Ecological Interactions of the Host-Insect System Quercus robur and Tortrix viridana

The interaction between herbivorous insects and their host plants is a never-ending race related to evolutionary adaptation. Plants have developed an armament against herbivore attacks including indirect defences which besides others are comprised of volatile substances, as well as toxic secondary metabolites act directly against feeding herbivores. Insects, however, can rapidly evolve mechanisms to adapt to these compounds to prevent being harmed by them. Thus, herbivorous insects represent a fascinating feeding guild that are comprised of several arthropod groups, and especially the lepidopteran genera that feed on tree species. One of these lepidopteran species is the green oak leaf roller, Tortrix viridana L., a major pest on oaks throughout Europe. Its’ defoliating larvae use different species of the genus Quercus and cause severe damage to the oaks. Defoliation leads to decrease of wood formation and fructifi cation, and to an increase of vulnerability to secondary pathogens (fungi, viruses and other insects). This tree-insect-system serve as a model system for a specialised herbivorous insect and its’ host plant from as well an ecological as a molecular point of view combined with modelling aspects