Attracting carnivorous arthropods with plant volatiles: The future of biocontrol or playing with fire?

Abstract

Herbivore-induced plant volatiles (HIPVs) are potent attractants for entomophagous arthropods and researchers have long speculated that HIPVs can be used to lure natural enemies into crops, reestablishing predator–prey relationships that become decoupled in disturbed agricultural habitats. This speculation has since become reality as the number of field trials investigating HIPV-mediated attraction and its consequences for pest suppression has risen dramatically over the past 10years. Here, I provide an overview of recent field efforts to augment natural enemy populations using HIPVs, with emphasis on those studies manipulating synthetic compounds in controlled-release dispensers, and outline a prospectus for future research needs. Specifically, I review and discuss: (i) choice of compounds and release rates; (ii) functional changes in predator and parasitoid communities; (iii) non-target effects; (iv) mechanisms of attraction and prey suppression; (v) spatial- and landscape-level considerations; (vi) context-dependent responses; and (vii) temporal stability of attraction.