Publication Date

2019

Document Type

Dissertation/Thesis

First Advisor

Irwin, Mitchell T.

Degree Name

M.A. (Master of Arts)

Legacy Department

Department of Anthropology

Abstract

Plant secondary metabolites (PSMs) are compounds found in plant tissues designed to deter herbivores. Tannins, a type of PSM, can bind to proteins and reduce their availability to consumers. The detoxification limitation hypothesis suggests herbivores will prefer foods with lower amounts of PSMs and exhibit decreasing rates of feeding when PSM levels are high in order to stabilize the amount of PSMs ingested. Although this hypothesis has been supported by observations from other mammalian groups, it has not been tested in lemurs with regards to their consumption of tannins.

I observed diademed sifakas (Propithecus diadema) over a 2-month period (June-August 2018) in both continuous and fragmented forests at Tsinjoarivo, Madagascar. I examined tannin concentration of the lemurs’ top food items and determined how effective the tannins of the top foods were at binding to proteins. I compared fragmented and continuous forests to determine if tannin concentration and/or effectiveness differed between forest types. I compared four common food items that were positive for tannins to determine if there was intraspecific variation in tannin content across three microhabitats (continuous interior, fragmented edge, fragmented interior).

Diademed sifakas consume tannins in their food, with eleven of the fourteen top foods eaten by the lemurs positive for tannins (four were positive in fragmented forests and seven were positive in continuous forests). Of the eleven top foods positive for tannins, six were 100% effective in binding to proteins (e.g., there was no protein available to the lemur that consumed it), resulting in some top foods within their diet exhibiting little to no available protein. Food items collected from the fragmented and continuous forest sites were similar in their tannin concentrations and the effectiveness at binding to proteins. Microhabitats did not significantly differ in terms of tannin content between sites; however, when only comparing microhabitats at the fragmented sites, the tannin content of leaves of Weinmannia sp. differed significantly. Overall our findings suggest sifakas are eating foods with virtually no protein, suggesting sifakas may be relying on their foods for other macronutrients such as carbohydrates and/or fats, contradicting existing notions that large-bodied primates feed on leaves to obtain protein--that is if the sifakas do not already exhibit an adaptation to tannin-rich food items such as tannin- binding salivary proteins.

This study is important for understanding dietary constraints on sifaka populations and the evolution of their diet choice strategies. It is also useful for conservation, as it identifies which plants are nutritionally beneficial for the lemurs; these plant species could be the focus of reforestation efforts as they are likely to be important for maintaining lemur populations within fragmented forest sites. Furthermore, a better understanding of lemurs’ protein intake is important for developing nutritional plans for translocated species and animal captivity.

Extent

119 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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