In 2003 years the behaviour of ant Lasius fuliginosus was explored. The trial was made in two ways: a) by different sizes of white sheet of paper then the weather conditions were sunny, cloudy, rainy; b) turning one part of path by cant of 180.

The ant system is a new meta-heuristic for hard combinatorial optimization problems. It is a population-based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem (TSP), but has been also successfully applied to problems such as quadratic assignment, job-shop scheduling, vehicle routing and graph coloring.In this paper we introduce a new rank based version of the ant system and present results of a computational study, where we compare the ant system with simulated annealing and a genetic algorithm on several TSP instances. It turns out that our rank based ant system can compete with the other methods in terms of average behavior, and shows even better worst case behavior. (author's abstract) / Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-04-18Bitstream added on 2014-06-13T20:07:20Z : No. of bitstreams: 1 oliveira_mfss_dr_rcla.pdf: 927200 bytes, checksum: 190eb33eedd48dc2ac945922c0eb1a87 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O presente trabalho teve por objetivo avaliar a eficiência dos óleos brutos de Carapa guianensis Aubl. (andiroba), Elaeis guineensis Jacq. (dendê), Sesamum indicum L. (gergelim), Ricinus communis L. (mamona), Azadirachta indica Juss (nim), Theobroma cacao L. (cacau), Anacardium occidentale L. (caju) e dos extratos de Anacardium occidentale no controle de formigas cortadeiras, utilizando como alvo a espécie Atta sexdens rubropilosa. De acordo com os resultados obtidos nos testes de toxicidade, alguns óleos brutos e extratos foram selecionados para serem incorporados em iscas ou aplicados por nebulização e testados em colônias de laboratório. Os óleos brutos e extratos mais eficientes no controle dessas colônias foram selecionados para testes de campo. Os resultados obtidos nos testes permitiram selecionar os óleos brutos de C. guianensis, E. guineensis, S. indicum, R. communis, A. indica, A. occidentale e os extratos hexânico, diclorometano, acetato de etila e metanólico de A. occidentale para serem aplicados por nebulização e os óleos brutos de E. guineensis, A. indica e A. occidentale para serem incorporados em iscas e testados em colônias de laboratório. Em colônias de laboratório, a nebulização com os óleos brutos de C. guianensis, E. guineensis, S. indicum, R. communis e A. indica não causaram efeitos deletérios nas colônias e, portanto, não devem ser indicados como produtos nebulizáveis no controle de formigas cortadeiras. No entanto, o óleo bruto e os extratos hexânico, diclorometano, acetato de etila e metanólico de A. occidentale propiciaram a extinção das colônias. As iscas contendo óleos brutos de E. guineensis, A. indica e A. occidentale não causaram nenhum efeito nas colônias e, portanto, não devem ser indicadas para o controle de formigas cortadeiras. O óleo bruto de A. occidentale foi testado em colônias de campo de Atta sexdens rubropilosa e Atta bisphaerica por meio da termonebulização e da nebuli / The present work aimed to evaluate the efficiency of crude oils of Carapa guianensis Aubl. (crabwood), Elaeis guineensis Jacq. (African oil palm), Sesamum indicum L. (sesame), Ricinus communis L. (castor beans), Azadirachta indica Juss (neem), Theobroma cacao L. (cocoa), Anacardium occidentale L. (cashew nut) and crude extracts of Anacardium occidentale on leafcutting ants control, using Atta sexdens rubropilosa as model. Toxicity bioassays with ant workers were done using: 1) treatments by incorporation of crude oils or extracts in artificial diet and 2) treatments by topic application of crude oils or extracts on the ants pronotum. According to obtained results in toxicity tests, some crude oils and extracts were select to be incorporated in baits or applied by nebulization and tested on laboratory colonies. The crude oils or extracts more efficient on laboratory colonies control were tested on field grown up colonies. The obtained results in all toxicity tests permitted to select crude oils of C. guianensis, E. guineensis, S. indicum, R. communis, A. indica, A. occidentale and hexane, dichloromethane, ethyl acetate and methanol extracts of A. occidentale to be applied by nebulization and crude oils of E. guineensis, A. indica and A. occidentale to be incorporated in baits and tested on laboratory colonies. On laboratory colonies, the nebulization with crude oils of C. guianensis, E. guineensis, S. indicum, R. communis and A. indica didn't cause any effect on colonies. Therefore, these crude oils don't must be used to leaf-cutting ants control. However, crude oil and hexane, dichloromethane, ethyl acetate and methanol extracts of A. occidentale propitiated the extinction of colonies. The E. guineensis, A. indica and A. occidentale baits didn't any cause effect on colonies hence it follows that these baits don't must be used to leaf-cutting ant's control.

Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-30Bitstream added on 2014-06-13T19:46:41Z : No. of bitstreams: 1 bution_ml_dr_rcla.pdf: 2579345 bytes, checksum: d33353301f6a8da2b554a3ec7b12d3f7 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Foram realizados estudos comparados do proventrículo, ventrículo, íleo e túbulos de Malpighi de três espécies pertencentes ao gênero Cephalotes: C. atratus, C. pusillus e C. clypeatus, objetivando buscar relações entre elas, assim como, diferenças histoquímicas e ultra-estruturais tanto da parede como do conteúdo destas porções do trato digestivo, que pudessem ser utilizadas para a melhor compreensão da função intestinal, bem como esclarecer quais e como os recursos alimentares são aproveitados em cada parte do trato digestivo. As características ultra-estruturais do ventrículo de Cephalotes atratus, C. clypeatus e C. pusillus, mostram que o epitélio do ventrículo repousa sobre uma lâmina basal contínua e é formado basicamente por três tipos celulares, sendo estas as células digestivas, as células regenerativas e as goblet cells. Nestas formigas, o retículo endoplasmático rugoso além de atuar na produção de enzimas digestivas também está envolvido na estocagem de íons em vacúolos especializados presentes no ventrículo. Estas concreções são os esferocristais e podem estar contribuindo com a estabilização do pH e permanência das bactérias simbiontes presentes por entre as microvilosidades. Secções realizadas ao longo do íleo revelaram diferenças entre três principais regiões: proximal, mediana e distal. As especializações estruturais presentes no íleo destas três espécies de formigas resultam em implicações especialmente relacionadas com as bactérias simbiontes aí hospedadas. Também foram realizados testes para verificar a diversidade da microbiota intestinal das porções em questão, usando a técnica DGGE. Assim sendo, o perfil molecular dos simbiontes do ventrículo e íleo de Cephalotes atratus, C. clypeatus e C. pusillus foi obtido analisando a região variável V3 do gene 16S do rDNA bacteriano... / This study compared the proventriculus midgut, ileum, and Malpighian tubules of three ants of the genus Cephalotes: C. atratus, C. pusillus, and C. clypeatus, by examining histochemical and ultrastructural differences in the wall and the content of these portions that could be used to better understand the intestinal function, as well as clarify which and how food resources are used in each part of the digestive tract. The ultrastructural analysis of the midgut of Cephalotes atratus, C. clypeatus, and C. pusillus reveled that the epithelium of the midgut lays on a basal lamina and is composed basically of three cell types: digestive cells, generative cells, and goblet cells. In these ants, the rough endoplasmic reticulum, in addition to producing digestive enzymes, is involved in ion storage in specialized vacuoles present in the midgut. These concretions are spherocrystals and may contribute to stabilize the pH and to maintain symbiotic bacteria found in between microvilli. Sections along the ileum revealed differences among the three main regions: proximal, medial, and distal. The structural specializations present in the ileum of these three ants have implications especially to the symbiotic bacteria. The DGGE method was also performed to assess the diversity of the intestinal microbiota of the portions of the digestive tract. The molecular profile of the symbionts of the midgut and ileum of Cephalotes atratus, C. clypeatus, and C. pusillus was obtained using the variable region V3 of the bacterial 16S rDNA gene sequence. Two samples of C. atratus, three of C. clypeatus, and six of C. pusillus were analyzed. The results showed similarity indices from 80% to 94% between the samples of symbionts from C. atratus and C. clypeatus, despite being collected in sites geographically distant. The variability of symbionts found in the samples of C. pusillus ranged from 45%... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-10-14Bitstream added on 2014-06-13T20:46:50Z : No. of bitstreams: 1 diniz_ea_dr_rcla.pdf: 624691 bytes, checksum: 0bce2c8708444f08d4428ee602667889 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho teve como objetivo o estudo da evolução dos comportamentos de preparação do substrato, cuidado com a cria e cuidado com a rainha e alados em formigas cultivadoras de fungo. Estas formigas pertencem à tribo Attini, subfamília Myrmicinae, e ocorrem exclusivamente no continente americano. Esta tribo contém aproximadamente 230 espécies, porém pouco se conhece da biologia da maioria delas, graças ao fato de serem extremamente crípticas e de não apresentarem importância econômica, como as formigas cortadeiras, que são as mais estudadas. Foram utilizadas seis espécies, que representam bem os diversos níveis da filogenia da tribo: Acromyrmex disciger, Apterostigma pilosum, Mycetarotes parallelus, Myrmicocrypta sp., Trachymyrmex fuscus e Trachymyrmex sp. nov. Os comportamentos foram estudados em ninhos mantidos em laboratório, com o auxílio de micro-câmeras e um aparelho gravador de vídeo. Os comportamentos foram analisados, caracterizados e quantificados. Os resultados foram divididos em três capítulos de acordo com o tipo de comportamento. No capítulo sobre a evolução dos comportamentos de preparação do substrato foi observado que, basicamente, o processo evoluiu no sentido de aumentar a capacidade das operárias em decompor inicialmente o substrato. As espécies basais, A. pilosum, M. parallelus e Myrmicocrypta sp. apresentaram um processamento mais simples com um número menor de comportamentos e principalmente sem os comportamentos do tratamento químico, que é responsável pela fragmentação do substrato ao mesmo tempo em que ele é tratado com enzimas digestivas. As duas espécies do gênero Trachymyrmex apresentaram um processo mais complexo com grande participação do tratamento químico. Em A. disciger, que é uma cortadeira, há uma intensa especialização do sistema de castas para o aumento da eficiência... / This work aims to study the evolution of the behaviors of substrate preparation, brood, queen and winged forms care in fungus growing ants. These ants are included in the tribe Attini, subfamily Myrmicinae, and occur exclusively in the american continent. This tribe contains approximately 230 species, but little is known about the biology of most of them, tanks to the fact that they show very cryptic habits and are not economically important, like the leaf cutting ants, which are the most studied. Six species were used in this work, which represent well all the levels of the phylogeny of the tribe: Acromyrmex disciger, Apterostigma pilosum, Mycetarotes parallelus, Myrmicocrypta sp., Trachymyrmex fuscus and Trachymyrmex sp. Nov. The behaviors were studied in laboratory nests, with a set of micro cameras and a video recording device. The behaviors were analyzed, characterized and quantified. The results were summarized and discussed in tree chapters, arranged by type of behavior. In the chapter about the evolution of the substrate preparation behaviors, basically it is assumed that this process evolved in order to develop the capacity of previously decompose the substrate by the workers. In the basal species, A. pilosum, M. parallelus and Myrmicocrypta sp. this process is very simple with a small number of behaviors and principally without the behaviors of chemical treatment, which are responsible for the fragmentation of the substrate as it is treated by with digestive enzymes. In the two species of the genus Trachymyrmex, the process became more complex and showed a greater participation of these behaviors. A. disciger, witch is a leaf cutting ant, showed an extensive specialization of physical castes in all the phases of the process which elevated it’s efficiency. In the chapter about the evolution of the behaviors of brood care... (Complete abstract click electronic access below)

The Coalition Structure Generation (CSG) problem requires finding an optimal partition of a set of n agents. An optimal partition means one that maximizes global welfare. Computing an optimal coalition structure is computationally hard especially when there are externalities, i.e., when the worth of a coalition is dependent on the organisation of agents outside the coalition. A number of algorithms were previously proposed to solve the CSG problem but most of these methods were designed for systems without externalities. Very little attention has been paid to finding optimal coalition structures in the presence of externalities, although externalities are a key feature of many real world multiagent systems. Moreover, the existing methods, being non-heuristic, have exponential time complexity which means that they are infeasible for any but systems comprised of a small number of agents. The aim of this research is to develop effective heuristic methods for finding optimal coalition structures in systems with externalities, where time taken to find a solution is more important than the quality of the solution. To this end, four different heuristics methods namely tabu search, simulated annealing, ant colony search and particle swarm optimisation are explored. In particular, neighbourhood operators were devised for the effective exploration of the search space and a compact representation method was formulated for storing details about the multiagent system. Using these, the heuristic methods were devised and their performance was evaluated extensively for a wide range of input data.

abstract: Like individual organisms, complex social groups are able to maintain predictable trajectories of growth, from initial colony foundation to mature reproductively capable units. They do so while simultaneously responding flexibly to variation in nutrient availability and intake. Leafcutter ant colonies function as tri-trophic systems, in which the ants harvest vegetation to grow a fungus that, in turn, serves as food for the colony. Fungal growth rates and colony worker production are interdependent, regulated by nutritional and behavioral feedbacks. Fungal growth and quality are directly affected by worker foraging decisions, while worker production is, in turn, dependent on the amount and condition of the fungus. In this dissertation, I first characterized the growth relationship between the workers and the fungus of the desert leafcutter ant Acromyrmex versicolor during early stages of colony development, from colony foundation by groups of queens through the beginnings of exponential growth. I found that this relationship undergoes a period of slow growth and instability when workers first emerge, and then becomes allometrically positive. I then evaluated how mass and element ratios of resources collected by the ants are translated into fungus and worker population growth, and refuse, finding that colony digestive efficiency is comparable to digestive efficiencies of other herbivorous insects and ruminants. To test how colonies behaviorally respond to perturbations of the fungus garden, I quantified activity levels and task performance of workers in colonies with either supplemented or diminished fungus gardens, and found that colonies adjusted activity and task allocation in response to the fungus garden size. Finally, to identify possible forms of nutrient limitation, I measured how colony performance was affected by changes in the relative amounts of carbohydrates, protein, and phosphorus available in the resources used to grow the fungus garden. From this experiment, I concluded that colony growth is primarily carbohydrate-limited. / Dissertation/Thesis / Ph.D. Biology 2011

In 2012, London successfully hosted the Games of the XXX Olympiad. The main legacy of hosting the event is the 560 acre, mixed use Queen Elizabeth Olympic Park located in Stratford in the heart of London s former industrial East End. The Park is located across the four Park Boroughs of Hackney, Newham, Tower Hamlets and Waltham Forest, each distinct in character but shaped by similar trends of urban regeneration and gentrification. This research examines the profiles, practices and perceptions of visitors to the Queen Elizabeth Olympic Park as an impact study of mega events conducted within five years after the London Olympics. It draws on research about mega events and urban regeneration with a focus on sports science and geography that has largely neglected visitor experiences as an outcome of mega events. Based on a mixed methods approach combining a longitudinal face-to-face visitor survey conducted over two years, a postal survey among local schools, and interviews with stakeholders, this thesis makes an original contribution to knowledge by proposing a new conceptual framework on mega event legacy and empirical findings on the use and perceptions of The Park by local, regional, national and international visitors. The conceptual approach (Chapter 3) bridges the two distinct literatures of mega-event legacy theory (and more broadly the sports literature) and actor-network theory. The framework allows for the study to approach the research questions from a tridic actor-network perspective, examining how material, immaterial and mainly human dynamic hybrids co-exist in complex webs of relations. It also allows for the unravelling of how these relations have given rise to impacts tied to the developments in the Queen Elizabeth Olympic Park. This unravelling is explored through the remainder of this thesis. Following the description and analysis of methods used in the thesis (Chapter 4), Chapter 5 provides a historic overview of the four Park Boroughs that define the study area of the thesis. The shifting nature of this multicultural area is contextualised in light of several catalytic events (industrialisation, de-industrialisation and finally the Olympic Games). At the heart of this examination is the intention to show that despite the narratives pedalled by policy makers, planners and politicians, areas of East London were inhabited by groups who for several centuries symbiotically produced and reproduced their own diverse identities and ultimately that of East London. Chapter 6 analyses and critiques 35 policy documents released during the Olympic cycle (broadly defined here as the period between 2003 and 2012) and follows both the visible and invisible actants. The key findings are that: poorly executed event planning is inextricably linked to a poor implementation of local community interests; there were unheard and excluded voices, particularly the disadvantaged and displaced, in these policy and planning documents and; that there was little opportunity for the youth voice to be heard. Finally, the analysis of policy documents has underlined the value of reflecting on legacy promises from a longer-term perspective, suggesting that the legally binding bid books should be compared with the actual outcomes from a long-term perspective. The typical visitor to the Queen Elizabeth Olympic Park (Chapter 7) is a white middle-aged male or female (71% over age 25, ~50/50 male and female). They will be visiting the sports facilities and their frequency of use suggests that they have monthly membership to one of the leisure centres. This indicates that they have a relatively high level of both social capital and disposable income. They will reside within the Park Boroughs, often within walking distance of the Park or close to a transport link with a direct transport connection, probably by the Underground system. They will not often visit the Park with under 18s and if they do visit with anyone, it will be their partner or friend, and thus they resemble very closely the typical affluent gentrifier couples. The term experience athlete was coined for these visitors with 53% being from the Park Boroughs. In addition, there were those who came to sight-see, designated as Games tourists of whom 56% of these were international visitors. While ~20% of the visitors to the Park were under age 18 most of these were under 12s attending with their parents. Young people and particularly young people from the Park Boroughs were largely absent from the Park, which was contributed to by discriminatory practices (often under the guise of security issues) which focused on groups of ethnic minority youth. The possible reasons for the absence of young people from the Park are explored and unravelled in Chapter 8 by discussing the results of the semi-structured interviews with local stakeholders and the postal survey with school staff. The key issues raised in this chapter were that: the lack of a representative youth voice with a hidden and perceived to be cosmetic contribution to legacy planning and; the lack of social and financial capital in school staff and young people in combination with the gentrifying process and; spatial factors such as distance from the Park and poor acces routes, all contributed to the absence of young people from the Park. Overall, this thesis stresses the importance of unravelling networks to their fullest extent to truly understand the impact such spaces have on diverse communities.

Havlík, M. Ant Colony Optimization: Implementation and testing of bio-inspired optimization method. Diploma thesis. Brno, 2015. This thesis deals with the implementation and testing of algorithm Ant Colony Optimization as a representative of the family of bio-inspired opti-mization methods. A given algorithm is described, analyzed and subsequently put into context with the problems which can be solved. Based on the collec-ted information is designed implementation that solves the Traveling sale-sman problem. Implementation contains graphical user interface to track the algorithm. Implementation is further optimized using parallel programming and other methods. Finally the implementation compared and summarized results.

abstract: An important component of insect social structure is the number of queens that cohabitate in a colony. Queen number is highly variable between and within species. It can begin at colony initiation when often unrelated queens form cooperative social groups, a strategy known as primary polygyny. The non-kin cooperative groups formed by primary polygyny have profound effects on the social dynamics and inclusive fitness benefits within a colony. Despite this, the evolution of non-kin queen cooperation has been relatively overlooked in considerations of the evolution of cooperative sociality. To date, studies examining the costs and benefits of primary polygyny have focused primarily on the advantages of multiple queens during colony founding and early growth, but the impact of their presence extends to colony maturity and reproduction. In this dissertation, I evaluate the ecological drivers and fitness consequences of non-kin queen cooperation, by comparing the reproduction of mature single-queen versus polygynous harvester ant (Pogonomyrmex californicus) colonies in the field. I captured and quantified the total number and biomass of reproductives across multiple mating seasons, comparing between populations that vary in the proportion of single queen versus polygynous colonies, to assess the fitness outcomes of queen cooperation. Colonies in a mainly polygynous site had lower reproductive investment than those in sites with predominantly single-queen colonies. The site dominated by polygyny had higher colony density and displayed evidence of resource limitation, pressures that may drive the evolution of queen cooperation. I also used microsatellite markers to examine how polygynous queens share worker and reproductive production with nest-mate queens. The majority of queens fairly contribute to worker production and equally share reproductive output. However, there is a low frequency of queens that under-produce workers and over-produce reproductive offspring. This suggests that cheating by reproducing queens is possible, but uncommon. Competitive pressure from neighboring colonies could reduce the success of colonies that contain cheaters and maintain a low frequency of this phenotype in the population. / Dissertation/Thesis / Doctoral Dissertation Biology 2017