Both of my Nepenthes robcantleyi are in spike. Just a comparison of the two as it emerged and emerging from the crown. I think one is male and the other is female. The male (I think) are arranged in neat rows and rounder and female (I think) is not as neat and slightly elongated. As it matures, the elongation is more prominent. Also there is a small appendages under the spike.
Female when it just emerged from the crown.
Same female spike a couple of weeks after showing the little appendages at the base of the flower stem.