Swarms of orange and black painted lady butterflies have been mesmerizing Southern Californians as close to a billion of them have been making their migration from Mexico to the Pacific Northwest. While this has happened before this is the largest such migration since 2005. As the New York Times explained, “substantial rainfall in the deserts near the Mexican border, where the North American painted ladies lay their eggs, is the reason for the unusually large swarms. The rain caused plants to thrive, giving the painted lady caterpillars plenty of food to fuel their transformation, said Arthur M. Shapiro, a professor of evolution and ecology at the University of California, Davis.”
March 18, 2019 » butterflies, California, insects, migration