AbstractHerbivore-induced plant volatile (HIPV)-mediated eavesdropping is a well-documented, inducible phenomenon that should—like any inducible phenomenon—incur fitness costs. Yet, ecological costs associated with volatile exposure alone are unclear. In a common garden experiment, we tested the hypothesis that exposure to a single HIPV would decrease herbivore damage at the cost of reduced plant growth and reproduction. Lima bean (Phaseolus lunatus) and pepper (Capsicum annuum) plants were exposed to a persistent, low-dose (~10ng/hour) of the green leaf volatile cis-3-hexenyl acetate (z3HAC), a ubiquitous HIPV. z3HAC-treated pepper plants were shorter, had less aboveground and belowground biomass, and produced fewer flowers and fruits relative to controls while z3HAC-treated lima bean plants were taller and produced more leaves and flowers than did controls. Natural herbivory was reduced in z3HAC-exposed lima bean plants, but not in pepper. Cyanogenic potential, a putative defense mechanism in lima bean, was lower in z3HAC-exposed leaves, suggesting a growth-defense tradeoffs from z3HAC exposure alone. Plant species-specific responses to an identical priming cue have important implications for ecological costs and benefits of volatile-mediated inter-plant communication under field conditions.
Oxylipin channelling in Nicotiana attenuata: lipoxygenase 2 supplies substrates for green leaf volatile production
