Changing patterns of land use in a Nevadan meadow have driven the rise, fall and subsequent rise of the local Edith checkerspot butterfly population, a study published this week in Nature reveals. The study shows how human activities can unwittingly drive evolutionary adaptation in the animal kingdom - a relationship that needs to be considered when planning conservation in human-altered habitats.
Twenty-five years ago, Michael Singer and Camille Parmesan described how an isolated population of Edith’s checkerspot butterflies, Euphydryas editha, in Carson City, Nevada, was starting to evolve a preference for the non-native plant Plantago lanceolata that had been introduced to the region through cattle ranching. In the new paper, the same team now show how the same butterfly population ended up abandoning its traditional food plant, Collinsia parviflora, and evolving complete dependence on this exotic plant, creating a lethal evolutionary trap. After ranching stopped in 2005, the trap was sprung. The local population crashed and went extinct.
The study clearly illustrates the potentially lethal evolutionary traps that human activities can unwittingly create for natural populations, but it also documents the dynamic nature of this relationship. After ranching stopped, the site was naturally recolonized as the butterflies returned to feeding on Collinsia, setting the stage for the entire process to start over.
Please note that there will be an accompanying Nature Video about this research. A preview of this is available now on the Nature Research press site.