The biodiversity and interactions among arthropods and their host plants in canola agroecosystems

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My research program uses canola plant communities as a model system for investigating hypotheses relating to how arthropod herbivores interact with their host plants and how plant structure and function can be affected by arthropods at various trophic levels. In Canada, canola cropping systems are widespread, comprising approximately four to five million hectares annually, and are associated with a vast diversity of arthropod species at several trophic levels. Canola systems can be readily manipulated structurally and temporally, occur in several ecoregions, and accommodate replicated experiments making them ideal for studying mechanisms associated with insect-host plant interactions, insect dispersal patterns, and shifts in insect biodiversity over space and time. My research encompasses three main themes. First, I am working to understand the processes that drive distribution patterns of insects in time and space in canola landscapes. By investigating dispersal and migration patterns of herbivores and their associated parasitoids, and by using geographical information systems technology to draw relationships between insect densities and factors responsible for them, this research will contribute new knowledge of the processes associated with insect colonization. This understanding can then lead to development of predictive models of how the arthropod community structure will respond to plant biotic and abiotic stress. Second, I will investigate how herbivores, predators, and parasitoids interact in monocultures and more biodiverse environments, and how predators and parasitoids can indirectly affect plant growth and plant community structure. My third research theme investigates how variation in host plant quality and plant community composition can cascade to higher trophic levels and how herbivory by one species can affect plant morphology and function. Funding from the NSERC Discovery program would support graduate student education in all three areas, and so facilitate training of the next generation of agroecologists.