Yaupon (Ilex vomitoria) is a caffeine-containing dioecious shrub native to the southeastern United States that was historically brewed into a stimulating beverage. We tested predictions of the carbon/nutrient balance (CNB) hypothesis by determining whether nitrogen availability and gender influence production of caffeine and related alkaloids as well as phenolic compounds in leaves of pot-grown yaupon plants fertilized with ammonium nitrate. The CNB hypothesis predicts that additional nitrogen should result in increased alkaloid concentrations and decreased phenolic concentrations. An extension of the CNB hypothesis to dioecious plants predicts that females have higher C/N ratios and therefore higher phenolic concentrations and lower alkaloid concentrations than male conspecifics. In our study, caffeine and total alkaloid concentrations were 5-10 times higher in fertilized than control plants but did not vary by gender. Nevertheless, an observed interaction between gender and fertilization suggests that females respond more to fertilization than males in caffeine production. In addition, fertilized plants not only contained higher concentrations of alkaloids and total nitrogen but also allocated a larger proportion of their nitrogen to alkaloid production than control plants. Total phenolic concentrations were higher in control females than control males as predicted by the CNB hypothesis, but did not vary by treatment nor were there differences by gender among fertilized plants. We also found high correlations between antioxidant capacity and both classes of phenolic compounds detected in our study (cinnamic acid derivatives and flavonoids) indicating that in addition to their putative defensive function against herbivores, phenolics protect yaupon from oxidative stress. Explanation of the inconsistencies between our data and predictions of the CNB hypothesis may benefit from a re-appraisal of the physiological mechanisms by which resource availability affects secondary metabolism as well as consideration of the selective pressures to which secondary metabolism responds.

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Mobile phones equipped with PC-like operating systems, GPS, internet connectivity, cameras, and video capabilities (e.g., smartphones) are used by 49% of Americans between the ages of 18 and 24 (Smith 2011). Immersed in digital technology from early childhood, members of this "Millennial Generation" are often frustrated with the passivity and isolation inherent in traditional forms of teaching (Chodorow 1996, Lieberman andMace 2010). To meet the pedagogical challenges these students present, faculty are increasingly encouraged to emphasize group-based learning and incorporate technology in the classroom to better engage students and enhance learning (Chodorow 1996, Jonas-Dwyer and Pospisil 2004).Courses in environmental biology provide a unique opportunity to complement traditional course activities with smartphone-based experiential learning. Many university campuses-even urban ones-have arboreta, are landscaped with native flora, or are near parks. To show how teachers can take advantage of these resources for teaching with smartphones, our graduate course in plant-animal interactions created an application (app) for identifying trees on the University of Florida campus. This app includes information on the animals with which these trees interact, a glossary, quizzes, and maps of