Author
Kuenen, Lodewyk | |
MILLAR, JOCELYN - UNIV OF CA, RIVERSIDE | |
MCELFRESH, STEVEN - UNIV OF CA, RIVERSIDE |
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/4/2009 Publication Date: 4/15/2010 Citation: Kuenen, L.P., Millar, J.G., Mcelfresh, S.J. 2010. Identification of Critical Secondary Components of the Sex Pheromone of the Navel Orangeworm (Lepidoptera: Pyralidae). Journal of Economic Entomology. 103(2):314-330. Interpretive Summary: We identified a four-component sex pheromone blend, from female pheromone glands, that is as attractive to male navel orangeworm (NOW), Amyelois transitella, as hexane extracts of these glands (pheromone source contact > 90%). This blend contains Z11,Z13-16:Ald, Z11,Z13-16:OH, Z11,E13-16:OH and (3Z,6Z,9Z,12Z,15Z-23:H)-tricosapentaene (C23 pentaene). The pentaene contrasts to the other three compound since it is a long chain hydrocarbon compared to short chain compounds with terminal functional groups. In addition, this compound is new to science. We used antennal responses of a related moth, Pyralis farinalis, to characterize the presence of the pentaene in the female pheromone gland extract from NOW; this was crucial for identifying this compound. The combination of short-chain acetates, aldehydes or alcohols plus long-chain polyunsaturated hydrocarbons in moth sex pheromone systems have only recently been documented in lepidopteran species and may indicate a new approach for examining pheromone blends that have been refractory to full elucidation so far and for any species where the “standard” identification approach is not yielding results. Technical Abstract: We identified a four-component sex pheromone blend that is as attractive to male navel orangeworm (NOW), Amyelois transitella, as hexane extracts from female pheromone glands. This blend contains Z11,Z13-16:Ald, Z11,Z13-16:OH, Z11,E13-16:OH and (3Z,6Z,9Z,12Z,15Z-23:H)-tricosapentaene (C23 pentaene). We identified numerous congeners of the above compounds including a second pentaene, (3Z,6Z,9Z,12Z,15Z-25:H)-pentacosapentaene (C25 pentaene). None of the other compounds we tested, including the C25 pentaene had any effect on the flight responses of NOW males. In GC-EAD analyses we employed antennae from another pyralid moth, Pyralis farinalis, to characterize the presence of the two pentaenes in the female pheromone gland extract from NOW; the latter gave only occasional weak EAD responses to these compounds in the extract and thus were originally discounted. The combination of this “cross” assay by EAD and thorough wind tunnel bioassays, that always included female gland extract as a positive control treatment, led us to this robust blend of compounds that are necessary for full male responsiveness. This type of combination of short-chain acetates, aldehydes or alcohols plus long-chain polyunsaturated hydrocarbons has now been documented in several lepidopteran species and may indicate a paradigm shift in the range of compounds that should be looked for in sex pheromone blends. This may be a special point of interest for examining pheromone blends that have been refractory to full elucidation so far. |