Rediscovery of the greater chestnut weevil highlights the growing power of digital tools in biodiversity science

The decline of the American chestnut (Castanea dentata) led to the presumed extinction of its host-specialist seed predator, the greater chestnut weevil (Curculio caryatrypes)—a textbook example of coextinction. Here, we report its rediscovery via digital community science observations from hybrid chestnut orchards in the eastern United States, confirmed by genomic data and field observations. This finding underscores the resilience of species in refugial habitats and the growing importance of digital platforms like iNaturalist, which combine global community participation with AI-assisted identification to enable rapid species detection. With over 225 million observations covering nearly 500,000 species, iNaturalist is emerging as one of the world’s largest biodiversity databases—with near-term projections of hundreds of millions of research-grade observations and major contributions to biodiversity science and conservation.