A comprehensive update on the morphology and distribution of the invasive scaffold-web spider Eidmannella pallida (Araneae, Nesticidae) with a focus on new records from Italy

Updated non-native distributional data of the invasive spider Eidmannella pallida (Emerton, 1875), Nesticidae, are herein summarized together with the morphological characters of the species. We report all the known localities from the literature. Furthermore, we present and discuss recent findings for the Italian peninsula. In particular, the species has been consistently found in vineyards and annual crop fields in North Italy and in olive groves in South Italy. We include a redescription of the species, and detailed illustrations of the diagnostic characters of both males and females, based on stereomicroscope and SEM images. The spreading potential of the species and its possible impacts on local communities are discussed. Our data suggest that E. pallida has high invasiveness potential and several new findings in non-native areas were recorded in the last years. We found that E. pallida can establish permanent populations in crop-dominated landscapes and has a tendency to exploit vulnerable ecosystems such as the subterranean environment. We thus recommend new and more comprehensive studies on this species to investigate in deeper detail its phylogeny, ecology, and micro-habitat preferences. A high effort should be placed to assess the potential negative effects of E. pallida on the endemic fauna in invaded areas, especially in caves.

An unexpected occurrence: discovery of the genus Cybaeopsis Strand, 1907 in Europe with the description of a new species from Italy (Arachnida, Araneae, Amaurobiidae)

We report on the unexpected finding of a new species of the genus Cybaeopsis Strand, 1907, C. lodoviciisp. nov. from the Northern Apennine Mountains in Italy. This is the first documented record of a Cybaeopsis species in Europe. Other currently known species of this genus have been previously recorded in North America, the Russian Far-East and Japan. The new species is illustrated and described based on both sexes. Another species from Portugal, Cybaeopsis theoblicki (Bosmans, 2021) comb. nov., recently described in the genus Callobius Chamberlin, 1947, is hereby transferred to Cybaeopsis on the basis of morphological characters. An updated key to the European genera of Amaurobiidae is provided.

The global spread of misinformation on spiders

In the internet era, the digital architecture that keeps us connected and informed may also amplify the spread of misinformation. This problem is gaining global attention, as evidence accumulates that misinformation may interfere with democratic processes and undermine collective responses to environmental and health crises^1,2. In an increasingly polluted information ecosystem, understanding the factors underlying the generation and spread of misinformation is becoming a pressing scientific and societal challenge³. Here, we studied the global spread of (mis-)information on spiders using a high-resolution global database of online newspaper articles on spider-human interactions, covering stories of spider-human encounters and biting events published from 2010-2020⁴. We found that 47% of articles contained errors and 43% were sensationalist. Moreover, we show that the flow of spider-related news occurs within a highly interconnected global network and provide evidence that sensationalism is a key factor underlying the spread of misinformation.

Species conservation profiles of the endemic spiders Troglohyphantes (Araneae, Linyphiidae) from the Alps and the north-western Dinarides

Background

The genus Troglohyphantes Joseph, 1882 (Araneae, Linyphiidae) includes 131 species, mainly distributed across the main European mountain ranges. The Alps and the north-western Dinarides account for 66 species, most of them showing narrow or even point-like distributions. The majority of Troglohyphantes spiders dwell in subterranean habitats including caves, mines, soil litter, rocky debris and other moist and shaded retreats. Despite being intensively studied from taxonomic, ecological and biogeographic standpoints, knowledge on the status of conservation and on the potential risk of extinction of these spiders is lagging. To date, only three species have been included in the global IUCN Red List, but their status has not been updated ever since their last assessment in 1996. The aim of this contribution is to assess the Alpine and north-western Dinaric species of the genus Troglohyphantes and to re-assess the species previously evaluated, according to the last version of the IUCN Red List Categories and Criteria.

New information

Amongst the 66 species here considered, 62 had sufficient data to allow the quantification of their Extent Of Occurrence (EOO) and Area Of Occupancy (AOO). Most of the species have a narrow distribution range, with an estimated EOO < 20,000 km² and AOO < 2,000 km², meeting the thresholds for the inclusion in the threatened categories. Five species have a more widespread distribution (EOO > 20,000 km²), extending across multiple countries. The quality of the data on distribution of four species was not sufficient to provide a reliable estimation of the distribution range.A continuing decline in EOO, AOO and habitat quality was inferred for 30 species. The majority of them were subterranean specialised species, with a reduced thermal tolerance and a low dispersal ability. Accordingly, changes in subterranean microclimatic conditions due to climate change represent a major threat for these species. Land-use change and habitat alteration were identified as additional relevant threats for several species.A considerable proportion of the species here assessed was found in protected areas and in sites of the Natura 2000 network. In addition, 14 species are formally protected by national and sub-national legislation. At present, 25 species are listed in the regional Red Lists.Long-term monitoring programmes, management plans for both the species and their habitats, expansion of the extant protected areas and designation of new ones, should be considered as the most effective approaches to species conservation.

Species-habitat networks elucidate landscape effects on habitat specialisation of natural enemies and pollinators

Measuring habitat specialisation is pivotal for predicting species extinctions and for understanding consequences on ecosystem functioning. Here, we sampled pollinator and natural enemy communities in all major habitat types occurring across multiple agricultural landscapes and used species-habitat networks to determine how habitat specialisation changed along gradients in landscape composition and configuration. Although it is well known that landscape simplification often causes the replacement of specialists with generalists, our study provided evidence for intraspecific variation in habitat specialisation, highlighting how a large number of arthropod species adapted their way of selecting habitat resources depending on the landscape structure. Groups with higher diet specialisation and limited foraging flexibility appeared to have a reduced ability to respond to landscape changes, indicating that some arthropod taxa are better able than others to adapt to an increasingly broad set of resources and persist in highly impacted landscapes.

A multidiversity approach to investigate the impact of mining exploitation on spider diversity in the abandoned mine district of Montevecchio-Ingurtosu (Sardinia, Italy)

The impact of mining activities on spider (Araneae) diversity and assemblages was studied in two abandoned mine sites in Sardinia (Italy), where mining activities started in the middle of the nineteenth century and closed down over a century later. Spider community composition was analysed in dumps, undisturbed forests and scrublands which represent the natural chronosequence following the abandonment of the mining district. The identification of spiders was performed at the lowest taxonomic level possible and differences in abundance, species richness (SR), and functional diversity (FD) were analysed. Nonmetric multidimensional scaling (NMDS) and a permutated multivariate analysis of variance (PERMANOVA) routine were conducted to evaluate the relationships of spider assemblages with land cover, and the indicator species analysis was performed to identify the typifying species. During the entire sampling period, 2312 spiders were captured, and approximately 80% of the total were identified at the species level (79 spider species belonging to 28 different families). No differences in abundance and SR were found, whereas FD, which showed the highest values in forests, significantly differed among sites. A distinct separation among assemblages and a significant effect of the land use on spider assemblages were found (PERMANOVA, R² = 0.59, p < 0.001). Twelve species were selected as indicator species. Our results underlined the possibility to consider ground-dwelling spiders as a valuable target group for biomonitoring programmes supporting projects of near-natural restoration and/or technical reclamation of mining sites.

Elevation to species level and redescription of Xysticus alpinus Kulczyński, 1887 stat. n. (Araneae, Thomisidae)

Xysticus alpinus Kulczyński, 1887 stat. n. from Central-Eastern Alps, previously considered a subspecies of X. lanio C. L. Koch, 1835, is analyzed in detail. Redescription of both sexes and illustrations of habitus and genitalia are provided. A careful comparison with the nominal species is carried out revealing clear differences in morphology and habitat preferences. In light of this evidence, its elevation to species level is proposed.

Ecological speciation in darkness? Spatial niche partitioning in sibling subterranean spiders (Araneae : Linyphiidae : Troglohyphantes)

Speciation in subterranean habitats is commonly explained as the result of divergent selection in geographically isolated populations; conversely, the contribution of niche partitioning in driving subterranean species diversification has been rarely quantified. The present study integrated molecular and morphological data with a hypervolume analysis based on functional traits to investigate a potential case of parapatric speciation by means of niche differentiation in two sibling spiders inhabiting contiguous subterranean habitats within a small alpine hypogean site. Troglohyphantes giachinoi, sp. nov. and T. bornensis are diagnosed by small details of the genitalia, which are likely to be involved in a reproductive barrier. Molecular analysis recovered the two species as sister, and revealed a deep genetic divergence that may trace back to the Messinian (~6 million years ago). The hypervolume analysis highlighted a marginal overlap in their ecological niches, coupled with morphological character displacement. Specifically, T. giachinoi, sp. nov. exhibits morphological traits suitable for thriving in the smaller pores of the superficial network of underground fissures (Milieu Souterrain Superficiel, MSS), whereas T. bornensis shows a greater adaptation to the deep subterranean habitat. Our results suggest that different selective regimes within the subterranean environment, i.e. deep caves v. MSS, may either drive local speciation or facilitate contiguous distributions of independently subterranean adapted species.

Distribution and medical aspects of Loxosceles rufescens, one of the most invasive spiders of the world (Araneae: Sicariidae)

Loxosceles rufescens is a circum-Mediterranean spider species, potentially harmful to humans. Its native area covers the Mediterranean Basin and Near East. Easily spread with transported goods, it is meanwhile an alien and invasive species to nearly all other continents and many islands. This species occurs in semi-arid steppe-like habitats, typically under stones and in cavities, which enables it to settle inside buildings when invading the synanthropic environment. This review analyses the literature of L. rufescens bites to humans (38 publications) of which only 11 publications refer to 12 verified spider bites (11% of the reported bites). Two published allegedly deadly spider bites (Thailand 2014 and Italy 2016) involve non-verified spider bites and are thus not reliable. The symptoms and therapy of these 11 verified bites are described: only five cases showed moderate systemic effects, nine cases developed necrosis, four cases needed surgical debridement, all cases healed without complications within a few weeks. In conclusion, L. rufescens is a spider species globally spread by human activity, it rarely bites humans and the bites are less harmful than often described. There is no known fatal issue.

Zora alpina Kulczyński, 1915 (Araneae: Miturgidae): description of the male, redescription of the female

Zora Koch, 1847 is a small genus distributed in the Holarctic region. The genus comprises 16 species, 14 of them distributed in the Palaearctic region and two from the Neartic (World Spider Catalog 2016). The European fauna includes 11 species (Nentwig et al. 2016), 8 of which are present in Italy (Pantini & Isaia 2016). Zora has historically been placed in several different families, but is now in the Miturgidae Simon, 1886 following the phylogenetic analyses of Ramirez (2014).

A new species-complex within the trapdoor spider genus Nemesia Audouin 1826 distributed in northern and central Italy, with descriptions of three new species (Araneae, Mygalomorphae, Nemesiidae)

Three new Nemesia Audouin 1826 species from northern and central Italy are named. They share a combination of sexual characters, not found in other described species. A new species-complex within Nemesia is here referred to as the apenninica group. Within the apenninica group, N. apenninica n. sp., N. hastensis n. sp., and N. pedemontana n. sp. differ in the morphology of the male palpal organ and the female spermathecae. The three species have different kinds of geographical distributions. While N. apenninica and N. hastensis have locally restricted and geographically separated distributions, the distribution of N. pedemontana overlaps with that of both of these species and extends widely in northern and central Italy. In its periphery, the distribution of N. pedemontana overlaps with that of species other than the apenninica group, e.g., N. meridionalis (Costa, 1835) in southern Italy and N. manderstjernae (L. Koch, 1871) and N. carminans (Latreille, 1818) in Liguria. Information on burrow structure, phenology and habitat are provided for all three new species. Some aspects of the behavior and feeding are discussed for N. pedemontana and N. hastensis.