From cabinets to collectomics: discovering females and primary larvae of Strepsiptera in a historical collection

Natural history collections house material from centuries of collecting efforts. In the Phyletisches Museum Jena (PMJ), ca. 1 Mio specimens are deposited, some of them dating back as far as the 17 th century. Modern imaging techniques have the potential to gain new insights from this historical material. However, a large part of the PMJ insect collection has not been revised by scientists in recent times. We screened the entire Auchenorrhyncha collection and found several specimens parasitized by two different species of the genus Halictophagus (Halictophagidae, Strepsiptera) that had previously been overlooked. These historical findings represent the only evidence to date of the occurrence of these two species in Germany and therefore suggest, at least historically, a larger distribution area than was previously known. In addition, hitherto unknown females and primary larvae were morphologically documented using state-of-the-art techniques such as synchrotron-radiation-based X-ray µCT and scanning electron microscopy. The data generated in this study cover the field of collectomics and can be seamlessly used as a basis for the emerging discipline of museomics. In taxonomic and systematic research and in the context of environmental change, pinned insects may play an outstanding role in the near future, as their DNA is not damaged by formalin fixation and thus can yield remarkable results even after more than 100 years. Our results underpin the value of historical material for modern research questions, especially for species that are difficult to find in nature.