Such priming effects were similarly observed in maize plants which had been exposed to VOCs emitted from maize plants infested with generalist herbivores [11]. Spodoptera littoralis did not activate genes that are responsive to wounding, jasmonic acid, or caterpillar regurgitant, but showed primed expression of these genes and reduced caterpillar feeding and development [11]. Exposure to the volatiles also enhanced the emission of volatiles in receiver plants that could attract carnivorous natural enemies, which could help the plants’ indirect defense