Chemoreception of host volatiles in the bark beetleIps typographus

Summary In the bark beetleIps typographus the stimulating effects of host odour constituents were studied by linking a gas Chromatograph (GC) with electrophysiological recordings from single olfactory receptor cells. Cells were exposed to the complete aroma of natural bark, extracts from host and non-host trees and fractions of these stimuli separated via a GC column. Four minor fractions belonging to two extracts were found to excite olfactory receptor cells. Responsive cells were divided into two main groups reacting exclusively to one fraction and suggesting that the cells were highly specialized to a particular host odour constituent. However, an effective extract or fraction could not be found for half of the olfactory units responding to natural bark, indicating that the relevant stimulatory compounds were lost during the extraction and/or GC procedure.Abbreviations EAG electroantennogram - GC gas-chromatograph