Parasitoid wasps and beyond: The need for DNA, morphology and deep taxonomic knowledge in modern biodiversity discovery

DNA-based approaches, particularly COI barcoding and genomic workflows, have contributed to establishing integrative taxonomy as the current standard, but have also been promoted as the primary, and sometimes sole, avenue for species discovery and delimitation in hyperdiverse insect groups such as Hymenoptera. Here, we examine the recent emphasis on DNA-based taxonomy and its implications for species diagnoses and long-term nomenclatural stability. We argue that molecular data are indispensable, but that integrative approaches combining morphological evidence with mitochondrial and nuclear markers provide the most robust framework for efficient species discovery and stable, testable species hypotheses. From our shared perspective of studying megadiverse parasitoid wasps, we further argue that the success of integrative taxonomy ultimately depends on researchers with both methodological skills and deep knowledge of the diversity, biology and evolution of their focal taxa. The global decline in expert taxonomists therefore represents a major challenge for biodiversity research, making the training of a new generation of integrative taxonomists essential.