Host and non-host odour signals governing host selection by the pine shoot beetle, Tomicus piniperda and the spruce bark beetle, Hylurgops palliatus (Col., Scolytidae)

Abstract:  Tomicus piniperda and Hylurgops palliatus colonize susceptible host trees by responding to host-specific odour signals as well as by avoiding volatiles emanating from non-host conifers. In the field, the pine shoot beetle, T. piniperda , responded in high numbers to natural odour sources provided by their host tree, Pinus sylvestris , while the non-host conifers Larix decidua , Picea abies , or Pseudotsuga menziesii were significantly less attractive. In contrast, the spruce bark beetle, Hylurgops palliatus , preferentially responded to its main host, P. abies . Furthermore, T. piniperda attacks on P. sylvestris bolts decreased in presence of bark and wood particles from the non-host P. abies , whereas particles from P. menziesii appeared not to affect T. piniperda attacks. Apparently, tree-specific volatiles act at close range as specific signals that lead to the successful discrimination and colonization of the respective host tree species.