The importance of protein in leaf selection of folivorous primates

Abstract

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 To test the prediction, we applied meta-analyses to analyze published and unpublished results of food selection for protein and fiber concentrations from 24 studies (some with multiple species) of folivorous primates.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.

The complexity of interacting nutritional drivers behind food selection, a review of northern cervids

“…, Ganzhorn et al. ). For example, if studies are limited to measures of crude or total energy, it is possible to overlook the different roles that the different energy‐providing constituents may have, as well as potentially conflicting interactions with other nutritional constituents.…”

Terrestriality and bacterial transfer: a comparative study of gut microbiomes in sympatric Malagasy mammals

“…The two artiodactyl species-cattle (herbivorous foregut fermenters) and bush pigs (omnivores with simple gut morphology)-harbored the most diverse microbiota (Kruskal-Wallis, FDR-adjusted P < 0.001; Fig. S3), whereas the three lemur species, two of which are hindgut fermenters [61,62], exhibited moderate microbial diversity (Fig. S3).…”

Cafeteria‐style feeding trials provide new insights into the diet and nutritional strategies of the black snub‐nosed monkey (Rhinopithecus strykeri): Implications for conservation

“…Similarly, we also found that ADF and ADL of food items consumed by captive R. strykeri did not differ significantly from nonconsumed food items. Taken together, these data suggest that the protein concentration of foliage rather than the fiber concentration may be a nutritional priority for R. strykeri , and that protein and fiber selection for many primate species may represent two separate goals or processes (Ganzhorn et al, 2017).…”