Susceptibility of eucalyptus species to Gonipterus scutellatus and electrophoretic profiles of adult marker proteins

In Chile, the Australian weevil Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae), specific to eucalyptus, was first detected in 1998. It has spread through the IV to IX Regions and could affect more than 525 thousand ha of Eucalyptus. The insect feeds on new foliage and causes losses in growth. The objectives of this study were to evaluate the susceptibility of Chile's most important eucalyptus species to damage by G. scutellatus, to characterize the molecular weight (kDa) of proteins of adult weevils that feed on the trees, and to identify marker proteins of the insects associated with the species of eucalyptus on which they feed. Susceptibility of Eucalyptus camaldulensis Dehnh., E. globulus sp. globulus Labill. and E. robusta Smith to adult insects was measured by leaf area loss. The proteins of the adults were analyzed by electrophoresis, comparing size and intensity of the bands of gels. E. camaldulensis was more susceptible (p<=0.05; 12.93% leaf area loss) than E. robusta (6.36%) or E. globulus (5.46%). Adults fed with E. robusta had the highest number of proteins (22). Those fed with each one of the three eucalyptus species separately had 15 proteins in common, and nine exhibited variations (marker proteins). Adult weevils fed E. robusta had seven marker proteins; E. camaldulensis and E. globulus had three marker proteins each. Weevils fed E. robusta had three marker proteins exclusive to these insects (9, 31 and 38 kDa), while those fed with E. camaldulensis and E. globulus had only one each (35 and 47 kDa). Thus, the three groups of weevils fed with different eucalyptus species had different protein profiles.