While listening to the radio show "To the Best of Our Knowledge" this past Sunday, I learned about coyotes in the Bronx, peregrine falcons nesting on skyscrapers in our big cities, and other manifestations of nature in the cities. I could have added my own story of nature in Madison - the appearance on my front porch in the Tenney-Lapham neighborhood of the pipevine swallowtail butterfly. Here's my account:

About fifteen years ago I planted a Dutchman's pipe vine (Aristolochia macrophylla) near my front porch. The vine is a native to the southeastern U.S. and was much planted earlier in the century as a fast growing screen for large porches. But it gradually lost favor and is not widely planted anymore. It has huge heart-shaped leaves and easily climbs to the top of my two-story house. In the spring it has a neat little flower in the shape of a pipe, hence its name. The vine covers the side of my house and envelops my front porch - I like it.

Earlier this summer a friend came over and saw about twenty quarter-inch caterpillars crawling on one of the leaves of the vine. John knew the vine was a pipe vine and that the pipevine swallowtail caterpillar only eats the leaves of the genus Aristolochia. So he wondered if these were pipevine swallowtail caterpillars.

Wisconsin does have some swallowtail butterflies, e.g., black swallowtails and eastern tiger swallowtails. However, the pipevine swallowtail butterfly is not native to Wisconsin since there are no native plants of Aristolochia for it to feed on. It has been recorded as a rare stray in Wisconsin. It's a large butterfly, mainly very dark and almost iridescent blue.

So John took a few of the caterpillars and I took the rest and raised them in an old aquarium. It's easy raising caterpillars - get an old yogurt container, fill it with water, put a hole in the lid, and stick a leaf of the preferred food source for the caterpillar to eat. After a few days, the caterpillars took on the characteristic look of the pipevine swallowtail caterpillar - there are large thick fleshy spikes that cover their body and they look pretty ferocious compared to most caterpillars.

After a few weeks they changed to the chrysalis stage. Most of the chrysalises were camouflage brown but a couple were iridescent green. I was curious as to the color variation in the chrysalises and even posted a message to a butterfly listserve. By this time you can see I was really getting into this.

Eventually most of them emerged from the chrysalises and flew away. I would see them gathering nectar from plants in my garden and making an occasional foray around the Dutchman's pipe vine to lay eggs.

Dave Fallows, who gives bird and butterfly walks in the Madison area and gives a nature report on WORT Tuesday mornings, heard about the butterflies and came over and saw one. He said it was the first pipevine swallowtail he had seen in Wisconsin in the over twenty years he has lived here. Les Ferge, a local entomologist, also heard about the butterflies and emailed me: "this is a very interesting and important sighting, as the Pipevine Swallowtail has historically been reported only a few times in Wisconsin. It is regarded as a rarely-occurring stray, and breeding populations would be most unusual."

I still have a lot of questions about the appearance of the butterflies on my front porch? How did they get here? Since I haven't paid attention to them before this year, how many years have they been here? Could this be their first year here, having been blown here on a southern wind? And since Aristolochia is so rarely grown in Wisconsin, how did they find my house? Could they be escapees from the Olbrich Gardens butterfly exhibit which has pipevine swallowtails? Will the chrysalises be able to survive the winter?

One doesn't have to travel far to see the wonders of nature. We just have to open our eyes to what we have in our own backyards and the mysterious swallowtail butterflies taught me that lesson again this summer.

- Bob Shaw

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