After spending their caterpillar days feeding on their noxious host plants, pipevines, these swallowtails are avoided by predators. In a process called Batesian mimicry, which most of us learned about through Monarchs and Viceroys, many other species have evolved to take advantage of this fashionable "don't-eat-me" look. Red-spotted Purples, dark female Tiger Swallowtails, and Spicebush Swallowtails, among others, are all similar enough to be ignored by the average flycatcher. After one bad pipevine hangover, no swallow is again interested in swallowing these swallowtails.