Byers, J.A., Schlyter, F., Birgersson, G., & Francke, W. 1990b. E-Myrcenol in Ips duplicatus: An aggregation pheromone component new for bark beetles. Experientia 46:1209-1211.

Slow rotating pair of sticky traps
Abstract-- Males of the Eurasian bark beetle Ips duplicatus (Coleoptera: Scolytidae), when feeding in host Norway spruce (Picea abies (L.) Karst.), produced and released ipsdienol and E-myrcenol, which we show to be aggregation pheromone components. Bioassays using walking beetles indicated that E-myrcenol in synergistic combination with ipsdienol is essential for attraction. Synergism of E-myrcenol and ipsdienol released at natural rates in the forest was also demonstrated with a new technique using mechanical slow-rotation of sticky traps.
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Chemical Ecology