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 22 for “"insect herbivory"”.
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An investigation into the rapidly induced chemical responses of Myrica gale to insect herbivory
The effect of natural herbivory on the secondary metabolism of Myrica gale was investigated. In a field experiment herbivory was found to elicit changes in both the leaf phenolics and the density of volatile oil glands. Lygocoris spinolai, a capsid bug, accounted for most of the observed herbivory. …
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Diel patterns of insect herbivory and plant secondary metabolites in understory shrubs on Barro Colorado Island
… of secondary metabolites as defenses against herbivory. In response, herbivorous insects have evolved a diversity of behavioral and biochemical counter-adaptations to these defenses. Despite that a significant portion of leaf area removal by insects in the tropics occurs at night, virtually …
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Interactions of insect herbivory and multiple abiotic stress agents on two wetland tree species in southeast Louisiana swamps
… and secondary productivity. In this study, insect-tree-health relationships were evaluated in field and in multifactor, greenhouse and larval rearing experiments incorporating these environmental stressors and nutrient enhancements under simulated diversion conditions. It was ascertained …
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Consequences of drought, flooding, and insect herbivory on the distributions of closely related willow and poplar (Salicaceae) species across hydrologic gradients in Minnesota wetlands
… the effect of environmental filtering and insect herbivory on distributions of 14 willow and poplar species across hydrologic gradients in Central Minnesota, combining field and greenhouse experiments, functional traits data, and phylogenetic analyses. At our study site, Cedar Creek …
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The Evolutionary Ecology of Arabidopsis Thaliana: Genotypic Diversity, Herbivory, and Elevated Carbon Dioxide
… I evaluated the impact of elevated CO2 and insect herbivory on the genotypic response of Arabidopsis thaliana . I performed greenhouse and field experiments to examine plant ecological traits related to life history, fitness, and resistance and their variation under different abiotic and …
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PATTERNS OF SEEDFALL AND SEEDLING ESTABLISHMENT IN AN EAST TEXAS RIVER FLOODPLAIN FOREST: THE CONTRIBUTION OF SEEDLING DYNAMICS TO SPECIES COEXISTENCE (PLANT DEMOGRAPHY, DISPERSAL, TREE REGENERATION, SURVIVORSHIP, MORTALITY)
… factors including flooding, drought, shading, insect herbivory, and fungal attack in causing seedling mortality. Tree species fell into two groups on the basis of their demographic characteristics and responses to unfavorable conditions. For heavy-seeded species, of which water oak was the …
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Hydrogen peroxide from photosynthesis: Theory and experiments linking elevated atmospheric CO2 with C3 plant chemical defense
… defense against biotic agents, herbivorous insects in particular. The argument that emerges from this review is that photosynthesis is the most likely operating cause behind the observed alteration of defense in C3 plants growing under elevated CO2. The proposed mechanism holds that elevated …
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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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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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Assessing the effects of invasive Ligustrum sinense and Lonicera japonica on rare and federally threatened Scutellaria montana
… occurrence in Chattanooga, TN. An interacting herbivory exclosure treatment was included to help isolate the effects of competition from non-insect herbivory, another possible pressure negatively influencing S. montana, and to isolate the effects of competition from apparent competition. I …
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DNA Methylation and Genetic Divergence Associated with an Inducible Defensive Response in Mimulus guttatus
… these mechanisms due to its striking response to insect herbivory. Monkeyflower responds to leaf damage by increasing the number of hair-like glandular trichomes, a putative defensive trait that reduces the magnitude of damage by insects. This plastic response is transgenerationally inherited in a …
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The Influence of Dense Understory Shrubs on the Ecology of Canopy Tree Recruitment in Southern Appalachian Forests
… mechanisms. Further, I found that the rates of insect herbivory on Quercus seedlings were positively correlated with R. maximum density. Kalmia latifolia had little influence on resource availability, seedling performance or herbivory rates, and does not appear to have a suppressive effect on …
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Evolutionary and genetic basis of morphological variation in Populus nigra (European black poplar)
… of quantitative trait loci (QTL) for insect herbivory in a common garden study of hybrid poplar indicated that leaf morphology might also be influenced by insect preference.<br/><br/>Among individuals, differences in leaf size corresponded to variation in cell number and not cell size, …
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Effects of Local Plant Neighborhood on Plant Herbivory in Perennial Polyculture Cropping Systems
… and row spacings) that could confer specialist insect pest resistance via reduced host plant apparency, changes in herbivore attraction, and host plant tissue quality. The three chapters in this dissertation examine these themes of perennial polyculture and effects of spatial heterogeneity on …
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Investigation of Protein-Protein Interactions among Nicotine Biosynthetic Enzymes and Characterization of a Nicotine Transporter
… where it is acts as a defense compound to deter insect herbivory. The research detailed in this dissertation addresses two aspects of nicotine physiology in tobacco: 1) an investigation of hypothesized protein-protein interactions among nicotine biosynthetic enzymes and 2) the characterization of …
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Constraints on plant resistance and tolerance trade-offs
Plant tissue loss due to herbivory is an important selective force for shaping plant phenotypes (Marquis 1992). Therefore, plants have evolved a variety of mechanisms to mitigate the negative effects of herbivory. Much of what we have learned, to date, on plant responses to their enemies …
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Resistance evaluation and management of Colorado potato beetle, Leptinotarsa decemlineata (Say), using novel chemistries
… this pest relies heavily on chemical control and insecticide resistance is a persistent problem. This phenomenon has increased the need for developing novel insecticides, resistance evaluation, and the development of alternative control strategies regarding this insect pest. From 2010 to 2013, …
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Forest Mortality in Lake Tahoe Basin from 1985-2010: Influences of Forest Type, Stand Density, Topography and Climate
… role of species traits, stand characteristics, insect herbivory, and climate for influencing forest mortality at both stand and landscape scales. Variable response to both climate and stand density means that scientists should be cautious about generalizing these effects to all western forests. …
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