Passiflora xiikzodz
(Decaloba/Cieca)
Campeche Mexico 1992

Ulmer, et al (Passiflora: Passionflowers of the World) comment that

"Passiflora xiikzodz is among the most bizarre passionflowers. It has no
nectary and produces no nectar; the pollinators of the plant are unknown and
their reward is unknown."

"Perhaps the flower mimics that of another family, or perhaps insects are
attracted by deceit. It is a mystery."

I do not think that this is a path that Passiflora have often gone down but
many orchids achieve pollination by deception e.g. giving false promises of
food or sex by their colour, shape and smell. So the question is what sort
of pollinator is the plant trying to fool and how?

A possibility is a small wasp such as here. It could be that the colour is mimicking a little pool of blood to attract a carrion-feeding wasp - looking at the Mayan link as it is only found close to Mayan ruins it seems there was usually plenty of the real thing about! Just because there is no reward does not
mean the pollinator will learn and avoid the flower. It may just think that
has failed to find where the nectar is and will keep looking. Most probably
it will end up making futile efforts to force its way through the operculum
to the nectar that isn't there. Pollinators know that sometimes they have to
struggle to get to the nectar. e.g. P. hahnii has a very similar operculum
which can only be pushed though by a strong large bee.