In insects, olfactory perception relies on interactions between odorant molecules and olfactory receptors (ORs) expressed in olfactory sensory neurons. Although numerous studies have characterized insect OR-ligand interactions, these data remain scattered across the literature and heterogeneous in terms of species, experimental systems, and reporting standards, limiting their systematic analysis.

The Molecule to Insect Olfactory Receptor database (M2iOR) is a curated, publicly accessible resource designed to centralize and standardize odorant–receptor interaction data. In its current release, M2iOR compiles more than 30000 bioassay experiments, extracted from peer-reviewed publications and public databases. The resource integrates ligand structures, receptor sequences, species annotations, mixture information, and detailed experimental metadata.

M2iOR provides flexible query tools allowing users to retrieve activity profiles for individual molecules or compound sets, identify agonists for specific insect ORs, allowing for comparative analyses across receptors, species, or assay systems. Advanced filtering based on curated metadata and batch search functionality support high-throughput analyses. For each query, users can visualize and download a curated aggregation of experimental results, including a binarized combinatorial representation of olfactory coding suitable for downstream computational studies.

M2iOR provides a comprehensive framework for data-driven research in insect olfaction and comparative chemosensory biology.