DISSERATION RESEARCH: The Effects of Habitat Variability on Host Plant-Herbivore

Bowers DEB-9623127大多数在空间背景下考察种群动态的研究都假设景观中生境斑块的大小、质量和数量不会随着时间的推移而变化。这样的假设在生物学上可能是不现实的。在许多情况下，生境斑块是生物单位，如寄主植物，其大小或数量可能随着居住在这些斑块内的种群在类似的时间范围内发生变化。这项研究将研究生境斑块大小和数量的变化对食草性昆虫--红马尾草甲虫--四眼金龟子及其寄主植物--马尾藻的丰富度和动态的影响。特别令人感兴趣的是甲虫的食草性在多大程度上导致了马利筋斑块的大小和数量的变化。实地观察将检查马利筋斑块的数量和大小以及甲虫丰度的年复一年的变化。对照实验将被用来检验成虫和幼虫食草性对马利筋生长和有性繁殖的影响。将使用模拟模型来综合观察和实验的结果，并调查栖息地变化对昆虫、草食动物及其寄主植物的长期影响。从这项研究中获得的知识将扩大我们对空间过程影响的理解，并有助于保护栖息地变化是一个因素的情况。

BOWERS DEB-9623127 Most studies examining population dynamics in a spatial context assume that the size, quality, and number of habitat patches within a landscape do not vary over time. Such an assumption may be biologically unrealistic. In many cases habitat patches are biological units, such as host plants, which may change in size or number over similar time frames as the populations residing within these patches. This research will investigate the effects of changes in the size and number of habitat patches on the abundance and dynamics of an insect herbivore, the red milkweed beetle, Tetraopes tetraophthalmus, and its host plant common milkweed, Asclepias syriaca. Of particular interest is the degree to which herbivory by the beetles is responsible for variation in milkweed patch size and number. Field observations will examine year to year changes in the number and size of milkweed patches as well as beetle abundance. Controlled experiments will be used to examine the effects of herbivory by adult and larval beetles on milkweed growth and sexual reproduction. Simulation modelling will be used to synthesize the results from the observations and experiments and investigate the long-term consequences of habitat variability for insect herbivores and their host-plants. Knowledge gained from this research will extend our understanding of the effects of spatial processes, and aid in conservation situations where habitat change is a factor.