Methyl Salicylate, Identified as Primary Odorant of a Specific Receptor Neuron Type, Inhibits Oviposition by the Moth Mamestra Brassicae L. (Lepidoptera, Noctuidae)

Abstract

The cabbage moth, Mamestra brassicae L. (Lepidoptera, Noctuidae), is a polyphagous species that is often choosing plants of Brassica as hosts for oviposition. In the search for biologically relevant odorants used by these moths, gas chromatography linked to electrophysiological recordings from single receptor neurons (RNs) has been employed, resulting in classification of distinct types of neurons. This study presents specific olfactory RNs responding to methyl salicylate (MeS) as primary odorant and showing a weak response to methyl benzoate, the 2 aromatic compounds occurring together in several plant species. In 2 cases, the neuron was colocated with another RN type responding to 6 green leaf volatiles: 1-hexanol, (3Z)-hexen-1-ol, (2E)-hexen-1-ol, (3Z)-hexenyl acetate, (2Z)-hexen-1-ol, and an unidentified compound. Whereas the specific RNs detected the minor amounts of MeS in some plants, the compound was not found by gas chromatography linked to mass spectrometry in intact plants, but it was found after herbivore attack. The behavioral effect of MeS was studied in outdoor test arenas with Brassica napus and artificial plants. These experiments indicated that mated M. brassicae females avoid plants with dispensers emitting MeS. As it is induced by caterpillar feeding, this compound may mediate a message to mated M. brassicae females that the plant is already occupied.

Defence mechanisms of Brassicaceae: implications for plant-insect interactions and potential for integrated pest management. A review

“…3), is a polyphagous insect, and the observed food plants of the cabbage moth include more than 70 species of 22 families, of which Brassicaceae and Chenopodiaceae are among the most preferred (Popova, 1993 as cited by Rojas et al, 2001;Ulland et al, 2008). The cabbage moth is widely distributed throughout most of Europe and Asia, from 30…”

“…The cabbage moth (M. brassicae) often chooses Brassica plants as hosts for oviposition (Ulland et al, 2008). The mortality of eggs, larvae, pupae and larval dispersal of the cabbage moth on white cabbage (B. oleracea var.…”

“…In two-choice tests, the females preferred to oviposit on cabbage rather than chrysanthemum, but there was no difference in the mean number of eggs laid on cabbage and tomato. Ulland et al (2008) identified methyl salicylate as primary odorant of a specific receptor neuron type, and showed that it inhibits oviposition by M. brassicae. The behavioural effect of methyl salicylate was studied in outdoor test arenas with B. napus and artificial plants (Ulland et al, 2008).…”

“…Ulland et al (2008) identified methyl salicylate as primary odorant of a specific receptor neuron type, and showed that it inhibits oviposition by M. brassicae. The behavioural effect of methyl salicylate was studied in outdoor test arenas with B. napus and artificial plants (Ulland et al, 2008). The experiments indicated that mated M. brassiace females avoid plants with dispensers emitting methyl salicylate.…”

Biosynthesis and emission of insect-induced methyl salicylate and methyl benzoate from rice

“…When tested in its pure, synthetic form, MeSA can attract several types of carnivores [8,10,47], suggesting that MeSA, singly or in combination with other volatiles, is an active signal for indirect defense of tested plants. In addition, MeSA released from cabbage plants infested by cabbage moth was shown to inhibit the oviposition of conspecific mated female moths [40], indicating that MeSA can also be detected by herbivores. Methyl benzoate is structurally highly similar to MeSA.…”