The emergence of specialization in heterogeneous artificial agent populations

In this dissertation, I present the Weight-Allocated Social Pressure System (WASPS). WASPS is a computational framework that when applied, can allow for the increase in agent specialization within a multi-agent population. Research has shown that specialization can lead to an overall increase in the productivity levels within a population [55]. WASPS aims to provide a mix of features from existing frameworks such as the genetic threshold and social inhibition models. It also subsumes these models, and allows hybrids of them to be created. It provides individual level behaviour as found in the genetic threshold model. As in some variations of the genetic threshold model [49], WASPS also allows for individual level learning. As found in the social inhibition models, WASPS allows for social influence, or population level learning. Unlike some models, WASPS allows agents to self-organize based on available tasks. In addition, it makes allowances for agents to allocate a resource among multiple tasks during a work period, wherein most models allow the selection of only one task. WASPS allows the assumption that agents are heterogeneous in their task performance aptitudes. It thus aims to create skill-based agent specialization within the population. This will allow more skilled agents to allocate more resources to tasks for which they have comparative advantages over their competition. Because WASPS is self-organizing, it can handle the addition and removal of agents from social networks, as well as changes in the connections between agents. WASPS does not limit the definition of many or its parameters, which allows it to deal with changing definitions for those parameters. For example, WASPS can easily adjust to deal with changing definitions of agent skill and influence. In fact, the individual level learning can be implemented in such a way that an agent can self-optimize even when it has no competitors to influence it

Modeling Decentralized Organizational Change in Honeybee Societies

Multi-agent organizations in dynamic environments, need to have the ability to adapt to environmental changes to ensure a continuation of proper functioning. Such adaptations can be made through a centralized decision process or come from the individuals within the organization. In the domain of social insects, such as honeybees and wasps, organizations are known to adapt in a decentralized fashion to environmental changes. An organizational model for decentralized organizational change is presented that can aid in analyzing and designing such organizations. The model is specified by dynamic properties at different aggregation levels. At the lowest level such properties characterize the behavior of individual roles, which can be related to higher level properties that express important elements such as survival of an organization. A honeybee colony is used as a case study

Inspired Design: Using Interdisciplinarity And Biomimicry For Software Innovation

This thesis presents research and proposes a framework for increasing the breadth and depth of interdisciplinary knowledge in the field of computer science. The intent is to address an increasing problem of complexity in software and computing systems. The approach is to equip software developers and computer scientists with a contextual perspective and a set of strategies for injecting innovation and creativity into the solutions they design by leveraging knowledge and models outside the traditional realm of computer science. A review of current and historical forms of interdisciplinarity and biomimicry are presented to build that context. The strategies presented include interdisciplinary education, interdisciplinary collaboration, interdisciplinary tools, biomimetic design, and the creation of new pattern languages based on nature\u27s design solutions. Each of these strategies stems from and leads to an open exchange of knowledge across disciplinary boundaries. When taken together, the knowledge and strategies presented are intended to inspire and foster a paradigm that recognizes the value of human and natural diversity as a source of innovation

Individuality and consistency in foraging behaviour of the Bumblebee Bombus terrestris

PhDMany vertebrates and a few invertebrates are known to show individual-specific consistency in their behaviour across time and situations, sometimes in ways that can be paralleled with human personality. Despite their relatively small brains, bees show remarkable cognitive abilities. It is therefore not unreasonable to speculate that, as other animals with such cognitive abilities, they too would be able to show some form of animal personality. The first three chapters of this work are theoretical and discuss relevant concepts and controversies in the field of animal personality. Chapter 4 explored the possibility of individual bees differing in their ability to learn to associate stimuli with reward. While some bees learned to differentiate between two stimuli with a high degree of accuracy, others made frequent mistakes, independently of the modality or dimension of the stimuli considered. Bees therefore appeared to differ individually in their ability to discriminate between stimuli. Chapter 5 of this work aimed at answering the question of whether individual bees consistently differ in their behaviour, which is a prerequisite to establishing the existence of personality in any animal. Individual bees’ response to novelty (neophobianeophilia) was found to be relatively predictable within a short time scale but not on the long term. Neophobia-neophilia is therefore an episodic personality trait. Chapter 6 was concerned with individual responses to a simulated predation threat. Individual bees were found to vary widely, both qualitatively and quantitatively. These responses were consistent through time and so were other features of their foraging behaviours. Taken together, my findings provide an insight into individual variations in foraging behaviour in the bumblebee Bombus terrestris and represent good evidence for the existence of individual consistency, thus paving the way for further research into personality traits in this species

Honey Bee Health

Over the past decade, the worldwide decline in honey bee populations has been an important issue due to its implications for beekeeping and honey production. Honey bee pathologies are continuously studied by researchers, in order to investigate the host–parasite relationship and its effect on honey bee colonies. For these reasons, the interest of the veterinary community towards this issue has increased recently, and honey bee health has also become a subject of public interest. Bacteria, such as Melissococcus plutonius and Paenibacillus larvae, microsporidia, such as Nosema apis and Nosema ceranae, fungi, such as Ascosphaera apis, mites, such as Varroa destructor, predatory wasps, including Vespa velutina, and invasive beetles, such as Aethina tumida, are “old” and “new” subjects of important veterinary interest. Recently, the role of host–pathogen interactions in bee health has been included in a multifactorial approach to the study of these insects’ health, which involves a dynamic balance among a range of threats and resources interacting at multiple levels. The aim of this Special Issue is to explore honey bee health through a series of research articles that are focused on different aspects of honey bee health at different levels, including molecular health, microbial health, population genetic health, and the interaction between invasive species that live in strict contact with honey bee populations

Prey-predator “Host-parasite” Models with Adaptive Dispersal: Application to Social Animals

abstract: Foraging strategies in social animals are often shaped by change in an organism's natural surrounding. Foraging behavior can hence be highly plastic, time, and condition dependent. The motivation of my research is to explore the effects of dispersal behavior in predators or parasites on population dynamics in heterogeneous environments by developing varied models in different contexts through closely working with ecologists. My models include Ordinary Differential Equation (ODE)-type meta population models and Delay Differential Equation (DDE) models with validation through data. I applied dynamical theory and bifurcation theory with carefully designed numerical simulations to have a better understanding on the profitability and cost of an adaptive dispersal in organisms. My work on the prey-predator models provide important insights on how different dispersal strategies may have different impacts on the spatial patterns and also shows that the change of dispersal strategy in organisms may have stabilizing or destabilizing effects leading to extinction or coexistence of species. I also develop models for honeybee population dynamics and its interaction with the parasitic Varroa mite. At first, I investigate the effect of dispersal on honeybee colonies under infestation by the Varroa mites. I then provide another single patch model by considering a stage structure time delay system from brood to adult honeybee. Through a close collaboration with a biologist, a honeybee and mite population data was first used to validate my model and I estimated certain unknown parameters by utilizing least square Monte Carlo method. My analytical, bifurcations, sensitivity analysis, and numerical studies first reveal the dynamical outcomes of migration. In addition, the results point us in the direction of the most sensitive life history parameters affecting the population size of a colony. These results provide novel insights on the effects of foraging and Varroa mites on colony survival.Dissertation/ThesisDoctoral Dissertation Applied Mathematics for the Life and Social Sciences 201

The assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services on pollinators, pollination and food production

The thematic assessment of pollinators, pollination and food production carried out under the auspices of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services aims to assess animal pollination as a regulating ecosystem service underpinning food production in the context of its contribution to nature’s gifts to people and supporting a good quality of life. To achieve this, it focuses on the role of native and managed pollinators, the status and trends of pollinators and pollinator-plant networks and pollination, drivers of change, impacts on human well-being, food production in response to pollination declines and deficits and the effectiveness of responses

Infection in Honey Bees

Honey bee pathogens are spread worldwide and are strongly related to the decline of honey bee populations, which has severe implications for beekeeping, honey production and ecology. Honey bee pathogens are continuously studied by researchers with the aim to better understand the host­–parasite relationship of these pathogens and the effects that they have on bee colonies. Honey bee pathogens include bacteria (i.e., Melissococcus plutonius and Paenibacillus larvae), microsporidia (i.e., Nosema apis and Nosema ceranae), fungi (i.e., Ascosphaera apis), protozoa (i.e., Lotmaria passim, Crithidia bombi and Crithidia mellificae) and viruses (i.e., ABPV, CBPV, IAPV, KBV, DWV, BQCV and SBV). All of these pathogens are able to infect other bee species; infections would have important implications for their life cycles (e.g., Osmia sp. and Bombus sp.) or cause unknown epidemiological effects for other hymenopterans. In addition, old and new invasive pests (such as Varroa destructor, Aethina tumida, Vespa velutina, etc.) necessitate more studies to define their role as possible vectors or possible sources of infection for honey bees. For these reasons, knowledge on honey bee pathogens has become a matter of public interest and is connected with the critical role of honey bee health. The aim of this Special Issue is to explore honey bee pathogens, considering any aspect in relation to host–pathogen interaction and highlighting the possible interaction and spillover with other bee species and invasive pests, through a series of research articles that focus on different aspects of pathologies

Causes and consequences of individual forager variability in social bees

Chez les pollinisateurs sociaux, comme l'abeille domestique (Apis mellifera L.) et le bourdon terrestre (Bombus terrestris L.), mes deux modèles d'étude, différents individus sont spécialisés dans différentes tâches. Il est admis que différents types de comportement de butinage contribuent à une optimisation des performances de la colonie. Actuellement, les populations de pollinisateurs sont exposées à des stress environnementaux, qui sont connus pour perturber le comportement des individus en visant directement leur cognition. Il est ainsi crucial de mieux comprendre comment les colonies d'abeilles et de bourdons maintiennent une activité de butinage efficace, et quels sont les effets de stress environnementaux sur les butineuses. Dans cette thèse, j'ai donc examiné les différentes stratégies de butinage pour différentes sources de nourriture, pollen et nectar, et les variabilités interindividuelles dans le comportement de butinage. Je me suis aussi intéressé à l'impact de stress tels que les pesticides sur l'efficacité de butinage. J'ai utilisé la technologie RFID pour suivre le comportement des abeilles tout au long de leur vie. J'ai trouvé que les colonies d'abeilles et de bourdons reposent sur un petit groupe d'individus très actifs qui fournissent la majorité de la nourriture pour la colonie. Chez les abeilles, ces individus très actifs sont aussi plus efficaces pour collecter nectar et pollen. J'ai aussi identifié l'existence de différentes stratégies pour la collecte de pollen ou de nectar. Ensuite, j'ai pu montrer que les bourdons ont des différences interindividuelles très marquées dans un test de navigation, une tâche cruciale dans le comportement de butinage. Finalement, j'ai testé l'effet néfaste de pesticides sur l'apprentissage visuel chez l'abeille. Cette thèse a pour but de mieux comprendre les causes de vulnérabilité des pollinisateurs aux stress environnementaux. Mes résultats soulignent le besoin de considérer la diversité comportementale comme une adaptation des espèces de pollinisateurs sociaux, mais aussi comme une potentielle cause de vulnérabilité de la colonie vis-à-vis des stress.In social insects, such as bees, different individuals specialise in the collection of different resources, and it is assumed that natural behavioural variability among foragers contributes to a self-organised optimisation of colony performance. Currently, bee populations are facing an increasing number of environmental stressors, known to disturb the behaviour of individuals, presumably upon their impact on cognitive capacities. Hence it is important to learn more about how stressors impact on individual foraging behaviour to understand how a colony maintains effective nutrition and development. In this thesis in cognitive ecology, I examined the different foraging strategies for the different macronutrient sources, pollen and nectar, and the inter-individual variation in bee foraging performance. I also looked at how stressors, such as pesticides, can impact on bee foraging efficiency. I compared two social Hymenoptera that vary in their level of social complexity: the European honey bee (Apis mellifera L.) and the buffed-tailed bumblebee (Bombus terrestris L.). I used Radio Frequency Identification (RFID) to automatically track the foraging behaviour of bees throughout their life. I found that honey bee and bumblebee colonies rely on a subset of very active bees to supply the whole colony needs. In honey bees, these foragers are more efficient and collect more pollen. I also identified different strategies for pollen or nectar collection in both species. Using manipulative experiments, I then showed that bees exhibit consistent inter-individual different behaviours in a spatial learning task and that pesticides impair visual learning. My thesis aims at better explaining the causes of vulnerability of pollinators to sublethal pesticides and other environmental stressors. The results highlight the need for considering behavioural diversity as an adaptation for social insects, as well as a potential dimension of colony-level vulnerability to environmental stressors that can impair the whole colony nutritional balance