Monarch butterflies eat only milkweed, a poisonous plant that should kill them. The butterflies thrive on it, even storing milkweed toxins in their bodies as a defense against hungry birds. For decades, scientists have marveled at this adaptation. On Thursday, a team of researchers announced they had pinpointed the key evolutionary steps that led to it...
Noah Whiteman, an evolutionary biologist at the University of California, Berkeley, led the effort to test this hypothesis. “These three mutations may be the thing that unlocked the door” for the butterflies, he said.