Monday, November 1, 2010

Runaway pipevine is an incubator for swallowtail butterflies

The large, yellow-speckled purple pipevine flower is surrounded by the plant's heart-shaped leaves

Simply Living

(First appeared in Orlando Sentinel October 31, 2010)

Sometimes you place a plant in your garden and forget all about it. That's how it has been for me with "Aristolochia elegans," better known as Dutchman's pipe, pipevine or calico flower.

Although I've been growing pipevine for about a decade, I've seldom paid much attention to it. This aggressive climber, which I started from a cutting, has been neglected since it was chopped back a couple of years ago to within a few inches of its woody-stemmed life. That means it has had the freedom to run wild.

Pipevines apparently thrive on a lack of human intervention because this year's growth is spectacular. My pipevine is a spreading mess in a once-tidy garden. The plant's thin, green tendrils have encircled everything within reach, including some plants that have met their demise beneath the pipevine's suffocating mass of heart-shaped leaves.

I suppose that such invasiveness should bother me, but it doesn't. It's hard to be upset about a plant that not only produces an abundance of large, odd-shaped, yellow-speckled, purple flowers but also acts as a host to two of the most beautiful butterflies around — the pipevine and polydamas swallowtails.

Swallowtails are a striking family of butterflies. Of the 700 or so species worldwide, eight live in Florida. Among those eight, the pipevine and polydamas have life cycles that depend on pipevines. After mating, female butterflies lay their round, orange eggs on the underside and stems of pipevine plants. About a week later, the larvae emerge to feed on the plant's leaves.

The selection of the pipevine as a host is not accidental. Plants in the pipevine family have chemicals that are poisonous to most animals, though not to these two species of swallowtail butterflies. When the hungry caterpillars munch away on pipevine leaves, toxic chemicals enter their bodies.

Those chemicals don't disappear. They stay with the larvae throughout its metamorphosis — from egg to larva to pupa to butterfly — and they poison any predator or parasite that decides to dine upon one of these attractive but lethal insects. So effective is this method of self-protection that other members of the swallowtail family mimic their cousins' appearance. Without having to consume the plant's poison, other butterflies have evolved into pipevine and polydamas lookalikes.

Most swallowtails are black butterflies with bright yellow, red and white markings. The pipevine swallowtail has beautiful iridescent blue hind wings and a curving arc of orange dots on its underwing. The polydamas swallowtail is also known as "gold rim" because of a band of yellow spots within the margins of the front and hind wings. The markings on both butterflies act as warning signals that tell would-be predators: Stay away!

Had I stayed away from the pipevine, I would have missed seeing all the caterpillars developing on the plant's leaves. Thanks to my daughter Amber, who was wandering the yard in search of cuttings for her own garden, we stopped at the overgrown pipevine and gave it a close look. It was probably the first time in more than a year that I had paid any attention to the plant. Although my intent was simply to point out the pipevine's peculiar flower — a large and suggestively shaped bloom that never fails to amuse me — what we discovered were dozens of swallowtail larvae munching away on the plant's leaves.

"Butterflies!" I exclaimed. "These little guys are going to turn into beautiful swallowtail butterflies!"

It's not every day you can plant a seed and grow a butterfly, but that's essentially what happens when the pipevine is added to the landscape. If that's not a redeeming feature, I don't know what is.

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