It is documented in the "Butterflies of North America a Natural History and Field Guide" by Dr. James Scott as being too toxic for Pipevive STs to finish their cycle. I have used A. elegans to collect egg, but raised the caterpillars on A. durior. Have you tried rearing Pipevine Swallowtails on A. elegans?

What is the difference between A. durior and A. trilobata, both commonly known as Dutchman's Pipe?

When misssherry submitted the original framework of the hostplant FAQ over 10 years ago, A. trilobata was one of the entries and mention is made of not using tropical pipevines for this swallowtail.

Take a look at the FAQ and see if the Pipevine entries need clarifying--it is very near the top of the whole hostplant list, and let me know, thanks.

Aristolochia Gigantea : A Death Sentence for Pipevine Swallowtail
From the Monarch Butterfly Garden website:

"1. Aristolochia durior or macrophylla- big leaf pipevine (native to the eastern US and recommended for USDA hardiness zones 4a-8b. I planted this in our garden and will be sure to post updates.)

2. Aristolochia tomentosa- woolly pipevine (native to the southeastern and central US. Recommended for USDA hardiness zones 5-10.)
   3. Aristolochia serpentaria - Virginia snakeroot (native to the eastern US and recommended for USDA hardiness zones 5a-8b. This species grows lower to the ground, earning its serpenty name.)
   4. Aristolochia californica- California pipevine (common to California. This climber also spreads like a ground cover. Recommended for USDA hardiness zones 8a-10b.)
   5. Aristolochia fimbriata- white-veined DutchmanâÂÂs pipe (a trailing plant with pretty foliage and easy to manage in the garden. USDA hardiness zones 7a-9b.)
   6. Aristolochia trilobata- DutchmanâÂÂs Pipe (unique colorful flowers, cold hardy to zone 10a.)
   7. Aristolochia clematitis- Birthwort (a rare, creeping vine with yellow flowers. Recommended for USDA hardiness zones 6b-9b.)
   8. Aristolochia watsonii- Desert pipevine (A low grower that could be an option for a hanging basket. Recommended for USDA hardiness zones above 9a.)"

Here is a link that might be useful: Aristolochia Gigantea : A Death Sentence for Pipevine Swallowtails

Aristolochia durior is the first thing on my list this season for my Midwest garden

Aristilochia durior is not native to the Midwest.

Here is a link that might be useful: Aristolochia durior information from USDA Plant Profiles

Oops! My best friend here in So. WI has one in his garden. I've been watching it for a few years now and it's flourishing, but no cats or butterflies sighted yet.
Pipevine Swallowtails are rare here but do make it here from time to time. One of my Mah Jongg buddies has PVS visit her gardens regularly every Summer, along with Giants and Spicebush Swallowtails. They are beating back Prickly Ash, and this must be the attraction to the Giants.

A. tomentosa would be native to WI:

"Aristolochia tomentosa- woolly pipevine (native to the southeastern and central US. Recommended for USDA hardiness zones 5-10.)"

The A. tomentosa is similar to A. durior, which is referred to as A.
macrophylla now.

Here is a link that might be useful: Native Pipevines (USDA Plant Profile)

Thank you, I'll keep an eye out for it. I think I know who'll have it.
Farmer's Market here I come!

Well, in a couple of months o_o