Volatiles Induced from (Dennstaedtiaceae) by Herbivores Attract (Hemiptera: Reduviidae): Clear Evidence of Indirect Defense in Fern.

Plants have evolved various self-defense mechanisms against insect feeding. There are many reports regarding both direct and indirect defense mechanisms in seed-plant. However, only direct defenses on ferns were considered and the indirect defense mechanism has never been reported. In this study, it was observed that the fern can attract the assassin bug in the field. We collected and analyzed volatiles from healthy individuals and the ones wounded by , using dynamic headspace and GC-MS. We recorded the electroantennogram responses of antennae of to different standards of volatile compounds identified from the GC-MS analysis. We also analyzed the behavior of male and female adults in response to volatiles collected from using a Y-tube olfactometer. The results showed that a number of volatile compounds were produced when the fern was damaged by . Electroantennography and Y-tube olfactometer results showed that some herbivore-induced volatiles and volatiles from undamaged leaves could attract . Our research suggests that can attract insect predators by releasing herbivory-induced volatile organic compounds, and for the first time we found ferns may also have indirect defense mechanisms using volatile organic compounds.