Response of mirid predators to synthetic herbivore-induced plant volatiles

Zoophytophagous plant bugs feed on plant tissue as a source of water and nutrients, besides feeding on prey. By phytophagy, mirid predators activate plant defense responses through different pathways, resulting, among others, in the release of herbivore-induced plant volatiles (HIPVs). These compounds could repel herbivores and attract parasitoids and predators, and synthetic versions could potentially be used in biological control. Nevertheless, little is known about the influence of synthetic volatiles on mirid attraction. Using Y-tube olfactometer trials, we evaluated the responses ofNesidiocoris tenuis(Reuter),Macrolophus pygmaeus(Rambur), andDicyphus bolivariLindberg (Hemiptera: Miridae), important natural enemies used to control various greenhouse pests, to 10 synthetic versions of HIPVs released from tomato (Solanum lycopersicumL., Solanaceae) plants induced byN. tenuisandM. pygmaeus.Nesidiocoris tenuisresponded to five of the 10 HIPVs, whereasM. pygmaeusandD. bolivariresponded to four of the 10 HIPVs. Two green leaf volatiles, (Z)-3-hexenyl propanoate and (Z)-3-hexenyl acetate, and the ester methyl salicylate (MeSA) were attractive to all three mirid predator species. Our results demonstrate that the volatiles released by tomato plants activated byN. tenuisandM. pygmaeusphytophagy are attractive to their conspecifics and also toD. bolivari. Further studies should evaluate the potential of these compounds to attract predatory mirids in the field. (AU)