giant nepenthes pitcher hold by one hand, nepenthes rafflesiana

absorption adaptation anatomy aquatic avoidance behavior biodiversity biomimicry botanical capture carnivorous carnivory charles collection darwin digestion digestive diversity downward-pointing ecological environments enzymes evolution fascinating feature flora fluid habitat hairs harvesting insect insectivorous interactions leaf mechanism modified morphology natural nectar nepenthes niche nutrient nutrient-poor organ pitcher plant plants predator predator-prey predatory prey rainforest rainwater relationship relationships role scientific selection shape slippery specialized strategy structure study surface survival symbiotic trap trapping tropical unique upper