Plants respond to herbivory by changing chemical profiles in an effort to limit further damage. Resistance to herbivores is typically characterized by an increase in compounds that are toxic, making the remaining tissue less palatable, and these responses can be rapid and localized or expressed in the whole plant. Reflectance spectroscopy represents an ideal approach to quantify real-time changes in plant metabolism in response to herbivory because the measurements are non-destructive, making them repeatable and capable of capturing the influence of herbivore damage on fine-scale temporal responses of plants. Here I describe experiments related to the ability of spectroscopy, paired with standard measurements of plant chemical composition, to understand and monitor chemically-mediated plant-herbivore interactions.
Results/Conclusions
Reflectance spectroscopy was able to characterize plant response to herbivory. First, I show that spectroscopy can track rapid induction profiles of cardenolides in common milkweed in response to damage. Second, I show changes in plant nutritional, morphological, and phenolic composition in wheat depend on the interaction compatibility of Hessian fly and varies between populations of virulent flies. Last, I show that below ground root feeding by an agronomic pest of maize alters foliar spectral profiles, but does so differently at different time periods and responses depend on co-occurring factors, such as the presence of abiotic stress. Combined, these outcomes highlight the utility of reflectance spectroscopy in plant-insect chemical ecology.