Progress and prospects on evolutionary developmental biology of butterfly wing patterns

Evolutionary developmental biology combines evolutionary biology and developmental biology, focusing on the evolution of developmental processes and the mechanisms of morphological diversification. Since the discovery of the homeobox gene in 1984, the genetic mechanisms of morphogenesis in multiple model organisms have been systematically studied. In contrast, non-model organisms are rich in complex evolutionary traits, yet their underlying genetic mechanisms have not yet been fully elucidated, so more relevant studies are still needed. Among non-model organisms, butterflies are rich in species diversity, with more than 18,700 species. In particular, butterfly wings have simple flat structures but exhibit diverse and complex patterns, likely associated with complex functions(e.g., defense and courtship) and subject to strong selective pressures, which makes them a classic system for evolutionary developmental biology studies. Early comparative morphological studies proposed the Nymphalid ground plan, providing a theoretical framework for the evolutionary developmental biology of butterfly wing patterns; a series of interference experiments on butterfly wing discs later confirmed the association between the wing developmental process and phenotypes. In recent years, by integrating genetics, developmental biology, and genomics research methods, genetic toolkit genes and loci involved in wing pattern regulation have been identified in several butterfly species, further improving the theoretical framework for studying butterfly wing pattern evolution and development. From the methodological perspective, experimental methods such as in situ hybridization and gene editing have played an important role in evolutionary developmental biology studies of butterfly wings, and the development of hybridization chain reaction technology and CRISPR/Cas9 gene editing technology has further advanced the feasibility of functional validation in butterflies. In the future, the development and optimization of lepidopteran RNA interference and gene editing technologies can promote functional studies, thus expanding the research systems of evolutionary developmental biology by comparing and analyzing complex traits. The above research can also be broadened to an ecological-evolutionary-developmental context to explore genetic and environmental factors that shape complex phenotypes(e.g., butterfly wing patterns), thereby deepening the understanding of key scientific issues such as the origin and evolution of biodiversity.