Shape and Size Adaptations of Planthoppers Along an Altitudinal Gradient on Mount Wilhelm (Papua New Guinea)

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.

Keywords: Fulgoromorpha; elevational gradient; environmental filtering; morphometric analysis; niche conservatism; phylogeny.

FIGURE 1

Placement of reference landmarks (points 1–11) and starting landmark for wing contour and length measurement (point 12) on a Cixiidae forewing.

FIGURE 2

Tree topology showing the two main clades (Cixiidae and Achilidae + Derbidae) with the altitude where each morpho‐species was collected. Number refers to the morpho‐species selected for the analysis.

FIGURE 3

PCA plot of forewing shape data. Cixiidae are shown in red, Derbidae in green and Achilidae in black. Shape variations along each axis are shown at the end of the corresponding axis.