Albert Fellows Dissertation Research Grant

CHES has long supported the pilot research and preliminary data collection of its graduate student members, but beginning in 2016 we expanded this initiative to include major funding of doctoral dissertation research itself. Thanks to the generous bequest of Mr. Albert Fellows, CHES inaugurated a program that each year awards a grant of $13,000 to two advanced CHES PhD graduate students pursuing scientific research bearing broadly on the survival of animals and plants threatened by the deterioration of the environment.

2019 Recipients

FosterFellows1Fred Foster

New methods for imaging tooth enamel microstructure in 3D: A case study in the enamel of Pan troglodytes and Homo sapiens

Chewing is one of the first steps in the process of digestion, during which forces are transmitted through tooth enamel and into particles of foods that are then broken down. Tooth enamel must therefore be capable of imparting forces large enough to break food apart without itself fracturing under the high stresses generated during chewing. Fred Foster’s research searches for evidence of evolved adaptations that reduce the likelihood of fracture within the small-scale structures that form enamel itself; i.e., “enamel microstructure.” Tooth enamel comprises many nanometer-scale crystallites that are glued together to form micrometer-scale prisms. These prisms are orientated in complex patterns that are hypothesized to resist the propagation of cracks that form within enamel due to crushing and grinding food. If a crack propagates entirely through the tooth, not only is chewing efficiency reduced through loss of tooth functionality, but risk of infection may increase when internal soft tissue is exposed. Consequently, there should be strong selective pressure on tooth structure to resist tooth fracture, which makes microstructural patterns in enamel prism orientation of special interest as a dietary adaptation.

FosterFellows2

A major confound in testing adaptive hypotheses about enamel microstructure lies in imaging small-scale features in three dimensions. Tooth enamel is formed from dense packed hydroxyapatite, which limits the use of conventional scanning technologies. Foster is using methods from material sciences to create 3D representations of enamel that can be used to assess the role of microstructure as a crack-stopping mechanism. Advances in X-Ray microCT technology have produced high-resolution scanners that can image tooth enamel in the Molecular Imaging Center at Rutgers University. Through a combination of serial scanning electron microscopy and ion beam milling, Foster will create a stack of images for 3D modeling, similar to how an MRI is used to create 3D models of soft tissue. Lower second molars from one human and one chimpanzee are used to evaluate how variation in enamel microstructure is related to diet. Chimpanzees have relatively thinner enamel than humans, despite generating more than twice the bite force and consuming hard foods more frequently. This incongruity between relative enamel thickness and dietary behavior provides Foster an opportunity to test how microstructure is related to dietary behavior in two closely related large-bodied hominoids. By comparing microstructure in 3D, he will be able to evaluate if and how differences in complexity affect the likelihood of tooth fracture that results from differences in dietary ecology.

 

Rebecca Brittain 20190515Rebecca Brittain

The role of the gut microbiome in digestion and energy production in wild Bornean orangutans (Pongo pygmaeus wurmbii) across shifting nutritional landscapes

Orangutans are great apes whose dietary preference for fruits confronts them with serious nutritional challenges in the Asian forests they inhabit. Fruit availability fluctuations are both extreme and unpredictable, particularly for the orangutans of Borneo, where feeding ecology can be described as oscillating between “feast and famine" periods. During famine times, total caloric intake of orangutans falls significantly as they are forced to switch from dwindling supplies of fruits to fibrous food items that are more abundant but much more difficult to digest, such as tree bark, pith, and mature leaves. Gut microbes are known to be key players in fiber digestion, partly because the microbial fermentation process produces molecules that are rapidly absorbed by host organisms and thus serve as a direct source of energy. The relative importance of microbial fermentation in helping organisms meet their minimum energetic requirements, however, varies among organisms. Ruminants, for example, fulfill 80 to 95% of their daily energetic needs through microbial fermentation, while highly folivorous howler monkeys obtain at least 30% of their daily energy from fermentation. While this figure is still unknown for wild orangutans, Brittain expects that microbial fermentation will prove to be extremely important for meeting energy requirements and, thus, a key component of the nutritional strategy adapting orangs to “feast and famine” ecological conditions.

The objective of this research is to measure the energetic and digestive roles of the gut microbiome in a population of wild Bornean orangutans (Pongo pygmaeus wurmbii) across their shifting nutritional landscape. Brittain’s overarching research question is: during low fruiting periods, when orangutans consume proportionally more dietary fiber, will the relative abundance of fiber-degrading gut microbes mirror this increase and also produce a corresponding increase in microbial energy production that compensates for caloric intake deficits? She will examine environmental changes in food availability, the nutritional contents of food items, and the gut microbe composition and microbial energy production from fecal samples at the Tuanan Orangutan Research Station, in Indonesian Borneo, which is CHES faculty member Dr. Erin Vogel’s field site of nearly 16 years. This research will advance our understanding of the gut microbiome’s role in the survival of wild mammals faced with unpredictable or changing nutritional landscapes. Brittain’s project will also contribute directly to conservation efforts for these critically endangered primates, particularly in Borneo where only 38 viable metapopulations with more than 100 individuals remain. By enhancing our understanding of orangutan health and well-being, the data will also improve captive management practices, as well as rehabilitation and release efforts.

2018 Recipients

FentonBaboons v1Melanie Fenton

Coercive and affiliate mating tactics in olive baboons (Papio anubis)

Studies of sexual selection in primates have long focused on the mating strategies of the sexes in relative isolation of one another (male-male competition, the effect of dominance rank, female choice). In recent decades, however, it has become clear that a full understanding of Darwin’s theory of sexual selection—and its relevance for explaining aspects of human behavior—requires more careful study of how male and female reproductive strategies interact, and particularly the circumstances under which they are in conflict with one another.

The goal of this study is to test several hypotheses concerning the nature of male-female interactions and the effect of these interactions on the probability of mating in olive baboons (Papio anubis) at CHES Faculty Ryne Palombit's field site. Fenton is collecting systematic behavioral and hormonal data to compare the mating benefits to males of coercive versus friendly social strategies of interaction with females. Sexual coercion can occur as a long-term strategy (“intimidation”) to promote future matings, or as a short term strategy (“harassment”) to gain immediate sexual opportunities. Conversely, males can obtain mating opportunities through the contrasting strategy of providing beneficial services to females, either as part of a long- term strategy of social bonding or as a short-term “groom-for-sex” tactic. Fenton is determining the benefits and costs of these various strategies for males and females. Variation in fecal glucocorticoid levels are being measured to test a crucial aspect of the sexual coercion hypothesis that male aggression is costly to females.

 

AlysseMoldawer v1Alysse Moldawer

A multi-species ethnography of Bornean orangutans at an active research field site

Alysse Moldawer is studying wild Bornean orangutans (Pongo pygmaeus wurmbii) as biological entities with cultural, political, and economic significance. The acquisition of knowledge about wild primates is not limited solely to scientific research methods, but arises through the cooperation of diverse people with varying historical, cultural, and political relationships to the organism. These groups of people include researchers (both international and national), governmental and non-governmental organizations, and local residents. The aim of Moldawer’s research is to examine how these people co-produce the knowledge about orangutans that is utilized in conducting research as well as applied in doing conservation work. Moldawer integrates methodologies from primate behavioral ecology, physiology, and ethnography to study how human-orangutan interactions can be understood as outcomes of the characteristics of orangutans and the humans belonging to these the different groups.

Moldawer’s research expands the use of social theory in the discipline of ethnoprimatology to explain how humans cooperate and interact with wild orangutans and one another. By utilizing science and technology studies to evaluate the relationship between science and conservation, her work will contribute to conservation initiatives generally as well as with respect to this highly endangered great ape.

 

2017 Recipients

LizBallare v1Liz Ballare

Health effects of rehabilitation and release in Bornean orangutans (Pongo pygmaeus wurmbii)

Wild orangutans are found only in Borneo and northern Sumatra. With increasing anthropogenic activities in these regions, both species (Pongo pygmaeus spp. and Pongo abelii) are listed as critically endangered. Rehabilitation and release programs have become a critical component of the Species Survival Plan. These management procedures place orangutans into new environments where they must quickly adapt to changes in enrichment, social structure, mate choice, and diet. Millions of dollars are spent on medical care, release, and informal observation of these individual orangutans, and yet we still know very little about how the health of these animals varies during the rehabilitation and release process.

This research systematically measures protein, energy balance, stress, and immune responsiveness from urine samples, as well as gastrointestinal parasites in feces throughout she rehabilitation process and after release at two sites operated by the Borneo Orangutan Survival Foundation in Central Kalimantan, Indonesia: the Nyaru Menteng Rehabilitation Center and the Bukit Batikap Conservation Forest. These data will be directly compared to corresponding data from a wild population that has been studied by Dr. Erin Vogel and colleagues for nearly 15 years at the Tuanan Orangutan Research Station, also in Central Kalimantan. Ballare’s goal is to better inform release monitoring methods and thereby improve significantly the orangutan’s chances of survival in the wild.

AlexPritchard v1Alex Pritchard

Personality of stress coping: Influence on social complexity

It has long been appreciated that “personality” describes consistent individual differences in behavior and cognition, and studies of humans additional suggest that personality-based attributes strongly affect the quality of individual social bonds. Central to this framework is the stress response system, an organism’s way of regulating behavioral and physiological reactions to challenges – or stressors – to maintain physiological stability.

This research examines how consistent individual differences in handling stress both affects and is affected by social life among wild olive baboons (Papio anubis) that have been studied by Ryne Palombit and students for many years. Pritchard will use systematic observational techniques, field experiments, social network analysis, and fecal hormone collection to measure individual differences in psychologically defined coping styles and coping outlets, basal glucocorticoid levels, and sociality. He’s particularly interested in the consequences of these differences for understanding the stability of the complex social relationships and coalitionary support system for which olive baboons are famous. His measurement of variation in stress hormones will add a valuable physiological dimension to this analysis of personality and social network. This study will contribute significantly to the growing data base on the phenomenon of “personality” in nonhumans, the eventual development of a unified evolutionary theory of personality, and our understanding of humans through study of a nonhuman primate characterized by pronounced behavioral variability and social complexity.

2016 Recipients

MareikeJaniak v1Mareike Janiak

Adaptations for insectivory in digestive enzymes of New World primates

The objective of this research is to identify functional genetic variation relating to chitinolytic and proteolytic digestive enzymes as adaptations for insectivory in New World monkeys (platyrrhines). Chitin is the main component of the cell walls of fungi and insect exoskeletons, both food resources for primates (Raubenheimer & Rothman, 2013; Hanson et al., 2006; Hilário & Ferrari, 2011). Whether human and non-human primates have the ability to digest chitin has not been conclusively answered, a knowledge gap this study aims to fill.

The improved understanding of digestive enzymes and relevant genetic variation found in New World monkeys that will be accomplished by this study will allow comparisons with other primate groups, such as Old World monkeys, apes, and humans. Furthermore, it will give us insight into the evolution of dietary ecologies and dietary adaptations of primates past and present, as well as a better grasp of the digestive capabilities of different species. Knowing the digestive abilities and limits of species has important implications for the conservation of all mammals, including primates. For example, the management of captive individuals can be improved by tailoring feeding decisions to the digestive abilities of each species. In the wild, decisions about the conservation/reconstruction of habitats and food resources (including insect species) can be informed by the dietary needs of local primate species.

 

StanKivai v1Stan Kivai

Nutritional and mechanical properties of plant foods with implications for juvenile foraging efficiency and conservation of Tana River mangabeys, Kenya

The ongoing debate about the competency of juvenile foraging (and hence survival) partly concerns the nature of juvenile-adult differences in feeding and whether differences are due to experience, body size, or both (Janson & van Schaik, 1993; Lonsford & Ross, 2012). Moreover, studies have yielded contradictory results about the timing of juvenile competence in feeding: in some species it appears to arise late in development, close to the time of maturity, while in other species it occurs long before maturity (Pereira & Fairbank, 2002; Gunst et al., 2010). Analysis that integrates field data on both the mechanical and nutritional characteristics of food items and how juveniles achieve foraging efficiency has yet to be attempted to resolve these theoretical debates. In this study, juvenile Tana River mangabeys (TRM) will be considerd to to address the following questions. Compared to adult females, how do juveniles differ in: (1) diet, particularly in food choice? (2) the influence of mechanical and nutritional properties on foraging decisions?; (3) behavioral strategies employed to overcome the nutritional and mechanical constraints? and, (4) use the data to foster long-term conservation of the Tana River primate community.

Data from this study also have broader implications for conservation. Food properties are known to influence primate habitat quality, population abundance, and persistence (Hanya & Chapman, 2013). And juvenile survival and recruitment into reproductive age class is a major focus in conservation of endangered species facing risk of extinction (Fryxell et al, 2014).