Honey bee foraging: persistence to non-rewarding feeding locations and waggle dance communication

The honey bee, Apis mellifera, is important in agriculture and also as a model species in scientific research. This Master’s thesis is focused on honey bee foraging behaviour. It contains two independent experiments, each on a different subject within the area of foraging. Both use a behavioural ecology approach, with one investigating foraging behaviour and the other foraging communication. These form chapters 2 and 3 of the thesis, after an introductory chapter. Chapter 2. Experiment 1: Persistence to unrewarding feeding locations by forager honey bees (Apis mellifera): the effects of experience, resource profitability, and season This study shows that the persistence of honey bee foragers to unrewarding food sources, measured both in duration and number of visits, was greater to locations that previously offered sucrose solution of higher concentration (2 versus 1molar) or were closer to the hive (20 versus 450m). Persistence was also greater in bees which had longer access at the feeder before the syrup was terminated (2 versus 0.5h). These results indicate that persistence is greater for more rewarding locations. However, persistence was not higher in the season of lowest nectar availability in the environment. Chapter 3. Experiment 2: Honey bee waggle dance communication: signal meaning and signal noise affect dance follower behaviour This study shows that honey bee foragers follow fewer waggle runs as the distance to the food source, that is advertised by the dance, increases, but invest more time in following these dances. This is because waggle run duration increases with increasing foraging distance. The number of waggle runs followed for distant food sources was further reduced by increased angular noise among waggle runs within a dance. The number of dance followers per dancing bee was affected by the time of year and varied among colonies. Both noise in the message, that is variation in the direction component, and the message itself, that is the distance of the advertised food location, affect dance following. These results indicate that dance followers pay attention to the costs and benefits associated with using dance information

Untersuchungen zur Funktion komplexer Lippenmuster der Sexualtäuschorchidee Ophrys heldreichii durch Lernversuche mit der Honigbiene

Sexualtäuschorchideen bieten ihren Bestäubern keine Belohnung sondern imitieren olfaktorische, visuelle und taktile Signale paarungsbereiter Weibchen, um potentielle Bestäubermännchen, hauptsächlich Hymenopteren, anzulocken. Bei der sogenannten Pseudokopulation, dem Versuch der Männchen mit der Blüte zu kopulieren, werden die Pollinien am Thorax oder Abdomen des Männchens angeheftet, sodass es bei Besuch einer weiteren Blüte zur Bestäubung kommt. Nahezu alle Arten der mediterranen Orchideengattung Ophrys betreiben sexuelle Täuschung. Während die meisten ein eher unauffälliges, einheitlich gefärbtes Labellum besitzen, zeigen die Blüten der Arten der Ophrys-holoserica-oestrifera-Gruppe, welche vor allem von Langhornbienen der Gattung Eucera und Tetralonia bestäubt werden, auffällige, sehr variable Muster. Diese Zeichnungen auf den Labella sind vermutlich nicht, wie lange angenommen, Imitationen weiblicher Signale, sondern dienen möglicherweise als Lernerleichterung für die Bestäuber, um ein Wiederkehren und damit eine Selbstbestäubung der Pflanzen zu verhindern. Hierfür müssten die Bienen jedoch in der Lage sein mit ihrem geringen räumlichen Auflösungsvermögen die kleinen und sehr komplexen Muster zu erkennen und zu differenzieren. Um herauszufinden, ob Blüten gleicher Pflanzen einander tatsächlich ähnlicher sind als jene verschiedener Pflanzen, wie es bisher angenommen wurde, wurden die Ähnlichkeiten der Muster auf den Labella von Ophrys heldreichii quantifiziert. Weiters wurden Verhaltensversuche mit Honigbienen durchgeführt, welche durch differentielle Konditionierung trainiert wurden zwischen unterschiedlichen Labellumzeichnungen zu unterscheiden. Dabei wurde untersucht, ob Muster verschiedener Pflanzenindividuen besser gelernt werden können als Muster desselben Blütenstandes und bis zu welchem Abstand zur Blüte die Tiere die Muster noch erkennen können. Die Quantifizierung der Ähnlichkeiten ergab zwischen den Mustern derselben Pflanze tatsächlich eine größere Übereinstimmung des Überlappungsgrades und des Schwarz-Weiß-Verhältnisses als zwischen jenen verschiedener Pflanzen. Die Verhaltensversuche zeigten, dass die Bienen in der Lage waren die variablen Blütenzeichnungen von Ophrys heldreichii zu erkennen und zu unterscheiden. Während Muster unterschiedlicher Pflanzen schnell gelernt und differenziert wurden, konnten die Tiere auch nach langem Training (bis zu 140 Entscheidungen) die Muster desselben Blütenstandes nicht, oder nur kaum, voneinander unterscheiden. Um die gelernten Bilder wiederzuerkennen mussten die Bienen sehr nah an die Stimuli heranfliegen, was darauf hindeuten könnte, dass sie hierfür die Strategie des „template-matchings“ anwandten. Diese Ergebnisse stützen die Hypothese, dass die variablen Muster auf den Blüten der Arten der Ophrys-holoserica-oestrifera-Gruppe der Lernerleichterung der Bestäuber dienen, um ein Wiederkehren dieser zu vermeiden und so das Risiko einer Selbstbestäubung zu reduzieren.Sexual deceptive orchids offer no reward for their pollinators; instead they mimic olfactory, visual and tactile signals of receptive females to attract males, mainly hymenopterans. During the so-called pseudocopulation, when a male attempts to copulate with the flower, the pollinia are transferred to its body, so that pollination can occur during a further visit on the next flower. Almost all species of the Mediterranean orchid genus Ophrys are sexual deceptive. While most species show an inconspicuous, uniform colored Labellum, members of the Ophrys-holoserica-oestrifera-group, which are pollinated primarily by long-horned bees of the genus Eucera and Tetralonia, possess conspicuous, variable patterns. These patterns are probably no imitations of female signals, as long assumed; instead they may have been involved to achieve pollinator’s learning. The patterns can prevent their return and so minimize the plant’s risk of self-pollination. However, this would require that bees, with their low visual spatial resolution, are able to detect and differentiate among the small and complex patterns. To determine if blossoms of the same plant are actually more similar than those of various plants, as was previously assumed, the similarities of the patterns of Ophrys heldreichii were quantified. Furthermore, various behavior experiments with honeybees were carried out. The bees were trained with differential conditioning to distinguish between labellum patterns. The study investigated whether pattern of different plants can be discriminated better than pattern of the same inflorescence and what is the minimum visual angle at which bees are able to recognize the stimuli. The quantification of the pattern similarity show that patterns of the same plant are indeed more similar to each other, than those of various plants, regarding to the degree of pattern overlap or the black-white-ratio. The results of the behavior experiments show, that bees are able to perceive and discriminate the different patterns of Ophrys heldreichii. While patterns of different plants could be quickly learned and differentiated, the bees were not, or just barely, able to discriminate between patterns of the same inflorescence, even after a long training period (up to 140 decisions). To recognize the learned images, the animals had to fly close to the stimuli which suggest, that they used a ‘template-matching’ strategy to solve the tasks. These results support the hypothesis that the variable pattern of the species of the Ophrys-holoserica-oestrifera group are used to increase the pollinators learning-efficiency in order to avoid a return to the same plant, and thus reduce the risk of self-pollination

Go with the flow : visually mediated flight control in bumblebees

Despite their small brains and tiny eyes, flying insects are capable of detecting and avoiding collisions with moving obstacles, and with remarkable precision they navigate through environments of different complexity. For this thesis, I have investigated how bumblebees use the pattern of apparent image motion that is generated in their eyes as they move through the world (known as optic flow), in order to control flight. I analysed the speed and position of bumblebee (Bombus terrestris) flight trajectories as they negotiated arenas of different dimensions and visual complexity. I also investigated the impact of optic flow on bumblebee learning flights, a special kind of flight designed to memorise the location of the nest or a newly discovered food source. The general aim of my research has been to understand how flying insects use vision to actively control their flight. The viewing angle at which optic flow is measured has important consequences for flight in densely cluttered environments, where timely control of position and speed are necessary for effective collision avoidance. I therefore investigated when, and how, bumblebees respond to sudden changes in the magnitude of optic flow. My results reveal that the visual region over which bumblebees measure optic flow is determined by the location in the frontal visual field where they experience the maximum magnitude of translational optic flow. This strategy ensures that bumblebees regulate their position and speed according to the nearest obstacles, allowing them to maximise flight efficiency and to minimise the risk of collision. My results further demonstrate that, when flying in narrow spaces, bumblebees use optic flow information from nearby surfaces in the lateral visual field to control flight, while in more open spaces they rely primarily on optic flow cues from the ventral field of view. This result strengthens the finding that bumblebees measure optic flow for flight control flexibly in their visual field, depending on where the maximum magnitude of translational optic flow occurs. It also adds another dimension to it by suggesting that bumblebees respond to optic flow cues in the ventral visual field if the magnitude is higher there than in the lateral visual field. Thus, the ability to flexibly use the surrounding optic flow field is of great importance when it comes to the control of cruising flight. For this thesis I also investigated the impact of ventral and panoramic optic flow on the control of learning flights in bumblebees. The results show that the presence of ventral optic flow is important for enabling bumblebees to perform well-controlled learning flights. Whether panoramic optic flow cues are present or not does not strongly affect the overall structure of the learning flight, although these cues might still be involved in fine-scale flight control. Finally, I found that, when the availability of ventral optic flow is limited to certain heights, bumblebees appear to adjust their flight parameters to maintain the perception of ventral optic flow cues. In summary, the results compiled in this thesis contribute to a better understanding of how insects use visual information to control their flight. Among other findings, my results emphasize the importance of a being able to flexibly measure optic flow in different parts of the visual field, something that enhances bees’ ability to avoid collisions

An ‘instinct for learning’: the learning flights and walks of bees, wasps and ants from the 1850s to now

This is the final version. Available on open access from the Company of Biologists via the DOI in this recordThe learning flights and walks of bees, wasps and ants are precisely coordinated movements that enable insects to memorise the visual surroundings of their nest or other significant places such as foraging sites. These movements occur on the first few occasions that an insect leaves its nest. They are of special interest because their discovery in the middle of the 19th century provided perhaps the first evidence that insects can learn and are not solely governed by instinct. Here, we recount the history of research on learning flights from their discovery to the present day. The first studies were conducted by skilled naturalists and then, over the following 50 years, by neuroethologists examining the insects’ learning behaviour in the context of experiments on insect navigation and its underlying neural mechanisms. The most important property of these movements is that insects repeatedly fixate their nest and look in other favoured directions, either in a preferred compass direction, such as North, or towards preferred objects close to the nest. Nest facing is accomplished through path integration. Memories of views along a favoured direction can later guide an insect's return to its nest. In some ant species, the favoured direction is adjusted to future foraging needs. These memories can then guide both the outward and homeward legs of a foraging trip. Current studies of central areas of the insect brain indicate what regions implement the behavioural manoeuvres underlying learning flights and the resulting visual memories.University of Susse

A Study of Hierarchical Concatenation Networks in the Area of Pattern Recognition

Hierarchical Concatenation Networks (HCN) are inspired by the way humans recognize patterns; i.e. by concatenating small features. In HCNs patterns are split into small parts, and then concatenated and activated in the network’s layers. The research in this thesis investigated and explored feature extraction methods, similarity measures, and classification using HCNs. Results indicate that HCNs can be used in automatic pattern recognition systems with better performance rate on the lower layer than the top layer

Life patterns : structure from wearable sensors

Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, February 2003.Includes bibliographical references (leaves 123-129).In this thesis I develop and evaluate computational methods for extracting life's patterns from wearable sensor data. Life patterns are the reoccurring events in daily behavior, such as those induced by the regular cycle of night and day, weekdays and weekends, work and play, eating and sleeping. My hypothesis is that since a "raw, low-level" wearable sensor stream is intimately connected to the individual's life, it provides the means to directly match similar events, statistically model habitual behavior and highlight hidden structures in a corpus of recorded memories. I approach the problem of computationally modeling daily human experience as a task of statistical data mining similar to the earlier efforts of speech researchers searching for the building block that were believed to make up speech. First we find the atomic immutable events that mark the succession of our daily activities. These are like the "phonemes" of our lives, but don't necessarily take on their finite and discrete nature. Since our activities and behaviors operate at multiple time-scales from seconds to weeks, we look at how these events combine into sequences, and then sequences of sequences, and so on. These are the words, sentences and grammars of an individual's daily experience. I have collected 100 days of wearable sensor data from an individual's life. I show through quantitative experiments that clustering, classification, and prediction is feasible on a data set of this nature. I give methods and results for determining the similarity between memories recorded at different moments in time, which allow me to associate almost every moment of an individual's life to another similar moment. I present models that accurately and automatically classify the sensor data into location and activity.(cont.) Finally, I show how to use the redundancies in an individual's life to predict his actions from his past behavior.by Brian Patrick Clarkson.Ph.D

Wiedererkennung ungefilterter und Fourier-gefilterter Schwarzweißmuster duch Honigbienen (Apis mellifera L.)

Honigbienen (Apis mellifera L.) sind in der Lage mit ihren Komplexaugen visuelle Muster wahrzunehmen und die Musterinformation im Zentralen Nervensystem zu speichern und für Ähnlichkeitsbewertungen wieder abzurufen. Die vorliegende Arbeit zeigt klare Evidenz gegen eine ausschließliche Bewertung von Schwarzweißmustern mit Hilfe von Template-Matching-Mechanismen. Mit systematisch abgewandelten Dressurparadigmen trainierte Bienen bewerteten Muster unabhängig von der erfolgten Dressur stets bevorzugt gemäß eher grober Mustereigenschaften, wie zum Beispiel die Parameter "schwarzer Musterzentralbereich" und "Musterzerstreutheit". Veränderte man in einem weiteren Versuchansatz die Musterinformation der Schwarzweißmuster zudem gezielt durch geeignete Fourier-Filterung, zeigte sich, dass Bienen zur Musterdiskriminierung bereits die Frequenzinformation von 2 - 8 Schwingungen/Bildbreite genügte. Diese Unschärfe der bewerteten Bildinformation ließ sich nicht ausschließlich aus den optischen Eigenschaften des visuellen Apparates der Bienen ableiten. Videodokumentationen und Einzelbildanalyse des Flugverhaltens der Bienen vor den Mustern ergaben zudem keinerlei Hinweise für eine Nutzung des Flugverhaltens als Bewertungsgrundlage zur Musterdiskriminierung. Die erhaltenen Ergebnisse zur Musterdiskriminierung wurden vor dem Hintergrund eines ökonomischen Entscheidungsmodells für menschliches Verhalten, den Frugalheuristiken, diskutiert und Hinweise auf eine ökonomische Bewertungsstrategie der Bienen entsprechend einer Take-The-Best-Heuristik gefunden.Honeybees (Apis mellifera L.) are able to perceive visual patterns through their compound eyes and store the visual information in the central nervous system for subsequent use in pattern discrimination tasks. This thesis provides clear evidence against the assumption that pattern discrimination relies exclusively on template matching mechanisms. Bees discriminated pairs of patterns preferential using extracted pattern parameters. Within this thesis the preferred parameters of the bees following the training paradigms were coarse parameters such as "black centre" and "pattern disruption". In experiments with Fourier filtered patterns the frequency information of the patterns were additionally reduced. The results showed that bees could discriminate patterns using only 2 - 8 cycles/pattern-width of the frequency information. The fuzziness of the exploited visual information could not be assigned to restrictions of the visual system of bees. Additional documentation and single picture analysis of the videotaped flight behaviour in front of the patterns provided no evidence for bees using their flight behaviour in order to enhance the pattern discrimination ability. Application of economic human decision models (frugal heuristics) to the behavioural results showed clues that bees'' decisions could be explained with the help of the Take-The-Best-heuristic