Host plant and natural enemy influences on survivorship in the milkweed leaf miner Liriomyza asc/epiadis
Rohde, Ashley T.
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The debate over the relative importance of bottom up and top down interactions in trophic systems has been a focus of ecological research for years. Asclepias syriaca, or the common milkweed, is a plant that grows in the northern United States and southern Canada and produces toxic cardenolides and thick latex as a defense against herbivory. I conducted a study to determine whether top down or bottom up interactions have a greater influence on the leaf miner fly species Liriomyza asclepiadis, which lives and feeds on A. syriaca, and in doing so also collected basic life history information for this ~ species. I conducted a population survey of L. asciepiadis, weighed the larvae, and measured each mine collected. I also took latex samples from A. syriaca and measured the surface area of leaves that had been parasitized. Samples of leaf, latex and larva material were run through a high pressure liquid chromatographer (HPLC) to determine cardenolide concentrations in each. The results of these tests showed that interactions in this system are driven largely from the bottom up.