Well according to wikipedia N. ampullaria is a vegetation eater: N. ampullaria has largely moved away from carnivory and acquires a substantial portion of its nutrients from digesting leaf matter that falls to the forest floor. It is thus partially detritivorous.
The species has developed several unique traits as a consequence of its adaptation to trapping leaf litter:
* It is the only species in the genus to lack "lunate" cells in its pitchers. These are modified stomatal guard cells which, it is thought, deny prey a foothold in the pitcher.
* The pitcher lid is atypical, being very small and reflexed, such that leaf litter is allowed to fall directly into the pitcher.
* Nectar glands, which play an important role in prey capture, are very rare and in some cases completely absent from the pitcher lid.
* The marginal glands of the peristome are greatly reduced compared to those of other species.
* In terrestrial pitchers, the glandular region extends almost to the peristome, such that there is little or no conductive waxy zone. The waxy zone functions by causing prey to slip and fall into the digestive fluid.
* The plant's architecture, consisting of subsurface runners and offshoots, is unusual for the genus. The species often forms a "carpet" of pitchers covering the soil. This serves to maximise the area over which falling debris may be intercepted.
* The pitchers of N. ampullaria are relatively long-lived, as the species relies on a slow accumulation of nutrients over time.
* It is thought that infaunal organisms, such as mosquito larvae, facilitate breakdown of leaf litter and aid in the transfer of nitrogen from it to the plant by means of the excretion of ammonium ions. Bacterial breakdown of leaf matter is also known to produce ammonium ions.
It has been shown that foliar stable nitrogen isotope (15N) abundance in N. ampullaria plants growing under forest canopy (litterfall present) is significantly lower than in plants without access to litterfall. Conversely, total nitrogen concentrations are higher in these plants compared to those growing in open sites with no litterfall. It has been estimated that N. ampullaria plants growing under forest canopy derive 35.7% (±0.1%) of their foliar nitrogen from leaf litter.