Variation in volatile emissions of Arabidopsis thaliana in response to damage produced by insects with different feeding behaviors

Plants are very sensitive to changes in their environment and produce airborne chemicals, referred to as volatiles, in response to many different stimuli, including insect herbivory. Plants can produce different suites of volatiles at different concentrations specific to the species of plant and the species of insect causing damage. In this study I determined the composition of volatile profiles released by the plant Arabidopsis thaliana in response to physical wounding and herbivory by two species of caterpillars: Pieris rapae, a dietary specialist on the Brassicaceae family and Spodoptera exigua, a dietary generalist, both of which can be major agricultural pests. We used a volatile collection system with adsorbent traps to capture volatiles and then analyzed them with a gas chromatograph-mass spectrometer (GC-MS). Using available standards, we developed a method to detect and quantify 19 compounds commonly produced by plants. We found treatment-specific responses in volatile profiles associated with both the amount of damage and the type of damage produced. Analysis of the volatiles produced over a time series shows differences in compounds produced at certain time periods, as a result of the different feeding behaviors of the two insects. Sampling volatile emissions can tell us what species of insect is damaging a crop and where the damage is occurring. Using this information, conservationists, farmers, and scientists can work to improve precision agriculture and integrated pest management.