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Plant productivity, consumer feeding preferences, and biological control in a terrestrial arthropod food web.

Matthew Patrick. Daugherty University of California, Berkeley. 2006

Dissertation Abstracts International 68-02B.

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題名:
Plant productivity, consumer feeding preferences, and biological control in a terrestrial arthropod food web.
著者: Matthew Patrick. Daugherty
University of California, Berkeley.
主題: Biology, Ecology; Biology, Microbiology
所屬期刊: Dissertation Abstracts International 68-02B.
描述: Understanding the dynamics of speciose food webs is a challenging, but important task for ecologists. I used mathematical models, manipulative experiments, and stable isotopes to understand how plant productivity and consumer feeding behaviors determine the dynamics of insects in California pear orchards---especially as they relate to biological control. This system is interesting because of the numerous generalist natural enemies (several of which are described as feeding on multiple herbivores, other predators, and even plant material) and because the main pest, pear psylla (Cacopsylla pyricola), responds strongly to fertilizer application. Both of these factors affect food web dynamics and contribute towards the uncertain nature of psylla biocontrol.
First, using a physiologically-structured model of plant growth, I show that different herbivore guilds can coexist, depending largely on plant productivity and allocation priorities. This result contradicts classical (predation-based) ideas about competitive exclusion and may be valuable for evaluating different weed biocontrol scenarios.
Next, I built on existing models of intraguild predation to explore the effects of alternative resources. Supplementary feeding on alternative resources affects predator coexistence, predator dominance along a productivity gradient, and resource suppression---with generally opposing patterns between when the top versus intermediate predator is supplemented.
I investigated the relative importance of top-down versus bottom-up control of psylla by manipulating plant nutrient availability and the presence of a dominant predator, Anthocoris nemoralis. The predator suppressed psylla populations, but the level of suppression was not dependent on nutrients---suggesting that limiting nutrients is an important feature for effective psylla management.
Finally, I attempted to quantify the prevalence and form of omnivory among pear orchard insects using stable isotopes. Unlike in aquatic systems, I found high levels of taxon-specific variation in isotopic signals that blurred the structure of the food web, suggesting that isotopes are not a "quick and dirty" method for disentangling terrestrial food webs.
出版者: Thesis (Ph.D.)--University of California, Berkeley, 2006.
建立日期: 2006
格式: 152 p..
語言: 英文
資源來源: NUTN ALEPH

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Plant productivity, consumer feeding preferences, and biological control in a terrestrial arthropod food web.

Matthew Patrick. Daugherty University of California, Berkeley. 2006

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