Gonipterus scutellatus (Coleoptera: Curculionidae) is a pest of eucalyptus in Chile. Susceptibility of Eucalyptus camaldulensis, E. globulus ssp. globulus, and E. robusta to larval feeding were studied by determining foliar area loss. The effect of feeding on larval protein profiles was analysed by electrophoresis. E. camaldulensis was more susceptible (11.21% foliar area consumed) than E. globulus (6.47%) and E. robusta (3.62%). Nineteen proteins were common in larvae fed the three kinds of food, whereas 11 exhibited variations (marker proteins). As all larvae came from E. globulus providing the same nutrition, relatively few species(20) proteins were detected in them. More proteins (30) were found in larvae feeding on E. robusta. The greatest number of marker proteins occurred in E. robusta (11), followed by E. camaldulensis (9), and E. globulus (1). Thus, larvae fed on three eucalyptus species had three different protein profiles.