title: Identification and electrophysiological studies of (4S,5S)-5-hydroxy-4-methyl-3-heptanone and 4-methyl-3,5-heptanedione in male lucerne weevils.
abstract: An investigation to identify a sex or aggregation pheromone of Sitona discoideus Gyllenhål (Coleoptera: Curculionidae) is presented. Antenna flicking and attraction behaviors evoked by conspecifics of both sexes were recorded in arena bioassays, where attraction of females to males was observed. Air entrainment of both males and females was conducted in separate chambers. Gas chromatographic-mass spectrometric analysis of headspace volatiles revealed that two male-specific compounds, 4-methyl-3,5-heptanedione (major) and (4S,5S)-5-hydroxy-4-methyl-3-heptanone (minor), were emitted during the autumnal post-aestivatory flight period. The stereoisomers of the minor component were separated by enantioselective gas chromatography and their absolute configurations assigned by NMR (diastereomers) and the known preference of enantioselective transesterification reactions catalyzed by Candida antarctica lipase B. Electroantennogram and single sensillum recording studies indicate that 4-methyl-3,5-heptanedione as well as all individual stereoisomers of 5-hydroxy-4-methyl-3-heptanone are detected by the antennae of male and female S. discoideus. Further, single sensillum recordings suggest that both sexes of S. discoideus have specialized olfactory receptor neurons (ORNs) for detecting 4-methyl-3,5-heptanedione and different populations of stereoselective ORNs for detecting the stereoisomers of 5-hydroxy-4-methyl-3-heptanone. Some of these stereoselective ORNs appear to be sex-specific in S. discoideus.
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited, PB 4704, Christchurch, 8140, New Zealand. rikard.unelius@lnu.se
authors.forename: C R
authors.initials: CR
authors.lastname: Unelius
authors.forename: K-C
authors.initials: KC
authors.lastname: Park
authors.forename: M
authors.initials: M
authors.lastname: McNeill
authors.forename: S L
authors.initials: SL
authors.lastname: Wee
authors.forename: B
authors.initials: B
authors.lastname: Bohman
authors.forename: D M
authors.initials: DM
authors.lastname: Suckling
mesh_terms: D000818:Animals; D057506:Arthropod Antennae / Q000187:drug effects; D001522:Behavior, Animal / Q000187:drug effects; D002849:Chromatography, Gas; D055724:Electrophysiological Phenomena / Q000187:drug effects*; D005260:Female; D007659:Ketones / Q000302:isolation & purification / Q000494:pharmacology; D008297:Male; D018034:Olfactory Receptor Neurons / Q000187:drug effects / Q000378:metabolism; D012724:Sex Attractants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D048889:Weevils / Q000737:chemistry* / Q000187:drug effects / Q000502:physiology*
chemical_list: D007659:Ketones; D012724:Sex Attractants; C008451:4-methyl-3-heptanone