Herbivore-induced extrafloral nectar production in lima bean plants enhanced by previous exposure to volatiles from infested conspecifics.

In response to herbivory by spider mites (Tetranychus urticae), lima bean plants produced significantly greater quantities of extrafloral nectar (EFN) than intact conspecific plants. Moreover, EFN amounts of infested plants depended on exposure to odor of infested neighbor plants. Two d after spider mite infestation, a test plant produced more EFN when exposed prior to infestation to volatiles from infested neighbor plants than when exposed to volatiles from uninfested conspecific plants. However, this effect was only detectable 2 d after spider mite infestation and vanished 4 d after infestation. These results suggest that EFN production is enhanced during the earlier stages of damage by T. urticae in response to previous exposure to volatiles from infested neighbor plants.