Chemical Characterization of the Volatile Emissions from the clone Populus x canadensis ‘Conti 12’ associated with Megaplatypus mutatus Chapuis attack.

ALEJANDRO LUCÍA; PAOLA A. GONZÁLEZ AUDINO; MASUH HECTOR

Congreso; I Congreso latinoamericano de Ecología Química; 2010

Megaplatypus mutatus (=Platypus mutatus) (Chapuis) (Coleoptera, Platypodidae) is an ambrosia beetle native to South America. The galleries weaken the tree trunks, causing them severe stem-breakage and mortality in commercial poplar plantations. The attack is initiated by pioneer males selecting a host tree to build a short nuptial gallery, from which they attract females using a sexual pheromone. The preference of attack by M. mutatus has been correlated with the increasing diameter.  In this work we explore the possibility that differential susceptibility of individual plants could be associated with volatiles emitted. With this aim we collected and analyzed volatiles emitted by wood-bark of both attacked and non attacked plants during M. mutatus flying season. Furthermore, we tested the biological activity of selected compounds in the volatile emissions with a walking behavioral assay. The comparison of the volatile profiles of attacked and non attacked trees showed both qualitative and quantitative differences. The attacked plants, unlike the non-attacked ones showed the following compounds: a long chain aldehyde of rt:20.57, α-ylangene, δ-cadinene, α-gurjunene and β-cubebene, while β-sesquiphelandrene and β-chamigrene were detected in non attacked plants but not in attacked ones. The results showed that α-Copaene is the common component of all the samples analyzed, its concentration being increased in attacked individuals. Behavioral bioassays analysis showed that males M. mutatus are attracted to α-copaene, while females are not. The relative increase of α-copaene in attacked individuals and the positive behavioral answer of males to it, could suggest that this compound may play a role in the orientation of the pioneer male towards the most suitable host.