Size doesn’t matter shape does: A morphological study of pitcher plant in distinct forest canopy structures

Abstract

Light exposure from the sun is the most crucial variable for producing optimal pitcher size and colour variation in Nepenthes. This study aimed to observe the effect of forest canopy structure on morphological character of Nepenthes ampullaria’s pitcher parts (longitudinal, front, and peristome) both on size and shape using Geometric morphometric (GM) approach and its prey diversity. We classified the forest canopy structure into two categories: inside the canopy and open space area (gap). We used Unmanned Aerial Vehicle (UAV) images to build Canopy Height Model (CHM). Then, ForestGapR R package used to analyse and generated the forest gaps area. The prey specimens and photograph samples comprised from 9 individuals with three lower pitchers in open space area with high light exposure as well as shaded area inside the canopy. Total of 54 images were marked by point and curve to generated a landmark analysis using GeoMorph R package. Based on GM analysis, we observed that the forest canopy structure could affect Nepenthes pitcher shape but not in pitcher size. Our field result revealed Nepenthes ampullaria likely dominated by darker colour with a red spot in the shaded area and bright green colour in the open. However, based on our study the pitcher in shaded area inside the canopy have a larger number of prey species than the open area.