Invertebrates, including spiders, are ubiquitous components of terrestrial ecosystems and are sensitive to rapid habitat fluctuations. Assessing populations of invertebrates can be a useful bioindicator of environmental change. In the ecological sector, such data is most often gathered with the use of pitfall traps or vacuum sampling; each technique having its own benefits and ethical considerations. In a modern world, where many invertebrate species are shown to be in decline, the ethical scrutiny and refinement of sampling methods is more pertinent than ever. This study evaluated spider populations across grassland locations in Cornwall, UK, using pitfall trapping and vacuum sampling, in order to assess which technique was the most effective in the collection of spiders. Vacuum sampling collected a significantly higher abundance and species richness of spiders than pitfall trapping. In order to assess the ethical implications of each technique, trapped bycatch was evaluated to order level. Vacuum sampling achieved a significantly higher abundance of bycatch, though no significant difference in the bycatch richness at order level could be detected. The study finds that vacuum sampling far outperforms pitfall trapping in measuring spider abundance and species richness and collects a greater number of non-target taxa should this be of interest to the operator. We suggest that the underlying ethical advantage of vacuum sampling is that it gives the operator control of which specimens are to be euthanized. This allows non-target taxa to be released back to the environment, whereas pitfall trapping does not. The results provide a strong argument for the use of vacuum sampling in the place of pitfall trapping in the collection of spiders, however further work is needed to improve repeatability and understand species collection biases.

Two species from the family Orsolobidae and one from Mecysmaucheniidae are reported from the Falkland Islands, with local distributions and descriptions. A new species of Orsolobidae, Osornolobus otariorum sp. nov., is described. The description and diagnosis of species in Osornolobus is discussed and the association between the three species and vegetation communities is analysed.

Tarantulas (Theraphosidae Thorell, 1869) are typically large-bodied spiders that are frequently kept in captivity as pets in private collections, exhibits in public collections (e.g. zoos), and study animals in research collections. Nevertheless, much of the information on captive maintenance of tarantulas is based on trial-and-error approaches, such that folklore husbandry rather than evidence-based husbandry is typical. In addition to the spider's welfare, some species also impose safety considerations for keepers due to aggressive defensive behaviours that include biting, particularly many Old World tarantulas. The orange baboon tarantula (Pterinochilus murinus Pocock, 1897) is a very commonly kept African species of harpactirine tarantula which is successfully maintained in diverse enclosure designs including arboreal, terrestrial, and fossorial setups. Here, we investigated experimentally how different captive enclosure designs influence defensive behaviour in P. murinus, and whether it is possible to improve both tarantula welfare and keeper safety via husbandry methods. We show that spiders were quicker to flee when kept in arboreal enclosures, but more quickly resorted to aggressive defensive behaviours (rearing and biting) when kept in terrestrial enclosures. Keeping this species in fossorial enclosure designs resulted in a relatively low propensity to flee, rear, and bite, suggesting that this design might be optimal for captive P. murinus welfare and keeper safety.

A new species of velvet spider (Araneae: Eresidae), Eresus urus sp. n., is described based on specimens of both sexes collected in Thi-Qar Province, southern Iraq. The description, diagnosis, digital photographs and a distribution map are provided.

The species names Clubiona venusta Paik, 1985, Kaitawa insulare (Marples, 1956), and Lycosa maculata Butt, Anwar & Tahir, 2006 are all primary homonyms without existing junior synonyms which could be revalidated to resolve the homonymies. Therefore, new replacement names are described for all three species.

Prey-predator interaction is mediated by prey defences and prey-predator size differences, but also by the characteristics of the predator, such as speed, subduing mechanisms, and defensive mechanisms against prey retaliation. Ricinuleids are particularly slow-moving arachnids, without venom but with a heavy armour covering the body. We looked at how such poorly known and unusual arachnids would deal with prey of different sizes, armours, and defensive mechanisms. We offered ants, millipedes, worms, and termites in the laboratory. The acceptance rate of ants was not different from other prey species, including unprotected termites; only 35% of the millipedes were accepted and, regarding prey size, larger worms tended to be less accepted than smaller worms (but the trend was not significant). The armour of ricinuleids likely protects them from ant stings, while well-armoured millipedes had only legs removed but were not killed, and the lack of venom may explain why smaller worms are preferred. The unusual prey-capture mechanism of ricinuleids provides a model to test how different predatory strategies interact with prey defences.

Two new eastern Asian species of Raveniola Zonstein, 1987, R. reuteri sp. nov. (♂), and R. yalong sp. nov. (♂♀), are diagnosed and described, based on specimens from Sichuan, China. The two new species are clearly distinguishable from all known Chinese congeners in details of colouration, different somatic structures (including shape and arrangement of the spinnerets), the unique conformation of the male palp and, in the case of R. yalong sp. nov., also in spermathecae. The characters that have taxonomic significance for dividing the known Eastern Asian Raveniola spp. into species groups are briefly considered, and the number and species composition of these possible groups are preliminarily discussed.

Global knowledge of spiders is hindered by information deficits that limit the scientific community′s understanding of their species diversity, ecology, distribution, and behaviour. This issue is particularly pronounced for species inhabiting less-studied environments, such as subterranean ecosystems. The number of records of alien species in subterranean ecosystems has risen in recent decades; however, the scientific literature on this topic is still mostly absent or primarily anecdotal. Howaia mogera (Yaginuma, 1972) is a spider species native to Asia associated with subterranean ecosystems, that currently shows a continuous expansion outside its native range. Here, we review the available scientific literature on records for Howaia mogera, trying to identify spatiotemporal patterns in research devoted to this species out of its native area. Secondly, we describe the first record of this species and genus in the Iberian Peninsula. The observations described took place in a subterranean archaeological area located under the town of Carmona, Seville, southwest Spain. The limited knowledge about the expansion pattern of the species in Spain and other countries poses a significant challenge for researchers and conservationists in the current context of global change, where biological invasions are among the most impactful drivers. The discrete behaviour of these species and the less-studied habitats they inhabit likely constrain a better understanding of their expansion elsewhere. Adequate monitoring of this species and cooperation between experts in subterranean ecosystems are essential for a more complete understanding of the processes that explain where and how the species is thriving outside its native area, the potential impacts on native invertebrates co-occurring in subterranean ecosystems, and the pathways used for its expansion.

Sandy beaches are dynamic and challenging ecosystems. The structure of the resident macrofaunal communities primarily arises from independent responses of individual species to physical environmental variables. For supralittoral species, the Habitat Safety Hypothesis (HSH) predicts an increase in population attributes from dissipative beaches (fine sand, gentle slope) to reflective beaches (coarse sand, steep slope). Salinity is considered an additional environmental stressor, particularly in transitional environments characterized by strong gradients. The simultaneous effects of morphodynamics and salinity on arachnids have not been tested before. We examined the effect of morphodynamics and salinity on the abundance and body traits of the sand-dwelling spider Allocosa senex. We conducted concurrent samplings of adult individuals in three pairs of beaches with contrasting morphodynamics, representing three distinct salinity regimes along the Uruguayan coast. Our findings aligned with the predictions of the HSH. Males were more abundant on reflective beaches, and in those beaches with lower salinities. Both sexes exhibited larger size, weight, and body condition in reflective beaches and also a decrease from inner-estuarine to oceanic beaches. Spiderling sizes also followed the same trend. These results emphasize the importance of considering both morphodynamics and salinity as critical factors shaping population attributes in sandy-beach arthropods.

A new species of the genus Actinopus Perty, 1833, belonging to the cucutaensis group, is described from Colombia. The new species, Actinopus embera sp. nov., was discovered in the departments of Córdoba, Bolivar, Sucre, and Atlántico, located along Colombia's Caribbean coast, and is readily distinguished by genital organ morphology. Additionally, we report a possible case of phoresis between a mite of the family Acaridae Latreille, 1802 and a female and three immature specimens of Actinopus embera sp. nov. from one of the type localities (Tiquisio, Bolívar). Finally, based on prior evidence and the events leading to the destruction of the type material, we propose Actinopus cucutaensis Mello-Leitão, 1941 as a species inquirenda.

A new species of trapdoor spider, Conothele mussoorie sp. nov., is described from the foothills of the Himalayas, marking the first record of this genus from the northernmost part of India. Detailed descriptions and illustrations of the female are provided.

Ten new species of the orb-weaving spider genus Alpaida O. Pickard-Cambridge, 1889 are described from Espírito Santo, Minas Gerais, and Rio de Janeiro states, Brazil: Alpaida batman sp. nov., A. capixaba sp. nov., A. linhares sp. nov., and A. sooretama sp. nov. come from Sooretama and Linhares (Espírito Santo state), while A. jequitiba sp. nov. from Parque Estadual dos Três Picos (Cachoeiras de Macacu), A. coati sp. nov. and A. serrana sp. nov., both from Parque Nacional da Serra dos Órgãos (Teresópolis), A. regua sp. nov. from Reserva Ecológica de Guapiaçu (REGUA, Cachoeiras de Macacu), and A. taquara from Parque Estadual da Pedra Branca (PEPB) and Ilha do Fundão (both Rio de Janeiro city), are all from Rio de Janeiro state. Alpaida pretiosa sp. nov. is found in all three states: Sooretama and Linhares (Espírito Santo state), Reserva União (Cachoeiras de Macacu, Rio de Janeiro state), and in Viçosa (Minas Gerais state). Additionally, we correct the mismatching of one of our males with females of another species from the literature, and expand the distribution of A. mendensis Baptista, Castanheira & Prado, 2018.

The genus Borneoridion Deeleman & Wunderlich, 2011, and its type species B. spinifer Deeleman & Wunderlich, 2011, are redescribed. Five new species from North Borneo (Malaysia): B. franki sp. nov., B. maximum sp. nov., B. nikkae sp. nov., B. paradoxum sp. nov., and B. pumilum sp. nov. are described.

We redescribe and illustrate the male of Thrixopelma ockerti Schmidt, 1994 presenting the first analysis of keels on the palpal bulb. Additionally, a new species Thrixopelma kimraykawsaki sp. nov. is described and illustrated from Peru, along with data on its natural history. This new species is known from Abancay, department of Apurimac, can be distinguished from other species by having a palpal bulb bearing a tegular heel, a spatulate embolus with well developed prolateral keels, and the presence of a retrolateral keel. Females are differentiated from other known Thrixopelma species by the shape of the spermathecae and the number of labial cuspules.

Closely related spiders often exhibit similarities in traits such as development, morphology and behaviour. Here, we compared development, adult body size and reproduction in two closely related spiders, the rabbit hutch spider, Steatoda bipunctata, and that triangulate cobweb spider, S. triangulosa (Araneae: Theridiidae). Both species are native to Eurasia and synanthropic, often co-occurring in the vicinity of human habitation. Development time from neonate to adult was similar in both species. Both species exhibited sexual-size dimorphism, where females were larger than males. Although females were also approximately the same body size, male S. bipunctata were significantly larger than male S. triangulosa. Mean brood sizes were also larger in S. bipunctata than S. triangulosa over the first seven egg sacs. Our results show that some traits in these two species overlap considerably, but with some differences such as in the degree of sexual size dimorphism and male morphology.

Two new species of the wolf spider genus Trabea (Araneae: Lycosidae) from South Africa, T. hirsuta sp. n. and T. obscura sp. n., are described for the first time. Additionally, the unknown female of T. natalensis Russell-Smith, 1982 and unknown male of T. rubriceps Lawrence, 1952 are described and illustrated. Additional information on the appearance of the male pedipalp of T. natalensis is given, together with new records for this species. A key to all species of Trabea from South Africa is provided.

New faunistic data on spiders of Azerbaijan are presented. Thirteen species are recorded from this country for the first time: Araniella villanii Zamani, Marusik & Šestáková, 2020 (Araneidae), Cesonia aspida Chatzaki, 2002, Civizelotes solstitialis (Levy, 1998), Cryptodrassus hungaricus (Balogh, 1935), Gnaphosa cumensis Ponomarev, 1981, G. ukrainica Ovtsharenko, Platnick & Song, 1992, Micaria atropatene Zamani & Marusik, 2021, Trichothyse senilis (O. Pickard-Cambridge, 1872), Turkozelotes attavirus Chatzaki, 2019 (all Gnaphosidae), Trichonephila clavata (L. Koch, 1878) (Nephilidae), Neottiura uncinata (Lucas, 1846), Paidiscura pallens (Blackwall, 1834) (both Theridiidae), and Xysticus edax (O. Pickard-Cambridge, 1872) (Thomisidae); the genera Cesonia Simon, 1893 and Trichonephila Dahl, 1911 are newly recorded from the Caucasus. The record of T. clavata represents the first documented introduction of this family in the Western Palaearctic.

A new species belonging to the genus Decaphora Franganillo, 1931, Decaphora tocatl spec. nov., is described from Jalisco, Mexico. The new species expands the known distribution of the genus and constitutes the westernmost record. Including the species described herein, three of the six currently known Decaphora species occur in Mexico.

Cyrtocarenum erlik sp. nov. is described based on two males collected from the Adana Province of Türkiye. The new species resembles the known species of the genus C. cunicularium, but differs from it in the tip morphology of its embolus. In addition to photographs of the new species, new distributional information about C. cunicularium, the known species of the genus from Türkiye, is also provided.

Habrocestum mookambikaense Sudhin, Sen, Caleb & Hegde, 2022 was originally described based on the female holotype from Karnataka. Here, a description of the male is provided for the first time, along with a female redescription based on fresh collections from Northern Western Ghats (Satara and Sindhudurg district, Maharashtra). The new locality lies about ∼430 km northward from its previously known record indicating that the species is more widely distributed than previously thought. Detailed illustrations of the species, including digital color images and a map showing the distribution of all Indian Habrocestum species are provided.

Ballooning is an aerial dispersal mechanism commonly used by spiders, primarily observed in small adults and juveniles of some species. Spiders can navigate through the air by deploying silk threads, covering varying distances. During the last decades, there has been increased attention to spider aerial dispersal studies, and different use of terminologies associated with ballooning. We surveyed research literature on aerial dispersal studies from 1966 up to 2024 to assess the variances in the number of studies on these topics and analyse the use of pre-ballooning and ballooning terms. We found a total of 216 research articles containing pre-ballooning behaviour terms such as ‘tip-toe’/ ‘tiptoe’/ ‘tiptoeing’ (n = 17), ‘drop on dragline’/ ‘dropping on dragline’ (n = 15) and terms such as ‘ballooning’ (n = 146), ‘rappel/rappelling/bridging’ (n = 74), ‘aerial dispersal’ (n = 104), ″aerial dispersion″ (n = 15), or ″aeronautic behaviour″ (n = 7). These studies were distributed into 192 research articles, 9 reviews, 3 book chapters, and 7 into other categories. Spider families with the most reports of ballooning were Linyphiidae, Theridiidae, and Araneidae. Tiptoeing is considered an indicator of ballooning behaviour; however, according to our results, there are some differences in the use of the concepts ‘drop on dragline/dropping on a dragline’ and ‘rappelling’ as pre-ballooning, ballooning or non-ballooning behaviours. We discuss the importance of fine-scaled behavioural descriptions of ballooning and the need to homogenize the criteria to smooth the way for future studies of this phenomenon in spiders.