Enantiospecific antennal response of bark beetles to spiroacetal (E)-conophthorin.
Optically pure synthetic enantiomers of (E)-conophthorin [(E)-7-methyl-1,6-dioxaspiro[4.5]decane], one of the volatiles affecting coniferophagous bark beetles, were tested on antennae of Ips typographus, I. duplicatus, I. subelongatus, Dendroctonus micans, and five Scolytus spp. by using combined gas chromatography-electroantennographic detection (GC-EAD). EAD dose-responses indicated that all three Ips species perceived only the naturally occurring and quantitatively dominant (5S,7S)-enantiomer, while its antipode, (5R,7R)-(E)-conophthorin was antennally inactive. Response thresholds for the Ips species were estimated as between 0.1 ng and 1 ng, or lower. The antennal responses of the Ips species caused by 100 ng of the (5R,7R)-enantiomer might be due to 1% impurity-(the active (5S,7S)-enantiomer) in the (5R,7R)-sample. At the 50-ng level, D. micans and five angiosperm Scolytus species (S. intracatus, S. mali, S. ratzeburgi, S. rugulosus, and S. scolytus) responded strongly to the (5S,7S)-enantiomer, while the (5R,7R)-enantiomer was antennally inactive. Currently updated knowledge on the natural occurrence, and electrophysiological and behavioral activity of (E)-conophthorin is summarized.
Zhang
Qing-He
QH
Department of Crop Science, Swedish University ofAgricultural Sciences, Alnarp. zhangq@ba.ars.usda.gov
Tolasch
Till
T
Schlyter
Fredrik
F
Francke
Wittko
W
D000080:Acetals / Q000737:chemistry / Q000494:pharmacology*; D000473:Alkanes / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D002849:Chromatography, Gas / Q000379:methods; D001517:Coleoptera / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D018034:Olfactory Receptor Neurons / Q000187:drug effects / Q000502:physiology*; D012903:Smell; D013045:Species Specificity; D013141:Spiro Compounds / Q000494:pharmacology*; D013237:Stereoisomerism
D000080:Acetals; D000473:Alkanes; C481308:Conophthorin; D013141:Spiro Compounds; C012867:decane