In the black cotton ecosystem of Laikipia, Kenya, four symbiotic ants coexist at a fine spatial scale on canopies of Senegalia drepanolobium. They exhibit different aggressive behaviours and modify their tree canopies differently. These diverse behaviours were expected to affect the associated canopy arthropod communities. At the Kenya long-term exclosure experiment (KLEE) and its immediate environs at Mpala Research Centre, Laikipia, the insect communities coexisting with each of the four ant species were characterized, and their response to different vertebrate herbivory. Other ant species inhabiting the tree canopies or the ground were surveyed too. Pitfall trapping was used in sampling terrestrial ants, while beating and mist-blowing were used in collecting arboreal insects. Different sampling methods had varying efficacies, revealing the importance of using several methods. There are at least sixteen ant species in this ecosystem, all occurring on the ground, but only ten species on the trees. Terrestrial ant communities in this ecosystem cannot be used as indicators of grazing pressure for range management. A total of 10,145 individual insects were collected from the tree canopies, comprising of 117 species from seven orders and 25 families, forming a complex community of species interacting at different levels. Symbiotic ant species had a significant effect on insect community structure and composition. Crematogaster sjostedti was associated with a community that was significantly different from the other ant species. There was no significant effect of vertebrate feeding pressure on the canopy insect community, but there was an interaction effect between ant species and treatments. Significant differences between ant species mostly occurred on treatment plots where only cows were allowed to graze. One or more of the ant species may be a keystone species in this ecosystem even though experimental manipulations failed to confirm earlier findings. It was concluded that the one-year period during which experimental manipulations were carried out was not long enough to reflect takeover effects on the insect community. The four symbiotic ant species colonizing S. drepanolobium comprises of two guilds, the hemipteran-tending ants (C. sjostedti and Crematogaster mimosae) and non-tending ants (Crematogaster nigriceps and Tetraponera penzigi). Communities associated with these guilds were found to be significantly different in all four diversity indices. The black cotton ecosystem is species-poor compared to other ecosystem such as forests. The number of insect species that colonizes S. drepanolobium and coexists with acacia-ants forms a large proportion of the invertebrate community. Therefore, this ecosystem should be conserved to safeguard this invertebrate community. This will also give scientists a chance to establish how the various insect species coexist with symbiotic ants on tree canopies.

O comportamento de insetos sociais, em especial de formigas, tem sido muito estudado nos últimos tempos, devido à capacidade destes insetos realizarem tarefas complexas a partir de interações entre indivíduos simples. Ao se moverem sobre um ambiente na busca de alimento, as formigas depositam no solo uma substância química, denominada feromônio, que atrai as formigas que se encontram no ninho e as guia em direção ao alimento encontrado. O processo de construção e seguimento destas trilhas permite que as formigas descubram os menores caminhos e as melhores fontes de alimento no ambiente. Com o objetivo de estudar as características das formigas que contribuem para a sua adaptação a diferentes condições do meio, diversos experimentos vêm sendo realizados com estes insetos. Dentro deste contexto, esta tese apresenta experimentos inéditos realizados com formigas em laboratório, sobre uma rede artificial de túneis, onde diversos caminhos interconectados conduzem a uma fonte de alimento. As decisões das formigas foram analisadas nos níveis individual e coletivo, sob mudanças no meio, compreendendo o bloqueio/desbloqueio de ramos. A medição de diversas características individuais das formigas permitiu desenvolver dois modelos matemáticos sobre o seu comportamento, que foram aplicados à situação em que não se alterou a condição do ambiente com relação ao acesso aos ramos (estática), como também a mudanças no meio (dinâmica). A análise realizada do comportamento coletivo foi utilizada na comparação dos resultados obtidos pelas simulações dos modelos. De forma geral, o segundo modelo proposto foi mais eficiente que o primeiro na situação estática, porém ele ainda necessita de ajustes nas demais situações. O bom desempenho do segundo modelo proposto levou a aplicação de sua principal característica, a função de escolha que considera a concentração de feromônio sobre os ramos do meio e a capacidade de orientação das formigas, a um problema de otimização combinatorial, o roteamento em redes de telecomunicações. O algoritmo de roteamento proposto foi avaliado sob variações no nível de tráfego e topologia da rede, e seu desempenho foi comparado ao de dois algoritmos usados por concessionárias de telecomunicações, considerando diversas medidas de desempenho. O algoritmo desenvolvido obteve resultados encorajadores, sugerindo a aplicabilidade da estrutura do modelo proposto a outros problemas complexos de otimização. / The behavior of social insects, particularly of ants, has been intensively studied in the last years, due to their capacity to perform complex tasks through interactions among simple individuals. When moving in the environment searching for food, ants deposit on the ground a chemical substance, called pheromone, to attract ants in the nest and guide them towards the source of food that was found. The process of laying/following the pheromone trails allows ants to find the shortest paths and best sources of food of the environment. With the aim to study the characteristics of the ants that contribute to their adaptation to different environment conditions, several experiments with ants have been performed and reported in this research. In this context, this thesis presents novel experiments with ants in the laboratory, in an artificial network of tunnels, where several interconnected paths lead the insects from the nest to the food source. Ants\' decision were analyzed according to the individual and collective levels, under changes in the environment, comprising the blockage/release of branches. The measure of several individual characteristics of ants allowed the development of two mathematical models of their behavior, which were applied to the non-changing (static) environment access to all branches and to changing (dynamic) access. The analysis of the collective behavior of ants in the experiments was used to compare the results derived from the simulations of the models. In general, the second proposed model was more accurate than the first one in simulating ants behavior for the static situation, however, it needs some improvements for the other situations. The satisfactory behavior of the second model led to apply its main feature, the choice taking into consideration the pheromone concentration over the branches and the ants ability to orient themselves, to solve an optimization problem, the routing in telecommunications networks. The proposed routing algorithm was evaluated under variations on the traffic level and topology of the network, and its performance was compared with two routing algorithms used by telecommunications companies, considering several performance measures. The developed algorithm produced encouraging results, suggesting the possibility to apply the framework of the proposed model to other optimization problems.

Sun Weng Hong. / Thesis submitted in: October 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 116-121). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.7 / Chapter 2. --- Ant Colony Optimization (ACO) --- p.9 / Chapter 2.1 --- ACO vs. Traditional Routing --- p.10 / Chapter 2.1.1 --- Routing information --- p.10 / Chapter 2.1.2 --- Routing overhead --- p.12 / Chapter 2.1.3 --- Adaptivity and Stagnation --- p.14 / Chapter 2.2 --- Approaches to Mitigate Stagnation --- p.15 / Chapter 2.2.1 --- Pheromone control --- p.15 / Chapter 2.2.1.1 --- Evaporation: --- p.15 / Chapter 2.2.1.2 --- Aging: --- p.16 / Chapter 2.2.1.3 --- Limiting and smoothing pheromone: --- p.17 / Chapter 2.2.2 --- Pheromone-Heuristic Control --- p.18 / Chapter 2.2.3 --- Privileged Pheromone Laying --- p.19 / Chapter 2.2.4 --- Critique and Comparison --- p.21 / Chapter 2.2.4.1 --- Aging --- p.22 / Chapter 2.2.4.2 --- Limiting pheromone --- p.22 / Chapter 2.2.4.3 --- Pheromone smoothing --- p.23 / Chapter 2.2.4.4 --- Evaporation --- p.25 / Chapter 2.2.4.5 --- Privileged Pheromone Laying --- p.25 / Chapter 2.2.4.6 --- Pheromone-heuristic control --- p.26 / Chapter 2.3 --- ACO in Routing and Load Balancing --- p.27 / Chapter 2.3.1 --- Ant-based Control and Its Ramifications --- p.27 / Chapter 2.3.2 --- AntNet and Its Extensions --- p.35 / Chapter 2.3.3 --- ASGA and SynthECA --- p.40 / Chapter 3. --- Multiple Ant Colony Optimization (MACO) --- p.45 / Chapter 4. --- MACO vs. ACO --- p.51 / Chapter 4.1 --- Analysis of MACO vs. ACO --- p.53 / Chapter 5. --- Applying MACO in Load Balancing --- p.89 / Chapter 5.1 --- Applying MACO in Load-balancing --- p.89 / Chapter 5.2 --- Problem Formulation --- p.91 / Chapter 5.3 --- Types of ant in MACO --- p.93 / Chapter 5.3.1 --- Allocator. --- p.94 / Chapter 5.3.2 --- Destagnator. --- p.95 / Chapter 5.3.3 --- Deallocator. --- p.100 / Chapter 5.4 --- Global Algorithm --- p.100 / Chapter 5.5 --- Discussion of the number of ant colonies --- p.103 / Chapter 6. --- Experimental Results --- p.105 / Chapter 7. --- Conclusion --- p.114 / Chapter 8. --- References --- p.116 / Appendix A. Ants in MACO --- p.122 / Appendix B. Ants in SACO. --- p.123

Maintenance of power plants is aimed at extending the life and reducing the risk of sudden breakdown of power generating units. Traditionally, power generating units have been scheduled for maintenance in periods to ensure that the demand of the system is fully met and the reliability of the system is maximized. However, in a deregulated power industry, the pressure of maintaining generating units is also driven by the potential revenue received by participating in the electricity market. Ideally, hydropower generating units are required to operate during periods when electricity prices are high and to be able to be taken offline for maintenance when the price is low. Therefore, determination of the optimum time periods for maintenance of generating units in a power system has become an important task from both a system reliability and an economic point of view. Due to the extremely large number of potential maintenance schedules, a systematic approach is required to ensure that optimal or near-optimal maintenance schedules are obtained within an acceptable timeframe. Metaheustics are high-level algorithmic frameworks that aim to solve combinatorial optimisation problems with a large search space in a reasonable computational run time. Inspired by the foraging behavior of ant colonies, Ant Colony Optimisation (ACO) is a relatively new metaheuristic for combinatorial optimisation. The application of ACO to a number of different applications has provided encouraging results when applied to scheduling, including the job-shop, flow-shop, machine tardiness and resource-constrained project scheduling problems. In this thesis, a formulation is developed that enables ACO to be applied to the generalized power plant maintenance scheduling optimisation (PPMSO) problem. The formulation caters for all constraints generally encountered as part of real-world PPMSO problems, including system demands and reliability levels, precedence rules between maintenance tasks, public holidays and minimum outage durations in the case of shortening of maintenance tasks. As part of the formulation, a new heuristic and a new local search strategy have been developed. The new ACO-PPMSO formulation has been tested extensively on two benchmark PPMSO problems from the literature, including a 21-unit and a 22-unit problem. It was found that the ACOPPMSO formulation resulted in significant improvements in performance for both case studies compared with the results obtained in previous studies. In addition, the new heuristic formulation was found to be useful in finding maintenance schedules that result in more evenly spread reserve capacity and resource allocations. When tested using a modified version of the 21-unit and the 22-unit problems, the new local search strategy specifically designed for duration shortening was found to be effective in searching locally for maintenance schedules that require minimal shortening of outage duration. The ACO-PPMSO formulation was also successfully able to cater for all constraints as specified in both original and the modified versions of the two benchmark case studies. In order to further test the ACO-PPMSO formulation developed, it was first applied to a scaled-down version of the Hydro Tasmania hydropower system (five power stations) and then to the full system (55 generating units). As part of the studies, the ACO-PPMSO formulation was linked with the simulation model used by Hydro Tasmania to assess the impact of various maintenance schedules on the total energy in storage of the system at the end of the planning horizon, the total thermal generation, the total number of days where the reliability level is not met, as well as the total unserved energy throughout the planning horizon. A number of constraints were considered, including the anticipated system demands, a 30% capacity reliability level, the minimum and maximum durations between related maintenance tasks, the precedence constraints and the minimum outage duration of each task in the case of shortening of maintenance tasks. The maintenance schedule was optimised for the maximum end-of-horizon total energy in storage, the minimum thermal generation and the minimum total outage durations shortened and deferred, under 77 different inflow conditions. The optimal maintenance schedule obtained compared favourably with that obtained by Hydro Tasmania over many years based on experience. Specifically, the ACO-PPMSO schedule results in higher end-of-horizon total energy in storage and satisfies both hard and soft constraints, which overall equates to over $0.5 million dollars of savings when compared to the schedule obtained using the practitioners’ experience and engineering judgment. The ACO-PPMSO algorithm was also shown to be a useful decision-making tool for scheduling maintenance under different circumstances when tested with four scenarios commonly encountered in practical maintenance scheduling problems. In conclusion, the ACO-PPMSO formulation developed, tested and applied as part of this thesis research provides a powerful and flexible means of obtaining optimal or near-optimal maintenance schedules for power plants. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1294672 / Thesis (Ph.D.) -- University of Adelaide, School of Civil and Environmental Engineering, 2007

O comportamento de insetos sociais, em especial de formigas, tem sido muito estudado nos últimos tempos, devido à capacidade destes insetos realizarem tarefas complexas a partir de interações entre indivíduos simples. Ao se moverem sobre um ambiente na busca de alimento, as formigas depositam no solo uma substância química, denominada feromônio, que atrai as formigas que se encontram no ninho e as guia em direção ao alimento encontrado. O processo de construção e seguimento destas trilhas permite que as formigas descubram os menores caminhos e as melhores fontes de alimento no ambiente. Com o objetivo de estudar as características das formigas que contribuem para a sua adaptação a diferentes condições do meio, diversos experimentos vêm sendo realizados com estes insetos. Dentro deste contexto, esta tese apresenta experimentos inéditos realizados com formigas em laboratório, sobre uma rede artificial de túneis, onde diversos caminhos interconectados conduzem a uma fonte de alimento. As decisões das formigas foram analisadas nos níveis individual e coletivo, sob mudanças no meio, compreendendo o bloqueio/desbloqueio de ramos. A medição de diversas características individuais das formigas permitiu desenvolver dois modelos matemáticos sobre o seu comportamento, que foram aplicados à situação em que não se alterou a condição do ambiente com relação ao acesso aos ramos (estática), como também a mudanças no meio (dinâmica). A análise realizada do comportamento coletivo foi utilizada na comparação dos resultados obtidos pelas simulações dos modelos. De forma geral, o segundo modelo proposto foi mais eficiente que o primeiro na situação estática, porém ele ainda necessita de ajustes nas demais situações. O bom desempenho do segundo modelo proposto levou a aplicação de sua principal característica, a função de escolha que considera a concentração de feromônio sobre os ramos do meio e a capacidade de orientação das formigas, a um problema de otimização combinatorial, o roteamento em redes de telecomunicações. O algoritmo de roteamento proposto foi avaliado sob variações no nível de tráfego e topologia da rede, e seu desempenho foi comparado ao de dois algoritmos usados por concessionárias de telecomunicações, considerando diversas medidas de desempenho. O algoritmo desenvolvido obteve resultados encorajadores, sugerindo a aplicabilidade da estrutura do modelo proposto a outros problemas complexos de otimização. / The behavior of social insects, particularly of ants, has been intensively studied in the last years, due to their capacity to perform complex tasks through interactions among simple individuals. When moving in the environment searching for food, ants deposit on the ground a chemical substance, called pheromone, to attract ants in the nest and guide them towards the source of food that was found. The process of laying/following the pheromone trails allows ants to find the shortest paths and best sources of food of the environment. With the aim to study the characteristics of the ants that contribute to their adaptation to different environment conditions, several experiments with ants have been performed and reported in this research. In this context, this thesis presents novel experiments with ants in the laboratory, in an artificial network of tunnels, where several interconnected paths lead the insects from the nest to the food source. Ants\' decision were analyzed according to the individual and collective levels, under changes in the environment, comprising the blockage/release of branches. The measure of several individual characteristics of ants allowed the development of two mathematical models of their behavior, which were applied to the non-changing (static) environment access to all branches and to changing (dynamic) access. The analysis of the collective behavior of ants in the experiments was used to compare the results derived from the simulations of the models. In general, the second proposed model was more accurate than the first one in simulating ants behavior for the static situation, however, it needs some improvements for the other situations. The satisfactory behavior of the second model led to apply its main feature, the choice taking into consideration the pheromone concentration over the branches and the ants ability to orient themselves, to solve an optimization problem, the routing in telecommunications networks. The proposed routing algorithm was evaluated under variations on the traffic level and topology of the network, and its performance was compared with two routing algorithms used by telecommunications companies, considering several performance measures. The developed algorithm produced encouraging results, suggesting the possibility to apply the framework of the proposed model to other optimization problems.

Orientador: João Vasconcellos Neto / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-19T19:51:55Z (GMT). No. of bitstreams: 1 Alves_TatianeGisele_M.pdf: 798527 bytes, checksum: 1a4e43c431da929637d06a17913050d8 (MD5) Previous issue date: 2011 / Resumo: A maior parte dos ambientes naturais têm sido convertidos para uso humano. Estas mudanças estão ocorrendo num ritmo nunca antes experimentado pela natureza. O aumento do conhecimento sobre a estrutura e o funcionamento dos ecossistemas auxilia na busca de respostas de como e que forma estas ações estão afetando os sistemas naturais, e consequentemente no planejamento de melhores estratégias de conservação. Uma das maneiras de acessar os processos ecológicos que são difíceis de monitorar é buscar grupos ou organismos que facilitem o entendimento destas intervenções. A sensibilidade das assembleias de formigas, combinada com a sua importância funcional e amostragem fácil, fazem delas bons organismos para estudos de conservação. O estudo avaliou a estrutura das assembleias de formigas em três unidades de conservação na Floresta Atlântica. As formigas foram amostradas em uma floresta contínua no Parque Estadual da Serra do Mar, sudeste do Brasil, em áreas mais preservadas e menos preservadas. O objetivo foi determinar se a riqueza, a composição e a abundância destes organismos diferem entre as áreas contrastantes em relação ao grau de perturbação antrópica. Os resultados mostraram que a riqueza não foi afetada nas áreas com diferentes históricos de perturbação, mas a composição mudou drasticamente em duas das três áreas. A abundância de formigas cortadeiras foi baixa em todas as áreas e não mostrou diferenças significativas, e a abundância de Ponerinae foi semelhante entre os diferentes contrastes. Os resultados do estudo sugerem que nos sistemas estudados, os efeitos nas assembleias são dependentes da intensidade e da frequência da perturbação, e do tempo de recuperação da área alterada / Abstract: The majority of the natural environments have been converted for human use. These changes are occurring in a level never experienced before by nature. Increased the knowledge about the structure and functioning of ecosystems helps in finding answers about how to and in what way these actions can affecting natural systems, and consequently in the planning of better conservation strategies. One way to access the ecological processes that are difficult to monitor is to find groups of organisms that are affect by these changes. The sensitivity of ant assemblages, combined with their functional importance and easy of sampling makes them excellent organisms for conservation studies. The present study evaluated the structure of ant assemblages in three protect areas in the Brazilian Atlantic Forest. Ants were sampled within a continuous forest in the Serra do Mar State Park, southeastern Brazil, in disturbed and undisturbed areas. The objective was to determine if richness, composition and abundance of ant assemblages differ between contrasting areas in relation to the degree of human disturbance. Results showed that ant richness has not changed between areas with different disturbance history, while the composition has changed dramatically in two of the three areas. The abundance of leaf-cutting ants was low in all sites and showed no significant differences, and the abundance of Ponerinae was similar across the contrasting areas surveyed. Results suggest that in the studied systems, the effects are dependent of the intensity and frequency of disturbance, and also of the recovery time of disturbed area / Mestrado / Ecologia / Mestre em Ecologia

Les fourmis, comme tous les Hyménoptères, sont caractérisées par un mode de détermination du sexe de type haplodiploïde. Les femelles sont issues d’œufs fertilisés et sont diploïdes alors que les mâles se développent à partir d’œufs non fertilisés par parthénogenèse arrhénotoque, et sont haploïdes. A quelques rares exceptions près, le déterminisme de la caste au sein du sexe femelle est réalisé de manière épigénétique :seules les larves diploïdes les mieux nourries et/ou celles produites après le repos hivernal se développent en femelles sexuées (reines), les autres en femelles non reproductrices (ouvrières). Récemment, plusieurs travaux ont montré que les reines de quelques espèces de fourmis sont capables de maximiser leur succès reproductif en exploitant de manière conditionnelle la reproduction sexuée et asexuée. Alors que les ouvrières sont produites à partir d’œufs fertilisés par reproduction sexuée classique, les jeunes femelles reproductrices sont issues d’œufs diploïdes produits par parthénogenèse thélytoque et sont, par conséquent, génétiquement très similaires à leur mère. L’espèce Cataglyphis cursor est le premier modèle chez lequel cette stratégie reproductrice a été mise en évidence (Pearcy et al. 2004b). Les sociétés de C. cursor sont strictement monogynes, les reines sont hautement polyandres et utilisent la reproduction sexuée et asexuée pour la production d’ouvrières et de femelles reproductrices, respectivement. La combinaison de la polyandrie et de la reproduction thélytoque permet aux reines de C. cursor d’optimiser le taux de transmission de leurs gènes via des filles reproductrices, tout en assurant une diversité génétique maximale au sein de la force ouvrière. Par ailleurs, les ouvrières de C. cursor ont conservé leurs ovaires et se reproduisent en l’absence de reine. Elles produisent alors des mâles (par parthénogenèse arrhénotoque), des femelles sexuées et des ouvrières (par parthénogenèse thélytoque) (Cagniant, 1973)<p>Les travaux réalisés dans le cadre de cette thèse de doctorat visent à déterminer si les stratégies reproductrices remarquables exploitées par C. cursor sont propres à l’espèce ou si elles ont évolué au sein de plusieurs espèces du genre. A cette fin, nos recherches s'articulent autour de 2 axes complémentaires. Premièrement, nous avons approfondi l'étude des stratégies reproductrices chez C. cursor en nous concentrant sur deux aspects. (i) Plusieurs hypothèses ont été proposées pour justifier l’évolution de la polyandrie chez les fourmis. Nos travaux ont testé et éliminé trois d’entre elles pour C. cursor :l’hypothèse de la limitation spermatique, celle des coûts des mâles diploïdes et celle selon laquelle une plus grande variabilité génétique des ouvrières améliorerait la division du travail. (ii) Nous avons mis en évidence l’existence d’un contrôle des reines dans le déterminisme de la caste chez cette espèce. Les reines ne produisent des œufs thélytoques qu’au début du printemps, lorsque les ouvrières élèvent les œufs en sexués. Plus tard dans la saison, les reines ne produisent plus que des œufs fertilisés qui se développeront en ouvrières. <p>Deuxièmement, à titre comparatif, nous avons analysé la structure socio-génétique de deux autres espèces de Cataglyphis :C. sabulosa et C. livida. Ces deux espèces sont monogynes et polyandres. Leurs ouvrières sont capables de pondre des œufs haploïdes mais seules les ouvrières de C. sabulosa ont produits des œufs diploïdes thélytoques. Aucune des reines des deux espèces n’utilisent la parthénogenèse thélytoque pour produire des femelles sexuées.<p>L’ensemble des résultats obtenus dans notre étude ont été replacés dans une perspective évolutive afin de préciser quand la polygynie, la polyandrie et la thélytoquie seraient apparues dans la phylogénie des Cataglyphis. <p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

[Truncated abstract] In the crop growing areas of Western Australia, two economically important weed species, Lolium rigidum Gaud. (annual ryegrass) and Raphanus raphanistrum L. (wild radish), have evolved widespread herbicide resistance to multiple chemistry groups. Consequently, grain growers in the region have adopted an integrated approach to weed management that includes many non herbicide tools, however many more are needed as these weed species become increasingly more difficult to control. This thesis examines, in a series of field trials carried out in the Western Australian crop growing area, the potential for weed seed predation of annual ryegrass and wild radish by naturally occurring granivores as a new weed management tool for grain growers . . . The study discusses the implications of these results with the view to manipulating predation of weed seed through agricultural management practices. Ants were shown to be the dominant seed predator in this environment, especially in the centre of fields. The study has identified that the ant species Melophorus turneri (Forel), Monomorium rothsteini (Forel), Pheidole hartmeyeri (Forel) and Rhytidoponera metallica (Smith) are potential biological control agents for annual ryegrass seeds while P. hartmeyeri was identified as the only species suitable for biological control of wild radish seed pods. Ants were found to be sensitive to disturbance and some to crop residue type and these effects are discussed in relation to seed removal. This study of weed seed predation in agricultural fields is the most complete in this environment and can be used to inform further work in this area. It has identified that naturally occurring granivores can be used as a weed management tool.

Orientadores: Antonio Carlos Moretti, Luis Leduino de Salles Neto / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-15T18:13:59Z (GMT). No. of bitstreams: 1 Marciniuk_FernandaLedo_M.pdf: 1221484 bytes, checksum: b1408936331c027b4c3cc1129bc0105a (MD5) Previous issue date: 2010 / Resumo: O problema de corte de estoque ordenado, um problema relativamente novo na literatura, e uma adaptação do problema de corte de estoque tradicional onde algumas restrições quanto a limitação do numero de ordens de produção em processamento são adicionadas. Esta dissertação tem como objetivo estudar uma nova abordagem deste problema utilizando uma aplicação da metaheurística colônia de formigas. Esta metaheurística utiliza os princípios de auto-organização de uma população de formigas visando a resolução de problemas de otimização combinatorial / Abstract: The Ordered Cutting Stock Problem (OCSP), a relatively recent problem in technical literarture, is a variant of the more well-known Cutting Stock Problem (CSP). This variant includes some new constraints in the mathematical formulation, regarding the number of production orders being processed simultaneously. This work studies a new approach to solve the OCSP, applying the Ant Colony Optimization (ACO) metaheurisitic. This metaheuristic is based in the self-organizing principles that govern ant population's behaviour, solving combinatorial optimization problems / Mestrado / Pesquisa Operacional / Mestre em Matemática Aplicada

Les insectes sociaux représentent le paradigme de la vie coopérative dans le règne animal. Ceci repose sur l’existence d’une division des activités reproductrices entre des individus reproducteurs (les reines et les mâles) et une majorité d’ouvrières sacrifiant leurs propres potentialités reproductives pour assurer l’essentiel des tâches logistiques nécessaires à l’essor des sociétés. Chez les Hyménoptères sociaux, l’analyse comparative des stratégies de reproduction révèle que la structure monogyne (une reine par société) et monandre (un seul accouplement par reine) est l’état ancestral des sociétés. Cette structure favorise une corrélation génétique élevée entre les ouvrières et le couvain qu’elles élèvent et, par conséquent, leur succès reproductif global (inclusive fitness). Cependant, un nombre croissant d’études génétiques montre que la structure des sociétés peut fortement s’éloigner de ce pattern. Ceci est particulièrement manifeste chez les fourmis, lesquelles présentent un très large polymorphisme social se traduisant par une grande variabilité du nombre de femelles reproductrices au sein des sociétés. Les formicidés sont également remarquables par la diversité de leurs modes de reproduction. Cette diversité concerne la fréquence des accouplements (monandrie/polyandrie) ou encore l’exploitation conditionnelle des modes de reproductions sexuée et asexuée. Chez quelques espèces, les futures reines sont en effet produites par parthénogenèse (elles sont des quasi-clones de leur mère), alors que les ouvrières sont issues d'une reproduction sexuée classique. Cette stratégie exceptionnelle permet aux reines d'accroître le taux de transmission de copies de leurs gènes dans la descendance, tout en conservant les bénéfices d'une diversité génétique dans la force ouvrière. Cette grande diversité de structures sociales et de modes de reproduction suggère l’action de nombreuses pressions sélectives. Les travaux réalisés dans le cadre de cette thèse de doctorat visent à déterminer les facteurs responsables du large polymorphisme social et des nombreux modes de reproduction observés chez les fourmis désertiques du genre Cataglyphis. Ils sont articulés autour de deux axes principaux. <p>Les analyses phylogénétiques montrent que la polyandrie est ancestrale au sein du genre Cataglyphis. Le premier axe de ce travail a pour but d’étudier les causes évolutives justifiant le maintien d’un tel système de reproduction au sein de ce genre. Ce travail porte sur les avantages d’une diversité génétique accrue parmi les ouvrières. Une telle diversité génétique permettrait notamment d'accroître le polymorphisme de taille des ouvrières et l'efficacité de la division du travail [Chapitre 1], ou la résistance aux pathogènes de la force ouvrière [Chapitre 2]. [1] Ce premier travail a été réalisé sur Cataglyphis cursor, une espèce strictement monogyne et polyandre. Les résultats de cette étude révèlent une très grande fidélité des ouvrières à la tâche. Ils montrent l’existence d’une association significative entre la tâche réalisée par une ouvrière et sa lignée paternelle, ainsi qu’entre la taille des ouvrières et la tâche effectuée. [2] Le second travail de cette thèse a été réalisé chez C. mauritanica. Nos résultats montrent que la résistance aux pathogènes diffère entre ouvrières issues de différentes lignées paternelles lorsque ces dernières sont isolées. Curieusement, cette différence s’estompe lorsque les lignées paternelles sont regroupées au sein des sociétés polyandres. Dès lors, la polyandrie permettrait d’homogénéiser l’immunité des sociétés. Nos données montrent cependant que la résistance des ouvrières à Metarhizium anisopliae n’est pas corrélée à la diversité génétique de la colonie ou au nombre d’accouplements des reines.<p>Le second axe de ce travail porte sur les stratégies de reproduction remarquables observées chez les espèces de Cataglyphis appartenant au groupe altisquamis :C. velox, C. mauritanica, C. humeya et C. hispanica. Ces espèces partagent une stratégie unique dans le règne animal, appelée hybridogénèse sociale. L’hybridogénèse classique est un système reproductif dans lequel les parents issus de lignées génétiques distinctes s’hybrident. Alors que les génomes maternels et paternels sont exprimés dans la lignée somatique des descendants, le génome paternel est systématiquement écarté de la lignée germinale. En conséquence, seul le génome maternel est transmis aux générations futures. Dans le schéma d’hybridogénèse sociale reporté dans ces travaux, les reines s’accouplent systématiquement avec un mâle originaire d’une lignée génétique distincte. Elles utilisent la reproduction sexuée pour la production d’une caste ouvrière stérile intégralement hybride (analogue à la lignée somatique) et la reproduction asexuée par parthénogénèse pour la production des castes reproductrices mâles et femelles (analogues à la lignée germinale). Dans ce système, bien que les génomes paternels et maternels soient exprimés dans la caste ouvrière, seul le génome maternel est transmis aux descendants reproducteurs [Chapitre 3]. Le groupe altisquamis est représenté par plusieurs espèces au sein desquelles deux lignées génétiques s’hybrident systématiquement pour la production de la caste ouvrière. Le dernier chapitre de cette thèse [4] est une analyse phylogéographique des espèces de ce groupe dans la péninsule ibérique. Les résultats confirment l’existence d’une seule paire de lignées génétiques au sein de chaque espèce. Ces résultats révèlent également une contradiction entre les marqueurs nucléaires et mitochondriaux traduisant la complexité du système reproductif. Ces travaux soulignent l’ambiguïté des relations phylogéniques entre espèces d’un tel système et discutent de son implication dans la spéciation des espèces hybridogénétiques. <p><p><p>Social insects represent the most extreme form of cooperative life in the animal kingdom. This is based on the existence of a division of reproductive activities between the reproductive individuals (queens and males) and a majority of workers performing all logistical tasks at the expense of their own reproduction. In social Hymenoptera, comparative analysis of reproductive strategies reveals that colonies headed by a single mated queen (monogyny/monoandry) is the ancestral structure of colonies. This structure provides a high genetic correlation between the workers and the brood they raise and, therefore, their overall reproductive success (inclusive fitness). However, an increasing number of genetic studies reveal that the reproductive structure of colonies can strongly differ from this pattern. This is particularly obvious in ants, which have a very large social polymorphism resulting in a large variability in the number of reproductive females within colonies. The Formicidae are also remarkable for the diversity of their modes of reproduction. This diversity relates to mating frequency (monoandry/polyandry) or conditional use of sexual and asexual reproduction. In some species, new queens are produced by parthenogenesis (they are almost clones of their mothers), while the workers arise from a classical sexual reproduction. By using alternative modes of reproduction for queen and worker castes, queens can increase the transmission rate of their genes to their reproductive female offspring while maintaining genetic diversity in the worker population. This high diversity of social structures and modes of reproduction suggests the occurrence of many selective forces. This thesis aimed at determining environmental and genetic factors responsible for the large social polymorphism and the high diversity of reproductive modes display by Cataglyphis desert ants. This thesis is divided into two main parts. <p>Phylogenetic analyses show that polyandry is ancestral across the genus Cataglyphis. The first part of this thesis examines the genetic hypothesis to account for the evolution and maintenance of multiple mating by queen in this genus. This work focuses on the benefits of increased genetic diversity among workers. Such genetic diversity may increase the size polymorphism of the worker force and improve efficiency of the division of labor [Chapter 1] or increase pathogen resistance of the colony [Chapter 2]. In Chapter 1, the genetic hypothesis to enhance efficiency of division of labor was tested on Cataglyphis cursor, a strictly monogynous and polyandrous species. The results reveal a great fidelity in task performance by workers. They reveal a significant association between patriline and task preference: workers belonging to different patrilines differ in their propensity to perform a given task. We also found that worker size is closely associated with task specialization. The second work of this thesis [Chapter 2] was performed in C. mauritanica. Our results show that resistance to pathogens differs between workers from different patrilines when patrilines are raised separately. Surprisingly, this difference disappears when the patrilines are grouped within polyandrous colonies. Therefore, polyandry would standardize the overall resistance of colonies. Consistent with this result, our data show a positive association between the number of matings by the queens and colony resistance to Metarhizium anisopliae. <p>The second part of this thesis expounds the unorthodox reproductive strategies observed in species belonging to the group Cataglyphis altisquamis: C. velox, C. mauritanica, C. hispanica and C. humeya. These species share a unique strategy in the animal kingdom, called social hybridogenesis. Hybridogenesis is a sexual reproductive system, whereby parents from different genetic origin hybridize. Both the maternal and paternal genomes are expressed in somatic tissues, but the paternal genome is systematically excluded from the germ line, which is therefore purely maternal. Consequently, only the maternal genome spread across generations. Here, we report a unique case of hybridogenesis at a social level. Queens mate exclusively with males originating from a different genetic lineage than their own to produce hybrid workers, while they use parthenogenesis to produce the male and female reproductive castes. In consequences, all sterile workers (somatic line) are sexually produced hybridogens, whereas sexual forms (germ line) are clonally produced. Thus, only maternal genes are perpetuated across generations [Chapter 3]. The group C. altisquamis is represented by several hybridogenetic species in which two highly divergent genetic lineages co-occur, despite their constant hybridization. The last chapter of this thesis [Chapter 4] is a phylogeographic analysis of C. altisquamis species in the Iberian Peninsula. Our results confirm the existence of a single pair of genetic lineages within each species. Our results also reveal strong incongruences between nuclear and mitochondrial markers that reflect the reproductive system complexities. These studies reveal phylogenetic ambiguities among these hybridogenetic species and discuss the involvement of such unconventional system in speciation process.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished