Many techniques are used today to study insect morphology, including light and electron microscopy. Most of them require to specifically prepare the sample, precluding its use for further investigation. In contrast, micro-CT allows a sample to be studied in a non-destructive and rapid process, even without specific treatments that might hinder the use of rare and hard-to-find species in nature. We used synchrotron radiation (SR) micro-CT and conventional micro-CT to prepare 3D reconstructions of Diptera, Coleoptera, and Hymenoptera species that had been processed with 4 common preparation procedures: critical-point drying, sputter-coating, resin embedding, and air-drying. Our results showed that it is possible to further utilize insect samples prepared with the aforementioned preparation techniques for the creation of 3D models. Specimens dried at the critical point showed the best results, allowing us to faithfully reconstruct both their external surface and their internal structures, while sputter-coated insects were the most troublesome for the 3D reconstruction procedure. Air-dried specimens were suitable for external morphological analyses, while anatomical investigation of soft internal organs was not possible due to their shrinking and collapsing. The sample included in resin allowed us to reconstruct and appreciate the external cuticle and the internal parts. In this work, we demonstrate that insect samples destined to different analyses can be used for new micro-CT studies, further deepening the possibility of state-of-the-art morphological analyses.

Glaciers are ecosystems hosting active communities, but the knowledge of the ecological processes that occur in these extreme environments is fragmented. More studies on the biodiversity, trophic networks and energy fluxes on glaciers are needed to better appreciate their ecological contribution on a global scale. This work shows the microbiological results of a research project that aims at describing the biodiversity and the ecological webs of the Forni Glacier (Stelvio National Park, Central Italian Alps). Samples were collected over two consecutive years from different supraglacial habitats, including cryoconite holes (i.e. small ponds full of melting water with a fine-grained sediment on the bottom), supraglacial sediment, bediere (i.e. supraglacial stream water), snow, dirt cones, moraines and ice. Englacial sediment samples and subglacial sediment samples were also collected on the second year. Microbial communities including bacteria, algae and fungi, were characterized by amplicon sequencing for all samples. The most abundant bacterial phyla resulted to be Pseudomonadota, Bacteroidota, Actinomycetota and Cyanobacteria, the most abundant fungal classes resulted to be Microbotryomycetes, Dothideomycetes, Leotiomycetes, Lecanoromycetes and Agaricomycetes, and the most abundant algal phyla resulted to be Chrysocapsales, Prasiolales and Chlamydomonadales. All microbial communities resulted to change according to habitat and sampling time. Finally, the microbiome of "ice fleas" (ice-dwelling glacial springtails) was also characterized from individuals collected on the second year, as they play a crucial role in connecting microbial communities with higher trophic levels. Results showed that all microbiome samples shared only one bacterial Amplicon Sequence Variant (ASV) of the family Comamonadaceae which may be involved in iron oxidation, which has high concentrations on Forni glacier. Overall, these results provide a good description of the microbial biodiversity of the supraglacial environment of Forni glacier and a first insight into the trophic network. Such studies are essential for properly understanding the dynamics of such a threatened ecosystem.

The genus Paussus is a highly specialized, charismatic group of ground beetles (Carabidae) classified in the subfamily Paussinae. All species of Paussus are obligate myrmecophiles (associates of ants). As with many other myrmecophilous or termitophilous beetles, Paussus have undergone extreme phenotypic adaptations for life with ants, at the level of head, antennae, and prothorax. Host data suggest that Paussus species are likely to be species-specific ant parasites, and the structural modifications of antennae and other body parts are likely under selection by their host ants. Investigating anatomical structures have been fundamental to better understand living organisms, and their interplay with the surrounding environment, which could induce significant morphological variation. In the last few years, bio-imaging techniques paired with geometric morphometrics (GM) overcame the limits of traditional anatomical studies, becoming widely non-invasive and highly informative for both internal and external characters. The use of Computed Tomography (CT) scanners definitively allowed to advance in the knowledge of either known or neglected biological structures. For this project, we used X-ray micro-computed tomography, in order to acquire 2D serial, cross-sections of various paussines samples, with a resolution between 0.954 and 2.44 micrometers. The 2D images in high resolution are then processed using a high-performance computer system and Thermo Scientific™ Amira™ Software and Thermo Scientific™ Avizo™ Software for the reconstruction of 3D models. With these models, we will be able to conduct a morphological study of the most variable parts in the body of the genus Paussus using 3D geometric morphometrics (3D GM), as these integrative techniques allows to describe in a quantitative way even subtle differences between structures, so as to determine whether the striking diversity of phenotypes is caused by the host or by other factors, overlapping the results obtained with the molecular part of phylogeny. These innovative practices help to deepen the meaning of shape in insect biology, from both structural and evolutionary views. They will allow, in particular, to describe the relationship between phylogeny and functional morphology in the extremely variable species of the subfamily Paussinae.