Carnivory
Nepenthes macrophylla has formed a mutualistic relationship with the mountain treeshrew (Tupaia montana). The pitchers of N. macrophylla exude a sugary reward on the reflexed pitcher lid and provide a perch for the visitor. The treeshrews eat this exudate and defecate into the pitchers, supplying the plant with valuable nitrogen.
A 2010 study showed that the shape and size of the pitcher orifice of N. macrophylla exactly match the dimensions of a typical Tupaia montana. A similar adaptation was found in N. lowii and N. rajah, and is also likely to be present in N. ephippiata. In all three of these species (N. ephippiata has not been investigated), the colour of the lower lid surface corresponds to T. montana visual sensitivity maxima in the green and blue wavebands, making it stand out against adjacent parts of the pitcher.
Read more about this topic: Nepenthes Macrophylla