Comparative analysis of monoterpene composition in four pine species with regard to suitability for needle consumer Diprion pini L

Abstract

In the needles of 4 pine species (Pinus. sylvestris, P. nigra, P. banksiana and P. strobus) 15 volatile monoterpenes were identified by GC-MS analysis using synthetic standards. Interspecific differences were established in the total amount of monoterpenes and their proportion. The principal component analysis (PCA) of the compounds revealed two clusters similar in the composition of monoterpenes. The clusters corresponded well to the oviposition preference of Diprion pini, which is among the main folivorous insects causing defoliation of Pinus spp. in Europe. One monoterpene cluster included P. banksiana and P. strobus (not suitable for D. pini oviposition, Barre et al., 2002) and another one included P. sylvestris and P. nigra (suitable for D. pini oviposition, Barre et al., 2002). The main compounds that stipulated cluster divergence were limonene, β-pinene and myrcene. Relative concentrations of these metabolites were significantly higher in P. banksiana and P. strobus. Further studies on the perception of monoterpenes and their behavioural effect on D. pini are in progress.