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1
Hu, David L. 1979. "The hydrodynamics of water-walking insects and spiders." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34981.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 142-152).
We present a combined experimental and theoretical investigation of the numerous hydrodynamic propulsion mechanisms employed by water-walking arthropods (insects and spiders). In our experimental study, high speed cinematography and flow visualization techniques are used to determine the form of the flows generated by water-walkers. In our supporting theoretical study we provide a formal fluid mechanical description of their locomotion. We focus on the most common means of walking on water such as the alternating tripod gait, rowing, galloping and leaping. We also examine quasi-static modes of propulsion in which the insect's legs are kept stationary: specifically, Marangoni propulsion and meniscus-climbing. Special attention is given to rationalizing the propulsion mechanisms of water-walking insects through consideration of the transfer of forces, momentum and energy between the creature and its environment.
by David Lite Hu.
Ph.D.
2
Oaten, Heather. "Local and landscape effects of field margins on aerially dispersing beneficial insects and spiders." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6944.
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Field margins were implemented in UK agri-environment schemes with the aim to increase farmland biodiversity. Recently aerially dispersing aphid enemies have been shown to provide the majority of aphid control in winter wheat fields but there is a lack of research conducted on the aerial predator guild. This thesis examines the effect field margins have on aphid predators at the single field scale, the landscape scale and, using results from a marking study, examines the direct use of a pollen and nectar rich field margin by Episyrphus balteatus. At the single field scale, field margins had a positive effect of the numbers of Cantharidae, Empididae, Linyphiidae and Tachyporus spp. in fields with sown margins compared to those without during wheat growth and total aphid predator numbers were significantly higher in fields with margin surrounds in early May but not later in the year. At the landscape scale, results from twelve winter wheat fields with varying densities of surrounding field margins showed predatory Tachyporus spp. to exhibit a positive correlation at scales above 500m radius and Cantharidae to exhibit a negative correlation at local scales. Implications for field margins exerting both positive and negative influences on the presence of aerially dispersing aphid predators in winter wheat fields are discussed. A marking study using rubidium chloride proved direct utilisation of a pollen and nectar rich field margin by the Syrphid Episyrphus balteatus, and the traps used in this study also highlighted the association in distributions between Empididae and cereal aphids. Overall it was concluded that the presence of field margins does have an effect on the spatial and temporal distributions of some aerially dispersing aphid predators, but the response of each predator group varies depending on numerous interlinking components of their life history and directions for future research are discussed.
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Chari, Lenin Dzibakwe. "Predators of aerial insects and riparian cross-boundary trophic dynamics: web-building spiders, dragonflies and damselflies." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/55791.
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This thesis characterises the cross-boundary trophic interactions of a relatively small model ecosystem, the Kowie River (Eastern Cape of South Africa), to explore their epistemic implications for systems ecology. Using web-building spiders and odonates (dragonflies and damselflies) as model organisms, I sought to investigate whether the diets of predators of aerial insects could be used to assess the strength of the trophic connectivity between freshwater and terrestrial systems in relation to variables such as stream width, distance from the river and aquatic insect emergence rates and abundances. Predator diet composition was determined by using a combination of diet analysis tools: direct observations of cross-subsidies, naturally-abundant stable (carbon and nitrogen) isotope analysis and fatty acid analysis. I also sought to reveal feeding niches and guilds among riparian aerial predators and investigate how the environment influenced predators’ access to aquatic prey subsidies. As emergent aquatic insect abundances decreased with an increase in distance from the river, and increased with stream width and seasonal changes from winter to summer, stable isotope and fatty acid analyses revealed distinct changes in web-building spider diet composition. Examination of the fatty acid eicosapentaenoic acid, a component commonly used as an indicator of consumer reliance on aquatic nutritional subsidies, showed that aquatic subsidies extended further inland at the wider sections of the river. Spiders and odonates at the wider sections of the Kowie River generally received more subsidies (56 – 70%) than those at the narrower sections (25 – 60%). When terrestrial insect biomass was distinctly low in winter, the benefit of aquatic subsidisation to spiders was relatively lower at the narrower sections of the Kowie River relative to the wide sections. As such, riparian areas adjacent to wide parts of the river were more likely to support larger populations of aerial predators than those at the narrow sections. Apart from the diet changes across time and space, there was evidence of inter-specific niche partitioning in both spiders and odonates, but no differences were observed between males and females of the same species. Results showed odonates of different sizes and hunting strategies had separate dietary niches, hence varied access to aquatic nutritional subsidies. The larger odonate taxa that frequently foraged mid-air had more varied diets and relied less on aquatic emergent insects than the smaller odonates that foraged from perches near the river. There was also evidence of niche partitioning amongst the spiders, as those that built horizontal webs captured more aquatic insects (40 – 78%) than the vertical orb-web builders (20 – 66%). This study showed that the nature and extent of trophic cross-boundary linkages in riparian areas largely depended on the availability of subsidies that varied seasonally and spatially. The width of the stream and seasonal variability emerged as important predictors of emergent insect abundances/biomasses that influenced predator feeding niches. The high mobility of odonates made their reliance on aquatic nutritional subsidies different from the less mobile spiders. The link between the width of the river and the extent of trophic connectivity has implications for riparian area management and definition of riparian buffer zones. However, the variation in diet niches amongst terrestrial consumers makes the results area-specific, and more studies are required that incorporate additional terrestrial predators in other fluvial systems so that we can make some generalizations on the dynamics of riparian trophic cross-boundary links.
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Mellbrand, Kajsa. "The Spider and the Sea : Effects of marine subsidies on the role of spiders in terrestrial food webs." Doctoral thesis, Stockholms universitet, Botaniska institutionen, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-27227.
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The purpose of this study was to identify if terrestrial arthropod predators on Baltic Sea shores vary in their use of marine versus terrestrial food items, and to construct a bottom-up food web for Baltic Sea shores. The inflow of marine nutrients in the area consists mainly of marine algal detritus and emerging aquatic insects (e.g. phantom midges, Chironomidae). Diets of coastal arthropods were examined using carbon and nitrogen stable isotope analysis, and a two source mixing model was used to examine proportions of marine carbon to diets. The results suggest that spiders are the terrestrial predators mainly utilizing nutrients and energy of marine origin on Baltic Sea shores, while insect predators such as beetles and hemipterans mainly utilize nutrients and energy derived from terrestrial sources, possibly due to differences in hunting behaviour. That spiders are the predators that benefit the most from the marine inflow suggest that eventual effects of marine subsidies for the coastal ecosystem as a whole are likely mediated by spiders.
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Loreaux, Hosanna B. "Nutrient Flux from Aquatic to Terrestrial Invertebrate Communities Across a Lakeside Ecotone." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1557912595532676.
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Burdon, Francis John. "The effects of stream productivity on aquatic-terrestrial linkages." Thesis, University of Canterbury. Biological Sciences, 2004. http://hdl.handle.net/10092/1415.
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The potential relationship between riparian arachnids and aquatic insect productivity was assessed in forest streams throughout the central South Island of New Zealand. Initially, a survey was conducted of thirty seven, first-third order forest streams. Streams were selected to represent a range of benthic invertebrate standing crops (as a surrogate measure of "productivity") from Banks Peninsula streams with relatively high benthic invertebrate densities to acid mine drainage streams near Reefton that were almost devoid of aquatic life. At each site benthic invertebrate densities and biomass were measured in riffle habitats and adjacent gravel bars were sampled for terrestrial invertebrates. At a sub-set of 16 sites, a 20 metre longitudinal web-building spider survey was conducted along each bank of the stream. As an additional component, a 20 metre transect starting at the stream margin and running perpendicularly into the forest was used to survey the density of web-building spiders with increasing distance from the stream. Results from the survey of in-situ stream insect biomass and gravel bar invertebrates showed a strong relationship between aquatic insect biomass and the biomass of riparian arachnids (R2 = 0.42, P < 0.001) having accounted for potentially confounding factors such as stream size, elevation, substrate and disturbance. The 20 metre longitudinal survey showed that streams with the highest in-situ insect biomass had significantly higher densities of web-building spiders along their banks (R2 = 0.28, P < 0.05), having accounted for potential confounding variables of elevation, habitat architecture and stream and channel width. The stream to forest survey showed a strong exponential decay in web-building spider densities with increasing distance from the stream (R2 = 0.96, P < 0.0001). Regardless of stream productivity web-building spiders were most abundant at the stream margins and rapidly declined to very low densities 20 metres from the stream. In order to further test the relationship between riparian web-building spider densities and stream insect productivity, a stream fertilization experiment was conducted on six first-second order streams in the Maimai experimental catchment, Reefton. Three streams were enriched by the addition of a fertiliser solution mainly consisting of sodium nitrate for seven months, and the other three streams were used as controls. Water chemistry, benthic invertebrate communities, emerging aquatic adults, and the densities of web-building spiders along the stream corridor and in the forest were monitored in three seasons (spring, summer and autumn) over the course of the nutrient-addition. By the end of the experiment, conductivity was significantly higher in nutrient-addition streams than in the control streams (F = 80.5, P < 0.001), but chlorophyll concentrations showed no significant differences between treatments. Both benthic mayfly densities (F = 6.15, P < 0.05) and the biomass of adult aquatic dipterans (Chironomidae, Simuliidae) (F = 9.25, P < 0.01) were significantly higher in nutrient-addition streams in the last sampling round. Spiders recorded from intercept traps indicated that by the end of the experiment spider activity was significantly higher within 2.5 metres of the nutrient-addition streams (F = 5.70, P < 0.01). However, seasonal densities of web-building spiders along the stream margin and in the forest decreased with no significant differences observed between nutrient-addition and control streams. The results from these studies indicate that adult insects emerging from streams represent an important source of prey that could influence the biomass and abundance of riparian arachnids. Additionally, the results imply that stream productivity and size could mediate the strength of the interaction between riparian and stream habitats. Moreover, feedback mechanisms present in both systems could have implications for such interactions. The elevated densities of web-building spiders observed at the stream margin led to the proposal of the "Highway Robber" hypothesis. This hypothesis suggests that such higher densities of spiders are the result of increased insect activity along the stream corridor: the emergence of adult aquatic insects was predicted to vary less over temporal and spatial scales than that of terrestrial insects due to the poorly synchronized life histories in many New Zealand stream insects. I conclude by suggesting that there are numerous anthropocentric perturbations such as loss of heterogeneity, introduced species, pollution and habitat degradation that could undermine and decouple the intimate linkages between aquatic and terrestrial ecosystems.
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Woloschuk, John Robert. "Testing Spillover of Nocturnal Predators in Agroecosystems: The Influence of Ditch Type and Prey Availability." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1573840600112587.
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Pepper, David R. "Actions of spider venoms on insect nerve and muscle." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280292.
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Greenwood, Michelle Joanne. "The population dynamics of a riparian spider: interactive effects of flow-related disturbance on cross-ecosystem subsidies and spider habitat." Thesis, University of Canterbury. Biological Sciences, 2007. http://hdl.handle.net/10092/1453.
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The transfer of prey resources between ecosystems can have dramatic consequences for both recipient and donor systems by altering food web stability and the likelihood of trophic effects cascading across the ecosystem boundary. Landscape-scale factors influence the importance, direction and magnitude of energy flows, but may also alter the ability of consumer organisms to respond to spatio-temporal changes in allochthonous prey availability. Here, I used flood and drying disturbance gradients to investigate interactions between these two processes on populations of a riparian fishing spider Dolomedes aquaticus (Pisauridae). The abundance of aquatic insects with a winged adult stage, a major component of the diet of D. aquaticus, was markedly higher at less flood-prone rivers and declined with increasing flood disturbance. It was expected that spider populations would be largest at these stable rivers where the aquatic prey abundance was highest. However, a habitat (loose, unembedded riverbank rocks) manipulation revealed that the lack of scouring floods at these sites led to habitat-limited populations, preventing response to the increased prey resource. In fact a peak shaped relationship of spider biomass and abundance was found, with the largest spider populations at intermediately disturbed rivers. In addition, patchy habitat availability was the most likely cause of the small scale (4 m2) aggregation of spiders seen at the most stable and disturbed rivers. These patterns were also associated with strong interactions between the spiders. Stable isotope analysis of field collected spiders and an experimental manipulation of spider densities and food availability indicated that cannibalism rates were likely to be significantly higher at stable and disturbed rivers than those intermediate on the disturbance gradient. Differences in D. aquaticus population size structure and life history traits across the flood disturbance gradient were driven by interactions between resource availability, environmental stability and cannibalism rates. To separate the effects of habitat availability and aquatic prey abundance I used drying rivers, as the amount of aquatic insect prey alters as the water recedes. Desiccation mortality and low aquatic prey biomass most likely caused the spiders' spatial distribution and size class structure to alter in drying river reaches, potentially also leading to differences in cannibalism rates. Overall, cross-ecosystem transfers of prey had large impacts on the distribution, cannibalism rates and life history traits of D. aquaticus but their effects were modified by the nature of the ecosystem boundary. Thus river flow regime controlled the magnitude of the subsidy and its use by a consumer. Hence, cross-ecosystem subsidies will not always lead to larger consumer populations and consumer responses will depend on interactions between large-scale processes.
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Rethwisch, Michael D., and Jessica Grudovich. "Spider mite management in spring alfalfa utilizing swather applied treatments, 2003." College of Agriculture, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/205399.
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An experiment was initiated utilizing a swather based sprayer to determine if miticides applied at cutting would be an effective control method of spider mites in low desert alfalfa hay. Two treatments (Trilogy, Trilogy + Kinetic) were applied the morning of May 23, 2003, to alfalfa with very high numbers of spider mites. Treatments had five replications, with plots sampled on June 2, 9 and 18. Data indicated a severe reduction in spider mite numbers as of June 2 in all treatments (including untreated) thought due to high temperatures experienced shortly after cutting that exceeded lethal thresholds for spider mite survival. Differences in treatments for spider mites or western flower thrips were not noted until June 18, when significantly fewer spider mites were noted in Trilogy treated plots than untreated check plots. Trilogy + Kinetic treatments resulted in numerically fewer spider mites than the untreated check on this sample date, but numerically more than Trilogy treatment.
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Rethwisch, Michael D., Manuel Luna, Michael Williams, Amanda Saenz, Mark Reay, and Jessica Grudovich. "Swather Applied Trilogy® Effects on Twospotted Spider Mite Populations and Resultant Alfalfa Yields and Quality." College of Agriculture, University of Arizona (Tucson, AZ), 2005. http://hdl.handle.net/10150/203839.
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Trilogy® was applied via swather at cutting in April to alfalfa infested with twospotted spider mites. Data from samples obtained at 12 days after application noted somewhat reduced spider populations as a result of Trilogy® application, although new growth was thought to be re-infested from previously cut alfalfa which was in contact with new growth. Western flower thrips later became very prominent in plots and resulted in greatly reduced spider mite populations. Trilogy® treatment resulted in increased yields thought due to larger stem diameters as a result of fewer spider mites early in study. Very slight increases were also noted for alfalfa quality parameters as a result of Trilogy® application. Economic analysis indicated that Trilogy® applied via swather in this experiment resulted in a net increase in alfalfa valued at $2.12/acre.
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Rethwisch, Michael D., Krystyl Bolin, Jessica L. Grudovich, Jessica Wellman, Dyke Charles Van, Juan Vingochea, Marlo Barron, and Mark Reay. "Effect of two-spotted spider mites and miticides on alfalfa hay produced for a late May cutting." College of Agriculture, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/203870.
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Three miticide treatments (milbemectin, clarified neem oil, and chlorpyrifos plus dimethoate) were compared with an untreated check to obtain information on the effects of twospotted spider mite (Tetranychus urticae) feeding on alfalfa yields, quality and economics, as well as crop responses to miticides. Mite infested alfalfa was treated just prior to first irrigation after cutting in spring 2003, and numbers of spider mites and western flower thrips (Frankliniella occidentalis) were obtained at weekly intervals thereafter for the next seven weeks. Data for plant parameters (stem widths, numbers of leaves, internode lengths) were obtained at harvest, as were hay yields and quality. The milbemectin treatment resulted in quickest reduction of spider mites (88.5% at 5 days after application) and also resulted in significantly higher yields than the untreated check (0.18 tons of hay/acre), attributed to the longer internodes and resultant tallest plants and significantly thicker stems than the untreated check. Clarified neem oil and chlorpyrifos plus dimethoate treatments did not control spider mites as quickly as milbemectin and yields were increased by only 0.04-0.05 tons hay per acre in this experiment compared with the untreated check. These two treatments also differed in their effects on stem widths and internode lengths, indicating that some results noted were a result of interactions of miticides with alfalfa as well as spider mite control.
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Rethwisch, Michael D., Bradley J. Griffin, Jessica L. Grudovich, Jessica Hawpe, Krystyl Bolin, Shirley Plemmons, Ben Hayden, Marlo Barron, Alvin Lau, and Mark Reay. "Evaluation of various miticidal products for two-spotted spider mite, alfalfa caterpillar, and beet armyworm control in alfalfa." College of Agriculture, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/205398.
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"A number of products with miticidal activity were applied both in the spring and summer of 2002 to alfalfa in the Blythe, CA, area to evaluate their efficacy for twospotted spider mite (Tetranychus urticae) control. These two application periods differed in regards to presence of western flower thrips (Frankliniella occidentalis), a predator of spider mites. Western flower thrips populations were high in the spring but essentially absent during the period following the summer application, providing contrasting data for effects of western flower thrips interactions with many miticides for spider mite control. Miticides tested included those currently utilized for mite control in alfalfa hay production as well as a number of new and/or potential products for alfalfa hay.
In the spring testing, most treatments had more spider mites than the untreated check at three days post treatment when western flower thrips were present and actively feeding on spider mites. Two fertilizer treatments that contained high amounts of sulfur also had more spider mites than the untreated check at three days post treatment, thought due to repellency of adult western flower thrips. Many of the treatments that had more spider mites than the check following the spring application are known to have thrips activity (Zephyr, Trilogy, Dimethoate, Lorsban, etc.). Fewer motile (adults and immatures, not eggs) spider mites than in the check were noted only from the Capture + Dimethoate 400, Capture, and the combination of the two Gowan numbered products (1528, 1549) at three days after treatment.
Products that provided excellent (90%+) control throughout the duration of the summer part of the experiment included two numbered compounds from Gowan (1528 and 1549), Capture + Dimethoate 400, Danitol, Zephyr + Trilogy, and a numbered compound from Valent USA (V-1283). The wide disparity in the two data sets indicate that western flower thrips presence/absence should be considered as part of the decision making process for spider mite control. "
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Evans, Samuel C. "Stochastic Modeling of Orb-Web Capture Mechanics Supports the Importance of Rare Large Prey for Spider Foraging Success and Suggests How Webs Sample Available Biomass." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1384443854.
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Castro, Thiago Rodrigues de. "Abundance, genetic diversity and persistence of Metarhizium spp. fungi from soil of strawberry crops and their potential as biological control agents against the two-spotted spider mite Tetranychus urticae." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-05072016-142832/.
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The growing demand for strawberries has imposed challenges, especially regarding the control of pests. Many farmers report problems with reduced chemical control efficiency, probably due to selection of resistant populations of insects and mites. An alternative is the use of biological control using pathogenic fungi as a tool in integrated pest management. Metarhizium spp. (Hypocreales: Clavicipitaceae) are generalist entomopathogenic fungi with worldwide distribution and can cause diseases in a large number of hosts. Many studies on the development of Metarhizium as a biological control agent were performed, but this bulk of knowledge is in remarkable contrast to the lack of research on the fundamental ecology of Metarhizium in agroecosystems. This thesis aimed to evaluate the establishment, persistence and dispersal of these entomopathogenic fungi in strawberry crop soil in Inconfidentes, Minas Gerais, Brazil; and to study the diversity and abundance of species of Metarhizium isolated from organic and conventional strawberry crop soils, and the field margins in Brazil and Denmark. The effectiveness of new species of Metarhizium recently found in Brazil, was evaluated against two spotted spider mite, Tetranychus urticae. Applied isolates of M. anisopliae (ESALQ1037) and M. robertsii (ESALQ1426) were able to persist for up to 12 months after the application within the soil, and disperse to other plots and colonize the rhizosphere of strawberry plants. In the plots where ESALQ1037 and ESALQ1426 were applied, 25% and 87.5% of the isolates recovered after 12 months consisted of the same isolates inoculated. A new taxonomically unassigned lineage, referred to as Metarhizium sp. Indet. 5 in this study, was found in strawberry crop margins. The dominant species of Metarhizium in Brazil and Denmark was Metarhizium robertsii and M. brunneum respectively. Further, Metarhizium pemphigi was first detected in Denmark in this study. Soil in organically grown strawberries harbored a more diverse population of Metarhizium spp. compared with conventionally grown strawberries. These studies showed for the first time the potential of new species of Metarhizium as spider mite biological control agents, the lowest median lethal time (LT50 = 4 ± 0.17 days) was observed in mites treated with the isolate ESALQ1638 of Metarhizium sp. indet. 1. The best isolates were ESALQPL63 of B. bassiana, ESALQ1608 and ESALQ1638 of Metarhizium sp. indet. 1 and ESALQ3069 and ESALQ3222 of M. pingshaense based on the survival curve, total mortality, percentage of sporulated cadavers and LT50. Knowledge of the diversity of Metarhizium spp. and persistence in strawberry soil generated in this study may be useful in developing conservation strategies and maximize the natural biological pest control.A crescente demanda por morangos vem impondo desafios, especialmente quanto ao controle das pragas. Muitos agricultores relatam problemas com a redução da eficiência do controle químico, provavelmente devido à seleção de populações resistentes de insetos e ácaros. Uma alternativa é o uso de controle biológico com fungos entomopatogênicos como ferramenta dentro do manejo integrado de pragas. Metarhizium spp. (Hypocreales: Clavicipitaceae), são fungos entomopatogênicos generalistas com distribuição cosmopolita e que podem causar doenças em um grande número de hospedeiros. Muitos estudos sobre o desenvolvimento de Metarhizium como agente de controle biológico foram realizados, mas este leque de conhecimento está em contraste com a notável falta de investigação sobre a ecologia de Metarhizium nos agroecossistemas. Esta tese teve como objetivo avaliar o estabelecimento, persistência e dispersão destes fungos entomopatogênicos em solo de morangueiro em Inconfidentes, Minas Gerais, Brasil; bem como estudar a diversidade e abundância de espécies de Metarhizium isolados do solo de cultivos orgânico e convencional de morangueiro, e das margens das plantações no Brasil e Dinamarca. A eficácia de novas espécies de Metarhizium, encontradas recentemente no Brasil, foi avaliada contra o ácaro rajado, Tetranychus urticae. Os isolados inoculados de M. anisopliae (ESALQ1037) e M. robertsii (ESALQ1426) foram capazes de persistir por até 12 meses após a aplicação no solo, além de dispersar para outras parcelas e colonizar a rizosfera dos morangueiros. Nas parcelas onde ESALQ1037 e ESALQ1426 foram aplicados, 25% e 87,5% dos isolados recuperados após 12 meses consistiam dos mesmos isolados inoculados. Uma nova linhagem não taxonomicamente identificada, referida neste trabalho como Metarhizium sp. Indet. 5, foi encontrada nas margens de morangueiros cultivados. A espécie dominante de Metarhizium no Brasil e Dinamarca foi Metarhizium robertsii e M. brunneum, respectivamente. Além disso, Metarhizium pemphigi foi detectado pela primeira vez na Dinamarca neste estudo. Solos de cultivo orgânico de morangueiro em geral apresentaram uma diversidade maior de Metarhizium do que solos de cultivos convencionais. Estes estudos revelaram pela primeira vez o potencial de novas espécies de Metarhizium como agentes de controle biológico do ácaro rajado, sendo o menor tempo letal mediano (TL50= 4 ± 0.17 dias) observado em ácaros tratados com o isolado ESALQ1638 de Metarhizium sp. indet. 1. Os melhores isolados foram ESALQPL63 de B. bassiana, ESALQ1608 e ESALQ1638 de Metarhizium sp. indet. 1 e ESALQ3069 e ESALQ3222 de M. pingshaense baseado na curva de sobrevivência, mortalidade total, porcentagem de cadáveres esporulados e TL50. O conhecimento da diversidade de Metarhizium spp. e persistência em solos de morango, gerados neste estudo, poderão ser úteis no desenvolvimento de estratégias de conservação e maximizar o controle biológico natural de pragas.
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Tagwireyi, Paradzayi. "Ant and spider dynamics in complex riverine landscapes of the Scioto River basin, Ohio: implications for riparian ecosystem structure and function." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1398983906.
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Caillon, Robin. "Biogéographie du microclimat foliaire : mécanismes et conséquences sur les relations plantes-insectes." Thesis, Tours, 2016. http://www.theses.fr/2016TOUR4006/document.
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Les performances du végétal et des arthropodes dont il constitue le microhabitat dépendent des températures de surface foliaire. Celles-ci peuvent dévier fortement de la température de l’air et présenter des niveaux d’hétérogénéité différents selon l'échelle spatiale considérée. La feuille atténue les températures extrêmes en rapprochant son amplitude de variation journalière de celle de la température de l’air. Cependant, cette réponse diminue l’hétérogénéité des températures de surface foliaire et les capacités de thermorégulation comportementale des arthropodes à l'échelle de la feuille. Les températures moyennes de surface foliaire atténuent peu le réchauffement, et déterminent localement la performance photosynthétique du végétal. De l’échelle de la feuille à celle de la canopée, les plantes montrent des réponses différentes au réchauffement. Ce type de changement d'échelle est primordial pour améliorer notre compréhension de l'impact des changements climatiquesPlant performance and leaf-dwelling arthropods are impacted by leaf surface temperatures. Leaf surface temperatures can show important deviation from air temperature and present different levels of heterogeneity depending on the spatial scale. The leaf buffers temperature extremes by getting closer in amplitude to air temperature. However, this physiological response decreases the heterogeneity of temperatures at the leaf surface and the opportunities for arthropods to behavioraly thermoregulate in this microclimate. Mean temperatures at the leaf surface show low buffering abilities in response to warming and locally determine photosynthetic performance. From the leaf to the canopy scale, plants show different responses to warming and scaling is crucial to increase our understanding of the impact of global warming
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Macel, Antoine Martine. "Contribution à l'étude des mécanismes intervenant dans le rapprochement des sexes chez Tegenaria domestica (Clerck) (araneae, agelanidae)." Nancy 1, 1987. http://www.theses.fr/1987NAN10304.
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Le rapprochement des sexes peut se faire de deux façons : le male suit des fils de cheminement déposés par la femelle, il semblerait que ces fils contiennent une phéromone ou bien il s'oriente sans l'aide des fils grace à une phéromone volatile émise par la femelle ou par la toile
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Bardwell, Carolyn J. "Predation behavior of spiders (Arachnida: Araneae) in Massachusetts cranberry bog ecosystems." 1995. https://scholarworks.umass.edu/theses/3066.
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Wisniewska, Joanna. "Spiders (Araneae) in the commercial apple orchards in Massachusetts." 1996. https://scholarworks.umass.edu/theses/3074.
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Richardson, Matthew L. "Species composition and genetic structure of grassland plant communities and their influence on spiders and herbivorous insects /." 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3363074.
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Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009.Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3281. Adviser: Lawrence M. Hanks. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.
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Mauda, Evans Vusani. "Ant and spider diversity in a rural landscape of the Vhembe Biosphere, South Africa." Diss., 2017. http://hdl.handle.net/11602/988.
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Li, Huei-Chou, and 李惠洲. "The Survey of Insect and Spider Fauna at Ten Elementary School Campuses in Yunlin, Taiwan." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/9ez98q.
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碩士國立嘉義大學
生物資源學系研究所
94
Abstract This study is a survey of insect fauna and arachnida fauna of ten elementary school campuses in Yunlin county. Five habitats of each campus were chosen as the monitoring sites. A pitfall trap was set up to monitor the insect fauna and spider fauna. Among the 15- month monitoring period, a total numbers of 14 orders, 169 families and 58625 insect individuals and 10 families and 1861 adult spider individuals were collected. Referring to the number of insects collected, hymenopteran had the highest proportion, followed by the dipteran. However, 46 families of Diptera had been collected and was the highest among all the insect orders. The insect constituent differed among different habitats. Higher numbers of ants and leaf hoppers were found in playgrounds. Formicidae and Entmobryidae are the dominant species in Ixora williamsii , Ficus microcarpa , and Duranta repens habitats. The human activity was the main influencing the values of richness index, evenness index, Shannon's index and Simpson's index found in playgrounds and flower bed habitats (e.g., D. repens in Er-lun elementary school, Ixora williamsii in Lai-huei elementary school, and Lantana camara in Wu-tsuo elementary school) were lower than other habitats. Higher richness index value were found on the more plant diverse habitats. Insects were active in summer (June to August) according to the bi-weekly survey. In order to have a clear picture of the infestation of red imported fire ant (Solenopsis invicta Buren)at campuses. A throughout ant survey was done in this studies, and a total of 5 subfamilies, 15 genera and 26 species were collected during 15 months. Among them, Monomorium chinense, Pheidole pieli, and Solenopsis geminata were dominant species. The diversity of ants was affected by the human activity as the insect did, e.g. the playgrounds and flower beds have lower species abundance and diversity. Morphological study was done by scanning electron microscopy to describe the characters as a basis to classify the ants collected during survey period. Referring to the Arachnida, 92% of spiders collected was constituted of Lycosidae and Linyphiidae. Higher numbers were found on summer and spring seasons with a very low number in winter. Disturbed habitat had very low numbers of spiders. From the above study, a database is expected to establish. These data would be valuable information for elementary school and junior high school teaching. Meanwhile, some of the information might be valuable for student’s scientific research.
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Gatarayiha, Mutimura Celestin. "Biological control of the two-spotted spider mite, Tetranychus urticae Koch (Acari : tetranychidae)." Thesis, 2009. http://hdl.handle.net/10413/650.
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The two-spotted spider mite (TSM), Tetranychus urticae Koch, is an important pest of many greenhouse and field crops worldwide. The development of resistance in TSM populations to chemical acaricides, allied with public health concerns about pesticide residues, has motivated the search for alternative control measures to suppress the pest. Hyphomycetous fungi are promising agents for mite control and the fungus Beauveria bassiana (Bb) (Balsamo) Vuillemin was investigated in this study as a biocontrol agent. The principal objectives of this study comprised: a) screening Bb strains for their pathogenicity against T. urticae; b) testing the effect of adjuvants on the efficacy of Bb; c) studying the effect of plant type on persistence of Bb and the efficacy of control of Bb against T. urticae; d) evaluating the field efficacy of Bb applications against T. urticae; e) testing the compatibility of Bb with selected fungicides; and f) assessing the synergy between Bb and soluble silicon for T. urticae control. Screening bioassays of sixty-two strains of Bb identified the two most effective strains, PPRI 7315 (R289) and PPRI 7861 (R444), that caused mortality levels of more than 80% of adult mites at 9 d post-inoculation with 2 × 108 conidia ml-1. These strains performed significantly better than the Bb commercial strain PPRI 5339, in laboratory bioassays. The two strains also attacked mite eggs, causing 53.4% and 55.5% reduction in egg hatchability at 2 × 108 conidia ml-1 respectively. However, PPRI 7861 showed relatively higher production of conidia in culture and was, therefore, selected for further trials under greenhouse and field conditions. Greenhouse evaluations of the effects of two adjuvants (Break-thru® and a paraffin oil-based emulsion) on efficacy of Bb demonstrated a higher efficacy of the biocontrol agent (BCA) when it was applied with Break-thru® or the oil solution than with water alone. Moreover, Bb conidia applied in Break-thru® solution resulted in greater control of TSM than conidia applied in the mineral oil. There was also a dose-response effect and the control of TSM by Bb increased when the concentration of conidia was increased. The control of TSM by Bb in beans (Phaseolus vulgaris L), cucumber (Cucumis sativus L.), eggplant (Solanum melongena L.), maize (Zea mays L.) and tomato (Solanum lycopersicum L.) was tested in greenhouse trials. On these crops, the persistence of conidia declined over time. The rate of decline was significantly higher on maize. However, TSM mortality was positively correlated with the amount of conidia deposited on leaves immediately after spraying, rather than their persistence over time. Higher levels of mortality of TSM due to Bb application were observed on beans, cucumber and eggplants, suggesting that the type of crop must be taken into consideration when Bb is applied as a BCA. Field efficacy of Bb against mites was evaluated in two trials on eggplants. Based on assessment of population densities of mites and leaf damage assessments; both trials showed that the strain PPRI 7861 controlled TSM in the field. Two commonly used fungicides, azoxystrobin and flutriafol, were investigated in vitro tests on culture medium and laboratory bioassays on detached bean leaves (Phaseolus vulgaris L.) for their effects on Bb. Azoxystrobin (a strobilurin) was less harmful to Bb while flutriafol was found to be inhibitory. Another important finding of this study was the substantial enhancement of Bb efficacy by soluble silicon. When Bb was combined with soluble Si, the control of TSM was better than when either of the two products was applied alone. Moreover, application of soluble Si as a plant fertilizer in hydroponic water nutrient increased accumulation of peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase enzymes in leaves of plants infested with TSM. Increased activity of these defense enzymes in leaves deters feeding behaviour of mites. We suggested that feeding stress renders them susceptible to Bb infection, which would explain the synergy observed between the two agents.Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
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Schoeman, Colin Stefan. "Ground - dwelling arthropods in a biosphere reserve: patterns of diversity and conservation implications." Thesis, 2019. http://hdl.handle.net/11602/1290.
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PhD (Zoology)Department of Zoology
Invertebrate diversity is often neglected in conservation planning initiatives. There are also very few large-scale diversity studies in Africa, with most studies being restricted to single properties and spatial extents that are on average not much larger than 30 km2. Here, we provide a comparative regional assessment, two orders of magnitude larger than usual (30 000 km2), of epigeal spider, beetle and millipede diversity in the Vhembe Biosphere Reserve – the largest biosphere reserve in South Africa, and one of the largest in Africa. Firstly we aim to provide an evaluation of the ability of a range of broad and fine scale predictors to explain the variation in the diversity of these taxa. Secondly, we measured cross-taxon congruence between our selected invertebrate taxa and woody vegetation, and within-taxon surrogate efficiency. Thirdly we evaluated performance of existing and proposed zonations in representing regional invertebrate species diversity. Finally, to aid in the development of species conservation profiles for lesser known taxa, annotated check lists are provided for two neglected but dominant epigeal beetle families, Tenebrionidae and Carabidae. Vegetation units explained the largest and most significant component of beetle and spider diversity (richness and complementarity of alpha and beta diversity). Elevation and mean annual temperature played a lesser but still significant role. Overall, woody vegetation was a poor surrogate, especially for millipedes which have several localized endemics. The use of higher taxa (genus and tribe in particular) shows the greatest potential for conservation planning. The current zonation of the Vhembe Biosphere Reserve performed significantly better than expected in representing invertebrate diversity across the region. The reality though is that conservation decision-making is largely informed by knowledge on the distribution of rare, localized or endangered species, for which detailed species inventories are 10 required. Though a coarse filter approach is recommended, the augmentation of species level data provides an extra filter, and contributes to our knowledge of what taxa are in urgent need of protection. Targeting rare and endangered species in transition zones and developing conservation assessments and plans for these in relatively small areas would compliment existing conservation initiatives in the VBR. Annotated check lists ofTenebrionidae of the Vhembe Biosphere suggest that the family is particularly speciose, the assemblage being comprised of an east African and a Kalahari element which contributes significantly to local endemicity, and yielded three new species, one of which is described in the revision to the genus Anaxius, a group largely restricted to the mountainous areas of Limpopo Province. Carabidae were also found to be speciose, with the assemblage comprised of a large proportion of stenotypic species. There is support for the use of vegetation types in conservation plans but these should be augmented with species level conservation initiatives that target particularly transition and buffer zones.
NRF
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Maas, Bea. "Birds, bats and arthropods in tropical agroforestry landscapes: Functional diversity, multitrophic interactions and crop yield." Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-0022-5E77-5.
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