If you were out and about in Page the last two weeks you surely noticed a larger than usual population of butterflies. The variety we were seeing the most — which had a brown, black and orange coloration — are a variety called painted ladies.
The Painted Lady is believed to be the most widespread butterfly species in the world. It is found in North and South America, as well as parts of Europe, Asia and Africa.
In North America, adult painted ladies over-winter in northern Mexico and the southern parts of Arizona, New Mexico, Texas and California. During the spring and summer, they migrate north, getting so far as southern Canada. At a certain time of the year, they turn around and fly back south.
As the butterflies migrate north, they lay eggs along the way.
Painted ladies are an irruptive species, meaning they can appear by the millions if conditions are right.
Entomologists estimate this year’s population of painted ladies in North America is in the hundreds of millions, said Rich Hofstetter, entomologist at Northern Arizona University.
The reason for this year’s larger than usual population of painted ladies is directly related to the wetter than usual winter which led to a larger than usual bloom of desert flowers, said Hofstetter.
“This year’s desert bloom was one of the biggest we’ve had in decades,” said Hofstetter. “The larger bloom of flowers meant more food for the butterflies. This created conditions that allowed for a healthier population of butterflies.”
Because of this year’s healthy population of butterflies they laid more eggs than usual and a larger than usual number of the eggs survived.
“The explosion of painted ladies that passed through northern Arizona during the last two weeks was the first generation of offspring from the butterflies that over-wintered in northern Mexico and Northern Arizona,” said Hofstetter.
An adult painted lady lives only about two weeks. Their migration from northern Mexico to southern Canada and back is comprised of several generations of butterflies. They lay their eggs on thistle, mallow or hollyhock leaves. Pupae eat continuously for five to 10 days on whatever plant they find themselves when they emerge from their egg, after which they pupate for seven to 10 days. Adults sip sweet thistle and clover nectar.