A Comprehensive Molecular and Evolutionary Characterization of Chemosensory-Related Genes in Calliptamus barbarus

Calliptamus barbarus (Costa, 1836) is a dominant grasshopper species in Xinjiang, characterized by high fecundity, polyphagy, and strong dispersal abilities. To investigate the molecular basis of its environmental sensing, we identified its chemosensory gene repertoire and performed a comparative analysis across six orthopteran species. We obtained 422 sequences across six major families: odorant receptors (ORs), ionotropic receptors (IRs), gustatory receptors (GRs), odorant-binding proteins (OBPs), chemosensory proteins (CSPs), and sensory neuron membrane proteins (SNMPs). Analysis of gene family dynamics identified 74 chemosensory genes associated with significant expansion events, including 40 ORs, 14 IRs, and 20 CSPs. Functional enrichment analysis revealed that these expanded gene families are associated with chemosensory behavior and olfactory transduction. Notably, core functional components such as Orco, SNMP1, and certain antennal IRs remain highly conserved across the six species. These variations in gene family size may represent molecular adaptations for environmental recognition. Our findings identify potential targets for future behavioral interference and sustainable pest management.