Réalisé en cotutelle avec l'Université Montpellier II / L’étude qualitative et quantitative du mode de développement des plantes envahissantes est actuellement considérée comme une étape clef dans la compréhension des phénomènes d’invasion. L’objectif de ce travail est de préciser les relations qui existent entre la structure architecturale des buissons et leur caractère proliférant. Nous avons sélectionné cinq espèces buissonnantes (Cornus sericea L., Cornaceae ; Prunus virginiana L., Rosaceae ; Rhamnus cathartica L., Rhamnaceae ; Rhus typhina L., Anacardiaceae ; Zanthoxylum americanum Mill., Rutaceae) qui sont connues pour leur aptitude à bloquer la succession végétale sous certaines conditions au Sud du Québec (Canada). L’analyse architecturale a permis chez ces espèces de caractériser les unités structurelles et leurs modifications ontogéniques. Ces modifications ontogéniques doivent être prise en compte afin d’obtenir une description complète de la plasticité phénotypique chez ces espèces. L’analyse des différentes unités structurelles révèle qu’elles ne possèdent pas la même signification fonctionnelle : les niveaux d’organisation les plus grands sont responsables majoritairement des capacités de plasticité phénotypique de la plante et de sa compétition. Ces analyses ont abouti à la définition de trois stratégies architecturales correspondant à des comportements individuels et qui sont également pertinentes pour expliquer la prolifération des populations. / Qualitative and quantitative studies of the pattern of invasive plant development is now considered a key aspect in understanding invasiveness. This work was performed to determine relationships between shrub architectural plasticity and proliferating behaviour. We selected five shrub species (Cornus sericea L., Cornaceae ; Prunus virginiana L., Rosaceae ; Rhamnus cathartica L., Rhamnaceae ; Rhus typhina L., Anacardiaceae ; Zanthoxylum americanum Mill., Rutaceae) known to arrest plant succession under certain conditions in Southern Québec, Canada. Architectural analysis revealed species’ structural units and their ontogenic changes. These ontogenic changes need to be calibrated if a full description of phenotypic plasticity is to be obtained. Analysis of the plant structural units reveals that they are of different functional significance: the higher the level of organization, the greater the capacity for phenotypic plasticity and competition. We defined three architectural strategies related to individual behaviours and which can relevantly explain the population proliferation of shrubs.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

L’environnement façonne la physiologie, la morphologie et le comportement des organismes par l’entremise de processus écologiques et évolutifs complexes et multidimensionnels. Le succès reproducteur des animaux est déterminé par la valeur adaptative d’un phénotype dans un environnement en modification constante selon une échelle temporelle d’une à plusieurs générations. De plus, les phénotypes sont façonnés par l’environnement, ce qui entraine des modifications adaptatives des stratégies de reproduction tout en imposant des contraintes. Dans cette thèse, considérant des punaises et leurs parasitoïdes comme organismes modèles, j’ai investigué comment plusieurs types de plasticité peuvent interagir pour influencer la valeur adaptative, et comment la plasticité des stratégies de reproduction répond à plusieurs composantes des changements environnementaux (qualité de l’hôte, radiation ultraviolette, température, invasion biologique). Premièrement, j’ai comparé la réponse comportementale et de traits d’histoire de vie à la variation de taille corporelle chez le parasitoïde Telenomus podisi Ashmead (Hymenoptera : Platygastridae), démontrant que les normes de réaction des comportements étaient plus souvent positives que celles des traits d’histoires de vie. Ensuite, j’ai démontré que la punaise prédatrice Podisus maculiventris Say (Hemiptera : Pentatomidae) peut contrôler la couleur de ses œufs, et que la pigmentation des œufs protège les embryons du rayonnement ultraviolet; une composante d’une stratégie complexe de ponte qui a évoluée en réponse à une multitude de facteurs environnementaux. Puis, j’ai testé comment le stress thermique affectait la dynamique de la mémoire du parasitoïde Trissolcus basalis (Wollaston) (Hymenoptera : Platygastridae) lors de l’apprentissage de la fiabilité des traces chimiques laissées par son hôte. Ces expériences ont révélé que des températures hautes et basses prévenaient l’oubli, affectant ainsi l’allocation du temps passé par les parasitoïdes dans des agrégats d’hôtes contenant des traces chimiques. J’ai aussi développé un cadre théorique général pour classifier les effets de la température sur l’ensemble des aspects comportementaux des ectothermes, distinguant les contraintes des adaptations. Finalement, j’ai testé l’habileté d’un parasitoïde indigène (T. podisi) à exploiter les œufs d’un nouveau ravageur invasif en agriculture, Halyomorpha halys Stål (Hemiptera : Pentatomidae). Les résultats ont montré que T. podisi attaque les œufs de H. halys, mais qu’il ne peut s’y développer, indiquant que le ravageur invasif s’avère un « piège évolutif » pour ce parasitoïde. Cela pourrait indirectement bénéficier aux espèces indigènes de punaises en agissant comme un puits écologique de ressources (œufs) et de temps pour le parasitoïde. Ces résultats ont des implications importantes sur la réponse des insectes, incluant ceux impliqués dans les programmes de lutte biologique, face aux changements environnementaux. / The environment shapes the physiology, morphology, and behaviour of organisms through complex, multidimensional ecological and evolutionary processes. The reproductive success of individual animals is determined by how well their phenotype is suited to an environment that is constantly changing over single and multi-generational time scales. At the same time, phenotypes are shaped by the environment, which triggers adaptive modifications of animal reproductive strategies while also imposing important constraints. In this thesis, using stink bugs and their parasitoids as model organisms, I considered how several types of plasticity can interact to influence biological fitness, and how plasticity in reproductive strategies responds to several important components of environmental change (host quality, ultraviolet radiation, temperature, biological invasions). Firstly, I compared the response of behavioural and life history traits to body size variation in the parasitoid Telenomus podisi Ashmead (Hymenoptera: Platygastridae), finding that reaction norms of behavioural traits more often had positive slopes than life history traits. Next, I found that the predatory stink bug Podisus maculiventris Say (Hemiptera: Pentatomidae) can selectively control the colouration of its eggs. Egg pigmentation in this species protects embryos against ultraviolet radiation as part of a complex oviposition strategy that evolved in response to a suite of environmental factors. Then, I tested how thermal stress affects the memory dynamics of the parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Platygastridae) learning the reliability of chemical traces left by its host. These experiments revealed that both high and low stressful temperatures prevented forgetting, affecting the time allocation of parasitoids on patches of host chemical traces. I also developed a general framework to classify temperature’s effects on all aspects of ectotherm behaviour, distinguishing constraints from adaptive behavioural adjustments. Finally, I tested the ability of an indigenous parasitoid (T. podisi) to attack the eggs of a new invasive pest of agriculture, Halyomorpha halys Stål (Hemiptera: Pentatomidae). The results showed that T. podisi attacks the eggs of H. halys but cannot develop, demonstrating that the invasive pest is an “evolutionary trap” for indigenous parasitoids, which could indirectly benefit native stink bug species by acting as an egg and time sink for the parasitoid. These findings have important implications for how insects, including those involved in biological control programs, respond to environmental change.

La variation phénotypique est essentielle à la persistance des organismes dans le temps ainsi qu’à la colonisation de nouveaux habitats. Les principales sources de variation phénotypique sont la génétique et l'épigénétique. L'épigénétique a été proposé comme un atout important pour les organismes asexués pour compenser le manque de diversité génétique. L'objectif de cette étude est d'évaluer si l’absence de variation génétique est compensée par l'épigénétique en comparant les profils de méthylation d’individus gynogènes et kleptogènes des hybrides de salamandre à points bleus. Les individus échantillonnés s’organisent en cinq groupes génétiquement différenciés, provenant du même haplome paternel A. jeffersonianum. Deux des cinq groupes sont exclusivement gynogènes, pour des raisons écologiques ou génomiques. Les trois autres groupes sont formés d’individus parfois kleptogènes, car ils présentent une variation génétique plus élevée au sein d’un site qu’entre les sites, en plus de porter des allèles très divergents par rapport à la distribution globale des allèles hybrides, trouvés en haute fréquence dans les populations sympatriques de A. laterale. Les patrons épigénétiques sont variables et distincts entre les cinq groupes génétiques. Les groupes gynogènes sont les seuls à présenter un effet environnemental significatif sur leurs patrons épigénétiques, suggérant que ces individus clonaux doivent être en mesure de maximiser leur potentiel de variation épigénétique pour faire face à des variations environnementales. / Phenotypic variation is critical to the persistence of organisms over time and the colonization of new habitats. The main consistent sources of phenotypic variation are genetics and epigenetics. Epigenetics was proposed as a valuable asset for asexual organisms to compensate or to complete genetic diversity. The objective of this study is to assess whether lack of genetic variation is compensated by epigenetics by comparing methylation patterns of gynogen and kleptogen individuals of the blue-spotted salamander hybrids. Individuals sampled clustered in five genetically differentiated groups, derived from the very same paternal A. jeffersonianum haplome. Two out of the five groups are exclusively gynogenetic, for either ecological or genomic factors. The other three groups occasionally formed kleptogen individuals, since they display a higher genetic variation within sites than among sites, in addition of displaying highly divergent alleles found in high frequency in the sympatric A. laterale populations. Epigenetic patterns are variable and distinct among the five genetic groups. Gynogenetic groups are the only one to display a significant environmental effect on their epigenetic pattern, suggesting clonal individuals must be able to make the most from their epigenetic variation potential to deal with environmental variations.

Le mélèze d'Europe (Larix decidua) est traditionnellement exploité pour son bois de qualité. Malheureusement, la culture de cette essence hors de son aire de distribution a été un échec. L'hybridation avec le mélèze du Japon (L. kaempferi) est une voie prometteuse, en particulier grâce à l'hétérosis manifesté par cet hybride. Au cours de cette dissertation, nous valorisons les données d'un diallèle multi-site intra- et inter-spécifique d'âge avancé. Le 1er chapitre présente l'analyse de traits de production et de qualité du bois. Nous confirmons ainsi l'hétérosis pour les traits liés au volume. Cet hétérosis n’entraîne pas de contrepartie en termes de qualité, et se montre stable d'un site à l'autre.Au contraire, d'autres traits ne présentent pas d'hétérosis, mais davantage d'héritabilité.Les performances additives pour ces traits sont stables d'un site à l'autre, et en espèce pure vs. en hybridation. Au cours du 2ème chapitre, nous nous intéressons au rôle de la plasticité phénotypique de traits de formation du bois dans la construction de l'hétérosis.Le mélèze hybride apparaît comme le taxon le plus plastique : tout comme ses espèces parentes, il produit un cerne de croissance étroit en conditions hydriques limitantes, mais sa croissance radiale surpasse celle de ses parents quand l'eau est abondante. Ce 2èmechapitre est également un premier pas vers la compréhension du rôle de la plasticité phénotypique dans la construction de l'architecture de la variance génétique entre la circonférence et la densité des troncs. Cette thèse se termine sur une synthèse, au cours de laquelle nous discutons les retombées de nos résultats pour l'amélioration du mélèze hybride. / European larch (Larix decidua) has been historically exploited within its natural rangefor its high quality wood, but the attempt to grow this species outside its native range was a failure. Hybridization with Japanese larch (L. kaempferi) is a promising path, in particular because of the heterosis this hybrid manifests. In this dissertation, we took advantage ofan old-enough, multi-site experiment with an inter-/intra-specific mating design. The first chapter presents the analysis of several traits involved in wood quality and productivity. We confirmed heterosis for volume related traits. The heterosis came with no counter part inwood quality, and it was stable across sites. Contrarily, some other traits showed no heterosis but higher heritabilities, and the additive performances for these traits were stable across sites and in pure species vs. in hybridization. In the second chapter, we investigated the role of phenotypic plasticity of some wood formation traits in the construction of the heterosis. Hybrid larch appeared as the most plastic taxon: it equaled the parental controls in producing narrow growth increments under drought, but it produced the largest rings in favorable water availability conditions. This second chapter was also a first step towards a better understanding of the role of phenotypic plasticity on the construction of the genetic variance architecture between larch stem circumference and density. The dissertation ends with a synthesis in which we discussed the implicationof our findings for the breeding of hybrid larch.

O feijão-fava (Phaseolus lunatus L.) é uma importante espécie da família Fabaceae, que possui ampla distribuição mundial. A origem e a domesticação da espécie são apontadas no continente americano, no entanto, os locais exatos ainda não estão totalmente esclarecidos, devido à ampla distribuição e a escassez de populações silvestres. Além disso, a perda de germoplasma de feijão-fava em muitas áreas de distribuição natural, o que mostra a importância dos Bancos de Germoplasma, da caracterização da diversidade e dos estudos de domesticação da espécie. O estudo da diversidade genética a nível molecular vem sendo bastante realizado, os marcadores moleculares de microssatélites (SSR), se destacam. O feijão-fava conta com poucos estudos usando como ferramentas os SSRs, não possuindo locos específicos para a espécie, o que limita o conhecimento sobre sua genética. Assim, objetivou-se desenvolver locos microssatélites nucleares (ncSSR) específicos a espécie para estudar a diversidade genética, bem como, o processo de domesticação entre acessos silvestres e domesticados em diferentes países (Brasil, México, Peru, Colômbia e Argentina), por marcadores SSR cloroplastidiais (cpSSR), além de estudar a plasticidade fenotípica de acessos brasileiros. Estimou-se a plasticidade fenotípica de 12 acessos do Brasil em quatro ambientes com diferentes adubos (1 - controle sem adubação; 2 - adubação mineral NPK; 3 - adubação orgânica de esterco bovino; 4 - adubação mineral e orgânica). O delineamento foi inteiramente casualizado com três repetições. Os caracteres avaliados foram: Número de Dias para Floração (NDF), Número de Dias para Maturação (NDM), Número de Vagens por Planta (NVP), Número de Sementes por Planta (NSP), Comprimento de vagem (CV), Largura da Vagem (LV), Número de Lóculos por Vagem (NLV), e Peso de Cem Sementes (P100S). Realizou-se a análise de variância e estimou-se o índice de Plasticidade Fenotípica (IPF) e a Correlação de Pearson entre os caracteres. Para a determinação da diversidade e estrutura genética foram usados marcadores microssatélites, sendo cinco locos cloroplastidiais (cpSSR) e três locos nucleares (ncSSR), em 44 acessos de feijão-fava. Foi possível detectar-se plasticidade fenotípica nos acessos de feijão-fava. Todos os caracteres, com exceção de NDF e NSV, apresentaram interação genótipo × ambiente significativa para os quatro ambientes avaliados. NVP e NSP tiveram os maiores IPF (0,82) e NDF o menor (0,06), sendo assim o mais e o menos plástico, respectivamente, nos quatro ambientes. A maior correlação positiva foi observada entre NVP x NSP, de modo que seus valores variam na mesma direção. NVP x P100S apresentaram a maior correlação negativa. A diversidade genética observada com marcadores microssatélites nucleares e cloroplastidiais mostrou-se maior em acessos do México (cpSSR = 0,163; ncSSR = 0,15), seguido do Brasil (cpSSR = 0,111; ncSSR = 0,00). Em nível de variedades, os acessos silvestres tiveram menor diversidade em cpSSR (0,16) e maior em ncSSR (0,14) do que os domesticados (cpSSR = 0,119; ncSSR = 0,02). Altos níveis de variação e diferenciação genética foram observadas entre países, com 94% da variação e Fst = 0,874 e entre variedades, com 87% e Fst = 0,944 em cpSSR. Já em ncSSR, variação e diferenciação maiores ocorreram entre acessos (61%; Fst = 0,771) e dentro de variedades (80%; Fst = 0,778). Essas diferenças podem estar relacionadas a diferenças no padrão de herança dos marcadores. Os SSR cloroplastidiais são mais conservados e tem herança maternal. Assim, os acessos de mesmo país conservam os mesmos haplótipos, apresentando baixa diferenciação entre eles. O contrário ocorre com os SSR nucleares, que possuem herança biparental e maior porcentagem de mutação. Apresentando assim, maior diferenciação entre os acessos, que é favorecida pelo sistema reprodutivo predominantemente autógamo. Os acessos domesticados brasileiros estão mais próximos geneticamente dos acessos silvestres mexicanos, podendo ter sido resultantes da domesticação de indivíduos silvestres do México. / Lima bean (Phaseolus lunatus L.) is an important species of the Fabaceae family, which is distributed worldwide. The origin and domestication of the species is not fully understood due to the wide distribution and lack of wild accessions, as well as the loss of germplasm in many areas of its natural distribution, which indicates the importance of germplasm banks and the characterization of diversity and of domestication studies. The study of genetic diversity at the molecular level has been quite accomplished, the molecular markers od microsatellites (SSR), stand out. The lima bean has few studies using as tools the SSRs, not having specific loci for the species, which limits the knowledge about its genetics. Thus, the objective was to develop specific nuclear microsatellite loci (ncSSR) to study the genetic diversity, as well as the domestication process involving wild and domesticated accessions in different countries (Brazil, Mexico, Peru, Colombia and Argentina), by chloroplastids SSR markers (cpSSR), besides to study the phenotypic plasticity of Brazilian accessions. The phenotypic plasticity of 12 accessions from Brazil was estimated in four environments with different fertilizers (1 - control without fertilization, 2 - mineral fertilization with NPK, 3 - organic fertilization with bovine manure, 4 - mineral [NPK] and organic fertilization [manure]). The design was completely randomized with three replicates. The evaluated traits were: Number of Days for Flowering (NDF), Number of Days for Maturation (NDM), Number of Pods per Plant (NVP), Number of Seeds per Plant (NSP), Pod Length (CV), Pod Width (LV), Number of Locules per Pod (NLV), and Weight of One Hundred Seeds (P100S). The analysis of variance was performed, the index of Phenotypic Plasticity (IPF) and the Pearson Correlation between the characters were estimated. Microsatellite markers were used for the determination of genetic diversity and structure, with five chloroplastid (cpSSR) and three nuclear loci (ncSSR) in 44 accessions of lima bean. There was phenotypic plasticity in the accessions of lima bean. All characters except for NDF and NSV presentated genotype x environment interaction significant for the four environments evaluated. NVP and NSP had the highest (0.82) and NDF the lowest (0.06) IPF, thus being the most and the least plastic, respectively, in the four environments. The highest positive correlation was observed between NVP x NSP, so that their values vary in the same direction. NVP and P100S had the highest negative correlation. The genetic diversity observed with nuclear and chloroplast microsatellite markers was greater in accessions from Mexico (cpSSR = 0.163; ncSSR = 0.15), followed by Brazil (cpSSR = 0.111; ncSSR = 0.00). At the variety level, wild accessions had lower diversity with cpSSR (0.16) and higher diversity with ncSSR (0.14) than domestic (cpSSR = 0.119; ncSSR = 0.02). High levels of variation and genetic differentiation were observed among countries, with 94% of the variation and Fst = 0.874, and between varieties, with 87% and Fst = 0.944 with cpSSR. With ncSSR, greater variation and differentiation occurred between accessions (61%, Fst = 0.771) and within varieties (80%, Fst = 0.788). These differences may be related to differences in the inheritance pattern of the markers. Chloroplast SSRs are more conserved and have maternal inheritance. Thus, accessions from the same country retain the same haplotypes, presenting low differentiation between them. The opposite occurs with nuclear SSR, which has a biparental inheritance and a higher percentage of mutation. Thus, a greater differentiation exists between the accessions, which is favored by the predominantly autogamous reproductive system. Brazilian domesticated accessions are genetically closest to the Mexican wild accessions, and may have resulted from the domestication of wild individuals from Mexico.

O dimorfismo sexual varia consideravelmente entre populações dentro de uma mesma espécie. Essa variação na direção e na magnitude do dimorfismo sexual é, em parte, devida às diferenças sexuais na respostas plásticas às condições e aos recursos ambientais. Por meio de experimentos em laboratório, sabe-se que a temperatura e a disponibilidade de alimento são fatores importantes na geração de variações morfológicas inter-individuais e que seus efeitos diferem entre machos e fêmeas. Usamos indivíduos da tesourinha Labidura xanthopus (Dermaptera) coletados em 20 localidades ao longo da costa brasileira para investigar como o tamanho corporal e o tamanho do armamento de machos e fêmeas variam em um gradiente natural de temperatura. O tamanho do corpo diminuiu com o aumento da temperatura, mas o dimorfismo sexual se manteve constante ao longo do gradiente de temperatura. Para o tamanho do armamento, encontramos uma relação negativa para machos e positiva para fêmeas. Conseqüentemente, a magnitude do dimorfismo sexual no tamanho do armamento diminuiu ao longo do gradiente de temperatura. Para entender o efeito da disponibilidade de alimento sobre a expressão de características morfológicas em cada um dos sexos, manipulamos a dieta durante o desenvolvimento de indivíduos provenientes de uma população de clima tropical e uma de clima temperado. Independente da população, o dimorfismo sexual foi causado por diferenças sexuais na dependência de condição. Machos e fêmeas diferiram não apenas na magnitude da resposta, mas também na direção. Em relação ao comprimento relativo dos fórceps, em particular, os resultados obtidos em laboratório não apóiam que a variação encontrada em campo se deve à disponibilidade de alimento. Outros fatores que não levamos em consideração, tais como densidade populacional, podem exercer um papel importante na resposta de machos e fêmeas em relação ao tamanho do armamento. Por fim, mais estudos experimentais comparando populações com diferenças marcantes de condições ambientais poderão lançar luz sobre quais fatores ecológicos podem ter favorecido a evolução do dimorfismo sexual dependente de condição / Sexual dimorphism varies considerably among populations within species. This variation in the direction and magnitude of sexual dimorphism is partially explained by sexual differences in phenotypically plastic responses to environmental conditions and resource availability. Laboratory experiments have already shown that temperature and food availability are important factors promoting inter-individual morphological variation and that their effects differ between males and females. We used individuals of the earwig Labidura xanthopus (Dermaptera) collected from 20 Brazilian localities to investigate how body size and weapon size of males and females vary across a natural temperature gradient. Body size decreased with increasing temperature, but sexual size dimorphism remained constant across the temperature gradient. For weapon size, we found a negative relationship for males and a positive relationship for females. Thus, the magnitude of sexual dimorphism in weapon size decreased across the temperature gradient. To understand the effect of food availability on the expression of morphological traits in each sex, we manipulated the diet of individuals from a tropical and temperate population. Regardless of the population, sexual dimorphism was caused by sex-differences in condition dependence. Males and females differed not only in the magnitude of their responses, but also in the direction. Regarding the relative length of the forceps, in particular, our results do not support the interpretation that the morphological variation observed in the field is explained by differences in food availability. Other factors not considered here, such as population density, may play an important role in determining weapon size variation in males and females under natural conditions. Finally, more experimental studies comparing populations with marked differences in environmental conditions may shed light on which ecological factors have favored the evolution of condition-dependent sexual dimorphism

Orientador: Massanori Takaki / Banca: Victor José Mendes Cardoso / Banca: Sergius Gandolfi / Banca: Débora Leonardo dos Santos / Banca: Dalva Maria Silva Matos / Resumo: As espécies invasoras são reconhecidas como um dos mais importantes e difíceis fatores que influenciam a conservação dos ecossistemas nativos. Na restauração de ambientes degradados, estas espécies podem afetar profundamente a trajetória do recobrimento vegetal pelas espécies nativas e, conseqüentemente, a composição do ecossistema. Um fator importante para o sucesso de algumas espécies vegetais invasoras é a plasticidade fenotípica, dandolhes grande capacidade de aclimatação em diversas condições ambientais. O conhecimento dos fatores ambientais e das características da planta que contribuem para o sucesso das espécies invasoras é de grande importância para predizer a habilidade de invasão e para esforços de manejo. Neste contexto, o objetivo principal deste estudo foi conhecer algumas características fisiológicas e ecológicas de Clausena excavata Burm. f., uma espécie de árvore exótica reconhecida como invasora em algumas regiões no mundo, no intuito de compreender o sucesso da espécie como invasora e contribuir com informações relevantes para possíveis tentativas de controle. Primeiramente, foram avaliados os efeitos da luz e da temperatura em sua germinação (condição controlada) e o efeito da luz na emergência de suas plântulas (condição natural, a pleno sol e sob a copa das árvores). As sementes germinaram tanto na presença como na ausência de luz, nas temperaturas de 20 a 35°C, sem diferença entre a porcentagem de sementes germinadas nas diferentes temperaturas. Sementes mantidas a 20°C, em ambas as condições de luz, germinaram mais lentamente em relação às demais temperaturas. Independente da temperatura, na presença de luz as sementes apresentaram uma germinação muito mais sincronizada do que aquelas mantidas no escuro. Tais resultados mostraram que as sementes de C. excavata são fotoblásticas neutra. Em campo, a emergência... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The invasive species are recognized one of more important and difficult factors that prejudice the conservation of native ecosystems. In the restoration of degraded environment, these species can to affect profoundly the trajectory of recovery by native species and, therefore, the ecosystems composition. An important factor to the success of invasive species is their phenotypic plasticity, which gives them a great ability to adjust in several environmental conditions. The knowledge of environmental factors and plant characteristics that contribute to the success of invasive species is very important to predict the invasion capacity and to manage efforts. In this context, the main objective of this study was to know some physiological and ecological characteristics of Clausena excavata Burm. f., a nonnative tree species recognized as invasive somewhere of the world, with intention to understand the success of this species as invasive and to contribute with relevant informations for a possible management. At first, were evaluated the effects of light and temperature on their seeds germination (controlled condition) and the effect of light on seedling emergence (natural condition, at full sun and shade). The seeds germinated in presence and absence of light, from 20 to 35°C, without difference among the germination percentage at different temperatures. Seeds maintained in 20°C, at both light conditions, germinated slowly than others temperatures. Independent of temperature, in light the seeds showed a germination more synchronized than the seeds kept in darkness. Those results showed that C. excavata have neuter photoblasics seeds. On the field, the emergence occurred at both environments, but at full sun all seeds produced a seedling. The seedling emergence occurred with same rate and synchronization index on two tested conditions. Thereafter, the seedlings were observed with purpose... (Complete abstract click electronic access below) / Doutor

As tecnologias baseadas em sensores estão cada vez mais disponíveis e podem ser usadas para coletar informações detalhadas sobre o comportamento animal. Com esta informação é possível avaliar o ritmo circadiano de variáveis comportamentais e monitorar sua resposta. A identificação de variações na resposta deste ritmo tem o potencial de detectar problemas de saúde e questões de bem-estar animal. O objetivo deste trabalho foi estudar os ritmos circadianos comportamentais como uma nova abordagem para monitorar ovelhas em sistemas extensivos e estudar a emissão de metano, eficiência alimentar e crescimento de novilhos de corte. Este trabalho foi composto por dois experimentos (ovinos e bovinos). Foram utilizados cochos automatizados e sensores de atividade baseados em acelerômetro para coletar informações detalhadas do comportamento ingestivo (bovinos) e do comportamento de atividade (ovinos e bovinos), juntamente com as características de desempenho animal. Estes dados foram utilizados para calcular a percentagem de comportamento cíclico harmônico/sincronizado a cada período de 24 h. Essa porcentagem é chamada de grau de acoplamento funcional (DFC) e é calculada com uso de um período móvel de sete dias. No experimento com ovinos, um total de 29 ovelhas Scottish Blackface foram monitoradas por quatro semanas em cada estação do ano, em sistema extensivo nas terras altas da Escócia. Dados meteorológicos foram coletados diariamente. Modelos estatísticos de regressão com efeito aleatório foram utilizados para avaliar a variação da resposta entre indivíduos. Houve uma forte dinâmica criada pelas estações do ano e pelo ciclo produtivo/fisiológico das ovelhas. Durante a primavera e o verão, o desvio padrão do DFC foi um melhor estimador do ganho de peso quando comparado ao índice de moção. A combinação da análise do DFC e o agrupamento de indivíduos com base em sua resposta às variáveis ambientais oferece potencial para obter informações relevantes para o manejo do rebanho. O experimento de bovinos foi conduzido com duas dietas contrastantes (volumoso: concentrado 8:92 e 50:50) e duas raças (40 mestiços Charolês e 40 Luing). Os padrões diurnos de ingestão e atividade foram altamente sincronizados. O ritmo circadiano da atividade foi importante para explicar as diferentes emissões de metano entre indivíduos, independente da raça ou dieta, e também teve ligação com a eficiência alimentar e o crescimento dos novilhos. Este trabalho mostra a importância dos ritmos circadianos comportamentais e como essas abordagens podem melhorar a qualidade e o significado dos dados provenientes de sensores automatizados. / Sensor-based technologies are becoming increasingly available and can be used to gather detailed information about animal behaviour. With this information it is possible to assess animal behavioural circadian rhythm and monitor its response. Identifying breakdowns of this rhythm has the potential to detect health problems and animal welfare issues. The aim of this work was to study the behavioural circadian rhythms as a novel approach to monitor sheep in extensive systems and to study the differences between beef steers production traits, in methane emission, feed efficiency and growth. This work consisted of two experiments, one dealing with sheep in an extensive system and the other with housed beef steers. Automated feed intake equipment and accelerometer-based activity sensors were used to collect detailed information on feed intake (for cattle) and activity behaviour (for sheep and cattle), alongside animal performance characteristics. These data were used to calculate the percentage of cyclic behaviour that is harmonic/synchronized to each 24 h period as Degree of Functional Coupling (DFC) shown within rolling seven day periods. In the sheep experiment, in total twenty-nine Scottish Blackface ewes were monitored for four consecutive weeks in each season across a full year, in an extensive system on Scottish upland pastures. Weather data were collected daily. Random regression statistical models were used to assess between-individual variation in response to the weather. There was a strong dynamic created by the seasons and by the production and physiological cycle in sheep in these high latitude systems. Over the spring and summer period, the variation in the response of DFC was a better estimator of BWG (Body Weight Gain) than the use of a simple motion index. The combination of circadian rhythm analysis and the clustering of individuals into groups based around their regression response to environmental variables provides considerable potential to glean information relevant for group and individual animal management. The cattle experiment was conducted with two contrasting diets (concentrate-based and mixed diet) and two breeds (40 crossbred Charolais and 40 purebred Luing). The diurnal patterns of feeding and activity behaviours were strong and highly synchronised. Activity rhythmicity was well suited to show up differences between individual methane emissions independent of breed or diet, and it was also well related to important production traits as feed efficiency and growth of beef steers. This work shows the importance of the behavioural circadian rhythms and that these approaches may enhance the quality and meaningfulness of data coming from automated sensors.

Le concept de niche a été défini par Hutchinson comme un espace multidimensionnel de variables environnementales où l'espèce survie. Au cours de ce travail, je me suis intéressée à différentes limites conceptuelles et opérationnelles du concept de niche. En m'appuyant sur le cas de l'adaptation à la salinité chez le genre Artemia – branchiopode extrêmophile – nous nous sommes intéressés : (i) aux mécanismes à l'origine du maintien du polymorphisme génétique d'une large population clonale, qui m'a permis de m'interroger sur l'échelle utile à l'application du concept de niche ; (ii) à l'impact de la flore bactérienne sur l'adaptation de l'artémie aux faibles salinités, qui m'a permis d'évaluer plus globalement l'impact que les interactions biotiques peuvent avoir dans le contexte multidimensionnel de la niche ; (iii) aux effets de la plasticité et de la qualité d'habitat sur l'adaptation de l'artémie aux fortes salinités, qui pose des questions opérationnelles sur l'évaluation de l'influence de ces facteurs sur la niche. Le travail détaillé dans ce manuscrit s'appuie sur des méthodologies variées et a apporté des éléments de réponses aux problématiques posées. Tout d'abord, nous avons pu montrer que la diversité génétique d'une large population clonale était structurée par des déterminants environnementaux tels que la salinité ou la température. Ce travail a aussi montré que dans le cas d'une population asexuée, le concept de niche pouvait s'appliquer à un groupe d'individu génétiquement proche et pouvant (selon le mode de reproduction) appartenir à une lignée commune. Ensuite, nous avons montré que la niche de la flore intestinale de l'artémie facilite la digestion des algues, mais contraint leur tolérance aux faibles salinités. Il faut alors envisager que les interactions biotiques peuvent avoir différents effets (parfois même contradictoires) sur les différents axes de la niche de l'espèce focale. Enfin, nous avons apporté des solutions méthodologiques pour évaluer séparément l'impact de la plasticité et de la qualité d'habitat sur l'adaptation des artémies aux fortes salinités. Au final, nous avons apporté des solutions conceptuelles et/ou opérationnelles permettant de solidifier le concept de niche qui est une notion clé en écologie évolutive. / Hutchinson defined the niche concept as the multidimensional space of environmental variables where the specie survives. During this work, I focused on several conceptual and operational limits of this concept. Basing our work on the adaptation to salinity of the genus Artemia – an extremophile branchipod – we studied: (i) mechanisms involved in the polymorphism maintenance in a large clonal population, which asked the question of the scaling in the use of the niche concept; (ii) impact of the gut microbiota on the adaptation to low salinities, which asked the question on the impact of biotic interactions on the niche; (iii) the effects of habitat quality and phenotypic plasticity on the tolerance to high salinities, which asked operational questions on the evaluation of theses factors and there impact on the niche. The work detailed in this manuscript is based on a large variety of methodologies and helped providing elements of answers to solve the problematic. First, we showed that the important diversity found in the large clonal population was structured by environmental variables such as salinity and temperature. Therefore, in the case of a large asexual population, the niche concept can apply to a group of genetically close individual that might share (depending on the reproduction mode) common ancestry. Then, we showed that the niche of the gut microbiota, associated with Artemia for algae digestion, constrained their host tolerance to low salinities. Thus, biotic interactions may have different effects (even conflicting sometimes) on the different axes of their host niche. Finally, we provided some methodological solutions to evaluate separately the impact of plasticity and habitat quality on the adaptation of Artemia to high salinities. In the end, we provided conceptual and/or operational solutions that strengthen the evolutionary ecology key concept of the niche.