title: First evidence of a volatile sex pheromone in lady beetles.
abstract: To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by virgin females of the multicolored Asian lady beetle, Harmonia axyridis (Pallas), which were either allowed or not allowed to feed on aphids. Virgin females in the presence of aphids, exhibited "calling behavior", which is commonly associated with the emission of a sex pheromone in several Coleoptera species. These calling females were found to release a blend of volatile compounds that is involved in the remote attraction (i.e., from a distance) of males. Gas Chromatography-Mass Spectrometry (GC-MS) analyses revealed that (-)-β-caryophyllene was the major constituent of the volatile blend (ranging from 80 to 86%), with four other chemical components also being present; β-elemene, methyl-eugenol, α-humulene, and α-bulnesene. In a second set of experiments, the emission of the five constituents identified from the blend was quantified daily over a 9-day period after exposure to aphids. We found that the quantity of all five chemicals significantly increased across the experimental period. Finally, we evaluated the activity of a synthetic blend of these chemicals by performing bioassays which demonstrated the same attractive effect in males only. The results confirm that female H. axyridis produce a volatile sex pheromone. These findings have potential in the development of more specific and efficient biological pest-control management methods aimed at manipulating the behavior of this invasive lady beetle.
authors.affiliation: Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
authors.forename: Bérénice
authors.initials: B
authors.lastname: Fassotte
authors.affiliation: Unit of Analysis Quality and Risk, Laboratory of Analytical Chemistry, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: Fischer
authors.affiliation: Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
authors.forename: Delphine
authors.initials: D
authors.lastname: Durieux
authors.affiliation: Unit of Analysis Quality and Risk, Laboratory of Analytical Chemistry, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
authors.forename: Georges
authors.initials: G
authors.lastname: Lognay
authors.affiliation: Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Haubruge
authors.affiliation: Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Francis
authors.affiliation: Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
authors.forename: François J
authors.initials: FJ
authors.lastname: Verheggen
mesh_terms: D000818:Animals; D001042:Aphids; D001517:Coleoptera; D004435:Eating; D005054:Eugenol / Q000031:analogs & derivatives / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D000081222:Monocyclic Sesquiterpenes; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes / Q000378:metabolism; D045789:Sesquiterpenes, Guaiane; D012724:Sex Attractants / Q000378:metabolism*; D012726:Sexual Behavior, Animal / Q000502:physiology*
chemical_list: D000081222:Monocyclic Sesquiterpenes; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; D045789:Sesquiterpenes, Guaiane; D012724:Sex Attractants; C512113:alpha-bulnesene; C038905:elemene; C005223:methyleugenol; D005054:Eugenol; C042686:humulene; C024714:caryophyllene