Lethal in high doses to humans and other animals, only monarch caterpillars can stomach milkweed nectar – and they rely on it alone for sustenance. In a story of toxin versus predator, milkweed and monarch make for unlikely yet perfectly-suited allies.
Cornell University professor Anurag Agrawal discusses his new book, Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.
Discover one of nature's most fascinating evolutionary relationships and gain insight into the future of monarchs – which are threatened and in decline.