Microplitis croceipes, one of the nectar feeding parasitoid wasps, has been found to associatively learn chemical cues through feeding. The experiments on M. croceipes are performed and recorded by a Sony camcorder in the USDA-ARS Biological Control Laboratory in Tifton, GA, USA. The experimental videos have shown that M. croceipes can respond to Coffee odour in this study. Their detection capabilities and the behaviour of M. croceipes with different levels of coffee odours were studied. First, the data that are related to trained M. croceipes behaviour was extracted from the experimental videos and stored in a Microsoft Excel database. The extracted data represent the behaviour of M. croceipes trained to 0.02g and then exposed to 0.001g, 0.005g, 0.01g, 0.02g and 0.04g of coffee. Secondly, indices were developed to uniquely characterise the behaviour of trained M. croceipes under different coffee concentrations. Thirdly, a preliminary model and its parameters were developed to classify the response of trained wasps when exposed to these five different coffee odours. In summary, the success of this thesis demonstrates the usefulness of data analysis for interpreting experimental data, developing indices, as well as understanding the design principles of a simple model based on trained wasps.

<p dir="ltr">Given the relatively poor visual acuity of compound eyes, many insects have developed alternative means for navigating their environment. For example, insects often rely on chemosensation to find food, mates, and inter- and intraspecific communication. Eusocial insects in particular have developed complex systems of pheromone communication to organize their colonies, enabling them to partition labor for foraging, brood care, and colony defense tasks to different portions of the colony. A variety of genes coding for proteins are involved in detecting these chemicals, including gustatory receptors, ionotropic receptors, and odorant receptors (ORs). Eusocial insects, and especially ants, have evolved an expanded clade of ORs in their genome, likely due to an increased reliance on pheromones compared to other insects. The ability to recognize nestmates from non-nestmates is one of the vital functions performed by these ORs, which detect hydrocarbons present on the cuticle to distinguish friend from foe. However, research into the details of nestmate recognition has been stymied due to difficulties in manipulating OR genes. Despite advances in genetic sequencing and manipulation technologies, strict reproductive divisions within most ant lineages make generating transgenic ants nearly impossible, and so we have been left with limited options to further investigate these receptors. To narrow down the ORs that could be involved in nestmate recognition in the Argentine ant (Mayr, 1868), I took a multi-pronged approach of generating tissue transcriptomes to identify ORs that are selectively upregulated in the antennae, as well as conducting a phylostratigraphic analysis to identify which OR genes arose more recently in the Argentine ant genome. While conducting these analyses, it became necessary to reannotate the set of Argentine ant OR genes, due to current published annotations not containing the full breadth of <i>L. humile</i> ORs. Finally, I orally administered fluorescently-labelled dsRNA to workers, and tracked the extent to which ingested dsRNA is capable of traversing the tissues of ant workers, to investigate whether RNAi is a viable method for investigating gene function for genes showing tissue-selective expression. I discovered a subset of OR genes that are highly expressed in the antennae and confirmed that dsRNA is able to reach the antennae and knock down OR gene expression through ingestion, meaning that RNA interference is a viable method for the practical study of ant OR genes and can be used to further explore how individual ORs regulate nestmate recognition.</p>

This thesis represents a comprehensive examination of the phonotactic behaviour (i.e. attraction to sound) of the female Gryllus bimaculatus under laboratory conditions. Chapter 2 is the first study to analyze the effect of substrate texture on walking performance in crickets. Substrate texture is found to play an essential role in the phonotactic responses of G. bimaculatus. Smooth substrate texture has a detrimental effect due to slipping, whereas a rough texture results in optimal walking performance due to the friction with the walking legs. Chapter 3 represents the first detailed lifetime study analysing phonotaxis in crickets. My results demonstrate that the optimal age to test phonotaxis in G. bimaculatus females is from day 7 to 24 after the final moult. I also found that selectiveness was persistent with age. These findings contradict the female choosiness hypothesis. This study is also the first to describe the effect of senescence on phonotaxis in insects, as responsiveness decreases with age. Chapter 4 compares the phonotactic behaviour of female crickets from different laboratory-bred colonies. From six tested cricket lab colonies, I found three groups statistically different from each other. Females raised under laboratory conditions at the University of Cambridge and Anglia Ruskin University were most reponsive at a frequency of 4.5 kHz, whereas females bred in Tokushima University in Japan were tuned towards a higher frequency of 5 kHz. These results suggest a degree of artificial allopatric speciation. Comparisons with crickets bred under low-quality conditions in a local pet shop demonstrate a loss of responsiveness, indicating that breeding conditions have a direct effect on phonotactic responsivity. Chapter 5 is the first study to report the presence of phonotaxis in males of G. bimaculatus. Previously it was unknown if G. bimaculatus males were able to perform phonotaxis, given that they were only recognised as endurance signal producers. In the present study, only 20% of the studied males (N=70) performed a weak phonotactic response. This finding has potential ecological implications in terms of male cricket territory establishment, and male-male interactions in the wild, which are discussed. Chapter 6 explores the song pattern recognition of the female G. bimaculatus by changing the duration of either the first, second or third pulse of the chirps. A long first pulse decreased the phonotactic response whereas phonotaxis remained strong when the third pulse was long. Chirps with three pulses of increasing duration of 5, 20 and 50 ms elicited phonotaxis, but the chirps were not attractive when played in reverse order. The data are in agreement with a mechanism in which processing of a sound pulse has an effect on the processing of the subsequent pulse, as outlined in the flow of activity in a delay-line and coincidence-detector circuit.

Die paläarktische omnivore Weichwanze Dicyphus errans Wolff (Heteroptera, Miridae, Bryocorinae) zeichnet sich durch ein ausgesprochen breites Spektrum an besetzten Wirtspflanzen und konsumierten Beutetieren aus. Über 150 von D. errans akzeptierte Pflanzenarten sind erstmalig belegt worden. Der erfolgreiche Verzehr von 15 Beute-tierarten wurde quantitativ nachgewiesen. Eine weitere Besonderheit der Wanze besteht in der Präferenz für glandulär behaarte Pflanzen. Die Weichwanze besetzt somit von vielen anderen Insekten gemiedene Nischen. Untersuchungen im Botanischen Garten der Technischen Universität Dresden (2000 bis 2002) ließen auf eine bemerkenswerte räuberische Aktivität und Anpassungsfähigkeit an unterschiedliche Habitate, Beutetiere und Klimabedingungen schließen. Die fortführenden Studien im Rahmen der vorliegenden Dissertation (2002 bis 2005) erbrachten umfassende Erkenntnisse über die Art D. errans im Hinblick auf deren Morphologie, Vermehrung und Haltung, Bionomie und Ökologie (Fekundität und Ontogenese in Abhängigkeit von ausgewählten Einflussfaktoren, Dormanz), Aufenthalt und Fortbewegung (räumliche Orientierung und strukturanalytische Studien zu den Interaktionen zwischen Wanze und Pflanzenoberflächen), den Nahrungserwerb (Verzehrleistung und Omnivorie) sowie Videodokumentationen der Lebensweise und des Verhaltens. Der Generalist und Opportunist D. errans integriert sich als Pflanzensaftsauger regulierendes Kompartiment neben echten Räubern und Parasitoiden in Biozönosen. Als omnivores Insekt übernimmt die Wanze eine intermediäre und supplementäre Position in Nahrungsnetzen. Die Lebensweise dieser Weichwanzenart erscheint sehr komplex. Die enge Assoziation mit Pflanzen tritt stark in den Vordergrund. Sie ist in jeglichen Betrachtungen von D. errans unbedingt zu berücksichtigen und bietet außerdem als ein Modellsystem ein spannendes Forschungsfeld im Hinblick auf die Adaptation partiell räuberisch lebender Insekten an behaarte Pflanzen. / The omnivorous mirid bug Dicyphus errans Wolff (Heteroptera, Miridae, Bryocorinae) lives on a wide range of host plants and feeds on various preys. Over 150 plant species accepted by the mirid bug have been identified. It was experimentally shown that 15 prey species are efficiently consumed. Another characteristical features of D. errans is that it preferes hairy plants. Thus, the mirid bug occupies unique niches avoided by many other insects. Investigations, carried out at the Botanical Garden of the Technical University of Dresden (2000-2002) gave evidence for a remarkable predatory activity and ability to adaptation to different habitats, preys and climate conditions. The studies presented in the dissertation (2002-2005) gave the comprehensive knowledge about the species D. errans, especially its morphology, rearing, bionomy and ecology (fecundity and ontogenesis depending on selected factors, dormancy), habitat preference and locomotion (spatial orientation and structural-analytical studies of the interactions between the bug and plant surfaces), foraging and food ingestion (predatory capacity and omnivory). In addition, video documentation of the modus vivendi and the behavior was performed. The generalist and opportunist D. errans lives together with predators and parasitoids and takes part in a biological control of phytophagous insects in biocenoses. The life history of this bug species appeared to be very complex. The close association to plants has to be considered. Dicyphus errans offers a model system for further research on omnivorous predatory insects connected with hairy plants.

Die paläarktische omnivore Weichwanze Dicyphus errans Wolff (Heteroptera, Miridae, Bryocorinae) zeichnet sich durch ein ausgesprochen breites Spektrum an besetzten Wirtspflanzen und konsumierten Beutetieren aus. Über 150 von D. errans akzeptierte Pflanzenarten sind erstmalig belegt worden. Der erfolgreiche Verzehr von 15 Beute-tierarten wurde quantitativ nachgewiesen. Eine weitere Besonderheit der Wanze besteht in der Präferenz für glandulär behaarte Pflanzen. Die Weichwanze besetzt somit von vielen anderen Insekten gemiedene Nischen. Untersuchungen im Botanischen Garten der Technischen Universität Dresden (2000 bis 2002) ließen auf eine bemerkenswerte räuberische Aktivität und Anpassungsfähigkeit an unterschiedliche Habitate, Beutetiere und Klimabedingungen schließen. Die fortführenden Studien im Rahmen der vorliegenden Dissertation (2002 bis 2005) erbrachten umfassende Erkenntnisse über die Art D. errans im Hinblick auf deren Morphologie, Vermehrung und Haltung, Bionomie und Ökologie (Fekundität und Ontogenese in Abhängigkeit von ausgewählten Einflussfaktoren, Dormanz), Aufenthalt und Fortbewegung (räumliche Orientierung und strukturanalytische Studien zu den Interaktionen zwischen Wanze und Pflanzenoberflächen), den Nahrungserwerb (Verzehrleistung und Omnivorie) sowie Videodokumentationen der Lebensweise und des Verhaltens. Der Generalist und Opportunist D. errans integriert sich als Pflanzensaftsauger regulierendes Kompartiment neben echten Räubern und Parasitoiden in Biozönosen. Als omnivores Insekt übernimmt die Wanze eine intermediäre und supplementäre Position in Nahrungsnetzen. Die Lebensweise dieser Weichwanzenart erscheint sehr komplex. Die enge Assoziation mit Pflanzen tritt stark in den Vordergrund. Sie ist in jeglichen Betrachtungen von D. errans unbedingt zu berücksichtigen und bietet außerdem als ein Modellsystem ein spannendes Forschungsfeld im Hinblick auf die Adaptation partiell räuberisch lebender Insekten an behaarte Pflanzen. / The omnivorous mirid bug Dicyphus errans Wolff (Heteroptera, Miridae, Bryocorinae) lives on a wide range of host plants and feeds on various preys. Over 150 plant species accepted by the mirid bug have been identified. It was experimentally shown that 15 prey species are efficiently consumed. Another characteristical features of D. errans is that it preferes hairy plants. Thus, the mirid bug occupies unique niches avoided by many other insects. Investigations, carried out at the Botanical Garden of the Technical University of Dresden (2000-2002) gave evidence for a remarkable predatory activity and ability to adaptation to different habitats, preys and climate conditions. The studies presented in the dissertation (2002-2005) gave the comprehensive knowledge about the species D. errans, especially its morphology, rearing, bionomy and ecology (fecundity and ontogenesis depending on selected factors, dormancy), habitat preference and locomotion (spatial orientation and structural-analytical studies of the interactions between the bug and plant surfaces), foraging and food ingestion (predatory capacity and omnivory). In addition, video documentation of the modus vivendi and the behavior was performed. The generalist and opportunist D. errans lives together with predators and parasitoids and takes part in a biological control of phytophagous insects in biocenoses. The life history of this bug species appeared to be very complex. The close association to plants has to be considered. Dicyphus errans offers a model system for further research on omnivorous predatory insects connected with hairy plants.