A Comparative Genomic Assessment of Invasive Potential in the Planthopper Orosanga japonica (Hemiptera: Ricaniidae)

Orosanga japonica (Hemiptera: Ricaniidae) is an invasive, polyphagous planthopper established in Türkiye since 2007 that threatens economically important perennial and field crops across the Black Sea region. Although its establishment and rapid spread suggest considerable adaptive capacity, the genomic basis of this potential remains unexplored. We combined whole-genome sequencing with RNA-Seq data to generate a functionally annotated genome, recovering 92.5% of conserved single-copy orthologs. Utilizing these resources, we performed comparative genomic analyses across 20 additional hemipteran and thysanopteran species, investigating gene family dynamics and genome-wide positive selection. These analyses revealed 52 gene families with statistically significant, lineage-specific size changes (24 expansions and 28 contractions): expanded families were enriched for C2H2 zinc-finger transcription factors, α/β-hydrolases, major facilitator transporters, serpins, and chemosensory proteins, whereas contracted families included a cytochrome P450 family. Additionally, branch site tests identified 122 candidate genes under lineage-specific positive selection. These loci fall into three functional categories potentially associated with invasion-related traits: host detection and neuronal excitability, stress tolerance (xenobiotic, oxidative, and proteostatic), and barrier remodeling. Together, these genomic signatures highlight candidate molecular mechanisms that may contribute to host detection, xenobiotic tolerance, and ecological plasticity, providing a framework for evolutionary analysis and the targeted management of this emerging agricultural pest.