German Barcode of Life reveals unexpected diversity of Ceraphronoidea (Hymenoptera)

Insect populations still experience marked declines globally, contributing to the ongoing biodiversity crisis. Counteracting these declines requires sound taxonomic and ecological knowledge on all levels of biodiversity, from genes to species to ecosystems. The superfamily Ceraphronoidea (Hymenoptera) has remained relatively obscure due to complex challenges in exploring its diversity and ecological roles. Despite their ecological importance as parasitoids or hyperparasitoids, these wasps are under-represented in scientific exploration and conservation. In a case study within the German Barcode of Life (GBOL) Dark Taxa project, we aim to bridge this knowledge gap through a comprehensive taxonomic investigation covering 2,136 specimens of Ceraphronoidea across 18 locations in the putatively well-studied State of Baden-Württemberg (south-western Germany). Our study identifies a surprising species richness of at least 193 conjectural species, based on COI-barcoding clusters, extrapolates key species richness estimators for the German ceraphronoid fauna and records a species new to the German fauna: Creator spissicornis (Hellén, 1966). By setting a foundational benchmark for Ceraphronoidea biodiversity, our research advocates for the inclusion of dark taxa in broader insect biodiversity assessments, contributing meaningfully to the discourse on conservation priorities and strategies.