Biológica Corrientes, Museo Argentino de Ciencias Naturales BR, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Corrientes, Argentina.
Martin M
MM
Kowalewski
Department of Biology, Berry College, Mt. Berry, Georgia.
Christopher B
CB
Mowry
Duke Lemur Center, Durham, North Carolina.
Erik R
ER
Patel
Département Hommes, Natures, Sociétés, CNRS/MNHN, UMR 7206, Brunoy, France.
Claire
C
Pichon
Department of Animal Biology, University of Antananarivo, Antananarivo, Madagascar.|Groupe d'Etude et de Recherche sur les Primates de Madagascar (GERP), Antananarivo, Madagascar.
Jose
J
Ralison
Applied Plant Ecology, University of Hamburg, Hamburg, Germany.
Christoph
C
Reisdorff
Département Hommes, Natures, Sociétés, CNRS/MNHN, UMR 7206, Brunoy, France.
Bruno
B
Simmen
Research School of Biology: Division of Evolution, Ecology and Genetics, The Australian National University, Canberra, ACT, Australia.
Eleanor
E
Stalenberg
Research School of Biology: Division of Evolution, Ecology and Genetics, The Australian National University, Canberra, ACT, Australia.
Danswell
D
Starrs
Animal Ecology and Conservation, University of Hamburg, Hamburg, Germany.
Juana
J
Terboven
Department of Anthropology, Stony Brook University, and Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, New York.
Patricia C
PC
Wright
Research School of Biology: Division of Evolution, Ecology and Genetics, The Australian National University, Canberra, ACT, Australia.
William J
WJ
Foley
D000818:Animals; D004043:Dietary Fiber; D005247:Feeding Behavior; D005518:Food Preferences; D018515:Plant Leaves; D011323:Primates
D004043:Dietary Fiber
food chemistry; food selection; leaf-eating; meta-analysis; protein availability