Volatiles from flowers ofPlatanthera bifolia(Orchidaceae) attractive to the silver Y moth,Autographa gamma(Lepidoptera: Noctuidae)

Abstract

We examined the attractiveness of a natural headspace sample ofPlatanthera bifoliablossoms, synthetic blends and single compounds to the silver Y moth,Autographa gamma,in a flight tunnel. The synthetic blend consisted of previously identified electrophysiologically active compounds fromP. bifolia: benzyl benzoate, benzyl salicylate, cinnamyl alcohol, lilac aldehydes, methyl benzoate and methyl salicylate. This blend had a similar attractivity as the natural headspace sample. Subtraction of lilac aldehydes significantly decreased attractiveness of the synthetic blend. When a mixture of lilac aldehydes was tested alone, it showed attractiveness similar to that of the synthetic blend. One or a mixture of lilac aldehydes accounts for the attraction of moths toP. bifolia. All other compounds elicited significantly lower responses. Results are discussed in relation to the pollination biology ofP. bifolia.