Digestive Strategies, Fruit Processing, and Seed Dispersal in the Chimpanzees (Pan Troglodytes) and Redtail Monkeys (Cercopithecus Ascanius) of Kibale National Park, Uganda

In this dissertation, I examine the anatomical and physiological factors that shape fruit-processing behavior in redtail monkeys and chimpanzees and relate these findings to their services as seed dispersers. I present data collected between 1993 and 1996, including: results from gut passage experiments conducted on captive Cercopithecus monkeys and chimpanzees; observations of frugivory and defecation in Kibale National Park, Uganda, and; results from Kibale seed fate experiments. Contrary to body size expectations, I found that redtails have significantly longer digestive transit times than chimpanzees; in fact, cercopithecines have longer transit times relative to body size than any other major primate taxon. Redtails also engage in fine oral processing, with heavy reliance on dentition and cheek pouches, resulting in a pattern of seed spitting; chimpanzees exhibit coarse oral processing and generally swallow seeds with little dental processing. An evaluation of the seed dispersal consequences of these fruit-processing behaviors indicates that redtails disperse seeds in close proximity to parent trees (84% of spit seeds $<$10 m of parent tree), and deposit them singly (100% of spit seeds deposited singly). In contrast, chimpanzees defecate seeds in large numbers (e.g., 149 large seeds/feces; 100s of small seeds/feces), far from parent trees. Results stemming from the seed fate experiments indicate that most (88%) primate-dispersed seeds are either damaged or removed by rodents. Seeds deposited in higher density clumps are more likely to succumb to fungal attack and rodent damage, while lower density dispersal clumps are more likely to be removed away from deposition sites. In my analysis, I argue that since swallowed seeds can represent an energetic cost to primates both in terms of ballast and in displacement of nutritious digesta, fruit-processing behavior is in part a function of digestive strategies and retention times. In addition, I suggest that derived increases in retention times enable cercopithecines to detoxify plant secondary metabolites and ferment structural carbohydrates more effectively than their hominoid counterparts. I discuss that this capacity may have given early cercopithecines a competitive advantage during periods of diminishing resources and may help explain the adaptive radiation of the Cercopithecinae beginning in the late Miocene.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Anthropology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Lambert, Joanna E.

Contributors dc:contributor

• Garber, Paul A.

• Biology, Animal Physiology

Language dc:language

eng

Identifier

(MiAaPQ)AAI9737171

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85305