SEX PHEROMONE OF TRYPODENDRON LINEATUM (COLEOPTERA: SCOLYTIDAE): PRODUCTION, BIO-ASSAY, AND PARTIAL ISOLATION

Abstract

AbstractOverwintering adult T. lineatum were collected in late April, and the females allowed to attack Douglas-fir logs in the laboratory. Frass was collected and preserved at −40°C prior to extraction in benzene and distillation. Distillate was chromatographed in a silica-gel column. An olfactometer was developed in which a positive bio-assay involved arrestment and turning reactions in a runway over a perforated area, underneath which the test substance was placed. Responses occurred to female frass and to sawdust from host logs but frass was far more potent. Peak response occurred to frass produced within 4 to 8 hours after attack. After 2 weeks, only very small amounts of weakly attractive frass were produced. Benzene extract and distillate of female frass evoked trace responses at very low concentrations, hut at 3.2 × 10−2 and 7.4 ×10−3 g-equiv of frass, for extract and distillate respectively, responses over 70% were common. Two fractions of ether eluate from the silica-gel column contained a highly attractive component which evoked responses in about 70% of the test males.