Hidden diversity on our doorstep

An international research team led by the LIB has described 14 previously unknown species of wasp from Europe, thereby impressively demonstrating just how little we know about the biodiversity right on our doorstep. The newly discovered species belong to the family Ceraphronidae: tiny parasitoid wasps, barely a millimetre in size, which live as larvae within a host organism and ultimately kill it. They are considered a so-called ‘dark taxon’: although they are very diverse in terms of individuals and species and are ecologically significant, many of their species remain undiscovered and are still completely in the dark.

The study focused on a newly defined group of species within the genus Aphanogmus, known as the Aphanogmus fumipennis species group. In total, the researchers examined 257 individuals from eight countries in the Western Palearctic, i.e. Europe including the Caucasus. Using an integrative approach that combines morphological characteristics (in particular the shape of male genitalia) with genetic data, they were able to distinguish 23 new species. 14 of these are described here for the first time.

Germany insufficiently explored

The findings for Germany are particularly noteworthy: ten of the newly described species have also been recorded in Germany, almost doubling the number of species previously known there from 12 to 22.

“The animals studied also include specimens from the LIB’s NaPa project (Nature-Positive Agriculture), from the garden of the Museum Koenig in Bonn, and from a private garden. The results show that even in regions thought to have been thoroughly studied, there is still an enormous amount of previously undiscovered biodiversity,”explains the study’s lead author, Tobias Salden, a PhD student at the LIB in Bonn.

Recent estimates by researchers in Stuttgart suggest that these 22 known species may account for less than ten per cent of the Ceraphronidae actually found in Germany. In other words, the vast majority of these tiny wasps right on our doorstep remain unknown.

Hotspot Georgia: Just the beginning

Another focus of the study was Georgia, where animals were specifically collected as part of the LIB’s CaBOL (Caucasus Barcode of Life) project. Eleven of the new species were discovered here alone. The total number of known species in the relevant superfamily, Ceraphronoidea, in the country has thus risen from three to 14.

“Yet even this figure reflects only a fraction of the actual diversity: unpublished findings show that there are at least 20 times as many species in Georgia,”emphasises Tobias Salden.

First major academic study in decades

The study also shows that the shortage of experts on particularly diverse groups of organisms can be addressed. For the first time, expertise on ceraphronids is now available in Germany as well. The last publication describing several Palearctic species of the genus Aphanogmus dates back more than six decades.

The new findings underscore the vital importance of modern biodiversity research, which combines integrative approaches with morphological and molecular data.

Small wasps, big impact

Parasitoid wasps play a vital role in almost all terrestrial ecosystems, for example in regulating insect populations. Research into their hidden species diversity is therefore crucial to understanding their role in natural and heavily human-influenced ecosystems. At the same time, they represent a significant proportion of biodiversity that has not yet been captured in monitoring and conservation efforts, particularly in light of the current massive decline in insect populations.

The current study makes it clear that research into biodiversity on our own doorstep is far from complete.

Publication

Salden T, Mikó I, Staverløkk A, Moser M, Vasilița C, van de Kamp T, Vogel J, Podsiadlowski L, Hein N, Japoshvili G, Peters RS (2026) Known unknowns at our doorstep: Description of 14 Western Palaearctic species within the newly defined Aphanogmus fumipennis species group (Hymenoptera, Ceraphronoidea, Ceraphronidae). Journal of Hymenoptera Research 99: 125-214. https://doi.org/10.3897/jhr.99.178410