Mechanism for rapid passive-dynamic prey capture in a pitcher plant

SignificanceCarnivorous pitcher plants have thus far been considered a classic example of passive, motionless pitfall traps. Here, we describe a rapid, passive-dynamic movement used by an AsianNepenthespitcher plant to capture insect prey. We show that the pitcher lid functions as a rain-driven torsion spring that combines material properties adapted for momentum transfer with a unique friction-reducing surface coating. Unlike other pitcher traps, this capture mechanism employs rapid movement. It also differs from the metabolically costly mechanisms of active carnivorous plants such as Venus flytraps because the movement is externally driven. It therefore establishes a new category of rapid plant movements that challenges the conventional distinction between active and passive carnivorous plant traps.