A key volatile infochemical that elicits a strong olfactory response of the predatory mite Neoseiulus californicus, an important natural enemy of the two-spotted spider mite Tetranychus urticae.
Herbivore-induced plant volatiles (HIPVs) emitted from lima bean leaves infested with the two-spotted spider mites Tetranychus urticae strongly attract the predatory mites Neoseiulus californicus. Among these HIPVs, methyl salicylate and linalool can attract the predators. Three green-leaf volatiles (GLVs) of (Z)-3-hexen-1-ol, (Z)-3-hexenyl acetate and (E)-2-hexenal, found in the odor blends from T. urticae-infested leaves and physically damaged leaves, can also attract the predators. To search for a strong predator attractant, the olfactory responses of N. californicus to each synthetic compound or their combinations were investigated in a Y-tube olfactometer. When presented a choice between a mixture of the five compounds (i.e. the two HIPVs and the three GLVs) and T. urticae-infested leaves, N. californicus did not discriminate between these odor sources. The same trend was observed when either a mixture of the two HIPVs or methyl salicylate vs. T. urticae-infested leaves were compared. In contrast, the predators preferred T. urticae-infested leaves to linalool, each of the three GLVs, or a mixture of the three GLVs. These results indicated that methyl salicylate is a strong predator attractant, and its potential attractiveness almost equaled that of the blend of HIPVs from T. urticae-infested leaves.
Shimoda
Takeshi
T
National Agricultural Research Center, Tsukuba, Ibaraki, 305-8666, Japan. oligota@affrc.go.jp
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D008925:Mites / Q000187:drug effects* / Q000502:physiology; D027805:Phaseolus / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D011235:Predatory Behavior / Q000187:drug effects*; D012459:Salicylates / Q000494:pharmacology*; D012903:Smell; D040102:Tetranychidae / Q000502:physiology; D014835:Volatilization
D010936:Plant Extracts; D012459:Salicylates; C033069:methyl salicylate