Mount Murud
On Mount Murud, "N. muluensis" grows in shady mossy forest. This population produces darker pitchers than the one from Mount Mulu, possibly due to greater exposure to ultraviolet light at higher altitudes. Two true toad species from Mount Murud, "Pelophryne linanitensis" and "Pelophryne murudensis", are sympatric with "N. muluensis" and may breed in its pitchers.