Les populations sont soumises à des pressions sélectives qui agissent sur certains traits entraînant une divergence phénotypique. L'évolution des morphologies adaptatives est souvent liée avec des changements de structures préexistantes. Les insectes semi-Aquatiques ont subi une croissance de pattes exagérée qui est associée à leur adaptation et locomotion efficace à la surface de l'eau. Cette croissance excessive a facilitée l'exploitation de l'habitat aquatique restreint pour les espèces terrestres apparentées. En outre, le groupe dérivé des gerris a subi des modifications supplémentaires au niveau des pattes, de sorte que la deuxième patte (P2) est plus longue que la troisième patte (P3). Ce plan d'organisation inversé par rapport à celui des espèces terrestres, est associé à la spécialisation pour une vie sur l'eau. Les gerris ont acquis un mode de locomotion dérivée qui consiste à ramer par des mouvements simultanés de leurs P2 et des mouvements plus subtils de leurs P3 pour s'orienter. La structure et la croissance des pattes des insectes semi-Aquatiques sont réalisées durant l'embryogenèse. En effet, la nymphe qui éclot possède des pattes fonctionnelles. Il a été démontré que le facteur de transcription Hox, Ubx, est impliqué dans cette inversion du plan des pattes. Cependant, les mécanismes génétiques responsables de ces adaptations restent toujours obscurs. La thèse présentée examine ces questions à travers deux axes : premièrement, déterminer les gènes et les voies de signalisation responsables du développement et de la croissance remarquable des pattes ; deuxièmement, étudier le rôle du gène Hox impliqué dans l'inversion du plan des pattes caractéristique des gerris / Populations are faced with selective pressures that act on certain traits resulting in phenotypic divergence. The evolution of adaptive morphological traits is often associated with changes in pre-Existing structures. In semiaquatic insects, a dramatic growth of thoracic appendages is associated with their adaptation and efficient locomotion on the water surface. This particular leg allometry facilitated the exploitation of aquatic habitats, a restricted niche for their terrestrial relatives; and hence opens a new array of ecological opportunities. Additionally, the derived group of water striders has undergone further appendage modification, such that T2-Legs are longer than T3-Legs, a ground plan associated with the specialization to open water. Water striders have evolved a derived mode of locomotion through rowing on water. They move their mid-Legs in simultaneous sweeping strokes for propulsion, and move their hind-Legs in fine movements for orientation. Leg specification and elongation in semiaquatic insects happens during early embryogenesis as the newly hatching nymphs emerge with functional legs. The Hox transcription factor Ubx was found to be implicated in the reversal in leg ground plan. Nonetheless, the genetic mechanisms underlying these leg adaptive changes are still poorly understood. The presented thesis investigates these questions through two main goals: first, to uncover the genes and pathways implicated in the development and dramatic elongation of the legs; second, to examine the dynamics of Hox control responsible for the reversal in leg ground plan characteristic of water striders

The possible relationship between CO2 responsiveness and body mass in birds was explored using newly acquired ventilatory data from the barn swallow, Hirundo rustica, and the pigeon, Columbia livia, and that from the literature on four other species. Ventilatory responsiveness (%ΔV̇) of birds to 5% inspired CO2 is scaled to body mass to the 0.145 power (%ΔV̇∝ Mb0.145). A similar allometric relationship exists for data on 7 species of eutherian mammals taken from the literature (%ΔV̇∝ Mb0.130). The reduced responsiveness to CO2 in small birds and mammals may be related to an elevated hypoxic ventilatory sensitivity, as demonstrated in mammals (Boggs and Tenney, Respir. Physiol. 58: 245-251, 1984). These scaling relationships may reflect a mechanism for minimizing the inhibition of ventilation resulting from excessive loss of CO2 which thereby permits a higher hypoxic ventilatory response in small species. Other mechanisms, however, could include size related differences in mechanics or alveolar ventilation.

Une des questions cruciales dans le débat écologique actuel est de déterminer si la plasticité phénotypique pourra permettre aux espèces de répondre au rythme rapide des changements environnementaux en cours. L’objectif général de cette thèse était d’étudier les effets d’un appauvrissement en acide gras polyinsaturés du type n-3 (AGLPI) sur la plasticité de deux espèces, le bar européen (Dicentrarchus labrax) et le bar rayé (Morone saxatilis). L’effet combiné d’une augmentation de la température et d’une réduction en disponibilité des AGLPI n-3 nutritionnels chez les juvéniles de bar européen a entrainé une modification importante des acides gras neutres musculaires ainsi qu’un taux de croissance et une masse hépatique plus faibles. À température élevée, une croissance accrue a été observée avec les deux régimes, suggérant une absence de carence. En revanche, l’aliment n’a pas eu d’effets sur les facteurs transcriptionnels hépatiques liés à la régulation de la bioconversion des AG. Les juvéniles nourris avec le régime appauvri en AGLPI n-3 présentaient une vitesse critique de nage accrue en présence de contraintes hypoxiques et hypoosmotiques. Chez le bar rayé, le régime alimentaire modifie les profils en AG du muscle (fraction neutre) et du foie. Le régime pauvre en AGLPI n-3 a été associé à une augmentation de la masse cardiaque, sans effet sur la croissance en eau froide. Un niveau de stress plus élevé associé à des mortalités a été observé en eau douce. Ces résultats contribuent à une meilleure compréhension de l’impact des changements globaux sur les organismes aquatiques et ouvrent la voie à de nouvelles perspectives de recherche. / One of the major questions in the current ecological debate about global change is whether phenotypic plasticity will enable species to respond to the rapid pace of ongoing environmental change. The general objective of this thesis was to study the effects of n-3 polyunsaturated fatty acid (n-3 PUFA) depletion on the plasticity of two species, the European bar (Dicentrarchus labrax) and the striped bass (Moronesaxatilis). In juvenile European bass, the combined effect of an increase in temperature and of a reduction in availability of n-3 nutritional PUFA resulted in marked modifications of the profile in neutral muscular fatty acids and a smaller liver mass.At high temperature, growth was increased with the two diets which suggests an absence of nutritional deficiency.Conversely, diet did not affect the hepatic transcriptional factors involved in regulation of FA bioconversion. Juveniles fed the low AGLPI n-3 diet had a higher critical swimming speed in presence of hypoxic or hypoosmotic constraints. In striped bass juveniles, AGLPI n-3nutritional availability brought modifications of lipid profile both in muscle (neutral fraction) and in liver. Diet with low AGLPI n-3 was associated with a larger cardiac mass, but had no effect on growth in cold water. A higher stress level was observed in FW which was associated to higher mortality.These results contribute to a better understanding of the impact of global changes on marine organisms and pave the way for new research perspectives.

This study focuses on a secondary contact zone between two sister species of woodrat, Neotoma fuscipes (dusky-footed woodrat) and N. macrotis (big-eared woodrat). Along the Nacimiento River, on the border of southern Monterey and northern San Luis Obispo counties, the ranges of these sister species of woodrats meet and overlap forming a secondary contact zone. The zone of secondary contact is estimated to include a 500-meter (~1,650 linear feet) portion of the Nacimiento River riparian corridor. This research examines quantifiable morphological change that is likely associated with heightened inter-specific competition within the contact zone. When in sympatry the sister species may compete for resources indirectly through exploitative competition, or directly through contest competition, or through a combination of these two processes. The prediction that heightened competition has resulted in distinctive morphological character shifts between allopatric and sympatric populations was tested my examining size and shape of adult woodrats along a 20-kilometer transect. It was confirmed that adults woodrats of the two sister taxa are morphologically distinct (N = 602) and that the phallus morphology was indeed a reliable means to identify adult male woodrats as to species (p < 0.0001, N = 331). A two model approach was used to examine convergence and divergence in size and shape of woodrats across the transect. Neotoma fuscipes exhibited a statistically significant divergerence from N. macrotis with regard to breadth of rostrum (p < 0.0001, N = 414) in a region of sympatry along the Nacimiento River. Based on the results on one statistical model, N. macrotis exhibited a statistically significant convergence with regard to body-size (p = 0.0240, N = 587) and length of hind foot (p < 0.0001, N = 563) towards those of N. fuscipes between zones of sympatry and allopatry. Alternatively, based on the results of a second statistical model that accounted for environmental variation within the system both species exhibited a statistically significant divergence with regard to body-size (p = 0.0054, N = 587) and towards that of N. fuscipes between zones of sympatry and allopatry. Also, N. macrotis exhibited a statistically significant convergence with regard to length of ear (p = 0.0022, N = 563) towards that of N. fuscipes. Based on the results of both models, detectable re-patterning of size-independent traits was observed to varying degrees. The morphological character shifts between sympatric populations and allopatric populations of woodrats suggest that ecological interactions between the species are occuring. Specifically, across the contact zone, patterns of variation in body-size and other morphological character traits are consistent with expectations of a combination of contest and exploitative competition.

No description available.

Le succès écologique des organismes dépend principalement de leur phénotype. Une composante important du phénotype est la morphologie fonctionnelle car elle influence la performance d’un organisme donné dans un milieu donné et donc reflète son écologie. Des disparités dans la morphologie fonctionnelle ou dans le développement entre espèces peuvent donc mener à des différences écologiques. Ce projet évalue le rôle des mécanismes de variation morphologique dans la production de différences écologiques entre espèces au sein des poissons hybrides du complexe Chrosomus eos-neogaeus. En utilisant la microtomodensitométrie à rayons X et la morphométrie géométrique 3D, la forme des éléments des mâchoires est décrite pour comparer la variation morphologique et les différences développementales entre les membres du complexe C. eos neogaeus. Les hybrides présentent autant de variation phénotypique que les espèces parentales et présentent des phénotypes nouveaux, dit transgressifs. Les hybrides présentent aussi des différences marquées avec les espèces parentales dans leur allométrie et dans leur intégration phénotypique. Finalement, ceux-ci semblent être plastiques et en mesure de modifier leur phénotype pour occuper plusieurs environnements. L’entièreté de ces résultats suggère que des changements dans le développement des hybrides entraînent une différenciation phénotypique et écologique avec les espèces parentales. / An organism’s success is highly dependent on its phenotype. A major component of the phenotype is functional morphology because of its role in determining performance in a given environment clues as to their ecology. Morphological disparity and developmental differences between species can thus lead to ecological differences. This project assesses the role that mechanisms capable of generating morphological variation have in producing ecological differences between species within the hybrid fishes of the Chrosomus eos-neogaeus complex. Using X-ray based computer-aided micro-tomography and 3D geometric morphometrics, the shape of bones composing the jaws was described to measure morphological variation and developmental differences in the C. eos-neogaeus complex. Chrosomus eos-neogaeus hybrids displayed as much variation as parental species and novel, deemed transgressive, phenotypes. Hybrids were also markedly different from parental species in their patterns of allometric scaling and phenotypic integration. Finally, hybrids appeared to be plastic and able to acclimate to different environments. The results of this study indicate that changes in the development of hybrids could lead to phenotypic and, in turn, ecological differences with parental species.

Many passerine birds, particularly corvids, are known to express complex cognitive skills comparable to those observed in primates. In order to examine how these similarities are reflected at the cellular level, I counted neurons and nonneuronal cells in passerine brains using the isotropic fractionator method. I show that, in these birds, neuronal numbers scale almost isometrically with telencephalic size, i.e., the average neuron size shows little increase and neuronal density decreases minimally as brains get larger. Neuronal densities in the passerine telencephalon exceed those observed in the primate cerebral cortex by a factor of 3-6. As a result, the number of telencephalic neurons in the Common Raven (Corvus corax) equals those observed in the cerebral cortex of small monkeys. The cerebellum features similar scaling rules. However, because the relative size of the cerebellum is smaller than in mammalian brains, cerebellar neurons make a much smaller proportion of total brain neurons than in mammals. In contrast to the little variation in neuronal densities in telencephalon and cerebellum, the density of neurons rapidly decreases with increasing structure size in the diencephalon, optic tectum and brain stem. For all examined brain structures, the densities of nonneuronal cells remain constant...

Este trabalho objetivou estudar a reprodução da tartaruga-da-Amazônia (Podocnemis expansa) através dos resultados obtidos em 25 anos de manejo executados pelo Projeto Quelônios da Amazônia. Para tanto foi descrito um capítulo introdutório que situa o histórico e atual situação da espécie na Amazônia brasileira destacando a importância do manejo de quelônios para a conservação e alternativas de uso sustentável. No capitulo dois, o Projeto é apresentado e analisado, tendo como objetivo a proteção e manejo da reprodução dos quelônios amazônicos, principalmente da tartaruga. Neste trabalho apresentamos os resultados obtidos do manejo nos rios Purus (AC e AM), Juruá e Uatumã (AM), Amazonas (AP, PA), Araguaia (GO, TO), Crixás- Açú (GO), das Mortes (MT), Xingú, Trombetas e Tapajós (PA), Guaporé (RO) e Branco (RR). Os resultados de 52 milhões de filhotes mostram os principais incrementos no recrutamento de fêmeas e no manejo da produção de filhotes tendo como referências os rios Tapajós (PA), Xingu (PA), Branco (RR), das Mortes (MT), Purus (AM) e Amazonas (AP). No capitulo três foi estudada alometria reprodutiva em P. expansa em três praias nos rios Branco (RR), Trombetas (PA) e Araguaia (GO), entre setembro de 2002 a fevereiro de 2003. Relações alométricas foram obtidas através de regressão linear. As fêmeas com classe de massa corpórea entre 25 e 30 kg produziram mais ovos. As classes de massa corpórea das fêmeas variando de 20 a 30 kg para o Araguaia, 25 a 40 kg para Roraima, e 25 a 35 kg para Trombetas, produziram mais filhotes. Os resultados subsidiarão planos de manejo com a espécie, possibilitando ajustes em programas de ranching e farming existentes. / This study aimed to analyze the reproduction of Giant Amazon Turtle (Podocnemis expansa) based on the results from 25 years of management carried out by the Projeto Quelônios da Amazônia (Project of Chelonian species in the Amazon). The historic process and the situation in nowadays of the species in the Brazilian Amazon, pointing out the importance of chelonian management for their conservation and sustainable use is presented in the introductory chapter. The objectives of the Project related to the protection and management of the reproduction of Chelonian species in the Amazon, specially the Giant Amazon, is presented and analyzed in the chapter two. The results obtained from the management of the turtle in the Purus River (AC, AM), Juruá and Uatumã Rivers (AM), Amazonas River (AP, PA), Araguaia River (GO, TO), Crixás-Açú River (GO), das Mortes River (MT), Xingú, Trombetas and Tapajós Rivers (PA), Guaporé River (RO) and Branco River (RR) are presented in this chapter. The results from the 52 millions of young turtles showed the main increments in the females recruitment and in the management of the production of young turtles in the Tapajós River (PA), Xingu River (PA), Branco River (RR), das Mortes River (MT), Purus River (AM) and in the Amazonas River (AP). The allometry of reproduction of P. expansa in the three beaches in the Branco River (RR), Trombetas River (PA) and Araguaia River (GO) between December 2002 and December 2003 is presented in the chapter three. Allometric relationships were obtained by linear regression. The females with body mass varying from 25 to 30 kg produced more eggs. The classes of females varying from 20 to 30 kg in the Araguaia, from 25 to 40 kg in the Roraima, and from 25 to 35 kg in the Trombetas produced more young turtles. The results could be used as a basis for the species management plan, allowing the improvement of ranching and farming programs.

Ainda que existam diversos registros de formas extremas de dimorfismo sexual, a função do alongado quarto par de pernas nos machos de muitas espécies de opiliões permanece desconhecida. Neste estudo, testamos quatro previsões sobre a hipótese de que a seleção sexual está direcionando o alongamento do quarto par de pernas nos machos de Longiperna zonata e Promitobates ornatus: (1) o coeficiente alométrico do comprimento do fêmur IV em machos será maior do que o das fêmeas; (2) machos com pernas IV mais compridas vão residir próximos a grupos de fêmeas; (3) machos envolvidos em interações agressivas terão fêmures mais compridos do que o tamanho médio da população; (4) a diferença de tamanho de perna entre os oponentes será menor do que a diferença esperada entre pares de machos escolhidos ao acaso na população. Como o previsto, o coeficiente alométrico do fêmur IV foi significativamente maior em machos do que em fêmeas nas duas espécies. O comprimento do fêmur IV está positivamente relacionado à chance de um macho ser encontrado próximo a um grupo de fêmeas. Finalmente, a média do comprimento do fêmur IV dos machos envolvidos em brigas foi significativamente maior que a de machos selecionados ao acaso da população. Adicionalmente, a média da diferença de tamanho entre pares de machos que brigaram foi significativamente menor que a média da diferença de tamanho de perna entre pares de machos selecionados ao acaso na população. Assim, a seleção sexual na forma de competição entre machos parece estar direcionando o dimorfismo sexual extremo no comprimento do fêmur nessas duas espécies de opiliões. / Although there are many reports of extreme forms of sexual dimorphism in harvestmen, the function of the elongated fourth pair of legs in males of many species remains unknown. We tested four predictions to address the hypothesis that sexual selection is driving the enlargement of the fourth pair of legs in males of Longiperna zonata and Promitobates ornatus: (1) the allometric coefficient of femur IV length in males will be higher than in females; (2) males with longer legs IV will reside closer to groups of females; (3) males involved in aggressive interactions will have longer femur IV than the population average size; (4) the size difference between contenders will be smaller than the difference expected between randomly chosen pairs of males in the population. As predicted, the allometric coefficient of femur IV length was significantly higher in males than in females of both species. Femur IV length was positively related to the chance of a male being found close to a group of females. Finally, the mean femur IV length of the males involved in fights was significantly larger than the mean of random samples of males from the population, and the average difference between male contenders was smaller than the average random expected difference of the population. Therefore, sexual selection in the form of male-male competition seems to be driving the extreme sexual dimorphism in femur length in these species.

O trabalho busca contribuir com a compreensão da conservação dos quelônios da espécie Podocnemis expansa através de estudos de ecologia reprodutiva, avanço das fronteiras agropecuárias e do histórico de fiscalização, caça e comercialização desses animais na região central do Corredor Ecológico Araguaia Bananal no Estado do Tocantins. A pesquisa apresenta uma abordagem metodológica dividida em quarto etapas distintas. Inicialmente, busca apresentar e analisar as projeções da produção agropecuária dos municípios de Caseara, Cristalândia, Formoso do Araguaia, Lagoa da Confusão, Marianópolis e Pium com a quantidade de fêmeas de quelônios da espécie P. expansa nidificando nas praias do rio Javaés durante o período de execução do Projeto Quelônios da Amazônia (PQA), compreendido entre 1985 e 2010. Os dados da produção agropecuária foram analisados para a série histórica de 1990 a 2015, através do número de cabeças de gado de corte e área plantada com lavoura temporária e lavoura permanente, todos para o conjunto dos municípios citados. Para análise e previsão dos dados, utilizou-se o modelo de séries temporais Autorregressivo Integrado de Médias Móveis de Box Jenkins (1976). Em seguida, buscou-se avaliar o perfil socioambiental das pessoas que utilizam e/ou comercializam esses animais a partir dos laudos de apreensão e de entrevistas semiestruturadas. Ao todo foram registrados 93 autos de infração, com 589 animais recapturados e devolvidos a natureza, sendo que destes mais de 80% são da espécie P. expansa. Os infratores autuados nas ações de fiscalização se configuram essencialmente como pessoas de baixa renda, com pouca ou nenhuma escolaridade e idade variando entre 21 e 75 anos, todos do sexo masculino. Nas entrevistas, 88,34% afirmaram consumir os animais, sendo que 51,45% apresentaram preferência pela P. expansa, 30,09% pelo P. unifilis, 6,70% consomem Chelonoidis sp e apenas 11,76% não consomem, desse total, 60,19% afirmaram não consumir ovos. 61,16% afirmaram que o principal período de captura é de agosto a dezembro e que os índios são os principais responsáveis pela captura e comercialização, sendo apontados por 49,51% dos entrevistados. Para grande maioria, 67%, não existe fiscalização na região e que, mesmo sem a fiscalização, é razoável a quantidade de animais na natureza. Para 41,74%, o manejo sustentável através de cotas seria a melhor alternativa para preservação e conservação das espécies. Na terceira etapa, foram avaliados os aspectos geomorfológicos das áreas de nidificação da P. expansa entre 1985 e 2010 em cinco praias do rio Javaés na região central do Parque Nacional do Araguaia na Ilha do Bananal. A densidade dos ninhos ao longo das praias mostrou uma preferência desses animais por ambientes que possuem características geomorfológicas distintas, seja em relação às dimensões físicas, elevação do banco de areia ou variações no nível de água no rio. Na quarta e última etapa da pesquisa, buscou-se avaliar o padrão reprodutivo das fêmeas de P. expansa em ambiente natural. O tamanho das fêmeas foi estimado a partir dos rastros deixados por elas durante a deambulação e/ou logo após a postura. Os resultados mostram que fêmeas maiores possuem ninhadas com mais ovos, filhotes maiores e com maior massa corporal. / The work seeks to contribute to the understanding of the conservation of the species of Podocnemis expansa by means of studies on reproductive ecology, the advancement of agricultural frontiers and the control, hunting and commercialization of these animals in the central region of the Araguaia Bananal Ecological Corridor in the State of Tocantins. The research presents a methodological approach divided into four distinct stages. Initially, it seeks to present and analyze the projections of the agricultural production of the municipalities of Caseara, Cristalândia, Formoso do Araguaia, Confusion Lagoon, Marianópolis and Pium with the number of females of species of P. expansa species nesting on the beaches of the Javaés river during the period (PQA) between 1985 and 2010. The data of agricultural production were analyzed for the historical series from 1990 to 2015, through the number of heads of cattle and area planted with temporary crops and crops all the municipalities mentioned. For the data analysis and prediction, the Box-Jenkins (1976) SelfCorrelated Integrated Average Averages model was used. Next, the objective was to evaluate the socioenvironmental profile of the people who use and / or commercialize these animals from the seizure reports and semi-structured interviews. In all, 93 infraction notices were registered, with 589 animals recaptured and returned to nature, of which more than 80% belong to the species P. expansa. The offenders assessed in the actions of inspection are essentially as low-income people, with little or no schooling and age ranging from 21 to 75, all males. In the interviews, 88.34% reported consuming the animals, and 51.45% preferred P. expansa, 30.09% P. unifilis, 6.70% consumed Chelonoidis sp and only 11.76% did not consume, of this total, 60.19% stated that they did not consume eggs. 61.16% stated that the main capture period is from August to December and that the Indians are the main responsible for capture and commercialization, being pointed out by 49.51% of the interviewees. For the great majority, 67%, there is no inspection in the region and, even without inspection, the amount of animals in the wild is reasonable. For 41.74%, sustainable management through quotas would be the best alternative for the preservation and conservation of species. In the third stage, the geomorphological aspects of the expansa nesting areas between 1985 and 2010 were evaluated in five beaches of the Javaés river in the central region of the Araguaia National Park on Bananal Island. The density of the nests along the beaches showed a preference of these animals for environments that have distinct geomorphological characteristics, either in relation to the physical dimensions, elevation of the sandbank or variations in the level of water in the river. In the fourth and last stage of the research, the objective was to evaluate the reproductive pattern of P. expansa females in a natural environment. The size of the females was estimated from the traces left by them during ambulation and / or shortly after laying. The results show that larger females have litters with more eggs, larger pups and larger body mass.