Passion flowers do draw ants its there defence the ants love them I have to watch the ants they eat my caterpillars .Not much you can do they help the passion flower but if you want butterflys you might have to put down seven dust around pot.

I notice ants on the flower buds occasionally and thought that maybe passion flower buds put out a sap similar to peonies. You may also notice ants if there are aphids on the plant. The ants will "farm" the aphids to get the dew that they excrete.
Karyn

Yup- the little "bumps" secrete a sugary substance ants like. In return, the ants protect the vine- "this is my food". They usually don't hurt anything (except you when you "threaten" them..) but some do "farm" aphids.

There's a sticky stuff called "tree tanglefoot" you can put around the trunk of the vine & any other paths to said vine- the ants get stuck in it & can't pass. I wouldn't bother tho unless you see them actively farming or chewing on the vine itself.

Sounds like your passion flower has fielded a little army to protect itself. I'd let 'em be.

My vine has attracted assassin bugs and anole lizards. Just noticed the lizard licking the droplets. No ants as yet, but my vine is potted.