title: Identification of the sex pheromone of the tree infesting Cossid Moth Coryphodema tristis (Lepidoptera: Cossidae).
abstract: The cossid moth (Coryphodema tristis) has a broad range of native tree hosts in South Africa. The moth recently moved into non-native Eucalyptus plantations in South Africa, on which it now causes significant damage. Here we investigate the chemicals involved in pheromone communication between the sexes of this moth in order to better understand its ecology, and with a view to potentially develop management tools for it. In particular, we characterize female gland extracts and headspace samples through coupled gas chromatography electro-antennographic detection (GC-EAD) and two dimensional gas chromatography mass spectrometry (GCxGC-MS). Tentative identities of the potential pheromone compounds were confirmed by comparing both retention time and mass spectra with authentic standards. Two electrophysiologically active pheromone compounds, tetradecyl acetate (14:OAc) and Z9-tetradecenyl acetate (Z9-14:OAc) were identified from pheromone gland extracts, and an additional compound (Z9-14:OH) from headspace samples. We further determined dose response curves for the identified compounds and six other structurally similar compounds that are common to the order Cossidae. Male antennae showed superior sensitivity toward Z9-14:OAc, Z7-tetradecenyl acetate (Z7-14:OAc), E9-tetradecenyl acetate (E9-14:OAc), Z9-tetradecenol (Z9-14:OH) and Z9-tetradecenal (Z9-14:Ald) when compared to female antennae. While we could show electrophysiological responses to single pheromone compounds, behavioral attraction of males was dependent on the synergistic effect of at least two of these compounds. Signal specificity is shown to be gained through pheromone blends. A field trial showed that a significant number of males were caught only in traps baited with a combination of Z9-14:OAc (circa 95% of the ratio) and Z9-14:OH. Addition of 14:OAc to this mixture also improved the number of males caught, although not significantly. This study represents a major step towards developing a useful attractant to be used in management tools for C. tristis and contributes to the understanding of chemical communication and biology of this group of insects.
authors.affiliation: Department of Chemistry/Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0002, Gauteng, South Africa.
authors.forename: Marc Clement
authors.initials: MC
authors.lastname: Bouwer
authors.affiliation: Department of Genetics/Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0002, Gauteng, South Africa.
authors.forename: Bernard
authors.initials: B
authors.lastname: Slippers
authors.affiliation: Department of Genetics/Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0002, Gauteng, South Africa.
authors.forename: Dawit
authors.initials: D
authors.lastname: Degefu
authors.affiliation: Department of Genetics/Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0002, Gauteng, South Africa.
authors.forename: Michael John
authors.initials: MJ
authors.lastname: Wingfield
authors.affiliation: Department of Agriculture, Fisheries and Forestry/Ecosciences Precinct, University of the Sunshine Coast, Brisbane, QLD 4001, Australia.
authors.forename: Simon
authors.initials: S
authors.lastname: Lawson
authors.affiliation: Department of Chemistry/Center for Chromatography, University of Pretoria, Pretoria 0002, Gauteng, South Africa.
authors.forename: Egmont Richard
authors.initials: ER
authors.lastname: Rohwer
mesh_terms: D000818:Animals; D004478:Ectoparasitic Infestations; D009036:Moths; D012724:Sex Attractants; D014197:Trees / Q000469:parasitology*
chemical_list: D012724:Sex Attractants
references.citation: J Chem Ecol. 2006 Mar;32(3):669-79
references.pmid: 16683203
references.citation: J Chem Ecol. 2007 Sep;33(9):1748-62
references.pmid: 17668268
references.citation: J Chem Ecol. 2005 Jan;31(1):39-48
references.pmid: 15839478
references.citation: J Chem Ecol. 1983 Feb;9(2):191-200
references.pmid: 24407337