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.
