What does Nepenthes ampullaria collect and digest unusually often?

Nepenthes ampullaria unusually often collects and digests leaf litter.

Unlike most pitcher plants, which primarily capture live insects and other small animals, N. ampullaria has become partly detritivorous. Its rounded pitchers commonly sit beneath forest canopies, where falling leaves accumulate and are broken down in the pitcher fluid. The plant absorbs nutrients released from this decomposing material, especially nitrogen.

Its structure reflects this lifestyle. The pitcher lid is small and reflexed rather than forming a broad cover, allowing leaves to fall directly inside. The plant also produces terrestrial pitchers in dense carpets, increasing the area available to intercept forest debris. Nectar glands and slippery zones are reduced compared with many insect-focused Nepenthes species.

The leaf litter is not necessarily digested by the plant alone. Bacteria and small organisms living inside the pitchers help decompose the material and release absorbable compounds. A 2011 study estimated that leaf litter supplied about 41.7% of laminar nitrogen and 54.8% of pitcher nitrogen. N. ampullaria still captures animal prey, but detritivory is its defining nutritional adaptation.