Establishing superfine nanofibrils for robust polyelectrolyte artificial spider silk and powerful artificial muscles.

Spider silk exhibits an excellent combination of high strength and toughness, which originates from the hierarchical self-assembled structure of spidroin during fiber spinning. In this work, superfine nanofibrils are established in polyelectrolyte artificial spider silk by optimizing the flexibility of polymer chains, which exhibits combination of breaking strength and toughness ranging from 1.83 GPa and 238 MJ m-3 to 0.53 GPa and 700 MJ m-3, respectively. This is achieved by introducing ions to control the dissociation of polymer chains and evaporation-induced self-assembly under external stress. In addition, the artificial spider silk possesses thermally-driven supercontraction ability. This work provides inspiration for the design of high-performance fiber materials.

Hot and scared: how do heatwaves and predation risk impact resource acquisition and allocation?

Heatwaves are increasingly prevalent and can constrain investment into important life-history traits. In addition to heatwaves, animals regularly encounter threats from other organisms in their environments, such as predators. The combination of these two environmental factors introduces a decision-making conflict-heat exposure requires more food intake to fuel investment into fitness-related traits, but foraging in the presence of predators increases the threat of mortality. Thus, we used female variable field crickets (Gryllus lineaticeps) to investigate the effects of heatwaves in conjunction with predation risk (exposed food and water sources, and exposure to scent from black widow spiders, Latrodectus hesperus) on resource acquisition (food intake) and allocation (investment into ovarian and somatic tissues). A simulated heatwave increased food intake and the allocation of resources to reproductive investment. Crickets exposed to high predation risk reduced food intake, but they were able to maintain reproductive investment at an expense to investment into somatic tissue. Thus, heatwaves and predation risk deprioritized investment into self-maintenance, which may impair key physiological processes. This study is an important step towards understanding the ecology of fear in a warming world.

Diversity and complexity of arthropod references in haiku.

Haiku are short poems, each composed of about 10 words, that typically describe moments in nature. People have written haiku since at least the 17th century, and the medium continues to be popular with poets, amateurs, educators, and students. Collectively, these poems represent an opportunity to understand which aspects of nature-e.g., which taxa and biological traits-resonate with humans and whether there are temporal trends in their representation or the emotions associated with these moments. We tested this potential using a mix of linguistic and biological methods, in analyses of nearly 4,000 haiku that reference arthropods. We documented the taxa and the life history traits represented in these poems and how they changed over time. We also analyzed the poems for emotion and tone. Our results reveal a mix of predictable trends and compelling surprises, each of which stand to potentially inform engagement strategies. At least 99 families of arthropods, in 28 orders, are represented in these haiku. The eight most commonly referenced taxa, from highest to lowest number of references, include: Lepidoptera, Hymenoptera, Diptera, Coleoptera, Araneae, Orthoptera, Hemiptera, and Odonata. Several common, conspicuous orders were never referenced, including Trichoptera, Plecoptera, and Megaloptera. The most commonly referenced traits relate to ecology (especially habitat, phenology, time of day), behavior (especially sound production), phenotype (especially color), and locomotion (especially flight). The least common traits in haiku relate to arthropod reproduction and physiology. Our analyses revealed few obvious temporal trends in the representations of taxa, biological traits, or emotion and tone. The broader implications of these results and possible future directions are discussed.

Endosymbiont diversity across native and invasive brown widow spider populations.

The invasive brown widow spider, Latrodectus geometricus (Araneae: Theridiidae), has spread in multiple locations around the world and, along with it, brought associated organisms such as endosymbionts. We investigated endosymbiont diversity and prevalence across putative native and invasive populations of this spider, predicting lower endosymbiont diversity across the invasive range compared to the native range. First, we characterized the microbial community in the putative native (South Africa) and invasive (Israel and the United States) ranges via high throughput 16S sequencing of 103 adult females. All specimens were dominated by reads from only 1-3 amplicon sequence variants (ASV), and most individuals were infected with an apparently uniform strain of Rhabdochlamydia. We also found Rhabdochlamydia in spider eggs, indicating that it is a maternally-inherited endosymbiont. Relatively few other ASV were detected, but included two variant Rhabdochlamydia strains and several Wolbachia, Spiroplasma and Enterobacteriaceae strains. We then diagnostically screened 118 adult female spiders from native and invasive populations specifically for Rhabdochlamydia and Wolbachia. We found Rhabdochlamydia in 86% of individuals and represented in all populations, which suggests that it is a consistent and potentially important associate of L. geometricus. Wolbachia was found at lower overall prevalence (14%) and was represented in all countries, but not all populations. In addition, we found evidence for geographic variation in endosymbiont prevalence: spiders from Israel were more likely to carry Rhabdochlamydia than those from the US and South Africa, and Wolbachia was geographically clustered in both Israel and South Africa. Characterizing endosymbiont prevalence and diversity is a first step in understanding their function inside the host and may shed light on the process of spread and population variability in cosmopolitan invasive species.

Chemical species recognition in an adaptive radiation of Hawaiian Tetragnatha spiders (Araneae: Tetragnathidae).

Studies of adaptive radiations have played a central role in our understanding of reproductive isolation. Yet the focus has been on human-biased visual and auditory signals, leaving gaps in our knowledge of other modalities. To date, studies on chemical signals in adaptive radiations have focused on systems with multimodal signalling, making it difficult to isolate the role chemicals play in reproductive isolation. In this study we examine the use of chemical signals in the species recognition and adaptive radiation of Hawaiian Tetragnatha spiders by focusing on entire communities of co-occurring species, and conducting behavioural assays in conjunction with chemical analysis of their silks using gas chromatography-mass spectrometry. Male spiders significantly preferred the silk extracts of conspecific mates over those of sympatric heterospecifics. The compounds found in the silk extracts, long chain alkyl methyl ethers, were remarkably species-specific in the combination and quantity. The differences in the profile were greatest between co-occurring species and between closely related sibling species. Lastly, there were significant differences in the chemical profile between two populations of a particular species. These findings provide key insights into the role chemical signals play in the attainment and maintenance of reproductive barriers between closely related co-occurring species.

Utility of accessible SARS-CoV-2 specific immunoassays in vaccinated adults with a history of advanced HIV infection.

Accessible SARS-CoV-2-specific immunoassays may inform clinical management in people with HIV, particularly in case of persisting immunodysfunction. We prospectively studied their application in vaccine recipients with HIV, purposely including participants with a history of advanced HIV infection. Participants received one (n = 250), two (n = 249) or three (n = 42) doses of the BNT162b2 vaccine. Adverse events were documented through questionnaires. Sample collection occurred pre-vaccination and a median of 4 weeks post-second dose and 14 weeks post-third dose. Anti-spike and anti-nucleocapsid antibodies were measured with the Roche Elecsys chemiluminescence immunoassays. Neutralising activity was evaluated using the GenScript cPass surrogate virus neutralisation test, following validation against a Plaque Reduction Neutralization Test. T-cell reactivity was assessed with the Roche SARS-CoV-2 IFNγ release assay. Primary vaccination (2 doses) was well tolerated and elicited measurable anti-spike antibodies in 202/206 (98.0%) participants. Anti-spike titres varied widely, influenced by previous SARS-CoV-2 exposure, ethnicity, intravenous drug use, CD4 counts and HIV viremia as independent predictors. A third vaccine dose significantly boosted anti-spike and neutralising responses, reducing variability. Anti-spike titres > 15 U/mL correlated with neutralising activity in 136/144 paired samples (94.4%). Three participants with detectable anti-S antibodies did not develop cPass neutralising responses post-third dose, yet displayed SARS-CoV-2 specific IFNγ responses. SARS-CoV-2 vaccination is well-tolerated and immunogenic in adults with HIV, with responses improving post-third dose. Anti-spike antibodies serve as a reliable indicator of neutralising activity. Discordances between anti-spike and neutralising responses were accompanied by detectable IFN-γ responses, underlining the complexity of the immune response in this population.

Association between resting-state connectivity patterns in the defensive system network and treatment response in spider phobia-a replication approach.

Although highly effective on average, exposure-based treatments do not work equally well for all patients with anxiety disorders. The identification of pre-treatment response-predicting patient characteristics may enable patient stratification. Preliminary research highlights the relevance of inhibitory fronto-limbic networks as such. We aimed to identify pre-treatment neural signatures differing between exposure treatment responders and non-responders in spider phobia and to validate results through rigorous replication. Data of a bi-centric intervention study comprised clinical phenotyping and pre-treatment resting-state functional connectivity (rsFC) data of n = 79 patients with spider phobia (discovery sample) and n = 69 patients (replication sample). RsFC data analyses were accomplished using the Matlab-based CONN-toolbox with harmonized analyses protocols at both sites. Treatment response was defined by a reduction of >30% symptom severity from pre- to post-treatment (Spider Phobia Questionnaire Score, primary outcome). Secondary outcome was defined by a reduction of >50% in a Behavioral Avoidance Test (BAT). Mean within-session fear reduction functioned as a process measure for exposure. Compared to non-responders and pre-treatment, results in the discovery sample seemed to indicate that responders exhibited stronger negative connectivity between frontal and limbic structures and were characterized by heightened connectivity between the amygdala and ventral visual pathway regions. Patients exhibiting high within-session fear reduction showed stronger excitatory connectivity within the prefrontal cortex than patients with low within-session fear reduction. Whereas these results could be replicated by another team using the same data (cross-team replication), cross-site replication of the discovery sample findings in the independent replication sample was unsuccessful. Results seem to support negative fronto-limbic connectivity as promising ingredient to enhance response rates in specific phobia but lack sufficient replication. Further research is needed to obtain a valid basis for clinical decision-making and the development of individually tailored treatment options. Notably, future studies should regularly include replication approaches in their protocols.

Three new genera of arboreal dark sac spiders from southern Africa (Araneae: Trachelidae).

As part of a revision of the Afrotropical species of Trachelas L. Koch, 1872 (Araneae: Trachelidae), we distinguished three new genera of primarily arboreal spiders from southern Africa that are described here: Coronarachne gen. nov., represented by four new species known from both sexes, C. denticulata sp. nov. (type species), C. penicillus sp. nov., C. setosa sp. nov. and C. unigena sp. nov., and C. neethlingi sp. nov., known only from the male; Falcaranea gen. nov., represented by three new species known from both sexes, F. amatola sp. nov., F. gladius sp. nov. (type species) and F. maputensis sp. nov.; and Trachecymbius gen. nov., represented by five new species, T. bosselaersi sp. nov. (), T. felis sp. nov. (), T. peterwebbi sp. nov. (), T. tyume sp. nov. (type species, ), and T. umbella sp. nov. (). These three genera share the presence of strongly protruding setal bases on the ventral surfaces of the anterior legs, which are more strongly developed in males and can be mistaken for small ventral cusps that are found in several trachelid genera. Identification keys are provided for each of the three genera and their phylogenetic affinities to other Afrotropical Trachelidae are evaluated based on the cytochrome oxidase c subunit I (COI) gene. Most of the species described here were common in canopy fogging samples, and to a lesser extent beating, but are clearly a prominent component of the arboreal trachelid fauna in savanna and forest habitats in southern Africa.

Cornifronus gen. nov., a new dark sac spider genus from China (Araneae: Trachelidae).

A new genus of the spider family Trachelidae L. Koch, 1872, Cornifronus gen. nov. from China is described, as well as one new species, C. simplex sp. nov. (), known only from Hainan and Yunnan Province.

Two new species of Fernandezina Birabn, 1951 (Araneae, Palpimanidae) from cave and epigean habitats in Brazil.

The South American palpimanid genus Fernandezina Birabn currently comprises 15 described species, all known from epigean environments. Representatives of Fernandezina are easily recognized by the unexpanded femora I in both sexes and by the dorsally extended opisthosomal scutum in males. Herein, F. fernandoi sp. nov. is described based on males and females from hypogean environments and F. angeloi sp. nov. is described based on a single male from a nearby epigean environment, both in Brazil. Additionally, we provide an identification key for the species of the genus.

A revision of the genus Coryssiphus Simon, 1903, with its transfer to Systariinae (Araneae: Miturgidae).

The genus Coryssiphus Simon, 1903 is redescribed and found to be composed of two species. Coryssiphus unicolor Simon, 1903 is synonymised with C. cinerascens Simon, 1903, being the female of that species. Coryssiphus praeustus Simon, 1903 and C. cinerascens are redescribed and the genus is transferred from Liocranidae to Miturgidae: Systariinae based on a number of somatic and genitalic characters. The peculiar presence of Coryssiphus in Africa is briefly discussed.

Revision of Neotropical wolf spider genus Arctosa C.L. Koch, 1847 (Araneae: Lycosidae), with description of seven new species.

The genus Arctosa C.L. Koch is redescribed and diagnosed. Seven new species are described, four of them based on both sexes (A. conflicta sp. nov., A. costenola sp. nov., A. jibarosa sp. nov. and A. villa sp. nov.), two only on females (A. ayaymama sp. nov. and A. mineira sp. nov.), and one only on the male (A. pacaya sp. nov.). We also propose the transference of Arctosa humicola (Bertkau, 1880) and Arctosa fusca (Keyserling, 1877) to Trochosa C.L. Koch, 1847, and the new synonymy of Arctosa inconspicua (Bryant, 1948) with Trochosa humicola (Bertkau, 1880) comb. nov. Besides, Arctosa andina (Chamberlin, 1916) and Arctosa pugil (Bertkau, 1880) are transferred to Hogna Simon, 1885, and Arctosa aussereri (Keyserling, 1877) to Prolycosides Mello-Leito, 1942. Additionally, eight lycosid species are synonymized with Prolycosides aussereri: Schizocosa proletaria (Tullgren, 1905); Arctosa workmani (Strand, 1909); Hogna planithoracis (Mello-Leito, 1938); Hogna variolosa (Mello-Leito, 1941); Megarctosa melanostoma (Mello-Leito, 1941); Hippasosa huachoi (Mello-Leito, 1942); Pirata abalosi (Mello-Leito, 1942); and Pirata soukupi (Mello-Leito, 1942). We also transfer Trochosa tenebrosa Keyserling, 1877 to Arctosa. The males of Arctosa tenebrosa (Keyserling, 1877) comb. nov. and Trochosa humicola (Bertkau, 1880) comb. nov. are described for the first time.

Taxonomic revision of the jumping spider genus Tullgrenella Mello-Leito, 1941 (Araneae: Salticidae: Freyina).

This paper presents a taxonomic revision of the genus Tullgrenella Mello-Leito, 1941. Four new species are described: Tullgrenella aisenbergae Marta, sp. nov. (Brazil) (), T. legalissima Marta & Hagopin sp. nov. (Uruguay) (), T. galianoae Marta, sp. nov. (Brazil) () and T. sciosciae Marta & Bustamante sp. nov. (Brazil) (). The males of T. corrugata Galiano, 1981 and T. peniaflorensis Galiano, 1970, and the female of T. selenita Galiano, 1970 are described for the first time. An updated diagnosis for the genus is provided based on the detailed comparative morphological studies. In addition, we present a proposal and discussion about the species groups of Tullgrenella based on the putative synapomorphies as well as the updated distribution of the genus in South America.

An update on the huntsman spider genus Uaiuara Rheims, 2013 (Araneae, Sparassidae, Sparianthinae).

The genus Uaiuara Rheims is revisited. A new species is described, based on females from Iquitos, Peru and new distribution records for Uaiuara amazonica (Simon, 1880) and U. quyguaba Rheims, 2013 are provided. In addition, an identification key and updated distribution maps are provided for all species.

Dai gen. nov., a new genus of Gnaphosinae (Araneae: Gnaphosidae) from Yunnan, China, with descriptions of two new species.

A new ground spider genus Dai gen. nov. of subfamily Gnaphosinae is described with the type species D. jinchii sp. nov. () and D. jijiao sp. nov. () from Yunnan Province, China.

Thriving in dry conditions: on the Neotropical spider genus Galapa (Araneae: Pholcidae).

The genus Galapa Huber, 2000 includes tiny spiders (body length <1.5 mm) restricted to semi-arid habitats. It has long been thought to be endemic to the Galapagos Islands until G. spiniphila Huber, 2020 was described from the Venezuelan Paraguan Peninsula. Here, we support this generic assignment with molecular (CO1) data and describe two new species from Colombia (G. gabito Huber sp. n.) and Costa Rica (G. murphyi Huber sp. n.), showing that the genus is actually widely distributed. Distribution modelling identifies several high suitability areas for Galapa, all of which are poorly sampled with respect to Pholcidae (ranging from Nicaragua to northern Peru and Guiana). Our results suggest a strong sampling bias against spiders restricted to dry tropical regions and habitats.

Notes on Chisosa (Araneae, Pholcidae), with the description of a new species from Mexico.

The genus Chisosa Huber, 2000 previously included only three species of small to tiny North American and Caribbean spiders that are rare in collections and poorly studied. Originally placed in the subfamily Ninetinae, Chisosa is currently considered a representative of Arteminae, close to the North American genus Physocyclus Simon, 1893. This placement has been suggested by molecular data, and it affects the interpretation of morphological characters that were originally thought to support the monophyly of Chisosa: they are shared with Physocyclus and thus plesiomorphic for Chisosa. Here we describe a new species from Mexico, C. calapa sp. nov., and restudy in detail the morphology (incl. ultrastructure) of the type species C. diluta (Gertsch & Mulaik, 1940) and of C. caquetio Huber, 2019, based on newly collected material. We document further similarities with Physocyclus but find only weak morphological support for the monophyly of Chisosa (body size reduction and short legs). In addition, we document surprisingly large genetic distances among C. caquetio specimens from Curaao (>14% CO1 K2P distances), possibly indicating species limits. Finally, we propose that the Dominican amber genus Serratochorus Wunderlich, 1988, based on a single male specimen, is also phylogenetically close to Chisosa and should be included in future studies on these enigmatic spiders.

On the taxonomy of the Zodarion thoni species-group (Araneae, Zodariidae), with description of a new species with an unmodified embolus.

A new species of Zodarion, belonging to Z. thoni-group, is described from the Taurus Mountains, Turkey. By now, it is the only known species with an unmodified embolic tip in this group. The syntypes of Z. rhodiense Caporiacco, 1948, Z. nigrifemur Caporiacco, 1948, and the holotype of Z. granulatum Kulczyski, 1908 are revised. Zodarion rhodiense sp. reval. is revalidated and Z. nigrifemur syn. n. is assigned as its junior synonym.

On the boundary of the jumping spider genus Rhyphelia Simon, 1902 (Araneae: Salticidae: Euophryini), with description of ten new species.

In this paper we synonymize Soesilarishius Makhan, 2007 with Rhyphelia Simon, 1902. We give new illustrations of the male holotype of the type species Rhyphelia variegata Simon, 1902 for comparisons, and describe the closely related Rhyphelia brevistylus sp. nov. () from the state of Bahia, Brazil. Additionally, we describe nine other new species from different Brazilian regions: Rhyphelia barbado sp. nov. () from Bahia, Rhyphelia bilineata sp. nov. () from Minas Gerais, Rhyphelia cotriguacuensis sp. nov. () from Mato Grosso, Rhyphelia gallina sp. nov. () from Acre, Rhyphelia novalima sp. nov. () and Rhyphelia okay sp. nov. () from Minas Gerais, Rhyphelia otti sp. nov. () from Rio Grande do Sul, Rhyphelia planaria sp. nov. () from So Paulo, and Rhyphelia tocantinensis sp. nov. () from Tocantins.