32. Effects of catalpa sphinx herbivory on defensive chemistry of catalpa trees

Abstract

Interactions between plants and insects can influence production of defensive chemicals within the plants. Presence of an herbivorous insect feeding on the leaf may illicit a response from the plant. Here we tested the hypothesis that herbivory by the catalpa sphinx, Ceratomia catalpae, a specialist herbivore of catalpa trees, Catalpa spp., affects production of the defensive compounds catalpol and catalposide. Catalpa leaves were collected over a 21-week span in 2015, spanning two generations of catalpa sphinx herbivory. Using high-pressure liquid chromatography (HPLC) to measure catalpol and catalposide, the amounts will be compared over time and in the presence and absence of catalpa sphinx herbivory. These results can contribute to a growing body of evidence showing the ability of herbivores to influence the expression of plant defensive traits.