Abstract
BACKGROUND: Aedes triseriatus is an endemic North American mosquito and the primary vector of La Crosse virus, the etiologic agent of La Crosse encephalitis. This neuroinvasive disease is the leading cause of arboviral encephalitis in the United States and disproportionately affects pediatric populations. Despite its medical importance, the genomic architecture and vectorial capacity of A. triseriatus remain incompletely understood. RESULTS: We generated a chromosome-scale genome assembly and developmental transcriptome for A. triseriatus using an integrated approach combining PacBio long-read sequencing, Hi-C scaffolding, and Illumina sequencing technologies. The final assembly spans approximately 2.4 Gb, representing the largest mosquito genome reported to date, and consists of chromosome-sized scaffolds supported by Hi-C data and manual curation. Transcriptome profiling across larvae, pupae, and adult males and females revealed dynamic, stage-specific gene expression patterns associated with distinct physiological processes. CONCLUSIONS: These genomic and transcriptomic resources provide a comprehensive foundation for investigating the molecular basis of La Crosse virus transmission, mosquito development, and vector–host interactions in A. triseriatus. The chromosome-scale assembly establishes an essential framework for future functional, evolutionary, and vector biology studies in this medically important species. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12864-026-12779-8.