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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Sperm competition and male forceps dimorphism in the European earwig Forficula auricularia (Dermaptera: Forficulina) /

Brown, Gordon S. January 2007 (has links)
Thesis (Ph.D.) - University of St Andrews, May 2007.
2

Aggregation, courtship, and behavioral interactions in European earwigs, Forficula auricularia L. (Dermaptera: Forficulidae)

Walker, Karen Ann 02 October 2007 (has links)
Due to its relatively cool, humid summers, southwestern Virginia provides an ideal climate for European earwigs, Forficula auricularia. In 1990 - 1992, nymphs were captured in wooden groove-board traps beginning in late May, adults were captured beginning in mid-June, and disappeared from sampling sites by September or October. Sex ratios were significantly female-biased most of the season, becoming more marked by the fall. The pest status of F. auncularia is exacerbated by its gregarious nature. Gas chromatography-mass spectroscopy and accompanying behavioral bioassays showed that aggregation occurred as a result of a pheromone located on the male cuticle, which is probably a minor component of the hydrocarbon profile. Approximately 88% of the detected volatiles on the cuticle were identified as a series of normal and branched alkanes. Fatty acids and hydrocarbons were also identified in nymphal and adult legs, but these extracts were not attractive. Frass, which also contained fatty acids and hydrocarbons, was attractive, but likely acquired its attractancy through the earwigs' proclivity for consuming carcasses and exuviae. The defensive quinones produced by F aunculana repel conspecifics. A study of the behavioral repertoire of F. aunculana showed that, contrary to previous reports, only nymphs are nocturnal. Many differences in behavior were due to gender, age, and partner age. (e.g., females spent more time feeding than did males, adults fed more when paired with nymphs than when paired with adults). Social behaviors (communal feeding, aggression, contact, and dorsal palpation) comprised <10% of the insect's behavioral repertoire. Since dorsal palpation, a previously undescribed behavior and a form of allogrooming, occurred more frequently during reproductive periods, it may have a sexual significance. Dorsal palpation also may augment the distribution of defensive quinones on the cuticle of F. auricularia. An analysis of nymphal group dynamics demonstrated that as group size increased, nymphs spent significantly less time feeding alone and grooming, but more time resting. Antennal contact rates between group members increased significantly with group size. Detailed observations of the courtship and mating of F. auricularia revealed a complex of sexual behaviors for both males and females. Receptive females were behaviorally active during courtship. The significance of the male cerci was demonstrated by their use in early courtship with displays, and later use as a tactile stimulus for the female; and study of males from which the cerci had been removed, which showed no mating by amputated males. Male forcep length was bimodally distributed and positively allometric, while female forcep length was normally distributed. Males with longer forceps did not have a mating advantage. Further research is needed to identify the chemical composition of the aggregation pheromone, and to quantify any advantages of body and forcep size on mating success. / Ph. D.
3

Sperm competition and male forceps dimorphism in the European earwig Forficula auricularia (Dermaptera: Forficulina)

Brown, Gordon S. January 2007 (has links)
The European earwig exhibits a remarkable male-dimorphism in forceps morphology that is associated with alternative reproductive tactics under the control of a conditional evolutionarily stable strategy. Populations on the small, rocky islands of the Farnes off the Northumberland coast are known to sustain populations with dramatically higher morph ratios than observed on the UK mainland. A survey conducted of island and mainland sites around the UK showed that the dimorphic populations of the Farnes are similar to other islands and that mainland populations generally exhibit low morph ratios. Additionally, a correlation between morph ratio and population density was found lending support to the hypothesis that the ESS thresholds that define the morph ratios have diverged through local adaptation. A set of seven microsatellite markers are presented that were developed from a Farne island population of F. auricularia with one additional, previously published locus. These eight markers exhibit genetic variability within and between populations and as such can potentially be applied at a range of scales, from broad-scale phylogeography to within population parentage studies. A phylogeographic study of the UK populations using these markers suggests a single postglacial colonisation from mainland Europe and give further support to the local adaptation hypothesis of ESS threshold evolution. A study of ejaculate size in F. auricularia showed that the males transfer free sperm at a steady rate and that the morphs do not differ in the number of sperm per ejaculate. Measurements of change in body-mass were found to be ineffective measures of ejaculate size, but that macrolabic males lost more weight during copula than brachylabic males. This may be the result of differential investment in accessory ejaculate components between the morphs, as a result of the differing risk of sperm competition.
4

Aspectos biológicos e toxicidade de produtos de origem vegetal a Euborellia annulipes / Biological aspects and toxicity of products of plant origin to Euborellia annulipes

Silva, Aldeni Barbosa da 09 March 2009 (has links)
Submitted by Katiane Souza (katyane.souza@gmail.com) on 2016-05-18T11:36:06Z No. of bitstreams: 1 arquivototal.pdf: 10156219 bytes, checksum: b07b75a7a10dfb56dd494879971fa975 (MD5) / Made available in DSpace on 2016-05-18T11:36:06Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 10156219 bytes, checksum: b07b75a7a10dfb56dd494879971fa975 (MD5) Previous issue date: 2009-03-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Among the methods of controlling insect pests, the use of pesticides has been reduced in negative consequences on the beneficial fauna and the environment, so it is therefore necessary to search for alternatives that minimize the adverse effects of pesticides on the environment. As alternatives to control pests, are being studied, several other techniques, which includes the use of origin plant substances because they have low toxicity to humans and animals, and for presenting performance against several species of pests, which assumes increasing importance in programs of integrated pest management (MIP), especially at a time when it discusses very integrated production towards sustainable agriculture. The insects belonging to the order Dermaptera, are still not well known and the information in the literature, characterized as predatory bodies with good ability. Among the biological agents with characteristics suitable for this purpose, the dermápteros have attracted great attention because predators are greedy, that is, with high ability to attack and feeding on different prey, particularly of eggs and immature stages insects of the orders Lepidoptera, Hemiptera, Coleoptera and Diptera. Considering the potential use of preying on programs for biological control, studies related to their biology and their selectivity in plant extracts become indispensable. Thus, the aim of this work was to study the biological aspects of Euborellia annulipes fed on Spodoptera frugiperda and Hyadaphis foeniculi and selectivity of this predator to products of plant origin in laboratory conditions. / Dentre os métodos de controle de insetos-praga, o uso de agrotóxicos vem sendo reduzido, em conseqüências negativas sobre a fauna benéfica e sobre o ambiente, fazendo-se, portanto, necessário a busca de alternativas que minimizem os efeitos adversos dos agrotóxicos sobre o meio ambiente. Como alternativas ao controle de pragas, estão sendo estudadas, várias outras técnicas, nas quais se inclui o uso de substâncias de origem vegetal, por terem baixa toxicidade ao homem e animais, e por apresentarem eficiência contra várias espécies de pragas, que assume importância cada vez maior em programas de manejo integrado de pragas (MIP), principalmente em um momento em que se discute muito a produção integrada rumo a uma agricultura sustentável. Os insetos pertencentes à ordem Dermaptera, ainda não são bem conhecidos e as informações existentes na literatura, os caracterizam como organismos com boa capacidade predatória. Dentre os agentes biológicos com características adequadas a esta finalidade, os Dermápteros têm despertado grande atenção, pois são predadores vorazes, isto é, com alta capacidade de ataque e que se alimentam de diversas presas, particularmente, de ovos e fases imaturas de insetos das ordens Lepidoptera, Hemiptera, Coleoptera e Diptera. Considerando-se o potencial de uso desse predador em programas de controle biológico, os estudos relacionados a sua biologia e a sua seletividade a extratos vegetais tornam-se imprescindíveis. Diante disso, o objetivo desse trabalho foi de estudar os aspectos biológicos de Euborellia annulipes alimentada com Spodoptera frugiperda e Hyadaphis foeniculi, e a seletividade desse predador a produtos de origem vegetal em condições de laboratório.
5

Cleptoptilia pela ave tesourinha Tachornis squamata (aves, Apodidae) no semiárido brasileiro / Cleptoptilia the flycatcher bird Tachornis squamata (birds, Apodidae) in the Brazilian semiarid region

Silva, Catharina Cristhina de Oliveira 25 February 2015 (has links)
Made available in DSpace on 2016-08-31T13:19:26Z (GMT). No. of bitstreams: 1 CatharinaCOS_DISSERT.pdf: 1608765 bytes, checksum: 513276c00b59014e7c86bfd1e5d0bd10 (MD5) Previous issue date: 2015-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The bird Neotropical Palm-Swift, Tachornis squamata (Apodiformes, Apodidae), steals feathers of other bird species by kleptoptily behavior. This particular behavior has been described for this bird species in the Amazon, however aspects of kleptoptily have not yet been investigated in other Neotropical biomes, where Neotropical Palm-Swift can be found. The aim of this study was to quantify the kleptoptily behavior of Neotropical Palm-Swift species in urban and non-urban areas in the Brazilian semi-arid region, Caatinga biome. In urban areas, the data collections were carried out between July 2013 and June 2014 between 06:00-10:00 a.m. and between 14:00- 17:00 p.m., in a total of 225h 45min of sampling effort. In non-urban area, the data collections were carried out between September 2013 and June 2014 between 06:00-10:00 a.m., in a total of 50h 30min of sampling effort. The kleptoptily behavior was quantified through of records the number of kleptoptily events, number event of kleptoptily attempts and the number of events which the Neotropical Palm-swift collected feathers that loosened in a spontaneous way of other birds. Were registered in urban areas, 39 kleptoptily events, 385 events of kleptoptily attempts and 875 events of collected feathers that loosened in a spontaneously way of other birds. Were registered in non-urban area, 25 kleptoptily events and 49 events of kleptoptily attempts. In this area were not registered events of collected feathers that loosened spontaneously of other birds. In urban area, the Neotropical Palm-Swift collected feathers of five species of birds, belonging to four families. In non-urban area, feathers were collected from seven species of birds, distributed in six families. In this study, in urban areas, the Neotropical Palm-Swifts were recorded collecting feathers in two different ways: through kleptoptily and through collected feathers that have broken off spontaneously of other birds. In non-urban area, the Neotropical Palm-Swifts only collected feathers through kleptoptily behavior. The different behavior of Neotropical Palm-Swift in the two study areas can be explained in part by synanthropic behavior of this species / A ave Tachornis squamata (Apodiformes, Apodidae), popularmente conhecida como tesourinha, rouba penas de outras espécies de aves pelo comportamento de cleptoptilia. Este comportamento específico foi descrito para o tesourinha na Amazônia, entretanto aspectos da cleptoptilia ainda não foram investigados em outros biomas da região Neotropical onde esta espécie de ave pode ser encontrada, bioma Caatinga. O objetivo desse estudo foi quantificar o comportamento de cleptoptilia da espécie tesourinha em área urbana e área não urbana na região semiárida do nordeste do Brasil. Em área urbana, as coletas de dados foram realizadas entre julho de 2013 e junho de 2014 entre 06:00h e 10:00h e entre 14:00h e 17:00h, e totalizando um esforço amostral de 225h e 45min de observações. Em área não urbana, as coletas de dados foram realizadas entre setembro de 2013 a junho de 2014 entre 06:00h e 10:00h, totalizando um esforço amostral de 50h e 30min de observações. O comportamento de cleptoptilia foi quantificado por meio dos seguintes registros: número de eventos de cleptoptilia, número de eventos de tentativas de cleptoptilia e número de eventos no qual as tesourinhas coletaram penas que se desprenderam de forma espontânea de outras aves. Foram registrados, em área urbana, 39 eventos de cleptoptilia, 385 eventos de tentativas de cleptoptilia e 875 eventos de penas coletadas que se desprenderam espontaneamente de outras aves. Foram registrados, em área não urbana, 25 eventos de cleptoptilia, 49 eventos de tentativas de cleptoptilia e não foram registrados eventos de penas coletadas que se desprenderam espontaneamente de outras aves. Em área urbana, foi registrado que o tesourinha coletou penas em cinco espécies de aves, pertencentes a quatro famílias. Em área não urbana, foi registrado que o tesourinha coletou penas em sete espécies de aves, distribuídas em seis famílias. Neste estudo, em área urbana, o tesourinha foi registrado coletando penas de duas formas distintas: por meio da cleptoptilia e por meio de penas coletadas que se desprenderam espontaneamente de outras aves. Em área não urbana, o tesourinha somente coletou penas por meio do comportamento de cleptoptilia. Esta diferença comportamental exibido pelo tesourinha nas duas áreas de estudo pode ser explicado, em parte, pelo comportamento sinantrópico desta espécie.
6

MULTISTABLE BIOINSPIRED SPRING ORIGAMI FOR REPROGRAMMABLE STRUCTURES AND ROBOTICS

Salvador Rojas III (17683905) 20 December 2023 (has links)
<p dir="ltr">Origami has emerged as a design paradigm to realize morphing structures with rich kinematic and mechanical properties. Biological examples augment the potential folding design space by suggesting intriguing routes for achieving and expanding crease patterns which traditional origami laws are unable to capture. Specifically, spring origami theory exploits the material system architecture and energy storage mechanism of the earwig wing featuring one of the highest folding ratios in the animal kingdom (1:18), minimal energy required for deployment and collapse of the wing, and bistability locking the wing in closed, and open configurations for crawling through tunnels, and flight, respectively. The central mechanism responsible for bistability in the wing features a non-developable crease pattern with a non-zero Gaussian curvature. Reconfiguring, or even flattening a structure with such an intrinsic property requires stretching or tearing; soft, rubbery material found in the creases of the central mechanism allows for stretching enabling shape transformations between open and closed states without tearing. In the first part of this thesis, such characteristics are transferred to a synthetic bistable soft robotic gripper leveraging the shape adaptability and conformability exhibited by the biological organism to minimize actuation energy. This is achieved by integrating soft, flexible material in the bioinspired gripper that allows kinematically driven geometries to grasp and manipulate objects without continuous actuation. Secondly, the stiffening effect from spring origami is utilized in a bioinspired wing for an aerial--aquatic robot. Transitions between air and sea in multimodal robots is challenging, however, a structurally efficient and multifunctional membrane is developed to increase locomotive capabilities and longer flights. This is motivated by the flying fish's locomotive modules and origami design principles for deployment and folding. Additionally, to keep the wing in a stiff state while gliding, spring origami bistable units are integrated into the membrane inducing self-stiffening and a global curvature reducing energy expenditure while generating lift. While the previous examples present solutions to adaptive manipulation and membrane multifunctionality, once programmed, their shapes are fixed. In the third application, a class of multistable self-folding origami architectures that are reprogrammable post fabrication are presented. This is achieved by encoding prestrain in bilayer creases with anisotropic shrinkage that change shape and induce a local curvature in the creases in response to external stimuli. The topology of the energy landscapes can thus be tuned as a function of the stimulation time and adaptable post fabrication. The proposed method and model allows for converting flat sheets with arranged facets and prestrained mountain-valley creases into self-folding multistable structures. Lasty, encoding crease prestrain is leveraged to manufacture a biomimetic earwig wing featuring the complex crease pattern, structural stability, and rapid closure of the biological counterpart. The presented method provides a route for encoding prestrain in self-folding origami, the multistability of which is adaptable after fabrication.</p>

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