Identification, synthesis and activity of sex pheromonegland components of the autumn gum moth (Lepidoptera:Geometridae), a defoliator of Eucalyptus

Summary. The autumn gum moth, Mnesampela privata(Guenée) (Lepidoptera: Geometridae), is native to Australiaand can be a pest of plantation eucalypts. Field-collectedand laboratory-reared female autumn gum moths weredissected to remove glands likely to contain components ofthe sex pheromone. Using gas chromatography (GC) andcombined gas chromatography–mass spectrometry (GC-MS),three compounds were identified from female extracts,namely (3Z,6Z,9Z)-3,6,9-nonadecatriene, 1-hexadecanoland 1-octadecanol (confirmed by comparison with syntheticsamples). Nonadecatriene elicited an antennal response inmale autumn gum moth during gas chromatographicanalyses combined with electroantennographic detection(GC-EAD). In electroantennogram (EAG) recording maleM. privata antennae responded to the nonadecatriene. Nonadecatriene was synthesised via Kolbe electrolysis,starting with (9Z,12Z,15Z)-octadeca-9,12,15-trienoic acid(linolenic acid) and propanoic acid or via an alternativefour-step method also starting from linolenic acid. In fieldtrials (3Z,6Z,9Z)-3,6,9-nonadecatriene proved attractiveto male moths. Thus, we conclude that (3Z,6Z,9Z)-3,6,9-nonadecatriene is a sex pheromone component of autumngum moth. This component has been identified in extractsfrom other geometrids in the same subfamily, Ennominae.However, to our knowledge this is the first example where(3Z,6Z,9Z)-3,6,9-nonadecatriene has been found in femalesand also proved attractive to male moths when presented on itsown. Our results are discussed in relation to other geometridpheromones.