The scientists speculated that ethylene gas was the distress signal released from the damaged leaves and that this discouraged further herbivory in the plants nearby.

Question

How might this hypothesis be tested?

Answer 1

You could set up tubes to dispense ethylene gas in some plants that are normally attractive food for animals. Let in some of the herbivores, turn on some of the gas dispensers (you want to control for any effect of the dispenser equipment), and see whether the presence of the gas deters herbivory.