The primary pollinator of this plant is hummingbirds, although it may also be visited by less typical pollinators. Where this plant grows that harbors year round populations of hummers - like SoCal - they are constant visitors when the vine is in bloom.

Do hummingbirds visit year round in your location?

How long has it been in bloom, and is there other things blooming that have pollenators and hummers? Do you have up feeders?

I've noticed sometimes when something is just starting it's first couple days of bloom that the critters might already be occupied with other stuff and it takes them a day or two to notice the new blooms.

Sometimes with hummers, I will hear them way more than I see them. Are you hearing them and maybe just not seeing them?

I live in Central Florida and I have three or four ruby-throated hummingbirds that visit my property daily. If we don't have a hard freeze I will have some hummers all year, although the ones that come with the migration seem to be different from the ones that over-winter here. I'm so pleased to hear that hummingbirds use them. I have many, many flowers blooming now, so there is a lot for them to choose--which may be why I don't see hummers using the flame vine flowers.

I have seen the butterfiles drinking from them.

Because my Flame Vines are where I do not see them as a matter of course, and because hummingbirds spend less time than butterflies drinking in any small area, it is unlikely that I and a hummingbird would be at a Flame Vine at the same time.