The ecology of alien insect herbivores

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My research program involves examination of factors affecting the establishment, spread and population growth of invasive alien insect species in agricultural systems, including their life history traits and interactions with host plants. Invasive alien species represent a considerable threat to agricultural and natural ecosystems, impacting ecosystem integrity and causing major economic losses. The next phase of my research program will focus on several unexamined aspects of the population dynamics of the swede midge and interactions with its host plants. I first documented the presence of the swede midge in Ontario in 2000, and it has spread rapidly throughout Ontario and Quebec since then. This small fly feeds and develops on cruciferous plants and causes the formation of galls and malformation of leaf, stem and flowering tissues. High levels of infestation in Ontario have led to the complete loss of broccoli and canola harvests in some fields. Life history characteristics of the swede midge, such as the possible occurrence of multiple emergence phenotypes and prolonged diapause, may be significant factors in its success as an invasive species. These life history characteristics will be examined and their impact on potential population growth and geographic range expansion of the swede midge will be determined. Another aspect of this research program will be determining the process of gall formation, determining what factors are responsible for gall initiation, and for the first time documenting the morphological and physiological differences in gall development between host plants that are susceptible and resistant to swede midge infestation. This research will improve our ability to accurately predict swede midge population dynamics and may also lead to the development of resistant crop varieties, thus reducing pesticide use and facilitating the adoption of ecologically-sound pest management practices.