Bark beetle pipetraps with funnels in spruce clearcut in Värmland. Each black plastic pipe has 900 holes (about 3 mm diameter)
for beetles (Ips typographus and Pityogenes chalcographus) to crawl through after landing.
Other beetles strike the pipe and fall down into the white funnel. Trees surrounding the clearcut are all
Norway spruce (Picea abies). Pipetraps containing aggregation pheromone baits are often used to mass trap bark beetles.
Both the male and the female are attracted by the pheromone (which is a mixture of two volatile chemicals, methyl butenol and cis-verbenol, in the
case of I. typographus; and chalcogran and methyl decadienoate in the case of P. chalcographus). Pipetraps are also useful to study
the behavior of these beetles in response to host tree volatiles (a volatile is a chemical that evaporates rapidly like pentane or alcohol). Also, the responses of
beetles to "inhibitors" can be tested (inhibitors are chemicals that the beetle tries to avoid, even if presented with the aggregation pheromone).
Verbenone is an inhibitor of attraction in many bark beetles such as Tomicus piniperda.
Images © 1996 by John A. Byers, Chemical Ecology.