Abstracts, Plant-herbivore Interactions PDF Download

Author: Shrub Sciences Laboratory
Publisher:
ISBN:
Category : Forage plants
Languages : en
Pages : 21

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Author: Tania N. Kim
Publisher:
ISBN:
Category : Botany
Languages : en
Pages :

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ABSTRACT: Ecological systems are dynamic, yet many experimental studies examine plant-herbivore interactions as from a simple, static, or single perspective. Reciprocal interactions can have profound effects on communities, and ignoring such feedbacks can result in mismatches between theoretical predictions and experimental results. In this dissertation, I examined reciprocal interactions between two plant species, Solanum carolinense and Solidago altissima and their insect herbivores. In chapter 2, I examined how insect herbivores influenced plant competition and coexistence. Theory suggests that herbivores influence plant communities by altering competitive interactions. Because the outcome of competition is influenced by both the per capita competitive ability of plants and demographic processes including density dependence and intrinsic population growth rates, measuring herbivore effects on all these processes is necessary to understand the mechanisms by which herbivores influence plant communities. I fit alternative competition models to data from a response surface experiment conducted over four years to examine how herbivores affected the outcome of competition between two perennial plants, Solanum carolinense and Solidago altissima . Within a growing season, herbivores reduced Solanum plant size, but did not affect Solidago, which exhibited compensatory growth. Across seasons, herbivores did not affect the density of Solanum but reduced both the density and population growth of Solidago. The best fit models indicated that the effects of herbivores varied with year. In some years, herbivores increased the per capita competitive effects of Solidago on Solanum; in other years herbivores influenced the intrinsic population growth rates of Solidago. I examined herbivore effects on the longer-term outcome of competition (over the time-scale of a typical old-field habitat) using simulations based on the best fit models. In the absence of herbivores, plant coexistence was observed. In the presence of herbivores, Solanum was excluded by Solidago in 60% of the simulations. I demonstrated that herbivores can influence the outcome of competition through both changes in per capita competitive effects and changes in demographic processes. I discuss the implications of these results for ecological succession and biocontrol. In chapter 3, I examined how plant community composition influenced damage patterns on plants. Neighboring plants can increase (associational susceptibility) or decrease (associational resistance) the likelihood of damage to a focal plant but their long-term consequences for plant competition and coexistence are unclear. Neighbor effects on damage can occur through changes in the relative density of the focal plant (i.e., frequency of the focal plant), the absolute density of the focal plant, or through the total density of plants, because the different mechanisms known to influence damage patterns (e.g., pest suppression by predators, herbivore foraging behavior, plant quality) respond to different features of the neighborhood. To examine the long-term consequences of neighbor effects for plant communities, an understanding of how density and frequency of plants influence damage is needed. Using a response surface experimental design, I examined the effects of plant density and frequency on damage to Solanum carolinense. I found non-linear effects of the frequency of heterospecific neighbors (Solidago altissima) on Solanum damage, and a positive effect of Solanum density on damage. The non-linear pattern suggests that multiple mechanisms may be operating to influence damage. Non-linear patterns may be common in other habitats but might be overlooked because traditional neighborhood studies use a very narrow range of densities in their experiments. I encourage future neighborhood studies to use response surface designs to determine the prevalence of non-linear relationships in nature. In chapter 4, I examined how neighborhood composition (i.e. plant density and frequency) influenced four mechanisms known to influence damage to plants (predator suppression, foraging behavior of herbivores, plant quality, and microclimate) using a response surface experimental design. An associational effect was observed between Solanum damage and the frequency of a heterospecific neighbor (Solidago altissima). Predator abundance and richness, soil moisture, and herbivore foraging strategies were all influenced by the frequency of Solidago, suggesting that these mechanisms may contribute to associational susceptibility in this interaction. Other mechanisms (microclimate and plant quality) were influenced by Solidago and total plant densities, respectively. This study showed that different mechanisms can be influenced by different components of the neighborhood and most likely interacts to influence damage to plants. I discuss the implications of these finding for agriculture and for understanding the long-term consequences of damage for plant communities. In chapter 5, I examined how herbivory, herbivore community composition, plant nutrient content, and herbivore performance varied with latitude. A longstanding theory in biogeography is that species interactions, including herbivory, are stronger in southern latitudes compared to those in the north. Because of this, the latitudinal gradients (LG) hypothesis in damage and plant defenses predicts that plants should be better defended in the tropics because selection for plant defenses is greater. Recent empirical studies suggest that the predictions from this hypothesis may be limited to a narrow range of systems (e.g. salt marshes). In efforts to understand why LG in herbivory and plant defenses are not prevalent as once thought, I examined relationships between herbivore abundance and richness, plant nutrient content, and latitude in old-field systems. I also examined latitudinal gradients in herbivore performance using generalist and specialist herbivores. Some relationships with latitude matched predictions from the LG hypothesis (e.g. plant nutrient content, damage to Solidago altissima), while others had opposite relationships (e.g. herbivore abundance and richness, damage to Solanum carolinense), and some relationships varied with leaf longevity. Herbivore responses varied with diet specialization and the exact relationship with latitude (linear, non-linear, positive, negative, or no relationship) varied with herbivore species. These results suggest that the predictions from the LG hypothesis are too simple; a more thorough investigation of relationships between herbivore abundance, damage, and plant resistance in other wide-ranging systems is needed.

Author: Juan Núñez-Farfán
Publisher: Springer
ISBN: 9783030460143
Category : Science
Languages : en
Pages : 376

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Plant-herbivore interactions are a central topic in evolutionary ecology. Historically, their study has been a cornerstone for coevolutionary theory. Starting from classic ecological studies at the phenotypic level, it has since expanded to molecular and genomic approaches. After a historical perspective, the book’s subsequent chapters cover a wide range of topics: from populations to ecosystems; plant- and herbivore-focused studies; in natural and in man-modified ecosystems; and both micro- and macro-evolutionary levels. All chapters include valuable background information and empirical evidence. Given its scope, the book will be of interest to both students and researchers, and will hopefully stimulate further research in this exciting field of evolutionary biology.

Author: Zhilan Feng
Publisher:
ISBN: 9781351640664
Category : Animal-plant relationships
Languages : en
Pages : 219

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Author: Robert Denno
Publisher: Elsevier
ISBN: 0323142877
Category : Science
Languages : en
Pages : 735

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Variable Plants and Herbivores in Natural and Managed Systems examines individual, population, species, and community responses of herbivores to plant variation, with emphasis on insects, fungi, bacteria, and viruses. It is divided into five parts encompassing 18 chapters that discuss variability as a mechanism of defense used by plants against their parasites and the effects of variability on herbivores at several different levels of complexity. After a brief discussion on plant-herbivore interactions, the first part of this book considers sources of within-plant variation and effects on the distribution and abundance of herbivores. Part II examines interplant variation, the co-evolutionary problems it poses for herbivores, and the ecological and evolutionary responses of these animals. It discusses the effects of host-plant variability on the fitness of sedentary herbivorous insects. Part III discusses the role of host variability in the evolution of feeding specialization, genetic differentiation, and race formation. The importance of host variation to the organization of herbivore communities and the manipulation of host-plant variability for the management of herbivore pest populations are presented in the remaining parts. This book will be helpful to agriculturists, silviculturists, biologists, and researchers who wish to expand their knowledge in dynamics of plant-herbivore relationships.

Author: Xoaquín Moreira
Publisher: Springer Nature
ISBN: 3031478142
Category : Science
Languages : en
Pages : 248

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Theory and early empirical work posed that herbivore pressure should be lower on islands than on the mainland owing to lower herbivore abundance and diversity in insular systems. Consequently, plant taxa found on islands are expected to be less protected or even to have lost their defences completely. While early observational studies supported the prediction of lower herbivory and plant defences on islands, recent island-mainland comparisons have yielded mixed results, with some studies finding no differences between islands and mainlands or, surprisingly, higher herbivory and plant defences on islands. In this book, the authors aim to re-assess current theory and initiate a new generation of work on insularity effects on plant-herbivore interactions. This book aims to fill the research gaps by integrating the research that has been done to date and by compiling and summarising new research on insularity effects on plant-herbivore interactions. It provides a critical examination of the patterns in light of classical theory and identifies potential mechanisms or underlying processes. It also aims to raise new questions that will form the basis for a revised and more robust research programme.

Author: Zhilan Feng
Publisher: CRC Press
ISBN: 9780367782054
Category : Animal-plant relationships
Languages : en
Pages : 0

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This book addresses mathematical models in the study of practical questions in ecology, particularly factors that affect herbivory. It will be of use for graduate students and researchers interested in mathematical biology and ecology.

Author: Andrés F. Cibils
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Gillian A. Cooper-Driver
Publisher: Springer Science & Business Media
ISBN: 1475796587
Category : Science
Languages : en
Pages : 251

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Chemical warfare between plants and their herbivores and pathogens was first brought to our attention by the publication 25 years ago of the paper by Fraenkel in Science. There, he pointed out that most plants have similar nutritional characteristics so that the selection of plants by insect herbivores must depend on the relative toxicity of secondary compounds. This led, rather gradually, to a host of papers on plant-herbivore interactions. More or less at the same time, insect physiologists and ecologists were starting to realise the importance of chemical communi cation systems in determining sexual and other characteristics of insect behaviour. Nine years ago the Phytochemical Society of North America published their Symposium on 'Biochemical Interaction Between Plants and Insects' in which the plant apparency theory was expounded by both Paul Feeny and Rex Cates and David Rhoades. This stated that plants which are apparent usually contain secondary components which reduce digestibility (tannins and lignins) while ephemeral plants have more toxic, and perhaps less costly, compounds such as alkaloids. These papers stimulated much research on biochemical ecology. The recognition of the importance of the biochemical factors in such interactions is not just of scientific interest. It is vitally important in programs for the production of new varieties of cultivated plants, especially in tropical countries where about one-third or more of the crops are lost to predation or disease.

Author: Shrub Research Consortium
Publisher:
ISBN:
Category :
Languages : en
Pages :

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