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The ant colony, known as a self-organized system, can adapt to the environment by a series of negative and positive feedbacks. There is still a lack of mechanistic understanding of how the factors, such as temperature and food, coordinate the labor of ants. According to the Metabolic Theory of Ecology (MTE), the metabolic rate could control ecological process at all levels. To analyze self-organized process of ant colony, we constructed an agent-based model to simulate the energy and population dynamics of ant colony. After parameterizing the model, we ran 20 parallel simulations for each experiment and parameter sweeps to find patterns and dependencies in the food and energy flow of the colony. Ultimately this model predicted that ant colonies can respond to changes of temperature and food availability and perform differently. We hope this study can improve our understanding on the self-organized process of ant colony.

Biodiversity trends (such as the relationship between species richness and temperature or productivity) are always defined for a particular taxon at a specific area (the entire range of the taxon or often just a region arbitrarily chosen by researchers). The form of these trends varies between taxa and regions. The weak relationship between richness and temperature or productivity is sometimes interpreted as a counterevidence for the hypothesis explaining diversity patterns by these variables. However, the delimitation of taxa or region may play a crucial role for the form of the trends. The aim of this thesis is to determine whether some taxon properties (its size) or region properties (its area, range of explanatory variables, the temperature-productivity relationship or average temperature) affect the strength and slope of the richness-temperature and richness-productivity relationships. 46 data sets of species richness for a wide range of plants, invertebrates and ectothermic vertebrates within different regions of the world were used for the analysis. While the taxon size is likely to affect the strength and slope of the relationship when comparing individual (nested) subclades within larger clade, the comparison of different taxa in different regions of the world shows only the effect of the region...

Understanding how temperature affects biological systems is a central question in ecology and evolutionary biology. Anthropogenic climate change adds urgency to this topic, as the demise or success of species under climate change is expected to depend on how temperature affects important aspects of organismal performance, such as growth, development, survival and reproduction. Rates of biological processes generally increase with increasing temperature up to some maximal temperature. Variation in the slope of the initial, rising phase has attracted considerable interest and forms the focus of this thesis. I explore variation in growth rate-temperature relationships over several levels of biological organization, both between and within species, over individuals’ lifetime, depending on the ecological context and in relation to important life history characteristics such as generation length and winter dormancy.       Specifically, I examine how a clade of temperate damselflies have adapted to their thermal environment along a 3,600 km long latitudinal transect spanning from Southern Spain to Northern Sweden. For each of six species, I sampled populations from close to the northern and southern range margin, as well from the center of the latitudinal range. I reared larvae in the laboratory at several temperatures in order to measure indiviudal growth rates. Very few studies of thermal adaptation have employed such an extensive sampling approach, and my finding reveal variation in temperature responses at several levels of organization.       My main finding was that temperature responses became steeper with increasing latitude, both between species but also between latitudinal populations of the same species. Additional genetic studies revealed that this trend was maintained despite strong gene flow. I highlight the need to use more refined characterizations of latitudinal temperature clines in order to explain these findings. I also show that species differ in their ability to acclimate to novel conditions during ontogeny, and propose that this may reflect a cost-benefit trade-off driven by whether seasonal transitions occur rapidly or gradually during ontogeny.       I also carried out a microcosm experiment, where two of the six species were reared either separately or together, to determine the interacting effects of temperature and competition on larval growth rates and population size structure. The results revealed that the effects of competition can be strong enough to completely overcome the rate-depressing effects of low temperatures. I also found that competition had stronger effects on the amount of variation in growth rates than on the average value.       In summary, my thesis offers several novel insights into how temperature affects biological systems, from individuals to populations and across species’ ranges. I also show how it is possible to refine our hypotheses about thermal adaptation by considering the interacting effects of ecology, life history and environmental variation.

Parmi les problèmes les plus fréquemment soulevés en biogéographie, figure celui de l’intégration des interactions écologiques dans les modèles de distribution d’espèces. Bien que la littérature scientifique apporte un ensemble de preuves soulignant le rôle prépondérant des interactions dans la structuration des communautés locales, on trouve relativement peu d’études révélant les empreintes laissées par les interactions dans les données de distribution d’espèces. Proposer une explication simple et claire à ce problème demeure un défi important que la biogéographie doit mener. Le problème majeur que pose l’absence de réponse claire sur le rôle des interactions aux larges échelles spatiales est que la plupart des scénarios de changements de biodiversité partent de l’hypothèse que les interactions sont négligeables. Si cette hypothèse est régulièrement rejetée, alors il faut réviser ces scénarios et soutenir le développement de méthodologies incluant les relations entre les espèces. Je commence cette thèse par un travail théorique sur le sujet car les théories classiques en biogéographie relèguent souvent au second plan les interactions écologiques. Au premier chapitre, je traite de l'intégration des interactions écologiques dans un modèle théorique de distribution d'espèces issue d'une des théories les plus importantes en biogéographie: la théorie de la biogéographie des îles. Ce travail montre comment les effets conjoints des facteurs biotiques et abiotiques changent les attendus de la théorie classique. En m'appuyant sur ce premier chapitre, je montre au second chapitre comment les interactions peuvent se répercuter dans les données de co-occurrence d’espèces. Ces données indiquent la présence ou l’absence de plusieurs espèces sur un même ensemble de sites dispersés sur de larges étendues spatiales. À l’aide d’un modèle probabiliste, j'obtiens des résultats théoriques liant les données de co-occurrence et l’information contenue dans les réseaux écologiques.Je démontre clairement que les interactions affectent les données de co-occurrence. Je montre également que plus le nombre d’interactions séparant deux espèces est grand, moins leur interactions indirect est détectable. De même si une espèce entretient de nombreuses interactions, il sera difficile de trouver une quelconque trace des interactions dans les données de co-occurrence pour cette espèce. Au troisième chapitre, je présente l’analyse de cinq jeux de données de co-occurrence pour lesquels la description des interactions était disponible. Avec ces donnés, j'ai été capable de confirmer les hypothèses du second chapitre en montrant que les espèces qui interagissent co-occurrent différemment de celles n’interagissant pas. Mes résultats indiquent aussi que l’abondance d'interactions est un frein à leur détection dans les données de co-occurrence. Cependant, en intégrant la similarité des facteurs abiotiques pour les différents sites, je montre que les signaux de co-occurrence s’affaiblissent pour parfois disparaitre. Mes résultats suggèrent donc qu’en utilisant des facteurs abiotiques pour inférer les probabilités de co-occurrence,une partie du lien entre les espèces est capturée, mais cette part est entachée d’une grande incertitude. Ceci vient questionner la qualité des prédictions données par les modèles classiques de distribution d'espèces actuellement utilisés. Les résultats de ma recherche apportent des éléments théoriques nouveaux sur le rôle des interactions écologiques dans le tracé des aires de répartition des espèces en plus de proposer une méthode originale pour étudier les données de co-occurrence d’espèces : les regarder à la lumière des réseaux écologiques. Avant de conclure ma thèse, je propose au chapitre 4 une démarche prometteuse pour aller encore améliorer l’intégration des interactions en biogéographie : les introduire par le biais des contraintes énergétiques, ce qui offre une base solide pour une théorie métabolique de la biogéographie. / One of the most pressing challenges currently in the field of biogeography is the successful integration of ecological interactions in species distribution models. Although the scientific literature points out the evidence of the controlling role interactions play on local community structure, relatively few studies have demonstrated its importance over large geographical gradients. Developing a concise, clear explanation for this issue remains a significant challenge that biogeographers need to answer. The main issue associated to the lack of a clear answer concerning the role of interactions at broad spatial scales is that most of scenarios of biodiversity changes assume that interactions can be ignored. When tested, if this hypothesis is proven false, then a re-consideration of species distribution models and their development must be undertaken to include relationships among species. I begin this thesis with a theoretical investigation on this topic, where classical theories have typically ignored ecological interactions. In the first chapter of the thesis I present the integration of interaction networks into a theoretical model of species distribution coming from one of the most important theory in biogeography: the theory of island biogeography. This work shows how together the biotic and abiotic factors can affect the expectations derived from the classical theory. Building upon the findings in the first chapter, in the second chapter, I show how interactions can affect co-occurrence (between species) data. Such data contains the presence or absence of several species for a similar set of sites dispersed along large latitudinal gradients. Using a probabilistic model, I obtain theoretical results linking co-occurrence data and the information included in ecological networks. I clearly demonstrate that interactions shape co-occurrence data. Furthermore, I show that the higher the number of links between two species, the more difficult it is to detect their indirect interaction. Similarly, if a species experiences many interactions, it is then challenging to detect any sign of interactions in co-occurrence data for this species.In the third chapter of the thesis, I assess five sets of co-occurrence data, which had descriptions of their interactions available. Using this data, I was able to confirm my hypotheses put forth in my second chapter, by showing that species co-occur differently from non-interacting one. These results also point out that the abundance of interaction must preclude their detection in co-occurrence data. However, when accounting for abiotic similarities among sites, signals of interactions are weakened. Therefore, my results suggest that using abiotic factors to infer co-occurrence probabilities capture a part of the link between species and further pinpoint the uncertainty associated to this part. As a result of these findings, the predictive power of classical species distribution models used to date is brought into question. My research findings bring new theoretical elements to the forefront when considering the influence of ecological interactions and how they shape species geographical distributions, while also introducing an original methodology for studying species co-occurrence: examining them in the light of ecological networks. Before concluding, my fourth and final chapter, I propose a promising new avenue to further investigate integrating species interactions in biogeography. Here, I introduce interactions in terms of energetic constraints, which will provide a sound basis for a metabolic theory of biogeography.

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Made available in DSpace on 2014-07-29T16:23:34Z (GMT). No. of bitstreams: 1 Tese Olivia P Pinese.pdf: 2123287 bytes, checksum: 99e595cec57e6cc0a2ec39d6250b54b0 (MD5) Previous issue date: 2012-02-13 / One of the oldest and best known global biological patterns in ecology is the latitudinal gradient of richness, characterized by a decrease in the number of species from Equator toward the poles. Several hypotheses, even today, attempt to explain the variation that occurs in the pattern of diversity of many animal and plants. Despite the advances that have been followed in Biogeography and Macroecology in recent decades, studies on biodiversity at a global scale have yet targeted mainly terrestrial and marine groups. This study presented three main objectives, first, to create a representative database of continental zooplankton diversity at global scale, that could demonstrate the distribution of richness patterns for their major groups (Total Zooplankton, Microcrustacea, Copepoda, Cladocera, Rotifera); second, to analyze the adequacy of global richness data to the Metabolic Theory of Ecology (MTE); and third, to establish the balance between local and regional components which determined the observed gradients. In this research, data collection was made from scientific papers concerning the diversity of continental zooplankton around the world. The sampling methodology effect on richness data was controlled through regressions, whose residuals were assumed as being the corrected richness. Latitudinal patterns analyses were performed with the corrected richness, developing latitudinal distribution graphs and global maps with color-weighted richness. The MTE was tested basically by analyzing the adequacy of the theory to angular coefficients, generated by multiple regressions between logarithm of raw richness, temperature (1/kT) and methodological variables. The contribution of local and regional components in determining richness was accessed through partial regressions. The results showed variation in the latitudinal patterns observed for different groups of zooplankton. Zooplanktonic crustaceans diversity peaked outside of Equator, while Rotifera diversity showed the classic latitudinal gradient, often found for many organisms around the world. Concerning the MTE, all groups showed different patterns from the one predicted by the theory. The local components were more crucial for crustaceans diversity while the regional components most strongly influenced total zooplankton richness and rotifers, which corroborates the observed results of latitudinal global patterns. This work represents a viable macroecological approach for access diversity patterns of biological groups whose taxonomic data and global geographical coverage about diversity knowledge are scarce, as they are for continental zooplankton organisms. / Um dos padrões biológicos globais mais antigos e conhecidos em Ecologia é o do gradiente latitudinal de riqueza, caracterizado pela diminuição no número de espécies do Equador em direção aos polos. Várias hipóteses, ainda hoje, tentam explicar esta variação, que ocorre no padrão de diversidade de muitos organismos animais e vegetais. Apesar dos avanços que se seguiram em Biogeografia e Macroecologia nas últimas décadas, estudos sobre biodiversidade em escala global ainda atentam-se principalmente para grupos terrestres e marinhos. O presente estudo apresentou três objetivos principais, primeiramente, construir um banco de dados representativo da diversidade do zooplâncton continental em escala global, capaz de demonstrar os padrões de distribuição de riqueza de espécies para seus principais grupos (Zooplâncton Total, Microcrustacea, Copepoda, Cladocera, Rotifera); segundo, analisar a adequabilidade dos dados de riqueza globais à Teoria Metabólica da Ecologia (Metabolic Theory of Ecology - MTE); e terceiro, estabelecer um balanço entre os componentes locais e regionais responsáveis pelos gradientes observados. A coleta de informações para a realização do trabalho foi feita a partir de publicações científicas sobre a diversidade do zooplâncton continental em todo o mundo. O efeito da metodologia de amostragem nos dados de riqueza foi controlado através de regressões, cujos resíduos foram utilizados como sendo a riqueza corrigida. As análises dos padrões latitudinais foram efetuadas a partir da riqueza corrigida, por meio da construção de gráficos de distribuição por latitudes e de mapas globais com a riqueza ponderada por cores. A MTE foi testada, basicamente, analisando-se a adequação da teoria aos valores dos coeficientes angulares gerados através de regressões múltiplas entre o logaritmo da riqueza bruta, a temperatura (1/kT) e as variáveis metodológicas. A contribuição dos componentes locais e regionais na determinação da riqueza foi acessada por meio de regressões parciais. Os resultados mostraram variação nos padrões latitudinais observados para os diferentes grupos do zooplâncton. Crustáceos zooplanctônicos apresentaram picos de diversidade fora do Equador, enquanto que a diversidade de Rotifera apresentou o gradiente latitudinal clássico, frequentemente encontrado para muitos organismos no mundo. Quanto à MTE, todos os grupos analisados apresentaram padrões diferentes do previsto pela teoria. Os componentes locais foram mais determinantes para a diversidade de Crustáceos e os componentes regionais influenciaram mais fortemente a riqueza de Zooplâncton Total e de Rotifera, o que condiz com os resultados observados para os padrões globais latitudinalmente. Este trabalho representa uma abordagem Macroecológica viável para o acesso de padrões de diversidade de grupos biológicos cujas informações taxonômicas e cobertura geográfica global do conhecimento sobre a diversidade ainda são escassos, como são para os organismos do zooplâncton continental.