Representing a group of successful biocontrol agents for various pest fruit flies, a parasitic wasp genus remains largely overlooked. While its most recent identification key dates back to 1969, many new species have been added since then. As if to make matters worse, this group of visually identical species most likely contains many species yet to be described as new to science.
Having recently studied a species group of these wasps in Central Europe, scientists Fabian Klimmek and Hannes Baur of the Natural History Museum Bern, Switzerland, not only demonstrate the need for a knowledge update, but also showcase the advantages of modern taxonomic software able to analyse large amounts of descriptive and quantitative data.
Published in the open access Biodiversity Data Journal, the team's taxonomic paper describes a new species - Pteromalus capito - and presents a discussion on the free-to-use Xper3, developed by the Laboratory of Informatics and Systematics of Pierre-and-Marie-Curie University. The software was used to create an openly available updated key for the species group Pteromalus albipennis.
The fully illustrated interactive database covers 27 species in the group and 18 related species, in addition to a complete diagnosis, a large set of body measurements and a total of 585 images, displaying most of the characteristic features for each species.
"Nowadays, advanced computer technology, measurement procedures and equipment allow more sophisticated ways to include quantitative characters, which greatly enhance the delimitation of cryptic species," explain the scientists.
"Recently developed software for the creation of biological identification keys like Xper3, Lucid or Delta could have the potential to replace traditional paper-based keys."
To put the statement into context, the authors give an example with one of the studied wasp species, whose identification would take 16 steps if the previously available identification key were used, whereas only 6 steps were needed with the interactive alternative.
One of the reasons tools like Xper3 are so fast and efficient is that the key's author can list all descriptive characters in a specific order and give them different weight in species delimitation. Thus, whenever an entomologist tries to identify a wasp specimen, the software will first run a check against the descriptors at the top, so that it can exclude non-matching taxons and provide a list of the remaining names. Whenever multiple names remain, a check further down the list is performed, until there is a single one left, which ought to be the one corresponding to the specimen. At any point, the researcher can access the chronology, in order to check for any potential mismatches without interrupting the process.
Being the product of digitally available software, interactive identification keys are not only easy, quick and inexpensive to publish, but they are also simple to edit and build on in a collaborative manner. Experts from all around the world could update the key, as long as the author grants them specific user rights. However, regardless of how many times the database is updated, a permanent URL link will continue to provide access to the latest version at all times.
To future-proof their key and its underlying data, the scientists have deposited all raw data files, R-scripts, photographs, files listing and prepared specimens at the research data Zenodo, created by OpenAIRE and CERN.
Explore further: A genus of European paper wasps revised for the first time using integrative taxonomy
Fabian Klimmek et al, An interactive key to Central European species of the Pteromalus albipennis species group and other species of the genus (Hymenoptera: Chalcidoidea: Pteromalidae), with the description of a new species, Biodiversity Data Journal (2018). DOI: 10.3897/BDJ.6.e27722