How Butterflies Self-Medicate

Just like us, the monarch butterfly sometimes gets sick thanks to a nasty parasite. But biologist Jaap de Roode noticed something interesting about the butterflies he was studying — infected female butterflies would choose to lay their eggs on a specific kind of plant that helped their offspring avoid getting sick. How do they know to choose this plant? Think of it as “the other butterfly effect” — in this fascinating discovery about brand-new science.