Whitney, Kenneth D.2014-10-152014-10-152012-122012-11-30December 2Ahern, Jeffrey. "The Evolutionary Ecology of Stereoisomeric Sesquiterpene Lactones in Xanthium strumarium." (2012) Diss., Rice University. <a href="https://hdl.handle.net/1911/77579">https://hdl.handle.net/1911/77579</a>.https://hdl.handle.net/1911/77579The ecological factors that maintain defensive chemical variation within and between plant species have intrigued ecologists for decades. While theory posits that polymorphisms may be maintained different forms of balancing selection, relatively few expeapplication/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.Sesquiterpene lactoneHerbivoryPolymorphismPlant defenseThesis2014-10-15123456789/ETD-2012-12-319