Synanthropic silverfish are the best-known and most widely distributed insects of the order Zygentoma. However, there is a great gap in the knowledge and confusion about the geographic distribution and the diagnostic characteristics that allow their identification. In this work, we provide an exhaustive and deep analysis of the most common 9 synanthropic silverfish of the world, combining previously published and newly derived morphological and molecular data. Updated descriptions of Ctenolepisma calvum ( Ritter, 1910) and Ctenolepisma (Sceletolepisma) villosum (Fabricius, 1775) are included, and morphological remarks, illustrations, and photographs of the remaining synanthropic species are provided to clarify their diagnosis and differentiation among them and from other free-living species. In addition, Ctenolepisma targionii (Grassi and Rovelli, 1889) is synonymized with C. villosum. A molecular phylogeny is presented based on the COI sequences of all the synanthropic species deposited in BOLD and GenBank, with 15 new sequences provided by this study. This has allowed us to detect and correct a series of identification errors based on the lack of morphological knowledge of several species. Moreover, 2 different lineages of Ctenolepisma longicaudatum Escherich, 1905 have also been detected. To help future studies, we also provide a taxonomic interpretation guide for the most important diagnostic characters of the order Zygentoma, as well as an identification key for all the Synanthropic studied species. Finally, an approximation of the global distribution of synanthropic silverfish is discussed. Several new records indicate that the expansion of these species, generally associated with the transport of goods and people, is still far from over.

Reticulitermes grassei is a subterranean termite species that forages on woody structures of the Iberian Peninsula, and is often a building and crops pest. A total of 23 microorganisms associated with the activity of R. grassei were isolated from colonized ecosystems in southern Spain. They were morphologically and molecularly characterized, with fungi being the most prevalent ones. The fungi showed high values of optimum growth temperature, suggesting that they could be able to survive and develop in warm regions. Their cellulolytic activity was tested in carboxymethylcellulose (CMC) agar, concluding that all fungal isolates produce cellulases, and the enzymatic index (EI) was revealed in CMC agar with Gram’s iodine solution, with Penicillium citrinum showing the highest EI and Trichoderma longibrachiatum the highest mycelial growth rate on CMC. A preliminary microorganism dispersion assay was carried out with the termites, concluding that these insects may have a positive influence on fungal dispersion and the subsequent colonization of new substrates. Our study suggests that fungi associated with R. grassei may potentially be of interest in biotechnological fields such as biofuel production and the food industry.

Background: Various animal taxa have specialized to living with social hosts. Depending on their level of specialization, these symbiotic animals are characterized by distinct behavioural, chemical, and morphological traits that enable close heterospecific interactions. Despite its functional importance, our understanding of the feeding ecology of animals living with social hosts remains limited. We examined how host specialization of silverfish co-habiting with ants affects several components of their feeding ecology. We combined stable isotope profiling, feeding assays, phylogenetic reconstruction, and microbial community characterization of the Neoasterolepisma silverfish genus and a wider nicoletiid and lepismatid silverfish panel where divergent myrmecophilous lifestyles are observed. Results: Stable isotope profiling (δ¹³C and δ¹⁵N) showed that the isotopic niches of granivorous Messor ants and Messor-specialized Neoasterolepisma exhibit a remarkable overlap within an ant nest. Trophic experiments and gut dissections further supported that these specialized Neoasterolepisma silverfish transitioned to a diet that includes plant seeds. In contrast, the isotopic niches of generalist Neoasterolepisma silverfish and generalist nicoletiid silverfish were clearly different from their ant hosts within the shared nest environment. The impact of the myrmecophilous lifestyle on feeding ecology was also evident in the internal silverfish microbiome. Compared to generalists, Messor-specialists exhibited a higher bacterial density and a higher proportion of heterofermentative lactic acid bacteria. Moreover, the nest environment explained the infection profile (or the 16S rRNA genotypes) of Weissella bacteria in Messor-specialized silverfish and the ant hosts. Conclusions: Together, we show that social hosts are important determinants for the feeding ecology of symbiotic animals and can induce diet convergence.

The Mediterranean Basin is considered one of the most important hotspots of biodiversity in the European region. Many taxa exhibit high levels of speciation and endemicity in this area. This is the case of the myrmecophilous insects of the families Lepismatidae and Nicoletiidae (Insecta: Zygentoma) that are further assessed in this study using unpublished and bibliographic data. A complete checklist of all ant-associated silverfish occurring in the Mediterranean Basin is presented, together with an updated identification key and interesting new records for several countries. Considering all described Zygentoma species, the myrmecophilous silverfish of the Mediterranean area represent 28% of all ant-associated species of the world and about 35% of the studied area. Even with the scarce knowledge of Zygentoma in other biogeographic areas and with insufficient sampling in other continents, we conclude that the Mediterranean region, and neighbouring areas of the Western Palaearctic, represent the most important biodiversity hotspot of ant-associated Lepismatidae (about 30% of the myrmecophilous species of this family described in the world so far), while the highest diversity of myrmecophilous Atelurinae is linked to tropical regions.

Wood is very present in the structures of old buildings and real estate with historical value. Yet, as a biodegradable material, it is highly vulnerable to adverse environmental conditions, such as permanent high humidity and attacks by xylophages. Furthermore, being a natural material, wood has great potential for low-carbon building within a circular economy. To preserve historical wooden structures, periodic inspections, preferably non-destructive or minimally invasive, are needed. Inspection may involve visual or resistographic testing techniques. However, both of these methods are time consuming and inaccurate. In this work, the joint use of techniques is proposed, in order to make multi-feature decisions about the repair or replacement of elements. The acoustic emission technique is proposed to determine active xylophages, the elastic wave technique to determine the dynamic elastic modulus and the resistance class, and finite element numerical modelling to determine the state of deformation and structural capacity. An old beam floor from a historic building in the center of Granada, Spain, was used as a practical case. The results demonstrate the effectiveness of a multi-analysis, instead of a single analysis, in arriving at correct decision making.

A survey of wingless insects belonging to the orders Microcoryphia (=Archaeognatha) and Zygentoma (=Thysanura s. str.) has been performed in subterranean habitats of central Iran. As a result, several new species have been discovered. In this work, three new species are described: a new species of bristletail of the family Machilidae,Haslundiellairanicasp. n., a new silverfish of the family Lepismatidae,Ctenolepismasubterraneumsp. n., and a new Nicoletiidae, Lepidospora (Brinckina) momtazianasp. n.These new taxa are compared with related species in their respective genera and keys for their identification are provided: one for all known species ofHaslundiellaand one for all basal insects of subterranean environments of Iran which includes those previously reported. Moreover, the previously published keys of IranianCtenolepismaand the subgenus Brinckina are modified to include the new species. Three additional species of Lepismatidae are reported in this work:Neoasterolepìsma palmoniiandCtenolepismatargioniiare newly recorded from Iran and both species, together withAcrotelsacollaris, are cited for the first time in the subterranean habitats. This survey progresses the knowledge on the biodiversity of these insects in Iran.