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Identification of (-)-β-Caryophyllene as a Gender-Specific Terpene Produced by the Multicolored Asian Lady Beetle

Abstract::
This work reports the development of novel techniques for characterizing volatile chemicals emitted by the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in an effort to identify semiochemicals involved in establishment and persistence of overwintering beetle aggregations. Volatiles emitted from live beetles were detected by using whole-air sampling and solid phase microextraction (SPME). Adsorbed volatiles were thermally desorbed and identified using gas chromatography-mass spectroscopy (GC/MS). By comparing chromatograms of volatiles emitted from live male and female beetles, a sesquiterpene, (-)-β-caryophyllene, was found only in the female beetles. The identity of (-)-β-caryophyllene was confirmed using NIST Library searches, comparing retention times with those of known standards and by higher resolution magnetic sector GC/MS. Although SPME trapping detected a wider array of compounds compared to whole-air sampling, the latter sampling method is better suited for automation. Unattended automated sampling is required for the continuous measurement of targeted compounds under dynamically changing incubation conditions. These incubation conditions, mimicking natural overwintering conditions, are essential to our long-term goal of using this technology to detect and identify the aggregation pheromone of H. axyridis.
Author(s):
Brown, A.E. , Riddick, E.W. , Aldrich, J.R. , Holmes, W.E.
Subject(s):
Harmonia axyridis , females , aggregation pheromones , solid phase extraction , microextraction , volatile organic compounds , sesquiterpenoids , gas chromatography , mass spectrometry
Description:
Includes references
Source:
Journal of chemical ecology 2006 Nov., v. 32, no. 11
Language:
English
Year:
2006
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
File:
Download [PDF]   
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.