Plant odour processing in the antennal lobe of male and female grapevine moths, Lobesia botrana (Lepidoptera: Tortricidae)

Abstract

Moths of Lobesia botrana (Lepidoptera: Tortricidae) are confronted with different volatiles emitted from the host plant during the different seasons. To test the hypothesis of plasticity of central plant odour processing in moths of different generations in the future, we first investigated the responses of antennal lobe (AL) interneurons of laboratory-reared virgin and mated males and females. We used intracellular recording and staining techniques while stimulating the antenna with a range of host and non-host plant odours. The AL structure of L. botrana is similar to that found in other Lepidoptera species studied. The most frequent physiological responses for all types of moths were obtained with ( E)-2-hexenal, and with thujyl alcohol and β-thujone, components of tansy, a behaviourally attractive non-host plant. Some broadly responding neurons were capable of distinguishing between different compounds through different response patterns (excitation/inhibition) and/or different dose–response characteristics. Response characteristics (response spectra, threshold and specificity) of neurons were similar, independent of sex or mating status of the moths. Significant differences between the groups were, however, found in the proportion of responding neurons for a few tested components.