I'm amazed at the amount of misinformation about butterflies and caterpillars out there! Maybe it's a result of the economy, I don't know, but you'd think a volunteer would know something as basic as what host plants pipevine swallowtails use.
They don't use passiflora - if there were cats on it, it's because they're resting there while molting, or somebody is trying to force them to eat it, which, as you have seen, they won't do.
Sherry

The only other supposed host plant I have read about is wild ginger, Asarum canadense. I assume this is true because we often find males patrolling where this plant grows and no A. serpentaria. I have yet to see a female laying on it though. I have tried it and the cats stick their toungue out at it (metaphorically speaking :)).

As Miss Sherry said, there is a lot of misinformation out there. That is why when I teach butterfly gardening classes, I don't give out lists. I teach people how to research plants and tell them use three sources to confirm the plant in question.

I visited a tropical butterfly house last winter and the staff person pointed to a Julia and said "I have those every summer in my yard" (in southern Ohio). I didn't argue. As tactfully as I could, I suggested that they should contact Ohio Lepidopterists because that would be a state record.
Sigh....

Cheers,
Elisabeth

Thanks. I was 95% sure that the P. biflora wasn't a host plant but wasn't saying anything. In all the years I visited this exhibit this was the first I've heard misinformation. Like I said it's also the first time I've seen it staffed with almost all volunteers who probably haven't had much training. At least they do provide pamphlets and other literature for sale that I'm pretty sure contains correct info.