Out of the Andes and up to the Arctic: multiple drivers promote rapid radiation in Colias butterflies

The drivers of insect radiation in mountain ecosystems are poorly understood compared to birds and plants. The drivers of insect radiation in mountain ecosystems are poorly understood compared to birds and plants. We studied the rapid radiation of the butterfly genus Colias, which has diversified in mountain ecosystems in Eurasia, Africa, and the Americas. Based on a dataset of 150 nuclear protein-coding genetic loci and whole mitochondrial genomes, we constructed a time-calibrated tree of the genus Colias with broad taxon sampling. We then inferred historical characteristics of this genus, including ancestral range reconstruction, historical diversification rates, and the evolution of host plant use. We found that rapid diversification was driven by several factors including favorably warm climates in the mid-Pliocene that promoted the population expansion, and the formation of the Isthmus of Panama and the Bering Land Bridge, which led to intercontinental dispersals that opened new ec..., ,