Speaker
Description
The Eurasian spruce bark beetle (Ips typographus) is both a keystone species and a major pest in spruce forests across Europe and Asia, contributing to large-scale damage during epidemic outbreaks. Previous studies on insect chemosensation, including bark beetles like I. typographus, have been biased towards the adult life stage, while the larval sensory biology is largely unexplored, particularly in Coleopterans. This is a knowledge gap worth considering, as larvae, together with symbiotic fungi, are directly responsible for the phloem degradation that causes spruce tree mortality.
In this study, we focus on the annotation and gene expression profiling of chemosensory genes in two instars of I. typographus larvae. Using available genome and adult antennal transcriptome assemblies, we have manually identified candidate gene models for their genomic position and exon-intron boundaries. Previous chemosensory gene annotation in I. typographus have been partial. Here, we provide a more complete set of candidate genes from key chemosensory gene families, including odorant receptors (ORs), gustatory receptors (GRs), ionotropic receptors (IRs), odorant binding proteins (OBPs), chemosensory proteins (CSPs) and sensory neuron membrane proteins (SNMPs).
Gene expression level analysis and identification of larval-specific chemoreceptors are currently underway using data from high-throughput RNA sequencing of heads from first-and third-instar larvae. These results will guide the functional characterization of larval-specific chemoreceptors and behavioral assays and will also be compared to adult expression profiles to reveal potential developmental shifts in chemosensory function across the I. typographus life cycle.
