Chemical Communication: The Effects of Stress-Induced Apocrine Sweat on Human Perceptions and Interactions

In times of stress, humans secrete a type of sweat (apocrine sweat) that they do not secrete at any other time. This sweat has been previously shown to influence others who are exposed to it. The current project seeks to explore how apocrine sweat influences the people who are exposed to it. Using the framework of Emotional Contagion Theory, two studies were conducted to assess the effects of stress-induced apocrine sweat on human perceptions and interactions. Study 1 saw participants exposed to either thermoregulatory sweat or apocrine sweat before watching a short, fear-inducing video. Participants then reported their levels of psychological fear, physical fear, and how afraid they thought others would be in response to the video. Results indicate that exposure to apocrine sweat increases the level of fear reported, and that this effect is stronger for women than it is for men. The effect is consistent regardless of how susceptible one is to other forms of emotional contagion. Study 2 saw a romantic couple exposed to either thermoregulatory sweat or apocrine sweat before engaging in a conflict discussion. Participants then reported on their levels of anger and their partner’s levels of anger as compared to their typical discussion about the topic. Results indicate that exposure to apocrine sweat is associated with a reduction in the couple’s levels of anger. This effect was equally strong for men and women, and was not influenced by susceptibility to other forms of emotional contagion. Overall, results indicate that apocrine sweat has discernable effects on human perceptions and interactions

Linked data as medium for distributed Multi-Agent Systems

The conceptual design and discussion of multi-agents systems (MAS) typically focuses on agents and their models, and the elements and effects in the environment which they perceive. This view, however, leaves out potential pitfalls in the later implementation of the system that may stem from limitations in data models, interfaces, or protocols by which agents and environments exchange information. By today, the research community agrees that for this, that the environment should be understood as well as abstraction layer by which agents access, interpret, and modify elements within the environment. This, however, blurs the the line of the environment being the sum of interactive elements and phenomena perceivable by agents, and the underlying technology by which this information and interactions are offered to agents. This thesis proposes as remedy to consider as third component of multi agent systems, besides agents and environments, the digital medium by which the environment is provided to agents. "Medium" then refers to exactly this technological component via which environment data is published interactively towards the agents, and via which agents perceive, interpret, and finally, modify the underlying environment data. Furthermore, this thesis will detail how MAS may use capabilities of a properly chosen medium to achieve coordinating system behaviors. A suitable candidate technology for digital agent media comes from the Semantic Web in form of Linked Data. In addition to conceptual discussions about the notions of digital agent media, this thesis will provide in detail a specification of a Linked Data agent medium, and detail on means to implement MAS around Linked Data media technologies.Sowohl der konzeptuelle Entwurf von, als auch die wissenschaftliche Diskussion über Multi-Agenten-Systeme (MAS) konzentrieren sich für gewöhnlich auf die Agenten selbst, die Agentenmodelle, sowie die Elemente und Effekte, die sie in ihrer Umgebung wahrnehmen. Diese Betrachtung lässt jedoch mögliche Probleme in einer späteren Implementierung aus, die von Einschränkungen in Datenmodellen, Schnittstellen, oder Protokollen herrühren können, über die Agenten und ihre Umgebung Informationen miteinander austauschen. Heutzutage ist sich die Forschungsgemeinschaft einig, dass die Umgebung als solche als Abstraktionsschicht verstanden werden sollte, über die Agenten Umgebungseffekte und -elemente wahrnehmen, interpretieren, und mit ihnen interagieren. Diese Betrachtungsweise verschleiert jedoch die Trennung zwischen der Umgebung als die Sammlung interaktiver Elemente und wahrnehmbarer Phänomene auf der einen Seite, und der zugrundeliegenden Technologie, über die diese Information den Agenten bereitgestellt wird, auf der anderen. Diese Dissertation schlägt als Lösung vor, zusätzlich zu Agenten undUmgebung ein digitales Medium, über das Agenten die Umgebung bereitgestellt wird, als drittes Element von Multi-Agenten-Systemen zu betrachten. Der Begriff "Medium" bezieht sich dann genau auf diese technologische Komponente, über die Umgebungsinformationen Agenten interaktiv bereitgestellt werden, und über die Agenten die zugrundeliegenden Daten wahrnehmen, interpretieren, und letztendlich modifizieren. Desweiteren wird diese Dissertation aufzeigen, wie die Eigenschaften eines sorgfältig gewählten Mediums ausgenutzt werden können, um ein koordiniertes Systemverhalten zu erreichen. Ein geeigneter Kandidat für ein digitales Agentenmedium findet sich im Ökosystem des „Semantic Web”, in Form von „Linked Data”, wörtlich („verknüpfte Daten”). Zusätzlich zu einer konzeptionellen Diskussion über die Natur digitaler Agenten- Media, spezifiziert diese Dissertation „Linked Data” als Agentenmedium detailliert aus, und beschreibt im Detail die Mittel, wie sich MAS um Linked Data Technologien herum implementieren lassen

An analysis of competitive traits in pest ant species

The successful spread of invasive species can often be explained by specific behavioral, morphological, chemical and genetic traits. Studies suggest that those traits are also present in native species that expand strikingly fast and turn into an issue for the environment. Mass occurrences of the native pest ant species Formica fuscocinerea have recently become a concern for leisure areas in Southern Germany. This thesis investigates whether these mass occurrences can similarly be explained by traits known from invasive species, such as a high interspecific dominance and extensive colony networks. As cooperation among large numbers of individuals requires pronounced communication abilities, this thesis also investigates whether pheromone communication contributes to the superiority of invasive ants. Therefore, competitive strength and pheromone communication of the invasive garden ant Lasius neglectus is compared with those of the two closely related native sister species Lasius niger and Lasius platythorax. Identifying the pheromones used for communication can facilitate more specific control of pest ant species. Targeted controlmethods use baits or traps that are equipped with species-specific pheromone attractants. Ants naturally use pheromone attractants produced in pheromone glands for foraging. This thesis compares hindgut, poison gland and Dufour’s gland pheromones of L. neglectus against those of L. niger and L. platythorax to identify species-specific attractants for the invasive garden ant. The results show that the native pest ant species F. fuscocinerea is able to dominate other ant species by pronounced interspecific aggression. In contrast, F. fuscocinerea does not show intraspecific aggression among individuals from distant populations indicating weak or nonexistent colony boundaries. Thus, the striking mass occurrences of F. fuscocinerea can be attributed to traits known from invasive ant species. The trail communication of the invasive garden ant L. neglectus seems to be adapted to the exploitation of stable and productive food sources. Lasius neglectus shows a higher precision in following hindgut trails than the native Lasius species. The pheromone blends of the studied glands are notably different. Of 60 identified substances are 9 specific to the invasive L. neglectus, 26 to L. niger and 4 to L. platythorax. The chemical attractant 2,6-dimethyl-3-ethyl-5-hepten-1-ol can unambiguously be assigned to the hindgut of the invasive garden ant L. neglectus. Thus, this substance is a promising candidate for a species-specific attractant in the control of the invasive garden ant L. neglectus. High interspecific aggression and supercolonial structures are important traits of invasive ant species and this dissertation suggests that they likewise enable the native pest ant F. fuscocinerea to become dominant. A considerably more sophisticated pheromone communication does not necessarily belong to traits of invasive ants, particularly L. neglectus. However, the findings are provisional and require further investigation. Yet, the analyses of the communication pheromones provide a basis for the species-specific control of L. neglectus.Die erfolgreiche Ausbreitung invasiver Arten kann häufig mit bestimmten Verhaltensweisen, morphologischen, chemischen und genetischen Eigenschaften erklärt werden. Untersuchungen lassen vermuten, dass diese Eigenschaften auch bei den heimischen Arten vorkommen, die sich auffallend schnell ausbreiten und zu einem Problem für die Umwelt werden. Massenvorkommen der heimischen Pestameisenart Formica fuscocinerea wurden jüngst zu einem großen Problem auf Freizeitflächen in Süddeutschland. Diese Arbeit untersucht, inwiefern dieseMassenvorkommen auf ähnlicheWeise durch Eigenschaften erklärt werden können, wie sie von invasiven Arten bekannt sind, wie etwa eine hohe zwischenartliche Dominanz und ausgedehnte Kolonievernetzung. Da die Kooperation einer großen Anzahl von Individuen ausgeprägte Kommunikationsfähigkeiten benötigt, untersucht diese Arbeit zudem, ob die Pheromonkommunikation zur Überlegenheit invasiver Arten beiträgt. Dafür werden die Konkurrenzstärke und die Pheromonkommunikation der invasiven Gartenameise Lasius neglectus mit denen zweier nah verwandter heimischer Schwesternarten Lasius niger und Lasius platythorax verglichen. Eine Identifikation der Pheromone, die für die Kommunikation verwendet werden, kann eine spezifischere Bekämpfung von Pestameisenarten ermöglichen. Zielgerichtete Kontrollmethoden verwenden Köder oder Fallen, diemit artspezifischen Pheromonlockstoffen ausgestattet sind. Ameisen verwenden Pheromonlockstoffe, die in Pheromondrüsen produziert werden, naturgemäß bei der Futtersuche. Diese Arbeit vergleicht Pheromone aus dem Enddarm, der Giftdrüse und der Dufourdrüse von L. neglectus mit denen von L. niger and L. platythorax um artspezifische Lockstoffe für die invasive Gartenarmeise zu identifizieren. Die Ergebnisse zeigen, dass die heimische Pestameisenart F. fuscocinerea in der Lage ist, andere Ameisen durch ausgeprägte zwischenartliche Aggression zu dominieren. ImGegensatz dazu zeigt F. fuscocinerea keine innerartliche Aggression zwischen Individuen von entfernten Populationen, was auf schwache oder nicht vorhandene Koloniegrenzen hinweist. Folglich können die auffälligen Massenauftreten von F. fuscocinerea Eigenschaften zugeschrieben werden, die von invasive Ameisenarten bekannt sind. Die Spurkommunikation der invasiven Gartenameise L. neglectus scheint an die Ausbeutung stabiler und ergiebiger Nahrungsquellen angepasst zu sein. Lasius neglectus zeigt eine höhere Präzision beim Verfolgen von Enddarmspuren als die heimischen Lasius Arten. Die Pheromonzusammensetzungen der untersuchten Drüsen sind deutlich unterschiedlich. Von 60 identifizierten Substanzen sind 9 spezifisch für die invasive L. neglectus, 26 für L. niger und 4 für L. platythorax. Der chemische Lockstoff 2,6-Dimethyl-3-ethyl-5-hepten-1-ol kann eindeutig dem Enddarmder invasive Gartenameise L. neglectus zugeordnet werden. Diese Substanz ist somit ein vielversprechender Kandidat für einen artspezifischen Lockstoff zur Bekämpfung der invasiven Gartenameise L. neglectus. Hohe zwischenartliche Aggression und superkoloniale Strukturen sind wichtigeMerkmale invasiver Ameisenarten und diese Arbeit weist darauf hin, dass sie in gleicher Weise der heimischen Pestart F. fuscocinerea ermöglichen dominant zu werden. Eine deutlich raffiniertere Pheromonkommunikation gehört allerdings nicht notwendigerweise zu den Merkmalen invasiver Ameisen, insbesondere nicht zu denen von L. neglectus. Die Erkenntnisse gelten jedoch nur vorläufig und benötigen weitere Untersuchungen. Dennoch bietet die Analyse der Kommunikationspheromone eine Grundlage für die artspezifische Kontrolle von L. neglectus

The influence of semiochemicals on the co-occurrence patterns of a global invader and native species

The success of invasive species in their introduced range is often influenced by interactions with resident species communities. Chemical communication is one the factors which contributes to a variety of aspects of a species life cycle, ranging from mating, to food localization and interactions with members of the same and other species. In my thesis, I investigate the effects of venoms and semiochemicals on interactions between the invasive Argentine ant (Linepethima humile) with other resident ant species and demonstrate how pheromones can potentially be utilized as an area wide control mechanism of this species, by disrupting their foraging success. I studied the effects of venom composition, their toxicity and utilization on the outcome of aggressive interactions between the Argentine ant and the four Monomorium species in New Zealand occurring. The toxicity of the venom of the two species co-occurring with Argentine ants was significantly higher than the toxicity of the species which do not. However, no correlation between venom toxicity and Monomorium survival was found. For M. antipodum a significant relationship between venom utilization and its mortality was found, indicating that the way venom is used might be an important aspect of these interactions. Physical Aggression between Monomorium and Argentine ants also had strong effects on Monomorium worker mortality, which provided evidence that a variety of factors and strategies contribute to the ability of interacting organisms to withstand the pressure of a dominant invader at high abundance. I conducted bioassays with food sources and synthetic trail pheromones, providing a proof of concept on disrupting the foraging ability of Argentine ants. Other resident species benefited from the reduced success of Argentine ants, but to a varying degree. Behavioural variations between the resident species provided an explanation for observed differences in foraging success and how much each of these individual competitors was able to increase their foraging. The mechanism for the observed increase in resource acquisition of resident species appeared to be a decrease in aggressive behaviour displayed by Argentine ants. I expanded the usage of the synthetic pheromone to a commercial vineyard, were Argentine ants can have negative effects on crop development by dispersing and tending to homopteran pest species. Argentine ants’ access to the crop canopy could be significantly reduced by placing pheromone dispensers at the base of the vine plant, while dispensers in the plant canopy had little effect on Argentine ant numbers. Doubling the amount of pheromone did not result in an additional reduction of ant activity. Lastly incorporating the knowledge gained in the previous chapter, I extended the application of the pheromone to a large field trial over a three month period. Argentine ant activity and foraging success was significantly supressed compared to untreated control plots, providing evidence that this form of large scale application might be a possible way to control large invasive ant populations by disrupting their trail following and foraging behaviour for a prolonged period of time. While initial calculations have suggested that the treatment is currently not feasible (13.3 US$/mg/ha), I found a significant reduction in body fat in workers collected from treated plots compared with untreated plots, suggesting adverse effects on nest fitness. My findings provide new insights into chemical communication between invasive and resident species, support existing dominance hierarchy models in ant populations, and help to establish a target specific potential management technique of wide-spread invasive ant species

8th International Symposium on fruit flies of economic importance

Sabater Muñoz, B.; Urbaneja García, A.; Navarro Llopis, V. (2010). 8th International Symposium on fruit flies of economic importance. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/11200Archivo delegad

Diversification spatiale des agroécosystèmes pour la lutte biologique contre les insectes ravageurs: Intérêts des associations de culture et des bandes fleuries

Facing the limits of input-intensive agriculture, agroecology aims at thinking ways to design a sustainable agriculture that is economically viable and socially relevant. It notably invites to mobilize ecological processes within agroecosystems in order to enhance the delivery of ecosystem services towards reducing the use of external inputs – among others insecticides. For enhancing biological control of insect pests, a strategy is to spatially diversify agroecosystems at the field scale. Whereas increasing plant diversity could directly negatively affect pest development on the one hand (i.e. bottom-up effect), providing flowering features could allow the enhancement of natural enemies and their direct effect on pest populations on the other hand (i.e. top-down effect). The present thesis focused on intercropping (i.e. the cultivation of at least two crop species simultaneously in a same field) as a way to diversify crop habitat, and the sowing of wildflower strips as a non-crop feature. A systematic analysis of the literature revealed that, in most of studies, wheat (Triticum aestivum L.)-based intercropping allows a reduction of insect pests on crops, without necessarily favouring their natural enemies, compared to pure-stands. Besides, the provision of flowering resources, by for instance sowing wildflower strips, can attract and support flower visiting predators and parasitoids. Hence, in a first set of field experiments, combining the two tactics of increasing crop diversity and providing flowering resources was tested. First in China, wheat crop was associated with oilseed rape (Brassica napus L.), but it neither allowed reducing aphid (Hemiptera: Aphididae) abundance nor enhancing their natural enemies compared to pure stands. Instead, aphid density – independently from the treatments – affected natural enemy abundance, and interspecific relations between aphids and their natural enemies were observed. Second in Belgium, wildflower strips were sown within a wheat field, which led to a reduction of aphid density in wheat plots in between flowering features and an increase of aphidophagous hoverflies (Diptera: Syrphidae) compared to pure-stand wheat. Nevertheless, the presence of flowering strips did not affect the other natural enemies, i.e. lacewings (Neuroptera: Chrysopidae), ladybeetles (Coleoptera: Coccinellidae) and parasitoid wasps (Hymenoptera: Braconidae). Therefore, a second set of field experiments focussed on ways to compose mixtures of wild flowers attractive to a diversity of natural enemies. Flower functional traits were considered due to their effect on insect behaviour. First, the hypothesis that mixtures with high functional diversity attract and support a high abundance and diversity of aphid flower visiting predators was tested. This hypothesis was not verified. Instead, the high density in the plots of some flower species (especially the Asteraceae Leucanthemum vulgare Lam.) known to be attractive to flower visitors was supposed to have overwhelmed the effect of functional diversity. Second, a methodology was developed to identify which flower traits significantly affect natural enemy abundance – in this experiment parasitoids of oilseed rape beetle pests (i.e. Meligethes spp. [Coleoptera: Nitidulidae] and Ceutorhynchus spp. [Coleoptera: Curculionidae]) – in flower mixtures. Among seven traits, visual traits (i.e. colour, ultra-violet reflectance) and the one related to food availability (i.e. corolla morphology) were found to significantly affect parasitoid abundance. These results highlight that (i) increasing plant diversity at the field scale can – but not systematically – favour a reduction of insect pests, (ii) including flowering features can enhance some – but not all – of their natural enemies, and (iii) in order to compose flower mixes attractive to natural enemies, specific flower traits – rather than functional diversity at the mixture level – can be considered. These results are discussed in a broader perspective. Indeed, strategies to spatially diversify crop and non-crop habitats in agroecosystems are various, as well as the ways to compose, manage and design such habitats. Also, processes at larger scales than the field may be determinant. Moreover, insects are not the only pests, and pests are not the only biotic or abiotic elements that need to be regulated in agroecosystems. Controlling multiple pests simultaneously but also enhancing the provision of multiple regulating services represent challenges for future research in agriculture.Face aux limites de l’agriculture intensive en intrants, l’agroécologie propose un cadre pour penser la conception d’une agriculture écologiquement durable, mais aussi économiquement viable et socialement responsable. Notamment, elle invite à mobiliser les processus écologiques au sein des agroécosystèmes dans le but d’accroitre la fourniture de services écosystémiques, pour réduire l’usage des intrants externes – parmi d’autres les insecticides. Une stratégie pour favoriser la lutte biologique contre les insectes ravageurs est de diversifier spatialement les agroécosystèmes à l’échelle parcellaire. D’un côté, accroitre la diversité végétale peut directement pénaliser le développement des ravageurs (effet « bottom-up »), d’un autre côté fournir une resource florale peut favoriser le développement d’ennemis naturels et potentiellement leur action de prédation et de parasitisme sur les ravageurs (effet « top-down »). Dans ce but, la présente thèse s’intéresse aux associations de cultures (cultiver au moins deux cultures simultanément dans la même parcelle) comme un outil de diversification des habitats cultivés, et au semis de bandes de fleurs sauvages comme habitat semi-naturel. Une analyse systématique de la littérature montre que, dans la plupart des études, les associations de cultures intégrant le blé (Triticum aestivum L.) permettent une réduction de l’abondance en insectes ravageurs, sans pour autant favoriser leurs ennemis naturels, en comparaison à des cultures pures. Par ailleurs, la fourniture de ressource florale, en semant par exemple des bandes de fleurs sauvages, peut attirer et maintenir des populations de prédateurs et de parasitoïdes. D’où, un premier ensemble d’expériences consista à évaluer en champ l’effet combiné de l’accroissement de la diversité végétale et de la fourniture de ressources florales sur les populations de ravageurs et d’ennemis naturels. Dans un premier temps en Chine, du blé fut associé à du colza (Brassica napus L.), mais cela ne permit ni de réduire les populations de pucerons (Hemiptera : Aphididae), ni d’accroitre celles de leurs ennemis naturels, en comparaison à des parcelles en culture pure. Les ennemis naturels furent plutôt affectés par l’abondance en pucerons – indépendamment des traitements – et des relations interspécifiques entre pucerons et ennemis naturels furent observées. Dans un second temps en Belgique, des bandes de fleurs sauvages furent semées au sein d’une parcelle de blé. Une moindre abondance en pucerons et un accroissement du nombre de syrphes aphidiphages (Diptera : Syrphidae) fut observé dans la culture entre les bandes fleuries en comparaison à des parcelles en culture pure. Néanmoins, la présence de fleurs sauvages n’affecta pas les autres ennemis naturels, précisément les chrysopes (Neuroptera : Chrysopidae), les coccinelles (Coleoptera : Coccinellidae) et les parasitoïdes (Hymenoptera : Braconidae). C’est pourquoi, un second ensemble d’expériences en champ se pencha sur la composition des mélanges fleuris et leur attractivité pour une diversité d’ennemis naturels. Les traits fonctionnels des fleurs furent considérés du fait de leur effet sur le comportement des insectes. Dans un premier temps, l’hypothèse que des mélanges fleuris ayant une diversité fonctionnelle élevée attirent et maintiennent une grande diversité et abondance de prédateurs de pucerons fut testée. Cette hypothèse ne fut pas vérifiée. Il fut supposé que la densité élevée, dans quelques unités expérimentales, de certaines espèces de fleurs (en particulier l’Asteraceae Leucanthemum vulgare Lam.) connues pour être particulièrement attractives, a pu prendre le dessus sur l’effet de la diversité fonctionnelle. Dans un second temps, une méthodologie fut développée dans le but d’identifier les traits fonctionnels qui effectivement affectent l’abondance des ennemis naturels – dans cette expérience les parasitoïdes des ravageurs coléoptères du colza (Meligethes spp. [Coleoptera : Nitidulidae] et Ceutorhynchus spp. [Coleoptera : Curculionidae]) – dans les mélanges fleuris. Parmi sept traits, ceux relatifs à la vision (couleur, réflectance ultra-violette) et à la disponibilité en ressource alimentaire (morphologie de la corolle) eurent un effet significatif sur l’abondance en parasitoïdes. Ces résultats soulignent que (i) accroitre la diversité végétale à l’échelle parcellaire peut – mais non systématiquement – favoriser une diminution de l’abondance en insectes ravageurs, (ii) inclure des espèces florales peut accroitre certains – mais pas tous les – ennemis naturels, et (iii) pour composer des mélanges fleuris attractifs pour les ennemis naturels, certains traits floraux particuliers – plutôt que la diversité fonctionnelle à l’échelle du mélange – pourraient être considérés. Ces résultats sont discutés dans une optique plus large. En effet, les stratégies de diversification des habitats cultivés et non-cultivés au sein des agroécosystèmes sont diverses, tout autant que les moyens de composer, gérer et agencer ces habitats. De plus, des processus à des échelles supérieures que celle du champ cultivé peuvent être déterminants. Enfin, les insectes ne sont pas les seuls ravageurs, et les ravageurs les seuls éléments biotiques ou abiotiques qui doivent être régulés dans les agroécosystèmes. Réguler les populations de ravageurs et offrir une diversité de services écosystémiques de manière conjointe représente un défi scientifique pour les recherches futures

Impacts, Monitoring and Management of Forest Pests and Diseases

Forest pests have diverse negative impacts on forestry economy, ecosystem services, biodiversity, and sustainable ecosystem management. The first step towards effectively managing forest pests would be to monitor their occurrence and assess their impact on forest ecosystems. The monitoring results can provide basic information for effective management strategies. The data from monitoring programs can result in the development of new methods for monitoring, assessing impact, and developing management techniques. This special issue aims to share information to assist in the effective management of forest pests, by understanding the responses of forest pests to natural and anthropogenic changes, and discussing new studies on the monitoring, assessment, and management of forest pests. The fourteen papers included in this issue focus on monitoring, assessing, and managing forest pests, including one editorial providing an overall idea of the monitoring, assessment and management of forest pests, two articles reviewing long-term changes in forest pests and forests, four papers focusing on the monitoring of forest pests, three papers on the assessment of forest pests, and four papers on the management of forest pests. These papers provide a better understanding of the structures and processes in forest ecosystems and fundamental information for the effective management of forest pests

Insiders\u27 Guide to the Student Academic Conference: 11th Annual SAC

Minnesota State University Moorhead Student Academic Conference abstract book