Volatile Organic Compounds from the ClonePopulus x canadensis“Conti” Associated withMegaplatypus mutatusAttack

Abstract

Megaplatypus mutatus(Chapuis) (Coleoptera, Platypodidae) is an ambrosia beetle native to South America. It builds internal galleries that weaken the tree trunks, causing them severe stem breakage and mortality in commercial poplar plantations. The host selection by maleM. mutatushas previously been correlated with the increasing diameter. This work explores the possibility that differential susceptibility of individual plants toM. mutatuscould be associated with volatiles emitted. The comparison of the VOCs profiles of attacked and nonattackedP.x canadensis“Conti” 12 duringM. mutatusflying season showed both qualitative and quantitative differences. The attacked plants, but not the nonattacked ones, showed the following compounds: a long chain aldehyde,α-ylangene,δ-cadinene,α-gurjunene, andβ-cubebene; on the other side,β-sesquiphellandrene andβ-chamigrene were detected only in nonattacked plants.α-Copaene is a common component of all the samples analyzed, but its proportion is increased in attacked individuals. Behavioral bioassays showed that males but not femalesM. mutatusare attracted toα-copaene. The relative increase ofα-copaene in attacked individuals and the positive behavioral answer of males to it suggest that this compound could play a role in the orientation of the pioneer male towards the most suitable host.