Genome and transcriptome-based identification and expression profiling of chemosensory gene families across developmental stages and tissues in <em>Sirex noctilio</em> (Hymenoptera: Siricidae)

The Sirex woodwasp (Sirex noctilio; Hymenoptera: Siricidae) is among the most destructive invasive pests affecting Pinus plantations worldwide. Chemosensory systems offer promising targets for pest control strategies, and the identification and characterization of chemosensation genes in non-model, economically significant insects such as S. noctilio is an important first step towards the development of such control methods. Here we sequenced and assembled a draft genome of S. noctilio and performed RNA-sequencing of 15 olfactory and non-olfactory tissues to study the expression patterns of chemosensation-related genes. Specific genes, such as SnocOR16 and SnocSNMP1, displayed tissue- and sex-specific expression patterns, making them particularly intriguing for their potential roles in chemosensation and oviposition. As woodwasps and their related lineages form a sister group to the majority of other Hymenoptera, including Apocrita, insights into their gene repertoires are crucial for tracing the evolutionary history of chemosensory multigene families of this ecologically and economically significant insect order. This study enhances our understanding of the molecular mechanisms underlying S. noctilio chemosensation, paving the way for further research in chemical ecology and the functional characterization of S. noctilio chemosensation genes.