10 Fascinating Facts About the Painted Lady Butterfly (Vanessa cardui)

Painted lady butterfly.
Painted lady butterfly. Getty Images/www.marekszczepanek.pl

The painted lady is one of the most familiar butterflies in the world, found on nearly all continents and in all climates. They are a favorite subject of study in elementary school classrooms and are a familiar visitor to most landscape gardens. Yet common as they are, painted ladies have some unique attributes.  Here are 10 fascinating facts about the painted lady, or Vanessa cardui.

1. The painted lady is the most widely distributed butterfly in the world. Venessa cardui inhabits every continent except Australia and Antarctica. You can find painted ladies everywhere from meadows to vacant lots. It's sometimes called the cosmopolitan butterfly, because of its global distribution. Although it is resident only in warmer climates, it often migrates into colder regions in spring and fall, making it the butterfly with the widest distribution of any species. 

2. The painted lady is sometimes called the thistle butterfly or the cosmopolitan butterfly. It is called the thistle butterfly because thistle plants are its favorite nectar plant for food; it is called the cosmopolitan butterfly because of its global distribution. Its scientific name—Vanessa cardui—translates as "butterfly of thistle." 

3. Painted ladies have unusual migration patterns. The painted lady is an irruptive migrant, meaning that it migrates independent of any seasonal or geographic patterns. Some evidence suggests that painted lady migrations may be linked to the El Niño climate pattern. In Mexico and some other regions, it appears that migration is sometimes related to overpopulation. The migrating populations that move from North Africa to Europe may include millions of butterflies, and migrating populations numbering hundreds of thousands of individuals are common.  In spring, painted ladies fly low when migrating, usually only 6 to 12 feet above the ground. This makes them highly visible to butterfly watchers, but also rather susceptible to colliding with cars. At other times, evidence suggests that painted ladies migrate at such high altitudes that they are not observed at all, simply appearing in a new region unexpectedly. 

4. Painted ladies fly fast and far. These medium-sized butterflies can cover a lot of ground, up to 100 miles per day during their migration. A painted lady is capable of reaching a speed of nearly 30 miles per hour. Painted ladies reach northern areas well ahead of some of their more famous migrating cousins, like monarch butterflies. And because they get such an early start to their spring travel, migrating painted ladies are able to feed on spring annuals, like fiddlenecks (Amsinckia).

5. Painted lady butterflies do not overwinter in cold regions. Unlike many other species of butterflies that migrate to warm climates in winter, painted ladies die once winter hits in colder regions. They are present in cold regions only because of their impressive ability to migrate long distances from their warm-weather breeding areas. 

6. Painted lady caterpillars eat thistle. Thistle, which can be an invasive weed, is one of the painted lady caterpillar's favorite food plants. The painted lady probably owes its global abundance to the fact that its larvae feed on such common plants. The painted lady also goes by the name thistle butterfly, and its scientific name—Vanessa cardui—means "butterfly of thistle." 

7. Painted ladies sometimes damage soybean crops. When the butterflies are found in large numbers, they can do serious damage to soybean crops. The damage occurs during the larval stages when caterpillars eat soybean foliage after hatching from eggs.  

8. Males use the perch and patrol method for finding mates. Male painted ladies actively patrol their territory for receptive females in the afternoon. Should a male butterfly find a mate, he will usually retreat with his partner to a treetop, where they will mate overnight.

9. Painted lady caterpillars weave silk tents. Unlike other caterpillars in the genus Vanessa, painted lady larvae construct their tents from silk. You'll usually find their fluffy shelters on thistle plants. Similar species, such as the American lady caterpillar, make their tents by stitching leaves together instead.

10. On overcast days, painted ladies can often be found on the ground, huddling in small depressions. On sunny days, the butterflies prefer open areas filled with colorful flowers.