Abstract
Mountains are an ideal context to study species community and adaptation in relation to environmental changes such as temperature and vegetation profile. Such changes produce different ecological niches that can be a source of local adaptations in the communities, like body size varying with elevation, for example. In this context, planthoppers (Insects, Hempitera, Fulgoromorpha) community and their species traits were studied along an altitudinal gradient in Mount Wilhelm (Papua New Guinea) to test niche and morphological trait conservatism in relation to environmental filtering. Niche conservatism is significant at high altitude for Cixiidae, and forewing shape is conserved. This is not the case for Achilidae and Derbidae, for which forewing shape is not conserved and forewing relative length increases in size with altitude. These variations in size and shape translate an adaptation of Achilidae and Derbidae to high altitudes; while closely related species of Cixiidae tend to keep the same ecological niche, and then, forewing size and shape are maintained.