Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 95 for “"Aphids"”.
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Strategies of Sexual Reproduction in Aphids
Die durchschnittliche Dauer der zweiten Kopulation von Uroleucon cirsii (L.) ist sowohl für Männchen als auch für Weibchen kürzer als die der ersten. Dies legt die Vermutung nahe, dass die männlichen Blattläusen zur Verfügung stehende Menge Sperma limitiert ist. Des weiteren wird Ejakulat von …
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Aphids as vectors of peanut mottle virus
… peanut mottle virus (PMV). The total number of aphids trapped in these crops are about equal and the reason for this differential percentage infection has not been demonstrated. Known vectors of PMV such as Aphis craccivora (Koch) and Myzus persicae (Sulzer) comprised 31% of the aphid population …
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EVOLUTIONARY AND MECHANISTIC INTERACTIONS IN VIRUS TRANSMISSION BY APHIDS
Virus transmission by aphids involves a combination of biological players that have co-evolved over years of interaction: plant hosts, aphid vectors, plant viruses and the aphid’s bacterial endosymbiont. In this interaction, plant hosts activate their immune defenses against plant viruses and …
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The effect of aphids in parasitoid-caterpillar-plant interactions
… host (M. sexta). Chapter 2 demonstrated that aphids reduced hornworm abundance and parasitism. Changes in hornworm abundance were not due to density-dependent changes in moth oviposition, but the proportion of caterpillars attacked by parasitoids was inversely density dependent with hornworm …
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Coevolution and consequences of symbioses between aphids and maternally transmitted bacteria
… often harbor maternally transmitted bacteria. Aphids engage in symbiotic interactions with several maternally transmitted bacteria, and many are known to associate with microbes known as secondary symbionts. These bacteria are typically not essential from the aphid's perspective, and until …
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Alfalfa Aphids From Pixel to Picture: Deciphering Symbiotic and Predatory Interactions Across Scales
… of Nevadan agriculture. Together with alfalfa aphids, these organisms exemplify the complex ecology of herbivory. This dissertation explores multiple dimensions of this ecology: the landscape context of aphid predation and biocontrol, interactions between the microbial symbionts of alfalfa and …
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Studies of Resistance to Aphids and Viruses in Arabidopsis thaliana and Capsicum annuum
… or fox1 did not diminish the resistance to aphids observed in Arabidopsis ago1.25 mutant plants. Aphid growth rates and fecundity on ago1/cyp82C2 or fox1/ago1 mutant plants did not significantly differ from aphid performance on wild-type plants. This indicates that deregulation of 4-OH-ICN …
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Modeling Mutualism and Competition in Interactive Population Dynamics: How Ants and Aphids Affect Lycaenid Butterfly Ecology
… dynamics of two interactive species, ants and aphids, we hope to generate a model which simultaneously predicts the fluctuation in the focal species while providing insight to the rich and complex interplay of mutualistic and competitive interactions in theoretical ecology. By using this model …
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Feeding determinants in aphids with special reference to the Rose Aphid Macrosiphum rosae (L.) / by Zhongkui Peng.
This thesis looks at aphid feeding determinants by type and location. It examines the role of leaf surface chemicals in the discrimination of host plants and the deterrent effect of catechin and its oxidative condensation products.
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Control of Turnip yellows virus: Assessing impact on oilseed rape quality traits and dissecting circulative transmission by aphids
… their genetic potential. TuYV is transmitted by aphids, sap-sucking hemipteroid insects, and the green peach aphid (GPA) is the predominant vector. TuYV can reduce oilseed rape yield by up to 26% in the UK and may also affect oil quality. Current control measures rely on insecticides; however, …
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The effect of aphid lethal paralysis virus (ALPV) on the biology of grain aphids in the Western Cape
… immunofluorescent technique in dissected aphids. This technique was found to be more sensitive when compared to DAS-ELISA. The choice of a sensitive, low cost .detection method was of importance to test for low levels of virus in infected aphid body tissues where inapparent infection could …
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The microclimate of corn and bean cropping systems: Its relationship with Dalbulus maidis, some aphids, and the diseases they transmit
Different vegetated surfaces create their very own microclimates. Mixed cropping systems rather than monocultures constitute a traditional planting technique in the tropics, and it has been observed that mixed crops are usually less prone to damage from pathogens carried by insects than …
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Induced Walking Behavior of Rhopalosiphum Padi L. (Homoptera: Aphididae)
… and combination of perturbations. Apterous aphids, caged overnight on oat plants in a 25-plant infestation focus in the center of each 900-plant plot, were subjected to a given perturbation or combination of perturbations after the cages were removed and then allowed to move freely within …
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Ecological and logistical considerations toward introducing Heringia calcarata to New Zealand
… WAA colony that did or did not contain mummified aphids parasitized by A. mali were deployed in pairs at the base of apple trees. There was no significant difference in the mean number of H. calcarata eggs deposited between shoots with parasitized (1.5 ± 0.34 SE) and non-parasitized colonies (1.75 …
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Preference and Performance of the Water Lily Aphid (Rhopalosiphum Nymphaeae) among Native and Invasive Duckweeds (Lemnaceae)
Water lily aphids, Rhopalosiphum nymphaeae, are a polyphagous species of insect that feed on a variety of host plants including members of the Lemnaceae family. Many studies have focused on the relationship between herbivore preference and performance on different host plants, and as such the goal …
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Dissecting the role of plant immunity in plant-aphid interactions
Aphids are economically important phloem-feeding insects that cause loss in plant productivity worldwide. This occurs through the removal of photoassimilates and the vectoring of hundreds of plant viruses. Plants possess a complex immune system in order to defend themselves from a range of …
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