The cabbage butterfly, voracious as a caterpillar, is every gardener’s menace. Turns out, these lovely white or sulfur yellow butterflies started trying to take over the planet long ago. Biologists used statistical methods to trace the path of Pieridae family butterflies as they diversified and their plant hosts fought back, over and over again. The study also finds that butterflies often regain hosts they haven’t used for millions of years.