Project description:<p> The casuarina moth (Lymantria xylina) is a notorious forestry pest, posing severe ecological and economic threats due to its destructive defoliation outbreaks and high invasive potential. Despite its significance, a high-quality reference genome has been lacking, limiting molecular-level investigations into its biology and hindering the development of effective pest management strategies. In this study, we report the first chromosome-level genome assembly of L. xylina generated through a combination of illumina short-reads, Oxford Nanopore long-reads, and Hi-C scaffolding. The final assembly spans 977.74 Mb, with 95.17% anchored to 31 pseudo-chromosomes, achieving a scaffold N50 of 34.15 Mb. Importantly, telomeric sequences were identified at both ends of all 31 pseudo-chromosomes, underscoring the exceptional quality and completeness of this reference genome. Quality assessment further revealed a BUSCO completeness of 94.5% and a consensus QV of 31.72. We also annotated 18,484 protein-coding genes, 95.21% of which were functionally assigned, and characterized genome-wide repetitive elements (77.18%).</p><p> Beyond the genome assembly, we generated comprehensive RNA-seq and metabolomic datasets across multiple diapause stages, enabling insights into gene expression dynamics and metabolic regulation during egg development. Together, these resources provide a valuable foundation for studying the genetic basis of host adaptation, invasiveness, and interactions with natural enemies such as nucleopolyhedrovirus and Beauveria bassiana.</p>