Donald Cipollini (Advisor), Thomas Rooney (Committee Member), John Stireman III (Committee Member)
Master of Science (MS)
Invasion of Alliaria petiolata has negative direct and indirect impacts on the systems in which they invade. This study focuses on further identifying impacts which this non-native A. petiolata has on herbivores whose range they have invaded. Oviposition on A. petiolata by the specialist butterfly, Pieris virginiensis, is known to be a mismatch event leading to larval death from sinigrin and alliarinoside. To observe if the related specialist, Anthocharis midea, falls into the same oviposition sink paired plot comparisons between native Cardamine concatenata and non-native A. petiolata were conducted. Early in the season paired-plot comparisons showed a preference for native C. concatenata while later comparisons a preference for A. petiolata. A significant influence of the date of oviposition on selected host was seen. Environmental stressors such as drought and disease can lead to changes in plant development and productivity. Trade-offs exists between defenses so as one area of defense is invested in other areas of defense will not be allocated resources because of the energetic costs. Under these environmental stressors resources should be shifted away from herbivory defense and with the reduction of secondary metabolites herbivores will be expected to perform better. Environmental stressors including drought and disease on larval performance and preference were investigated. Influences of drought stress on non-native A. petiolata were not sufficient enough to allow for specialist herbivores A. midea and P. virginiensis to reach pupation. Generalist herbivore Trichoplusia ni, the cabbage looper, was short lived and unable to reach pupation on any A. petiolata, normally watered or drought stressed. Anthocharis midea preference assays show a clear preference for native C. concatenata over non-native A. petiolata, severely drought stressed C. concatenata over normally watered plants and no preference between drought stressed or normally watered A. petiolata. Presence of white rust, Albugo candida, on the native host negatively influenced growth and larval weight of P. virginiensis. As larvae develop, they become more mobile and have been seen to move from leaves to floral parts of host. As native C. concatenata and invasive A. petiolata grow in close proximity transfer between the native and non-native A. petiolata is possible. Simulation of this transfer resulted in larval death for A. midea, while once transferred, later instar P. virginiensis ceased feeding and began pupation.
Department or Program
Department of Biological Sciences
Year Degree Awarded
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