The mechanisms underlying the diversification of herbivorous insects remain a fundamental question in evolutionary biology. To address this, my research focuses on the coevolutionary arms-race between swallowtail butterflies (Papilionidae) and their host plants—a classic model proposed in coevolutionary hypothesis. Using a macroevolutionary framework and a variety of genomic and transcriptomic approaches, I aim to identify the genomic mechanisms of the swallowtails’ adaptation to different host plants and the molecular signatures associated with host-shift events.