Influence of Plant and Soil Chemistry on Food Selection, Ranging Patterns, and Biomass of Colobus guereza in Kakamega Forest, Kenya

Abstract

Nutritional factors are among the most important influences on primate food choice. We examined the influence of macronutrients, minerals, and secondary compounds on leaf choices by members of a foli-frugivorous population of eastern black-and-white colobus-or guerezas (Colobus guereza)-inhabiting the Kakamega Forest, Kenya. Macronutrients exerted a complex influence on guereza leaf choice at Kakamega. At a broad level, protein content was the primary factor determining whether or not guerezas consumed specific leaf items, with eaten leaves at or above a protein threshold of ca. 14% dry matter. However, a finer grade analysis considering the selection ratios of only items eaten revealed that fiber played a much greater role than protein in influencing the rates at which different items were eaten relative to their abundance in the forest. Most minerals did not appear to influence leaf choice, though guerezas did exhibit strong selectivity for leaves rich in zinc. Guerezas avoided most leaves high in secondary compounds, though their top food item (Prunus africana mature leaves) contained some of the highest condensed tannin concentrations of any leaves in their diet. Kakamega 674 Fashing, Dierenfeld, and Mowry guerezas periodically traveled great distances to exploit rare foods (bark from exotic Myrtaceae trees and soil) outside their normal home ranges. Our results suggest that these journeys were driven by the fact that these rare foods contained exceptionally high sodium concentrations, a mineral believed to be deficient in the guereza's usual diet. Lastly, our results are consistent with the pattern established across other Paleotropical rain forests in which colobine biomass can be predicted by the protein-to-fiber ratio in mature leaves. Of the 8 rain forests for which the relevant data are available, Kakamega features the second highest mature leaf protein-to-fiber ratio as well as the second highest colobine biomass.

Linking feeding ecology and population abundance: a review of food resource limitation on primates

“…For example, Waterman et al (1988) proposed that the weighted contributions of the protein-to-fiber ratios of the mature leaves of the most abundant trees in a particular area could predict the biomass of folivorous colobines. This index of dietary quality has been applied successfully to predict the biomass of folivorous monkeys at local Ganzhorn 2002) and regional (Waterman et al 1988;Oates et al 1990;Ganzhorn 1995;Chapman et al 2004;Fashing et al 2007) scales. Davies (1994) suggested that the year-round availability of digestible mature leaves with high protein-to-fiber ratios, which are used by colobus species when other, more preferred foods are unavailable, serves to limit the size of colobine populations (i.e., high protein-to-fiber mature leaves are important fallback foods).…”

Additional Information Concerning ‘Erratum to: Western Purple-Faced Langurs (Semnopithecus vetulus nestor) Feed on Ripe and Ripening Fruit in Human-Modified Environments in Sri Lanka’

“…These citations follow other second papers in the IJP sharing a dataset with previous papers (e.g. Davies et al 1999;Li and Rogers 2006;Fashing et al 2007). During the review, I revised the paragraph (content) linking the 2 papers as suggested by Dr. Setchell, and we both referred to the 2007 paper.…”

Condensed Tannin Intake in Spiny-Forest-Dwelling Lemur catta at Berenty Reserve, Madagascar, during Reproductive Periods

“…Marked interspecific variability is found between primates with respect to choice or avoidance of plant foods high in tannins and phenolics [Milton, 1979;Oates et al, 1980;Wrangham and Waterman, 1981;Glander, 1982;Oates, 1988; Gould /Constabel /Mellway /Rambeloarivony 1996;Bocian, 1997;Remis et al, 2001;Chapman and Chapman, 2002;Fashing et al, 2007]; however, most primate species include at least some plant foods in their diet and therefore regularly ingest tannins and phenolics to a certain degree.…”

“…Plants containing tannins are astringent and unpalatable, an adaptation to deter consumption by herbivores [Janzen, 1974;McKey et al, 1978;Chapman and Chapman, 2002]. Some primate species or populations actively avoid potential food items containing moderate to high amounts of tannins, for example red colobus and black-and-white colobus at Kibale, Uganda [Oates, et al, 1977;Chapman and Chapman, 2002], and at Kakamega Forest, Kenya [Fashing et al, 2007], lesser bamboo lemurs and brown mouse lemurs [Ganzhorn, 1989] and vervets [Wrangham and Waterman, 1981], while others do not, e.g. howler monkeys [Milton, 1979;Milton et al, 1980], Verreaux's sifaka [Carrai et al, 2003;Yamashita, 2008], diademed sifaka and indri Mowry, 2003, 2006], greater dwarf lemurs and brown lemurs [Ganzhorn, 1989] and lowland gorillas [Remis and Kerr, 2002].…”