Chromosome-level genome assembly of the Erythrina Gall Wasp, Quadrastichus erythrinae (Hymenoptera: Eulophidae)

The erythrina gall wasp, Quadrastichus erythrinae , is an invasive gall-inducing chalcidoid wasp and a major pest of the endemic wiliwili tree ( Erythrina sandwicensis ) in Hawai□i. As a foundation to associated research, we generated a chromosome-level genome assembly from a wild-collected female measuring <2 mm. The final assembly consists of five scaffolds representing the five autosomes totaling 399 Mb (N50 = 75.6 Mb) and one unplaced 16 kb contig. BUSCO analysis recovers 91.1% of conserved Hymenoptera orthologs, representing the first chromosome-scale genome for the genus Quadrastichus . Comparative genomic analyses reveal syntenic conservation across Hymenoptera despite deep evolutionary divergence, with strongest collinearity to the chalcidoid Nasonia vitripennis . Genome size variation is largely explained by repeat content, and Q. erythrinae exhibits high proportions of unclassified transposable elements similar to the cynipid gall inducer. We also assembled a complete genome of its endosymbiont, Wolbachia pipientis . Together, these genomic resources provide a foundation for comparative, evolutionary, and applied research aimed at managing this invasive pest.