Autonomous Role Assignment Using Contact Stimuli in Swarm Robotic Systems

This study proposes a novel autonomous role assignment method for swarm robotic systems using the response threshold model based on local interactions in a dynamic environment. Ants are social insects with high and low pheromone sensitivity. The pheromone sensitivity of ants is related to autonomous role assignment. The response threshold model was proposed to describe the pheromone sensitivity of ants. The conventional response threshold model assumes that an ant knows the number of workers in an ant colony. However, it is difficult for an ant to contact all workers because its functions are very limited. Therefore, our proposed method adopts a response threshold model based on contact stimuli with foraging ants instead of the worker ratio in an ant colony. In this study, to evaluate the proposed method’s robustness in dynamic environments, we apply it to ant foraging problems in environments with varying amounts and distributions of feeds

Amplifying the Prediction of Team Performance through Swarm Intelligence and Machine Learning

Modern companies are increasingly relying on groups of individuals to reach organizational goals and objectives, however many organizations struggle to cultivate optimal teams that can maximize performance. Fortunately, existing research has established that group personality composition (GPC), across five dimensions of personality, is a promising indicator of team effectiveness. Additionally, recent advances in technology have enabled groups of humans to form real-time, closed-loop systems that are modeled after natural swarms, like flocks of birds and colonies of bees. These Artificial Swarm Intelligences (ASI) have been shown to amplify performance in a wide range of tasks, from forecasting financial markets to prioritizing conflicting objectives. The present research examines the effects of group personality composition on team performance and investigates the impact of measuring GPC through ASI systems. 541 participants, across 111 groups, were administered a set of well-accepted and vetted psychometric assessments to capture the personality configurations and social sensitivities of teams. While group-level personality averages explained 10% of the variance in team performance, when group personality composition was measured through human swarms, it was able to explain 29% of the variance, representing a 19% amplification in predictive capacity. Finally, a series of machine learning models were applied and trained to predict group effectiveness. Multivariate Linear Regression and Logistic Regression achieved the highest performance exhibiting 0.19 mean squared error and 81.8% classification accuracy

Inverse Design of Three-Dimensional Frequency Selective Structures and Metamaterials using Multi-Objective Lazy Ant Colony Optimization

With the rise of big data and the “internet of things,” wireless signals permeate today’s environment more than ever before. As the demand for information and security continues to expand, the need for filtering a crowded signal space will become increasingly important. Although existing devices can achieve this with additional components, such as in-line filters and low noise amplifiers, these approaches introduce additional bulk, cost and complexity. An alternative, low-cost solution to filtering these signals can be achieved through the use of Frequency Selective Surfaces (FSSs), which are commonly used in antennas, polarizers, radomes, and intelligent architecture. FSSs typically consist of a doubly-periodic array of unit cells, which acts as a spatial electromagnetic filter that selectively rejects or transmits electromagnetic waves, based on the unit cell’s geometry and material properties. Unlike traditional analog filters, spatial filters must also account for the polarization and incidence angle of signals; thus, an ideal FSS maintains a given frequency response for all polarizations and incidence angles. Traditional FSS designs have ranged from planar structures with canonical shapes to miniaturized and multi-layer designs using fractals and other space-filling geometries. More recently, FSS research has expanded into three-dimensional (3D) designs, which have demonstrated enhanced fields of view over traditional planar and multi-layer designs. To date, nearly all FSSs still suffer from significant shifts in resonant frequencies or onset of grating lobes at incidence angles beyond 60 degrees in one or more polarizations. Additionally, while recent advances in additive manufacturing techniques have made fully 3D FSS designs increasingly popular, design tools to exploit these fabrication methods to develop FSSs with ultra-wide Fields of View (FOV) do not currently exist. In this dissertation, a Multi-Objective Lazy Ant Colony Optimization (MOLACO) scheme will be introduced and applied to the problem of 3D FSS design for extreme FOVs. The versatility of this algorithm will further be demonstrated through application to the design of meander line antennas, optical antennas, and phase-gradient metasurfaces

The Effects of Landscape and Experience on the Navigation and Foraging Behaviour of Bumblebees, Bombus terrestris

Bumblebees live in an environment where the spatial distribution of foraging resources is always changing. In order to keep track of such changes, bumblebees employ a variety of different navigation and foraging strategies. Although a substantial amount of research has investigated the different navigation and foraging behaviours of bumblebees, much less is known of the effects that landscape features have on bumblebee behaviour. In this thesis, a series of experiments were conducted in order to investigate the role that landscape features have on the navigation and foraging behaviour of Bombus terrestris and whether individuals’ experience influences such behaviour. A hedgerow situated next to the colony was not found to significantly shape the flight paths or foraging choices of naïve bumblebees. Homing success was investigated and used as a proxy for foraging range in different environment types. Both the release distance and the type of environment were found to have a significant effect on the homing success of Bombus terrestris workers. Previous experience of the landscape was also found to significantly affect the time it took bumblebees to return to the colony (homing duration) as well as the likelihood of staying out overnight before returning to the colony. When focusing on the first five flights of a naïve bumblebee worker, experience was not found to significantly affect flight duration. Experience, however, significantly affected the weight of pollen foraged. The observed behaviour of bumblebee gynes provisioning their maternal colony with pollen was also investigated. The influx of pollen into the colony was found to affect this behaviour, suggesting that gynes will provision the maternal colony in response to its nutritional needs. The overall results are also discussed within the context of informing landscape management practices. The results presented in this thesis point to the critical role that factors such as the physical landscape and individual experience play in influencing bumblebee behaviour.South Devon Area of Outstanding Natural Beauty (AONB) Uni

The expression and function of gustatory receptors in the honeybee (Apis mellifera)

PhDThe ability to accurately assess the chemical environment is vital to the honeybee and as bees mature, their demands upon their chemical senses change. While honeybee olfaction has been intensively studied, the physiological mechanisms of bee gustation have only recently come to light. Robertson and Wanner (2006) were the first to identify honeybee gustatory receptors (Grs) and in comparison to other insect species, honeybees possess surprisingly few Gr genes (Apis: 10 Gr genes). The current project aimed to assess the expression of honeybee Gr genes and relate this to selection of the two most concentrated components of floral nectar; sugars and amino acids. The behavioural experiments demonstrated that bees are able to differentiate between the two major floral monosaccharides, with both newly emerged and forager bees exhibiting a slight fructose preference over glucose. Additionally, while no individual amino acid solution was preferred over sucrose alone, newly emerged bees were most willing to consume an eight amino acid mixture, probably due to its protein-resemblance, a major dietary component for young bees. Interestingly, the analysis of anatomical receptor gene expression discovered all 10 Gr genes in every gustatory appendage assayed (mouthparts, tarsi and antennae). All receptor genes were additionally expressed internally (gut and brain) indicating that, as in other insect species, honeybee Grs may play a role in nutrient sensing and feeding regulation. Some differential Gr gene expression was discovered between newly emerged and forager bees, indicating altered gustatory sensitivity with task differentiation. Finally, the expression of Gr genes in the forager brain were dependent on the nutritional status of the individual as well as nutritional experience. The current study demonstrated that AmGr3 may be acting as a nutrient sensor, with altered gene expression following starvation or changes in diet.Newcastle University Faculty of Medical science

Variation in and Responses to Brood Pheromone of the Honey Bee (Apis mellifera)

Brood pheromone of the honey bee, (Apis mellifera) has been shown to elicit a wide array of primer and releaser effects on non‐foragers and foragers leading to the regulation of nursing, pollen foraging, and behavioral development such that the behavior of the colony may be regulated by the amount and condition of the larvae. To date, all studies into the effects of brood pheromone have either used uncharacterized whole extracts or a single blend of brood pheromone characterized from a population of honey bees in France. The variation in the relative proportions of the ten fatty‐acid ester components that characterize brood pheromone and some effects of this variation on pollen foraging and sucrose response thresholds were therefore observed. The objectives met in this dissertation were to determine whether changes in brood pheromone component proportions (blend) or amount communicates larval nutritional status and reports the results of observations of nurses and foragers in response to blends of brood pheromone from deprived and‐non deprived larvae, to measure how changes in brood pheromone blend changed pollen foraging behavior and if such changes could account for the pollen foraging differences between Africanized and European bees, and finally to observe the effects of exposure time on brood pheromone blend and to observe whether non‐foragers made contact with the pheromone. Brood pheromone was found to vary by larval rearing environment, but did not elicit the expected behaviors that would support a cue of nutritional status. Brood pheromone also varied significantly by mitochondrial lineage/population source and responses to brood pheromone appeared to be coadapted to blend, suggesting that brood pheromone may be important in race recognition. Finally, brood pheromone varied significantly over time and was found to be removed from sources by bees, suggesting possible mechanisms for loss of effect. Combined the results of this research indicate that brood pheromone blend differences lead to profound changes in colony behavior related to pollen foraging and food provisioning, providing novel tools for colony manipulation and mechanisms for understanding brood rearing division of labor and chemical communication

Bases comportementales et génétiques des apprentissages aversif et appétitif chez l'abeille, Apis mellifera

In a dynamic world, animals constantly face environmental changes that may affect them (Alock, 1997). Their survival depends on their ability to integrate this information in order to adapt their behaviors to subsequent positive or negative outcomes, in other words to their appetitive and aversive learning abilities. This thesis investigates the behavioral, molecular and genetic basis of aversive learning and its putative relationship with appetitive learning in a social group. The honeybee is a social insect which constitutes a profitable model for this study thanks to appetitive conditioning of the proboscis extension response (PER) and aversive conditioning of the sting extension response (SER) protocols that have been developed. To date, aversive conditioning of the SER has involved the use of electric shocks as a negative reinforcement. However, this stimulus is ecologically irrelevant for honeybees and electric currents pass through almost every part of the bee’s body making it difficult to study the dedicated structures and sensory pathways responsible for its detection. In the first chapter, we assessed the impact of high temperatures on SER, a stimulus that is also highly aversive. We showed that a SER may be triggered by heat stimulation of mouthparts, forelegs and antennae. In addition, we demonstrated that honeybees are able to associate an odor with high temperatures, resulting in the odor alone triggering the SER after conditioning. In the second chapter, we mapped the heat sensitivity of the bee’s body recording SER subsequent to heat stimulation. This work revealed that heat stimulation of almost every body structures (beside the wings and the tip of the abdomen) induces a SER. Furthermore, these stimulations may act as aversive reinforcement during an olfactory conditioning of the SER. We then focused on putative peripheral receptors involved in high temperature detection, specifically focusing on HsTRPA (Hymenoptra specific Transient Receptor Potential). Using a neuropharmalogical approach, we showed that HsTRPA exogenous inhibitor injections decrease SER triggered by high temperatures yet have no impact on sucrose PER. These results suggest a putative involvement of HsTRPA in the detection of high temperatures in honeybees. In the third chapter, we investigated the relationship between appetitive and aversive learning. By combining thermal aversive conditioning with the PER conditioning protocol, we studied the distribution of hedonic learning abilities in the hive. Since the queen mates with 15-20 males, the hive is, thus, genetically segmented in as many different patrilines. Our data shows that individual sensitivity to aversive (heat) and appetitive reinforcement varies among workers and determines their learning success in each hedonic modality. In addition, we observed that the better an individual (and therefore a patriline) is at appetitive learning, the less successful it will be in aversive learning, and vice versa. The forth chapter focused on the behavioral plasticity induced by the two types of conditioning. PER and SER are binary responses in an “all or nothing” fashion and subtle behavioral variations are difficult to observe. We therefore investigated if honeybee antennal movements may yield a finer measurement to integrate appetitive and aversive learning. We developed a motion capture system that records antennal movements at high speed. We showed that honeybees modify their antennal response to an odor previously associated with sucrose reward however thermal aversive conditioning did not induce any antennal movement modifications. During this PhD work, we developed two new behavioral assays in harnessed individuals, furthering our understanding on aversive learning in the honeybee. Within the hive, we observed a trade-off between appetitive and aversive hedonic learning, which was genetically influenced. Such cognitive specialization could play a key role in social evolution.Dans un monde dynamique la survie des animaux dépend de leur capacité à intégrer des signaux environnementaux afin d'adapter leur comportement à la survenue de conséquences positives (nourriture) ou négatives (dangers) c'est-à-dire de leurs capacités d’apprentissages associatifs appétitif et aversif. Pendant ce travail de thèse, nous nous sommes intéressés aux bases comportementales, moléculaires et génétiques de l'apprentissage aversif et aux relations existant entre apprentissages aversif et appétitif au sein d'un groupe social. L'abeille est un insecte eusocial qui constitue un modèle de choix pour cette étude grâce à l'existence des protocoles de conditionnement appétitif de la réponse d'extension du proboscis (REP) et de conditionnement aversif de la réponse d'extension du dard (RED). Jusqu'à présent, le renforcement utilisé dans le conditionnement aversif de la RED était un choc électrique. Ce stimulus traversant la majeure partie du corps de l'abeille, il est peu aisé d'étudier les structures responsables de sa détection. Dans un premier chapitre, nous avons donc testé l’effet d’une forte température (65°C) sur la RED. Nous montrons qu’une stimulation thermique au niveau des pièces buccales, des pattes ou des antennes induit une RED. De plus, les abeilles parviennent à associer une odeur à la présentation concomitante d'une forte température. Dans un deuxième chapitre, nous avons cartographié la sensibilité thermique du corps des abeilles en mesurant la RED. Ce travail a montré que la stimulation de presque toutes les parties du corps induit une RED. De plus, ces stimulations peuvent jouer le rôle de renforcement aversif lors d’un conditionnement olfactif de la RED. Nous nous sommes ensuite intéressés aux récepteurs périphériques potentiellement impliqués dans la détection des fortes températures, et en particulier à HsTRPA (Hymenoptera specific Transient Receptor Potential A). Nous montrons que l’injection d'inhibiteurs exogènes de HsTRPA réduit les RED à la température. Ces résultats suggèrent l’implication possible d’HsTRPA dans la détection de la température chez l’abeille. Dans un troisième chapitre, nous nous sommes intéressés aux relations existant entre les capacités d’apprentissages aversif et appétitif des abeilles. En nous appuyant sur le protocole aversif thermique, combiné au protocole de conditionnement de la REP existant, nous avons étudié la distribution des capacités hédoniques appétitive et aversive au sein d'une ruche. La reine étant fécondée par 15-20 mâles, la ruche est segmentée génétiquement en autant de lignées paternelles différentes. Nos données montrent que la sensibilité des individus aux renforcements aversif (chaleur) et appétitif (sucre) détermine leurs performances d'apprentissage au sein de chaque modalité hédonique. Nous montrons de plus l’existence d’un trade-off, sous déterminisme génotypique, entre les capacités cognitives appétitive et aversive au sein de la colonie. Le quatrième chapitre a étudié la plasticité comportementale induite par les deux types de conditionnement. La REP et la RED étant des réponses de type "tout ou rien", nous nous sommes demandé si les mouvements antennaires des abeilles pouvaient procurer une mesure fine et intégrer des apprentissages appétitif et aversif. Nous avons développé un système de capture vidéo enregistrant les mouvements antennaires à haute vitesse. Nous montrons que les abeilles modifient leur réponse antennaire à une odeur après un apprentissage appétitif mais pas après un apprentissage aversif. Durant ce travail de thèse, nous avons ainsi développé deux nouveaux protocoles comportementaux en contention, et avons procuré de nouvelles données sur l’apprentissage aversif chez l’abeille. Nous avons observé un trade-off au sein de la ruche entre les capacités hédoniques appétitive et aversive, sous déterminisme génétique. De telles spécialisations cognitives pourraient jouer un rôle prépondérant dans l'évolution des groupes sociaux

Pollination Ecology and Pollination Evolutionary Processes with Relevance in Ecosystem Restoration – Pollination Biology of Diuris: Testing for Batesian Mimicry in Southwestern Australia

Mimicry is based on the interaction between a mimic, a model and a receiver. While there is increasing recognition of Batesian floral mimicry in plants, there are few confirmed cases where mimicry involves more than one model species. The Australian orchid genus Diuris has been long hypothesised to engage in guild mimicry of a range of co-occurring pea plants (Faboideae). Some clades of Diuris are superficially similar in both colour and shape to those of a guild of yellow and brown pea plants (Faboideae). Here, we test for pollination via mimicry of pea plants in Diuris (Orchidaceae). Additionally, we test for further ecological interactions (non-model plants, pollination limitation, habitat size and plant frequency) in order to assess the reproductive success of the orchids. For addressing these hypothesis we select two study species, occurring in different habitat: Diuris brumalis (Jarrah forest) and Diuris magnifica (Banksia woodland), the latter occurring in fragmented habitat. We test for floral mimicry criteria in both of the species. In order to frame the pollination ecology of the putative model plants, we verify the type of pollinator interactions (generalised vs specialized) occurring in four communities of pea plants in the southwestern Australian Floristic Region (SWAFR). D. brumalis, D. magnifica and the pea plants showed strong flower similarity and were likely to be perceived as the same by pollinators, native bees (Trichocolletes; Colletidae). However, in D. brumalis the orchid reproductive success increased with the local abundance of the model species (Daviesia spp.), while in D. magnifica the reproductive success wasn’t in relation to the putative models. Alternatively, D. magnifica reproductive success was influenced by a non-model pea plant (Hardenbergia) which is locally abundant and widespread in all the study sites. Additionally, habitat size and orchid plant frequency influenced the orchid reproductive success. Pea plant species were visited by between one and four genera of native bees, indicating variation in levels of specialisation of the pollination systems of Faboideae. Several pea plant species showed specialised interactions with bee genera attracted. Unexpectedly, some pea plant species frequently attracted beetles that may play an important role in pollination. Evidence for mimicry of multiple models suggests that D. brumalis and D. magnifica may be engaged in guild mimicry system. Interestingly, D. brumalis and D. magnifica belongs to a complex of species with similar floral traits, suggesting that this represents a useful system for investigating speciation in lineages that employ mimicry of food plants. Furthermore, the study on pollination of Faboideae species of SWAFR, offers a pivotal research for next investigations on pollinator webs and syndromes of Australian pea plants scarcely documented until now