Transcriptome Analysis and Identification of Chemosensory Membrane Proteins in the Head of Euplatypus parallelus

<i>Euplatypus parallelus</i> is a polyphagous pest capable of harming multiple plant species. Adult beetles invade tree trunks by boring holes, which negatively impacts the trees' growth and may result in tree death. <i>E. parallelus</i> depends on plant volatiles to identify and locate appropriate hosts for feeding or reproduction, with its olfactory system playing a vital role in volatile detection. In this work, we applied transcriptomics, phylogenetic analysis, and expression analysis to investigate four chemosensory membrane protein gene families that play a role in olfaction in <i>E. parallelus</i>. Based on the annotation analysis, 41 odorant receptors (ORs), 12 gustatory receptors (GRs), 14 ionotropic receptors (IRs), and 4 sensory neuron membrane proteins (SNMPs) were identified in the head. We used differential gene expression (DGE) and fragments per kilobase per million (FPKM) values to compare the transcription levels of chemosensory membrane protein gene families between males and females. The data indicate that the chemosensory membrane protein gene families in <i>E. parallelus</i> exhibit different expression levels in male and female heads, with some genes showing significant differences and displaying sex-biased expression. These results offer a basis for future exploration of the functions of chemosensory membrane protein gene families in <i>E. parallelus</i> and offer a theoretical framework for designing innovative eco-friendly control technologies.