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 31 for “"Insect herbivores"”.
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Intraspecific plant polyploidy effects on goldenrod insect herbivores
… use by seven taxonomically diverse herbivorous insect species is non-random with respect to ploidy level across this distribution. Sampling of S. altissima populations along a 400 mi longitudinal transect across Iowa and neighboring states revealed that substantial ploidy variation exists across …
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Density and Dispersion of Insect Herbivores on Lamb's-Quarters (Chenopodium Album)
Seven species of leaf-feeding insects were found on lamb's-quarters plants (Chenopodium album L. Chenopodiaceae) in central Illinois. The two most abundant were the microlepidopteran leaf miner Chrysopora lingulacella Clemens (Lepidoptera: Gelechiidae), which was abundant in sheltered areas in the …
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Understanding How Whole Genome Duplication in Plants Impacts Herbivore-plant Interactions
<p>Herbivory by insect herbivores is a strong selective force in many communities. Although herbivore-plant interactions have been a focus of interest for decades, we are still exploring how large-scale genetic changes in the host plant alters their interactions with insect herbivores. One such …
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Hypersensitive Response in Live Oak: Characterization and Efficacy Against a Host of Specific Gall-Forming Wasp
… and spread of host-plant-specific pathogens and insect herbivores are fundamentally affected by plant defenses. Hypersensitive response (HR) is a plant defense classically recognized as resulting from a gene-for-gene interaction between pathogens and plants. More recently HR arising from …
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Insect herbivore communities colonising the flower-heads of Berkheya in South Africa and Carduoideae in Europe and California
… conclusions can be made about the association of insect herbivores with Berkheya and thistles and whether there are any 'rules' that have influenced the evolution of these associations. It is shown repeatedly that there are significant and interesting correlations between characteristics of the …
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Foliar Herbivory on Understory Oaks as a Function of Forest Type and Prescribed Burning
Loss of oak seedling and sapling leaf area to insect herbivores has not been well characterized in Ozark forests, but may be a critical variable affecting current and future forest health. This study quantified loss of oak seedling and sapling leaf area to insect herbivores in recently burned or …
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Molecular and Functional Characterization of Terpene Chemical Defense in Arabidopsis Roots in Interaction with the Herbivore Bradysia spp. (fungus gnat)
… together sustain plant growth and development. Insect herbivores pose a constant threat to both above- and belowground plant tissues. To ward off herbivorous insects, plants have developed different strategies such as direct and indirect chemical defense mechanisms. Research has primarily …
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Diet Breadth Evolution and Diversification of a Generalist Insect Herbivore
<p>Insect herbivores are one of the most diverse groups of multicellular organisms, and the vast majority are specialists, which feed on only a few plant species. The factors that cause some herbivores to be specialists and others to be generalists are still unclear. It is known that the selective …
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Cyanogenesis and the feeding preference of Acraea horta (L.) (Lepidoptera : Acraeinae)
… diversified with the plants producing them as herbivores evolved various means of coping with their toxicity. In what follows I present an overview of events leading to the establishment of this theory, and a history of the discovery that some insect herbivores have turned the toxicity of plant …
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Entomological considerations for domestication of pennycress, Thlaspi arvense, as a cash cover crop
… of the interactions between pennycress and insect herbivore communities and agroecosystems remains limited. This research aimed to fill these knowledge gaps and support the development of integrated pest management (IPM) programs for this emerging crop.First, a comprehensive review was …
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An investigation into the rapidly induced chemical responses of Myrica gale to insect herbivory
… set of plants (the controls) were kept free of insect herbivores while a second set sustained capsid bug herbivory. The terpenoid and phenolic profile of leaves from each set was obtained on a weekly basis using GLC and IIPLC respectively. GC-MS was used to identify constituents of the volatile …
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Interactions between Bromus tectorum, grasshoppers, and native plants in sagebrush steppe communities
… that B. tectorum dominance is enhanced by native herbivores through the mechanism of apparent competition: species competing indirectly through shared natural enemies. If an invasive exotic is a less preferred food source for herbivores than native plants, per capita feeding impacts may increase …
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Predicting Insect Herbivore Distribution Using Climatic and Biotic Variables
… species distribution in nature. The abundance of insect herbivores can vary greatly spatially and temporally. These variations can be explained by abiotic variables such as precipitation, they can also be explained by biotic variables such as nutrient availability. Here I present two field …
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Evolution, function and manipulation of methyl halide production in plants
… plants did not affect the performance of insect herbivores, nor did it alter the microbial diversity of the rhizosphere in these lines. Microarray analysis of WT and hol mutant plants pointed to a function of HOL in starch/carbon metabolism and stress response pathways in A. thaliana. …
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Diverse functions of the two segmentally duplicated 9-lipoxygenases ZmLOX4 and ZmLOX5 of maize
… highlighted in host defenses to pathogens and insects, the functions of 9-LOXs and 9-LOX derived oxylipins remain obscure for both monocots and dicots. The objective of this study was to elucidate the biochemical, molecular and physiological roles of a segmentaly duplicated pair of 9-LOXs, …
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Effects of nitrogen and water on growth, photosynthesis, and leaf properties of deciduous tree species with consequences for gypsy moth herbivory
… availability are more susceptible to drought and insect herbivory. I grew seedlings of gray birch (Betula populifolia), yellow birch (B. alleghaniensis), and red oak (Quercus rubra) for two years under varying levels of N and water availability in the field. Growth and biomass allocation were …
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Induced resistance in soybean: Studies with the Mexican bean beetle and the soybean looper
… effect in soybean can be induced by previous insect herbivory as well as by mechanical injury. There seems to be no interplant transfer of inducing signals, as uninjured plants growing in the same pots as injured plants are not induced. Various induction factors were compared and the results …
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Investigating Causal Relationships between Global Change and Insect Interaction Networks: Insights into Dietary Specialization, Interaction Diversity, and Disturbances
… between global change and diversity of insect interaction networks through quantifying effects of biotic and abiotic gradients on dietary specialization, interaction diversity, and related attributes of arthropod communities. My focus on how specialization varies across gradients and is …
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