Prospects for Complete DNA Barcode Coverage of the New Zealand Insect Fauna

The accurate identification of insects supports conservation, biosecurity and ecological monitoring. However, morphological identification is constrained by taxonomic complexity, undescribed diversity, and limited expertise. DNA barcoding can alleviate some of these challenges and complement morphological identification, if reference data are comprehensive and reliable. We assessed the taxonomic, geographic and elevational coverage of New Zealand insect DNA barcodes using taxonomic names from the New Zealand Organisms Register, published estimates of undescribed species richness, and DNA barcode metadata. Only 18% of described native and exotic insect species currently have DNA barcodes, with higher coverage for exotic (59%) than native species (12%). DNA barcode coverage varies from complete in several single-species orders to very low in hyperdiverse orders such as Coleoptera (7%) and Diptera (5%), while moderately diverse aquatic orders reach 31%-91% coverage. Low elevation and populated regions are overrepresented in the DNA barcode data, and many species identifications are based on bioinformatic approaches rather than taxonomic or diagnostic expertise. Despite these biases, we propose that a complete national DNA barcode library for described insect species is highly achievable given access to well-curated insect collections and species name databases for tracking progress. Complete DNA barcoding of undescribed species will be more challenging and will require targeting underrepresented taxa, geographic regions and elevations. Sampling will need to incorporate field surveys with bulk specimen collection, environmental DNA, museomic approaches and expert-verified identifications. Completing this library will strengthen New Zealand's regional and national-scale biodiversity monitoring using environmental DNA, with important contributions to biosecurity and conservation outcomes.