In 1993, a paper published in Nature showed that an isolated population of Edith’s checkerspot butterfly (Euphydryas editha) in a meadow in Carson City, Nevada, was starting to evolve a preference for the non-native plant Plantago lanceolata, which was introduced to the region through cattle ranching. Twenty-five years on, in this week’s issue, Michael Singer and Camille Parmesan show how the butterfly population ended up evolving complete dependence on the exotic plant. As a result, after cattle ranching ceased in 2005 and Plantago became briefly embedded in cool, lush grasses, the butterfly population went extinct. In 2013–4, a natural recolonization returned the insects to their traditional host, and their diet to its starting point. The findings illustrate the potentially lethal eco-evolutionary traps that human activities can unwittingly create for natural populations, and the importance of taking these traps into account in the conservation of human-modified habitats.