Butterflies are a diverse and charismatic insect group that are thought to have evolved with plants and dispersed throughout the world in response to key geological events. However, these hypotheses have not been extensively tested because a comprehensive phylogenetic framework and datasets for butterfly larval hosts and global distributions are lacking. We sequenced 391 genes from nearly 2,300 butterfly species, sampled from 90 countries and 28 specimen collections, to reconstruct a new phylogenomic tree of butterflies representing 92% of all genera. Our phylogeny has strong support for nearly all nodes and demonstrates that at least 36 butterfly tribes require reclassification. Divergence time analyses imply an origin ~100 million years ago for butterflies and indicate that all but one family were present before the K/Pg extinction event. We aggregated larval host datasets and global distribution records and found that butterflies are likely to have first fed on Fabaceae and originated in what is now the Americas. Soon after the Cretaceous Thermal Maximum, butterflies crossed Beringia and diversified in the Palaeotropics. Our results also reveal that most butterfly species are specialists that feed on only one larval host plant family. However, generalist butterflies that consume two or more plant families usually feed on closely related plants.

蝴蝶是一个多样化且富有魅力的昆虫群体，人们认为它们是与植物一起进化的，并为了应对重大地质事件而散布到世界各地。然而，这些假设尚未得到广泛测试，因为缺乏蝴蝶幼虫宿主和全球分布的全面系统发育框架和数据集。我们对来自 90 个国家和 28 个标本馆的近 2,300 个蝴蝶物种的 391 个基因进行了测序，以重建代表所有属 92% 的蝴蝶的新系统发育树。我们的系统发育对几乎所有节点都有强有力的支持，并表明至少有 36 个蝴蝶部落需要重新分类。分歧时间分析表明蝴蝶的起源约为 1 亿年前，并表明除一个家族外，所有蝴蝶家族都在 K/Pg 灭绝事件之前存在。我们汇总了幼虫宿主数据集和全球分布记录，发现蝴蝶很可能首先以豆科植物为食，起源于现在的美洲。白垩纪最热期过后不久，蝴蝶穿越白令陆桥并在古热带地区实现多样化。我们的研究结果还表明，大多数蝴蝶物种都是只以一种幼虫寄主植物家族为食的专家。然而，捕食两种或两种以上植物科的通才蝴蝶通常以密切相关的植物为食。