The first chromosome-level genome assembly of a green lacewing Chrysopa pallens and its implication for biological control.

Many lacewing species (Insecta: Neuroptera) are important predators of pests with great potential in biological control. So far, there is no chromosome-level published genome available for Neuroptera. Here we report a high-quality chromosome-level reference genome for a green lacewing species Chrysopa pallens (Neuroptera: Chrysopidae), which is one of the most important insect natural enemies used in pest biocontrol. The genome was sequenced using a combination of PacBio and Hi-C technologies and assembled into seven chromosomes with a total size of 517.21 Mb, occupying 96.07% of the genome sequence. A total of 12,840 protein-coding genes were identified and approximately 206.21 Mb of repeated sequences were annotated. Phylogenetic analyses indicated that C. pallens diverged from its common ancestor with Tribolium castaneum (Coleoptera) approximately 300 million years ago. The gene families involved in digestion, detoxification, chemoreception, carbohydrate metabolism, immunity, nerves and development were significantly expanded, revealing the potential genomic basis for the polyphagia of C. pallens and its role as an excellent biocontrol agent. This high-quality genome of C. pallens will provide an important genomic resource for future population genetics, evolutionary and phylogenetic investigations of Chrysopidae as well as comparative genomic studies of Neuropterida and other insects.