Transcriptome-wide identification and expression profiling of chemosensory genes in rice grasshopper <i>Oxya intricata</i> (Orthoptera: Acrididae)

Chemosensory systems play an essential role in insect survival and reproduction, mediating behaviours such as host location, mating and oviposition. The rice grasshopper Oxya intricata is an important rice pest in Asia, yet the molecular basis of its olfaction remains poorly understood. In this study, we sequenced antennal transcriptomes from adult males and females and systematically identified chemosensory-related genes. A total of 104 candidates were identified, including 14 odorant-binding proteins (OBPs), 12 chemosensory proteins (CSPs), 67 odorant receptors (ORs), nine ionotropic receptors (IRs) and two sensory neuron membrane proteins (SNMPs). Expression profiling by quantitative real-time PCR revealed broad antennal enrichment across families, with subsets showing antenna-specific or sex-biased patterns, suggesting differential chemosensory deployment between tissues and sexes. Several OBPs, CSPs and ORs were also elevated in maxillary palps or tarsi, raising the possibility that these genes may be associated with contact or near-field chemosensation. Collectively, these results provide the first comprehensive survey of chemosensory genes in O. intricata and establish a molecular resource for future functional analyses of odour coding. The identified gene set offers tractable targets for ligand screening and behavioural assays, and may inform future efforts to develop semiochemical-based monitoring and management strategies for this economically important pest.