No abstract

Nearly 50 volatile compounds are identified from hindguts of the pine engraver Ips acuminutus, I. sexdentutus and I. lecontei. Among these, or-phellandren-8-01, ipsdienon, ipsenon and others are described from bark beetles for the first time. The quantitative composition of the odour bouquet of both sexes largely de ends on the phase of colonization; after the initial phase of attack, they are particularly rich in oxiized monoterpenes. I. ucuminutus and I. Zecontei contain the male specific terpene alcohols (+)-ipsdienol and (-)-ipsenol in high optical purity while I. sexdentutus roduces racemates. Racemic ipsdienol proves attractive to I. sexdentutus under field conditions, gut does not seem to promote the subsequent steps in colonization such as landing or penetrating the bark.Woll. (GIESEN et al. 1984). Both species synergize the attractant ter ene hydroxylated is0 rene derivative, 2-methyl-3-buten-2-01.On the other R and, intensely investigated pheromone systems such as the tri artite mixture proposed for I. araconfusus (WOOD et al. 1967) fail to composition of the three terpene alcohols is copied synthetically (LIGHT 1980). fusus Lanier, by SILVERSTEIN et al. (1966), and their subsequent d iscovery in behaviour and perception (PAYNE 1979; DICKENS 1978). Neverthe r ess, uncerchemical signa f s. So far, some biological activity has been demonstrated with alcohol (S)-cis-verbenol, and ipsdienol, respectively, with a highly vo f atile in B uce mass aggregation under fie1 8 conditions even, when the enantiomeric ' This work was supported by the "Deutsche Forschungsgemeinschaft" and "Fonds der chemischen Industrie". U.S.

No abstract

SummaryThe predator, Rhizophagus grandis, is linked to its specific prey, Dendroctonus micans, by semiochemical signals regulating oviposition and long range orientation. A mixture of simple oxygenated monoterpenes [(-)-fenchone, (-)-pinocamphone, rac. camphor, terpinene-4-ol, borneol, fenchol and verbenone], identified from the frass of D: micans has been found to be extremely active in a flight windtunnel as a long-range attractant for the predator. The mixture elicited 84 07o of the response to larval frass of the prey. Excluding pinocamphone from the mixture did not influence its activity. Also, changing the absolute configurations of some of the components (fenchol, terpinene-4-ol and borneol) did not influence the predators' response. However, the addition of (-)-a-terpineol increased the attractivity of the synthetic blend to almost that of larval frass of the prey. Ecological implications of the identified semiochemicals and their use in pest management are discussed.

No abstract