Adaptive significance and ontogenetic variability of the waxy zone in Nepenthes rafflesiana

The slippery waxy zone in the upper part of pitchers has long been considered the key trapping structure of the Nepenthes carnivorous plants; however, the presence of wax is reported to be variable within and between species of this species-rich genus. This study raises the question of the adaptive significance of the waxy zone and investigates the basis for an ontogenetic cause of its variability and correlation with pitcher shape.