Why I planted pipevine
The colorful caterpillars you see below munching away on my pipevine (Aristolochia species) are going to turn into beautiful pipevine swallowtail butterflies (Battus philenor), and this vine's being eaten is exactly what I was hoping for when I planted it. This may seem counterintuitive, but the truth is that if you are going to support butterflies, you need both larval and nectar plants, and the larval plants get eaten. Pipevine (or Dutchman's pipe) is the primary food source for the pipevine swallowtail, and I have friends who grow it who say theirs has been completely defoliated three times in a season. I spied two swallowtail cats yesterday and today there were six, so I am hoping to be so lucky. Pipevine's a vigorous grower and I have no doubt it can handle whatever eating occurs. If you want to support pipevine swallowtails, plant one (there are species that will grow in most parts of the country), and celebrate when the eating begins.
Chomp, chomp. This is why you plant larval plants for butterflies.
You can find hints of the butterfly's coloration in the wild-looking caterpillar.
Here you can get an idea of where pipevine gets its common name.
What the above will grow into. (Photo via Wikipedia.)