Les pressions de sélection exercées par les parasites ont permis l’évolution de mécanismes complexes de défense chez les espèces hôtes qui limitent la transmission parasitaire. En complément de leur système immunitaire physiologique, les animaux ont développé un « système immunitaire comportemental » comprenant un ensemble sophistiqué de stratégies d’évitement parasitaire représentant une première ligne de défense pour diminuer la probabilité de rencontre avec différents parasites. Cependant, ces stratégies comportementales n’ont été que peu étudiées chez les espèces de mammifères vivant en milieu naturel. Au cours de ma thèse, j’ai donc étudié les stratégies d’évitement parasitaire dans une population sauvage de mandrills (Mandrillus sphinx), un primate de l’Ancien Monde vivant dans les forêts denses équatoriales d’Afrique et soumis à de forces pressions parasitaires. Je me suis en particulier intéressée aux différentes stratégies comportementales qui ont évolué en réponse au risque de contamination par deux types distincts de parasites gastro-intestinaux présentant des traits d’histoire de vie et des modes de transmission contrastés : les nématodes, transmis par l’environnement, et les protozoaires, transmis par contacts sociaux. A partir d’observations récoltées sur le long-terme, de test expérimentaux et d’analyses chimiques, mes études ont mis en évidence deux stratégies comportementales différentes, soulignant le lien étroit entre l’écologie des parasites et la réponse comportementale des hôtes. D’une part, les mandrills évitent les matières fécales lorsqu’ils fourragent et évitent également les habitats précédemment contaminés par des nématodes fécaux émis lors de la dernière visite de ces habitats. D’autre part, les mandrills évitent de toiletter leurs partenaires sociaux parasités par des protozoaires fécaux, particulièrement autour de la zone anale. Cette stratégie comportementale s’avère être efficace puisque les individus parasités présentent des kystes infectieux de protozoaires sur leurs corps, concentrés au niveau de la zone anale, et la richesse en protozoaire des individus augmente lorsqu’ils toilettent des congénères très parasités. De plus, nous avons montré que cet évitement des individus parasités était guidé par un mécanisme olfactif : les protozoaires influencent l’odeur des matières fécales et les individus discriminent et évitent l’odeur des matières fécales provenant d’individus parasités. Cette plasticité comportementale face au risque parasitaire pourrait constituer un des mécanismes majeurs permettant aux espèces sociales de diminuer le risque accru de contamination associé à la vie en groupe. L’ensemble de nos résultats permettent de mieux appréhender les conséquences évolutives des pressions de sélection exercées par les parasites sur différentes caractéristiques socio-écologiques des animaux, tels que l’utilisation de l’espace et les comportements sociaux. / Parasite-mediated selection has driven the emergence of complex hosts’ defense mechanisms to limit the spread of parasites. In addition to their physiological immune system, animals have developed a “behavioral immune system” comprising a sophisticated set of parasite avoidance strategies that represents a first line of defense to decrease parasite encounter rates. However, behavioral adaptations to the threat of parasites have been poorly investigated in wild populations of mammals. In an attempt to fill this gap, during my PhD, I studied parasite avoidance strategies in a wild group of mandrills (Mandrillus sphinx), an Old World primate inhabiting dense equatorial rainforests of Africa and facing intensive parasite pressures in its natural habitat. In particular, I investigated the different behavioral strategies of defense that evolved to decrease contamination risk by two different classes of gastro-intestinal parasites exhibiting contrasted life-history traits and modes of transmission: environmentally transmitted nematodes and socially transmitted protozoa. Based on long-term observations, controlled experiments and chemical analyses, my studies document two distinct behavioral strategies emphasizing the close relationship between parasites’ ecology and hosts’ behavioral responses. On the one hand, mandrills exhibit fecal avoidance behavior when foraging and also avoid ranging in habitats previously contaminated with fecal nematodes released during the previous visit. On the other hand, mandrills avoid grooming social partners highly parasitized with fecal protozoa, particularly around the peri-anal area. This behavioral strategy appears to be operational because parasitized individuals harbor infectious protozoan cysts on their body, concentrated on the peri-anal region, and individual’s protozoan richness increases when grooming highly parasitized conspecifics. We further found that avoidance of parasitized individuals is guided by an olfactory mechanism, as protozoa influence the host’s fecal odor and mandrills discriminate and selectively avoid olfactory cues from individuals parasitized with protozoa. Such parasite-induced behavioral plasticity could be one of the major mechanisms allowing social species to cope with the increased risk of parasitism associated with group-living. Altogether, these findings shed light on the evolutionary consequences of parasite-mediated selection on several socioecological characteristics of animals, including space use and social behavior.

Apes share a distinct set of morphological and anatomical characteristics that allow us to use our arms and hands in unique ways. Apes also have relatively larger brains with similar sulcal patterning indicating there is a distinctively hominoid brain structure. These features in great apes have consistently been linked with higher cognitive skills and are considered to be the precursors leading to the exceptional developments of humans over evolutionary time – establishing the physiological basis that allows us to make and use tools to modify our environments and build our unique cultures. This study examines the general model that orthogrady and suspensory postures were the antecedents for enhanced manipulative ability in apes, which consequently set the stage for enhanced cognitive abilities in early hominoids. The primary hypothesis is that if single-handed prehensility is enhanced by suspensory orthogrady, then we may predict ape feeding style will differ significantly from that of pronograde monkeys, allowing them to access foods in unique ways. Using sympatric white-handed gibbons, Hylobates lar, representative of orthograde apes, and pig-tailed macaques, Maccaca leonina, representative of pronograde monkeys, as models, the comparative feeding styles of primates were analyzed focusing on their positional behaviour and manual skill. Results support the hypothesis that gibbons exhibit a unique feeding style associated with their orthogrady/suspensory postures in comparison with pronograde macaques. This was demonstrated by their increased access to food in the trees with more stable postures, an expanded foraging radius, and more frequent use of the terminal branches, and was evident in their complex manipulative skills with larger manual repertoires, more variability in wrist use, and more sophisticated manual techniques. Moreover, significant differences in positional behaviour and manual skill demonstrated by gibbons and macaques were evident even when feeding on the same types of foods within their shared environment. This study proposes that the combined uniquely ape traits to forage in suspensory orthograde postures with precision dexterity have allowed apes to become highly selective feeders within their environments, leading to advance manual dexterity and cognitive prowess in apes.

No description available.

In the United States, there are currently more than 40 million postmenopausal women. These women are faced with a variety of physiological changes including ovarian steroid withdrawal and alterations in hypothalamic neurons. Within the hypothalamic infundibular nucleus of postmenopausal women, there is neuronal hypertrophy and an increase in neurokinin B gene expression. Recent studies identified the kisspeptins and dynorphins as major regulators of reproduction. In our first experiment, we examined the location and alterations of KiSS-1 mRNA-expressing neurons in the hypothalami of pre and postmenopausal women. KiSS-1 neurons were largely confined to the infundibular nucleus, and in postmenopausal women, exhibited neuronal hypertrophy and increased gene expression. To determine if these changes could result from alterations in ovarian steroids, we investigated KiSS-1 gene expression in the hypothalamic infundibular nucleus of non-human primates. Similar to the findings in postmenopausal women, ovariectomy of monkeys resulted in neuronal hypertrophy and increased KiSS-1 gene expression within the infundibular nucleus. Further, estrogen treatment of ovariectomized monkeys yielded a dramatic decrease in KiSS-1 gene expression. Together, these findings suggest that the postmenopausal alterations in KiSS-1 neurons are secondary to ovarian failure.In a second study, we examined alterations in dynorphin gene expression in the hypothalami of pre and postmenopausal women. Dynorphin mRNA-expressing neurons were identified in multiple nuclei. Numbers of dynorphin neurons were decreased within the mPOA and infundibular nucleus of postmenopausal women. In the infundibular nucleus of postmenopausal women, dynorphin neurons were hypertrophied. To determine the contribution of ovarian steroids on dynorphin gene expression, we examined dynorphin mRNA in a monkey model of menopause. Young ovariectomized monkeys exhibited hypertrophy of dynorphin neurons, with no changes in dynorphin gene expression. Estrogen replacement yielded a decrease in neuronal size and an increase in dynorphin neuron number.In future studies, we will use Quantum Dot FISH to determine if NKB, KiSS-1, and dynorphin are colocalized in the hypertrophied neurons. These neuropeptides are involved in the regulation of GnRH and changes in their gene expression likely contribute to postmenopausal alterations in reproductive hormones. Our findings provide greater understanding of the postmenopausal condition and offer opportunities for pharmaceutical investigation and treatment.

Long calls are highly stereotyped calls used by primates to communicate across distances; the function of these calls has been debated. Goustard (1983:405) defines them as " ... an extended utterance which has a high degree of structural organization." Habitat structure has been considered a shaping force of the acoustic structure of nonhuman primate long calls as part of the local adaptation hypothesis (Brown et al. 1995). This study examines the effect of phylogeny, habitat density, diet, and social and mating systems as seen through the structure of the fundamental frequency (the lowest frequency of the call; Rogers 2000; Ey, Pfefferle, and Fischer 2007). Results of ANOVA and post hoc tests indicate there are both phylogenetic and habitat-related influences in the acoustic structure of the first phrase (first part of the long call separated from the next by a discrete break). Dietary preferences and social and mating systems are also correlated with acoustic structure.

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No description available.

This thesis explores the implications of non-human primates’ propensity to hyperbolically discount the future. Hyperbolic discounting occurs when small, near-term rewards are preferred over larger rewards that are realized at a future point in time, but these preferences do not hold when the choice between long term and short term rewards is made at a time far removed from when the choice produces rewards-- i.e., at a time when the payoff of the choice is distant. I discuss two mutually exclusive models that attempt to explain why non-human primates hyperbolically discount: the cognitivist and the behaviorist model. I then present evidence that supports the cognitivist model and undermines the behaviorist model. I then argue that a “War of Interests” (WOI) occurs within the non-human primate mind. I explain this WOI model, discuss its philosophical implications, and then conclude with a general theory of the non-human primate mind.

The retina contributes to visual submodalities by anatomically and functionally distinct parallel pathways. In this thesis, the synaptic connectivity of cell types in parallel visual pathways in marmoset (New World primate) and macaque (Old World primate) retinas are studied. / In Chapter 1 the main anatomical and physiological properties of parallel pathways in the primate retina are described. / Diffuse bipolar (DB) cells receive synaptic input from multiple cones and provide output to ganglion cells, but their synaptic connectivity in the inner plexiform layer is not well understood. In Chapter 2, the stratification and synaptic connectivity of DB6 axon terminals are described. It is shown that the axons of DB6 cells stratify in the same region as rod bipolar cells and blue-OFF/yellow-ON ganglion cells. The majority (86%) of their synaptic output is onto amacrine cells; only 14% goes to ganglion cells. The DB6 cells may synapse with amacrine cells in the rod pathway and the blue-OFF/yellow-ON ganglion cells. / The inhibitory neurotransmitter glycine is used by about half of all amacrine cells. Using immunohistochemical methods, the experiments in Chapter 3 investigated whether different bipolar and amacrine cell types differ with respect to the expression of glycine receptor (GlyR) subtypes. Postembedding electron microscopy showed the postsynaptic location of the a1, a2 and a3 subunits of the GlyR. Double immunofluorescence demonstrated that firstly, the three a subunits are clustered at different postsynaptic sites, and secondly that OFF bipolar types are predominantly associated with the a1 subunit, whereas ON bipolar types are predominantly associated with the a2 subunit. This shows that different amacrine cell types at synapses express different types of glycine receptors. / The midget pathway is involved in processing red-green colour vision and high spatial acuity. In Chapter 4, the synaptic connectivity of OFF midget bipolar cells was investigated in the central retina of marmosets and macaque. The OFF midget bipolar cells and their synapses were identified immunohistochemically. Midget ganglion cells in marmosets were retrogradely labelled from the parvocellular layers of the dorsal lateral geniculate nucleus. Consistent with previous studies of Old World primates, it is shown that in marmoset the midget bipolar cells contact midget ganglion cells at a ratio of 1:1. The number of output synapses was quantified for 330 OFF midget bipolar cells (n = 104, dichromatic marmoset; n = 108, trichromatic marmoset; n = 118, macaque). The average number of output synapses per axon terminal was comparable for all animal phenotypes. In all animals the number of output synapses per axon terminal showed a unimodal distribution. Our results suggest that the midget circuitry in central retina is comparable in dichromatic and trichromatic animals. / The midget pathway in mid-peripheral retina has been suggested to involve colour selective wiring of midget bipolar to midget ganglion cells. The question whether there is anatomical evidence for colour selective wiring was addressed in Chapter 5, in double labelled preparations of marmoset retina where OFF midget bipolar and OFF midget ganglion cells were identified. The relationship of the bipolar axon terminal mosaic and the dendritic fields of midget ganglion cells was analysed. No anatomical evidence for colour-selective connectivity in the inner retina of marmosets was found.

Orientador: Luiz Carlos Vulcano / Resumo: O Alouatta guariba clamitans, também conhecido como Bugio Ruivo, é um primata do novo mundo com ampla distribuição na América do Sul. No Brasil, a espécie encontra-se em extinção em alguns Estados. No presente estudo foi utilizado um espécime macho de Alouatta guariba clamitans para dissecção anatômica, dois espécimes machos para confecção de pranchas anatômicas e 16 espécimes hígidos, 8 fêmeas e 8 machos, para realização de exames de tomografia computadorizada abdominal. Foi realizada a descrição anatômica e tomográfica das principais estruturas abdominais da espécie. Os bugios possuem o trato digestório ocupando a maior parte da cavidade abdominal, com ceco e cólon bastante desenvolvidos. As estruturas possuem grande mobilidade e deslocam de acordo com a quantidade de conteúdo gasoso no estômago, jejuno, ceco e cólon. As glândulas adrenais são relativamente grandes e de fácil identificação. Os rins são retroperitoniais, unipiramidais e com grande mobilidade, principalmente o direito. As características observadas foram compatíveis com animais ceco-cólicos fermentativos, que utilizam parte do requerimento energético baseado na fermentação. Os segmentos intestinais foram facilmente identificados por suas características marcantes. A tomografia computadorizada foi eficiente para descrever a anatomia dos animais, porém é importante considerar a grande variação topográfica ao utilizar este método de imagem. / Abstract: The Alouatta guariba clamitans or Brown Howler Monkey is a primate of the New World with ample distribution in the South America. In Brazil, the species is extinct in some States. In the present study was used one specimen for anatomical dissection, two for anatomical plates and 16 healthy specimens, 8 females and 8 males, for computed tomography abdominal exams. The major of abdominal structures were described for the species. The digestive tract of Howler monkey occupied the main part of the abdominal cavity, with a large cecum and colon. Structures have a great mobility and can move into the abdome acoording the quantity gas into the stomach, jejunum, cecum and colon. Adrenal glands are relatively large and easy to identify. The kidneys are retroperitoneal, unipyramidal and with great mobility, especially the right kidney. The characteristics were compatible with caecol-colic fermentation animals that use part of the energy requirements based on fermentation. Intestinal segments were easily identified by specific characteristics. Computed tomography was efficient to describe the anatomy of animals; however, it is important to consider a wide variation of abdominal topographic structures. / Doutor