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Frequently Asked Questions
Are painted lady butterflies indigenous to my state? Painted ladies are native almost everywhere, from Canada, Iceland and the United States to Europe, Asia and South Africa. Their worldwide distribution accounts for one of their common names, “Cosmopolitan Butterfly.” Where can we find painted ladies in the wild? Painted ladies prefer sunny, open habitat with lots of small flowering plants—fields, meadows, marshes, dunes, grassy parks and yards. Do painted ladies migrate? Painted ladies are one-way migrators. Every spring, they fly northward from warm regions near the equator. Most of the painted ladies we see in the United States have arrived from the deserts of southern Arizona and Mexico. Where do they go in the fall? After two or more generations, adult butterflies enter a hibernation phase and may survive the winter. For the most part, populations in temperate areas are drastically depleted in freezing weather and depend on spring migrations to restore their numbers. Occasionally, painted ladies survive winter temperatures in their chrysalises, suspended between caterpillar and butterfly. What are those little balls in the bottom of my caterpillar cup? Those are caterpillar excrement, called “fras.” Fras and webs are signs of healthy caterpillars. Why do caterpillars spin webs? A caterpillar’s web is its defense against many dangers. For example, despite the hooks on the bottoms of their prolegs, caterpillars can easily be blown off host plants, especially when they are molting. Their sticky webs glue painted lady caterpillars to the leaves they feed on. Also, caterpillars are vulnerable to many predators. Webs help protect them from animals that hunt them for food and from insect parasites looking for caterpillars to host their own larvae. What is that black thing hanging on the bottom of the chrysalis? Is it the caterpillar’s head? Nope, it’s the caterpillar’s last exoskeleton, crumpled into a ball and stuck to the chrysalis. Painted lady caterpillars molt—shed their exoskeletons—five times, the last time just before they pupate. Often the exoskeleton doesn’t fall completely away from the pupating caterpillar but gets stuck on the outside of the chrysalis as it hardens. What happens in the chrysalis? How does the caterpillar get to be a butterfly? Inside the pupal exoskeleton, the caterpillar’s organs liquefy in a process much like digestion. Some tiny cell clusters, called “imaginal buds,” remain intact. These growth centers contain the chromosomes that carry the butterfly’s genes. They have been inactive throughout the caterpillar’s life, protected deep inside its body. Now the caterpillar body excretes a hormone that signals them to start growing and form all of the butterfly’s body parts. As they develop, imaginal buds absorb nutrients contained in the liquefied caterpillar body. In a few days, the pupa becomes semi-transparent, and the colorful butterfly begins to appear faintly inside. A day or two later, the butterfly emerges. Is that blood dripping from our emerging butterflies? No, that bright pink fluid, called “meconium,” contains the last traces of the caterpillar’s liquefied body and some other wastes that have collected during metamorphosis. The butterfly expels meconium through its anal opening. Are painted lady caterpillars environmental pests? Painted ladies are “defoliators”: periodically large caterpillar populations infest plants of the thistle family and consume all of their leaves. Adult butterflies may lay their eggs on soybean, sunflower, canola, mint and other crops, but painted lady caterpillars thrive best on weeds. In most countries, painted ladies are not considered pests—in gardens or in fields.
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