Insect Ecology at Purdue - Ian Kaplan's Lab

Crop Domestication

We are interested in documenting potential changes in plant defenses over the course of domestication by comparing resistance across a range of plant-types, including wild, landrace, heirloom, and modern high-yielding lines. It is generally believed that selection for growth and yield in a pest-free environment (i.e., with high insecticide input) has inadvertently resulted in the loss of beneficial traits from crops compared with wild progenitors. We are testing this hypothesis in the Solanaceae, one of the most agriculturally important plant families in the world. To do so, several projects in the lab are working with solanaceous crops (e.g., tomato, pepper, tobacco) and their wild relatives. These studies quantify changes in tolerance, direct defense—toxins—and indirect defense—attraction of enemies to volatiles emitted from wounded plants—using our beloved tritrophic model system of Manduca sexta (hornworms) and Cotesia congregata.

tomato lines

Figure 1. Common garden testing tomato lines for insect colonization and damage.

Also, we have a separate ongoing project investigating changes in floral scent and associated attraction of native bees in wild and domesticated watermelon. Despite the historic focus on flower color and shape, floral volatiles are increasingly appreciated for their role in pollinator foraging decisions. However, it is unknown whether volatile-mediated pollinator attraction was affected by selection for modern watermelon lines. Restoring or enhancing this trait is critical as watermelon is a monoecious crop with separate male and female flowers, and in seedless production pollen donor and receiver plants are physically separated from one another. Current project directions include measuring a suite of floral traits (volatiles, nectar, pollen) that may correlate with bee activity, and documenting corresponding responses by herbivores.

collecting volatiles from watermelon flower

Figure 2. Collecting volatiles from a watermelon flower in the field.