Volatiles of Bracket Fungi Fomitopsis pinicola and Fomes fomentarius and Their Functions as Insect Attractants

Volatiles released from fruiting bodies of the polypores Fomitopsis pinicola and Fomes fomentarius (Polyporaceae) were collected by entrainment and SPME techniques and analyzed by GC-MS. The most significant difference between the two species was found in the terpene fraction. F. fomentarius emitted a more complex blend, with more than 10 sesquiterpenes. During the sporulating phase, the release of (R)- and (S)-oct-1-en-3-ol, octan-3-one, and some sesquiterpene hydrocarbons (mainly -barbatene) increased in F. pinicola, whereas in F. fomentarius the release of octan-3-one, cis-furanoid linalool oxide, -phellandrene, -myrcene, and several sesquiterpene hydrocarbons increased. -Barbatene was identified for the first time in fungi. Chopping of the fruiting bodies altered the odor composition more in F. fomentarius than in F. pinicola. Five volatiles giving a typical fungal odor (rac-oct-1-en-3-ol, nonan-1-ol, rac-octan-3-ol, octan-1-ol, and octan-3-one) were tested for insect attraction in the field. Females of the three wood-living generalist beetles Malthodes fuscus, Anaspis marginicollis, and A. rufilabris and both sexes of the moth Epinotia tedella were attracted to rac-oct-1-en-3-ol. The generalist predator on fungus-insects Lordithon lunulatus was attracted to rac-oct-1-en-3-ol and octan-3-one in combination. Previous results regarding the host-specific attraction of beetles to the odors emanating from chopped fruiting bodies of F. pinicola and F. fomentarius are discussed in the light of this investigation.