PHEROMONE SPECIFICITY IN ERIOCRANIA-SEMIPURPURELLA (STEPHENS) AND ERIOCRANIA-SANGII (WOOD) (LEPIDOPTERA, ERIOCRANIIDAE) BASED ON CHIRALITY OF SEMIOCHEMICALS

The fifth abdominal segment of female Eriocrania semipurpurella (Steph ens) and E. sangii (Wood) contains a pair of exocrine glands. Hexane e xtracts of this segment were prepared from both species and analyzed b y gas chromatography with simultaneous flame ionization and electroant ennographic detection (EAD). For both species, the EAD active peaks we re identified as nonan-2-one, (Z)-6-nonen-2-one, and (Z)-6-nonen-2-ol by means of mass spectrometry and comparison of retention indices with those of synthetic standards. Enantiomeric separation of chiral alcoh ols from the female extracts was achieved by gas chromatographic analy sis on a cyclodextrin column. In E. semipurpurella, a mixture of (2S,6 Z)-nonen-2-ol and (2R,6Z)-nonen-2-ol (2:1) was found, whereas in E. sa ngii (2S,6Z)-nonen-2-ol was the predominant enantiomer and only traces of the R enantiomer were indicated by the antennal response. In held tests, a blend of the three compounds was not attractive to conspecifi c males. A subtractive assay showed that the alcohol in various enanti omeric mixtures was the only attractive compound, whereas addition of (Z)-6-nonen-2-one to the alcohol completely inhibited the attraction o f both species. A trapping experiment including a wide range of ratios between the R and S enantiomers showed that baits containing 95-100% of the S enantiomer were attractive to male E. sangii, whereas males o f E. semipurpurella were attracted to all tested ratios of the enantio mers. However, the response profiles of male E. semipurpurella differe d between populations from southern Sweden, south Finland, and the Kol a Peninsula in Russia. In south Sweden males were maximally attracted to a racemic mixture of the alcohols. At the Kola Peninsula E. semipur purella was attracted to baits containing 95-100% of the R enantiomer. In south Finland all tested ratios between 0 and 100% R enantiomer tr apped E. semipurpurella, but the trap catches appeared to be bimodally distributed with peaks around 15 and 70% R enantiomer. The trapping r esults suggest the existence of pheromone races or sibling species amo ng the specimens identified as E. semipurpurella.