Thesis (Ph.D.)--Mississippi State University. Department of Wildlife and Fisheries. / Title from title screen. Includes bibliographical references.

<p> </p><p>Due to recent crop-raiding incidents an eight weeks field study to survey threats to endemic gorillas have been conducted in Okwangwo Division of Cross River National Park, Nigeria. The report ratifies that smaller mammals than gorillas are responsible for a majority of damage done to Okwangwo farm crops. Additionally the report identifies issues that need to be dealt with in order to secure regional gorilla protection; most acute is the necessity to relocate three villages that remains within the park, and inclusion of villages that are excluded from Support Zone status in the Bumaji area. Collected data expands previously established gorilla range; therefore valuations concerning gorilla habitat range with non-specific suggestions for restructure of park borders are submitted.</p><p> </p>

The availability of high-throughput sequencing technologies has enabled metagenomicinvestigations into complex bacterial communities with unprecedented resolution andthroughput. The production of dedicated data sets for metagenomic analyses is, however, acostly process and, frequently, the first research questions focus on the study species itself. Ifthe source material is represented by fecal samples, target capture of host-specific sequencesis applied to enrich the complex DNA mixtures contained within a typical fecal DNA extract.Yet, even after this enrichment, the samples still contain a large amount of environmentalDNA that is usually left unanalysed. In my study I investigate the possibility of using shotgunsequencing data that has been subjected to target enrichment for mtDNA from the hostspecies, Grauer’s gorilla (Gorilla beringei graueri), for further analysis of the microbialcommunity present in these samples. The purpose of these analyses is to study the differencesin the bacterial communities present within a high-altitude Grauer’s gorilla, low-altitudeGrauer’s gorilla, and a sympatric chimpanzee population. Additionally, I explore the adaptivepotential of the gut microbiota within these great ape populations.I evaluated the impact that the enrichment process had on the microbial community by usingpre- and post-capture museum preserved samples. In addition to this, I also analysed the effectof two different extraction methods on the bacterial communities.My results show that the relative abundances of the bacterial taxa remain relatively unaffectedby the enrichment process and the extraction methods. The overall number of taxa is,however, reduced by each additional capture round and is not consistent between theextraction methods. This means that both the enrichment and extraction processes introducebiases that require the usage of abundance-based distance measures for biological inferences.Additionally, even if the data cannot be used to study the bacterial communities in anunbiased manner, it provides useful comparative insights for samples that were treated in thesame fashion.With this background, I used museum and fecal samples to perform cluster analysis to explorethe relationships between the gut microbiota of the three great ape populations. I found thatpopulations cluster by species first, and only then group according to habitat. I further foundthat a bacterial taxon that degrades plant matter is enriched in the gut microbiota of all threegreat ape species, where it could help with the digestion of vegetative foods. Another bacterialtaxon that consumes glucose is enriched in the gut microbiota of the low-altitude gorilla andchimpanzee populations, where it could help with the modulation of the host’s mucosalimmune system, and could point to the availability of fruit in the animals diet. In addition, Ifound a bacterial taxon that is linked with diarrhea in humans to be part of the gut microbiotaof the habituated high-altitude gorilla population, which could indicate that this pathogen hasbeen transmitted to the gorillas from their interaction with humans, or it could be indicative ofthe presence of a contaminated water source.

This study compares social behavior of infants of resident mothers and infants of immigrant mothers in social groups of the mountain gorilla, Gorilla gorilla beringei. Infants of immigrant mothers spent more time in proximity to their mothers during group resting. They spent more time in solo play and less time in social play during group feeding. Their opportunity for social interaction with peers may be restricted mostly to group rest periods and their social play levels during this time are higher than infants with resident mothers. However, during both group resting and feeding they spent less time near other infants and they initiated fewer dyadic play bouts.

Studies of comparative morphology clearly distinguish the shoulder morphology of Homo from that of the other hominoids. While the shoulder morphology of non-human hominoids is thought to signal adaptations to arboreal locomotion, human shoulder morphology is understood to have lost this adaptation during hominin evolution. Ideas how non-human hominoid shoulder morphology is advantageous in an arboreal context suggest that the specific shoulder morphological traits enhance the arm-raising mechanism. However, this idea has not been biomechanically tested. This thesis constitutes the first analysis of the biomechanical consequences of two distinct shoulder morphologies within Hominoidea by comparing the glenohumeral muscle capabilities of Gorilla to Homo. The biomechanical capabilities are evaluated by constructing a computational musculoskeletal model of a gorilla thorax, shoulder girdle and upper arm, which is used to predict relevant biomechanical metrics such as muscle moments and moment arms. Muscle moments and moment arms are predicted for two important mechanisms, arm-raising and arm-lowering. The predictions are compared to those of an already existing human musculoskeletal model in order to evaluate differences in arm-raising and arm-lowering capability based on the two distinct thorax and shoulder girdle morphologies. The results of the biomechanical analyses show that the arm-lowering mechanism is enhanced in Gorilla compared to Homo, instead of the arm-raising mechanism. The enhanced arm-lowering mechanism is evident by greater moment capacities of two important arm-lowering muscles, pectoralis major and teres major. The greater moments are the result of greater muscle force capacities and greater moment arms, due to the beneficial musculoskeletal geometry of Gorilla. The results highlight that a more distal muscle insertion along the humerus has the greatest enhancing effect on the arm-lowering moment arms of teres major and pectoralis major. Furthermore, thorax and shoulder girdle morphological traits that are well known to distinguish non-human apes from humans were found to contribute to the enhancement of the arm-lowering mechanism. The more cranially oriented glenoid, obliquely oriented scapular spine and cranial scapula position on the thorax enabled certain muscles to act as arm-lowering muscles in Gorilla, contrary to the arm-raising action capability that is predicted for Homo. The enhanced arm-lowering capability is likely advantageous for the arboreal locomotion of apes. During hoisting behaviours that are known to occur during suspension and vertical climbing, arm-lowering is used to lift the heavy body of the apes upward. The results of this thesis in conjunction with earlier EMG studies suggest those muscles which are highly activated during these hoisting behaviours also have enhanced arm-lowering capacities in Gorilla and potentially other non-human hominoids compared to Homo. As such, the results highlight shoulder morphological traits that are biomechanically important for the arboreal locomotor behaviour of apes. By this, the thesis demonstrates a link between the conformation of shoulder morphological traits and their biomechanical capability, which will aid future functional interpretations of extant and extinct species.:Acknowledgements Bibliographische Darstellung Summary Zusammenfassung Chapter 1: Exploring the functional morphology of the Gorilla shoulder through musculoskeletal modelling Chapter 2: Comparison of the arm-lowering performance between Gorilla and Homo through musculoskeletal modeling Conclusion Appendix A: Supplementary Information for Chapter 1 Appendix B: Supplementary Information for Chapter 2 Appendix C: Curriculum Vitae Appendix D: Author Contributions

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24076号 / 理博第4843号 / 新制||理||1693(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 中川 尚史, 准教授 中村 美知夫, 教授 中務 真人 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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Les SIV infectant les chimpanzés et les gorilles sont les précurseurs des virus de l'immunodéficience humaine de type 1. Les quatre groupes du VIH-1 sont le résultat de quatre transmissions virales des grands singes à l'Homme. Des méthodes non invasives ont permis d'identifier le réservoir des VIH-1 M et N dans deux communautés de chimpanzés (Ptt) au Cameroun et de montrer que les gorilles (Ggg) sont infectés par un SIV proche des VIH-1 O et P. Si le SIVgor n'a jamais été détecté chez les chimpanzés, la phylogénie montre que les Ptt ont transmis ce virus aux gorilles. Par une méthode pluridisciplinaire, nous avons étudié les caractéristiques de l'infection SIVgor en milieu naturel. Nous avons prospecté 13 sites au Cameroun et 2 en RCA. Au total, 2120 fèces de gorilles et 442 de chimpanzés ont été collectées. L'infection SIVgor a été détectée dans 3 sites Camerounais et les prévalences varient entre 3,2% et 4,6%, résultats plus faibles que ceux retrouvés chez les chimpanzés. Nous avons ensuite montré que plusieurs groupes sociaux de Ggg dont les domaines vitaux se chevauchent sont infectés et que les prévalences SIV dans les groupes peuvent dépasser 25%. Les virus touchant les gorilles du même groupe sont génétiquement proches montrant des liens épidémiologiques. Enfin, un suivi de l'infection réalisé de 2004 à 2009 sur un site a permis de découvrir un foyer d'infection, 2 cas de séroconversions et de retrouver une femelle gorille infectée à 5 ans d'intervalle. Dans ce site, la prévalence SIV est stable et le nombre de femelles infectées est plus important que le nombre de mâles. La structure sociale des gorilles et leur comportement peuvent alors expliquer en partie la répartition et la prévalence du SIVgor, ainsi que les différences avec l'infection chez les chimpanzés.Cette étude multidisciplinaire montre la faisabilité du suivi de l'infection SIV chez les gorilles en milieu naturel. Si le SIVgor est pathogène, le suivi pourra s'avérer essentiel chez cette espèce menacée d'extinction. / SIV infecting chimpanzees and gorillas are the precursors of the Human Immunodeficiency Virus type 1. The four groups of HIV-1 are the results of four different viral transmissions from apes to humans. Using non invasive methods we discovered the reservoir of HIV-1 M and N in two communities of chimpanzees (Ptt) in Cameroon and found that Gorillas (Ggg) are infected by a SIV close to HIV-1 O and P. While SIVgor has not yet been detected in chimpanzees, phylogeny shows that Ptt transmitted this virus to Ggg. Using a multidisciplinary approach, we studied the characteristics of the infection in wild living gorillas. We prospected 13 sites in Cameroon and 3 in CAR. 2120 fecal samples of gorillas and 442 of chimpanzees were collected. SIVgor infection was detected in 3 sites in Cameroon and the prevalence ranges from 3.2% to 4.6%, lower than in chimpanzees. Several social groups of gorillas with overlapping home-ranges were infected and the prevalence within group could exceed 25%. Viruses of the same group are genetically close, showing epidemiologic links. In a follow up study between 2004 and 2009 on one site, we discovered a focus of infection with 2 cases of seroconvertion and we re-sampled one infected female 5 years after. In this site, the prevalence of SIVgor is stable and the number of infected females is higher than the males. The social structure of gorillas and their behavior can partly explain for the repartition and prevalence of SIVgor, as well as the differences with the infection in chimpanzees. This multidisciplinary study proves the feasibility of a follow up study in wild living gorillas. If SIVgor turns out to be pathogenic, a follow up will be essential for this endangered species.

Nous avons étudié la latéralité gestuelle intraspécifique de chimpanzés et de gorilles captifs dans des contextes socio-écologiques proches des conditions naturelles de vie. Nous avons montré que les chimpanzés et les gorilles étudiés présentaient un biais populationnel pour la main droite pour la majorité des gestes les plus fréquents de leur répertoire. Par la mise en oeuvre d’une approche multifactorielle, nous avons montré pour la première fois que la latéralité gestuelle intraspécifique de ces primates était influencée par plusieurs facteurs et par leurs interactions: contexte de l’interaction (champs visuels de l’émetteur et du récepteur et contexte émotionnel), caractéristique du geste (modalité sensorielle, utilisation d'un outil de communication, degré de partage et durée du geste) et par certaines composantes sociodémographiques, particulièrement le rang hiérarchique de l’émetteur et son âge dans une moindre mesure. De plus, nous avons comparé la latéralité manuelle des chimpanzés lors de l'utilisation d'outil pour des actions non-communicatives et des gestes intraspécifiques. Notre analyse multifactorielle suggère que l’utilisation d’outil dans les gestes serait plus contrôlée par l'hémisphère cérébral gauche que l’utilisation d’outil dans des actions non-communicatives. Globalement, nos résultats vérifient le modèle de Ghirlanda et collègues (2009) selon lequel les biais de latéralité au niveau populationnel pourraient être expliqués par une stratégie évolutive stable basée sur les interactions intraspécifiques. Nos résultats sont également en accord avec les études mettant en évidence l'utilisation préférentielle de la main droite pour la communication gestuelle des primates non humains et suggérant que la latéralité gestuelle serait un précurseur de la spécialisation hémisphérique gauche pour le langage. En outre, nos résultats confortent l'hypothèse que certaines espèces de primates pourraient avoir un traitement spécifique de l’hémisphère gauche pour les gestes communicatifs distinct de celui des actions manuelles non-communicatives. Du point de l’évolution, nos résultats soulignent l’importance d’étudier en détail la latéralité intraspécifique en considérant des espèces de différents degrés de socialité et en prenant en compte des contextes socioécologiques proches des conditions naturelles ainsi que de multiples facteurs potentiellement influents. / We studied intraspecific gestural laterality of captive chimpanzees and gorillas in real-life social-ecological relevant contexts. We evidenced that chimpanzees (respectively gorillas) exhibited a right-hand bias at the population level for the majority of the most frequent gestures of their specific natural communication repertoire. By designing and applying a multifactorial approach, we showed for the first time that intraspecific gestural laterality of primates was influenced by several factors and their mutual intertwinement: interactional context (visual fields of both signaller and recipient as well as emotional context), gesture characteristic (sensory modality, use of a communication tool, sharing degree, and gesture duration) and by some socio-demographic components in particular signaller’s hierarchical rank, and to a lesser extent signaller’s age. Similarities but also some discrepancies between chimpanzees and gorillas may be related to the lateralization of emotional processing, to communication strategies, and to social selection pressures related to the social structure and dynamics of the study species. Moreover, we compared manual laterality of tool use by chimpanzees in both non-communication actions and intraspecific gestures. Our multifactorial analysis showed that tool-use in gestures appear to be governed more by the left cerebral hemisphere than tool-use in non-communication actions. Our findings support Ghirlanda and colleagues’ (2009) model postulating that population-level bias could be explained by an evolutionary stable strategy based on intraspecific interactions. Our results also agree with previous reports evidencing predominant right-hand use by nonhuman primates for gestural communication and suggesting that gestural laterality would be a precursor of the left-brain specialization for language. Furthermore, our results support the hypothesis that some primate species may have a specific left-cerebral system processing gestures distinct from the cerebral system processing non-communication manual actions. From an evolutionary point of view, our findings emphasize the importance to study intraspecific laterality in detail by considering species varying in their degree of sociality and taking into account real-life social-ecological contexts and multiple potentially influential factors.