I recently read an article about nepenthes pitchers glowing under UV light, which could be another method of trapping. I have a spare UVB bulb so I thought I would try it out and the effects were incredible, honestly these crappy photos do not do it justice. If you have a UV light I highly suggest you try this.
N. robcantleyi in normal light
in UVB spectrum
glandulifera x boschiana
Nepenthes eymae x steno x lowii x tm looked awesome