Genome assembly of the ectoparasitoid wasp Theocolax elegans

The ectoparasitoid wasp Theocolax elegans is a cosmopolitan and generalist pteromalid parasitoid of several major storage insect pests, and can effectively suppress a host population in warehouses. However, little molecular information about this wasp is currently available. In this study, we assembled the genome of T. elegans using PacBio long-read sequencing, Illumina sequencing, and Hi-C methods. The genome assembly is 662.73 Mb in length with contig and scaffold N50 values of 1.15 Mb and 88.8 Mb, respectively. The genome contains 56.4% repeat sequences and 23,212 protein-coding genes were annotated. Phylogenomic analyses revealed that T. elegans diverged from the lineage leading to subfamily Pteromalinae ( Nasonia vitripennis and Pteromalus puparum ) approximately 110.5 million years ago. We identified 130 significantly expanded gene families, 34 contracted families, 248 fast-evolving genes, and 365 positively selected genes in T. elegans . Additionally, 260 olfactory receptors and 285 venom proteins were identified. This genome assembly provides valuable genetic bases for future investigations on evolution, molecular biology and application of T. elegans .