On Mount Trusmadi, N. fusca has been observed growing epiphytically on Eleocarpus trees at an elevation of almost 1800 m. A lone plant growing on a ridge top at 1962 m was found to have a small bush frog (probably Philautus aurantium) in one of its partly dried, 15 cm-long pitchers. Scattered plants have also been recorded from a rocky clearing at c. 1592 m, growing alongside Gleichenia truncata ferns and bamboo orchids; these plants have rather unremarkable red-speckled but otherwise plain green pitchers, though unusually the stem and underside of the midrib are almost black.