Electrophysiological responses of four fungivorous coleoptera to volatiles of Trametes versicolor: implications for host selection

Fungi of the genus Trametes are known as important wood decomposers and are colonized by various species of Coleoptera and other arthropods. The aim of the present study was to investigate the importance of volatile chemical compounds as key attraction factors in recognition and host selection by species of Erotylidae (Dacne bipustulata, Tritoma bipustulata) as well as Cisidae (Sulcacis affinis) and Tenebrionidae (Diaperis boleti). Volatiles from freshly collected Trametes versicolor were collected by headspace sampling technique and identified by combined gas chromatography–mass spectrometry (GC–MS). To evaluate the biological significance of the volatiles we performed behavioural tests and recorded antennal responses of the fungus-inhabiting species by gas chromatography with electroantennographic detection (GC-EAD). The scent of T. versicolor was found to be dominated by sesquiterpenes; in GC-EAD 6 of these compounds elicited reproducible antennal signals in the tested species. Highly significant attraction effects to the fungus, the obtained odour samples and previously described fungal C₈-compounds were observed in behavioural tests. The possibility to detect these chemical compounds as a key cue for host selection implicate that beetles are able to discriminate between fungi of different age as well as different stages of colonization.