Whole genome assembly and annotation of the acorn weevil, Curculio nanulus (Coleoptera: Curculionidae)

Abstract

The acorn weevil Curculio nanulus (Coleoptera: Curculionidae) is a seed predator that lays its eggs inside developing acorns and hickory nuts in the western United States. The female weevil uses her elongated rostrum to excavate a hole into the seed, creating a protected site for oviposition. Natural history traits among Curculio species--such as host-specificity and variation in larval diapause--suggest a dynamic evolutionary relationship with their host plants. These traits are best studied through a comparative genomic framework, but such analyses cannot currently be undertaken due to the lack of whole genome assemblies for Curculio species. To address this gap, we generated a whole genome assembly for C. nanulus using PacBio HiFi sequencing. The resulting assembly is [~]1.5 Gbp in length, with high contiguity (contig N50 = 7.7 Mbp) and gene completeness (USCO score: 97.46%). To enable comparative analysis, we also assembled the genome of the pecan weevil, Curculio caryae, using publicly available PacBio HiFi reads. For both species, we annotated repetitive elements and protein-coding genes, and compared these features with those of other weevil genomes. Our results reveal a marked expansion of repetitive elements within Curculio and its close relatives. These genomic resources provide a foundation for investigating seed predation, co-speciation, and host-parasite evolutionary dynamics in Curculio and related taxa, as well as their impacts on forest ecology.