To our present knowledge Auchenorrhyncha are represented in Reunion island by 102 species described : 66 Fulgoromorpha and 36 Cicadomorpha. Inmost of the undisturbed biotopes studied, Fulgoromorpha show more significant diversity than Cicadomorpha. Except for Delphacidae and Flatidae which feed primarily on exotic plants, the other families of the Fulgoromorpha are characterised by a strong proportion of endemic species mainly dependent on indigenous plants. Our research shows preferential trophic relation between some Fulgoromorpha families or species and particular plant taxa. This is the case with Derbidae which are all associated with indigenous Monocotyledones. Achilidae and a new endemic species of Meenoplidae attached to the new genus Insulisia Bonfils,1998, seem to be monophagous on some indigenous plants. Cixiidae and other families are mostly polyphagous but linked with indigenous plants. These preferential associations between endemic Fulgoromorpha and indigenous plants allow to provide informations on the structure and evolution of ecosystems in Reunion island. With the objective of maintaining the original character of Reunion biodiversity, these studies would allow to direct conservation decisions for this endangered insular biotope. Lastly, these results also open new fields of research : comparative studies of the evolution of Mascarene islands environments, as well as modalities of Mascarenes colonization by Auchenorrhyncha.