The present study contains information about a small number of spiders collected between 2018 and 2023. The spiders were determined to species level and partially assisted by genetic barcoding of the COI gene. Among the resulting 33 species, 23 species and three genera, are recorded from Georgia for the first time, of which 11 are new records for the entire Caucasus. Of the 26 barcoded specimens representing 18 species, six species (Agroeca maculataL. Koch, 1879;Aituaria eriashvilii(Marusik, 1987);Evippa sjostedtiSchenkel, 1936; Lathys cf. lehtineni Kovblyuk, Kastrygina & Omelko, 2014;Zelotes segrex(Simon, 1878);Lathys lehtineniKovblyuk, Kastrygina & Omelko, 2014;Maculoncus obscurusTanasevitch, Ponomarev & Chumachenko, 2016) are barcoded for the first time. In addition, 12 new regional records for 10 species are provided. The collecting information for each record is provided in detail, together with a discussion of the barcoding results and remarks, supported by 48 diagnostic drawings of 22 first-recorded species. A potential synonymy ofPelecopsis odontophora(Kulczyński, 1895) withP. parallela(Wider, 1834) andBassaniodes loeffleri(Roewer, 1955) withB. pseudorectilineus(Wunderlich, 1995) is discussed.

The Arctic is projected to be severely impacted by changes in temperature and precipitation. Species react to these changes by shifts in ranges, phenology, and body size. In ectotherms, the patterns of body size clines and their underlying mechanisms are often hard to untangle. Mountains provide a space-for-time substitute to study these shifts along multiple spatial gradients. As such, mobility and dispersal capacity might conceal reactions with elevation. We test this influence on body size clines by comparing two common arthropods of the alpine tundra. We find that high mobility in the lycosid spider Pardosa palustris blurs elevational effects. Partially low mobility at least during development makes the carabid beetle Amara alpina more susceptible to elevational effects. Specific life-history mechanisms, such as brood care in lycosid spiders and holometabolic development in carabid beetles, are the possible cause.

Large‐scale barcoding projects help to aggregate information on genetic variability of multiple species throughout their ranges. Comparing DNA sequences of both non‐conspecific and conspecific individuals from distant parts of their ranges helps to compare level of genetic isolation‐by‐distance patterns in different species and adaptive types. We compared mitochondrial CO1 gene sequences of 223 spiders from Georgia (Caucasus), representing 124 species and eight families, with 3097 homological sequences from spiders mostly from Europe, but also from other parts of the World. In most families, a significant isolation‐by distance pattern was observed on family level. On species level, a significant isolation‐by‐distance was observed in 40 species, although this low proportion is most likely related to a lack of data. Simultaneously, remarkable differences in spatial structure were shown for different species. Although the majority of the studied species have a broad western Palearctic range, web‐building spiders from families Araneidae, Theridiidae, and Linyphiidae are less isolated spatially than flower spiders (Thomisidae), jumping spiders (Salticidae), wolf spiders (Lycosidae), sac spiders (Clubionidae), and ground spiders (Gnaphosidae). This pattern is related with more common ballooning in web building than in actively hunting spiders, which commonly remain isolated since preglacial time. Ground spiders build the most isolated populations in the Caucasus.

Differentiations in reproductive traits along climatic gradients can be substantial for a species to spread along a wide spatial range. We compared the reproductive effort allocated to first egg sacs of five species of the genus Pardosa: P. palustris (Linnaeus 1758), P. amentata (Clerck 1757), P. lugubris (Walckenaer 1802), P. hyperborea (Thorell 1872), and P. riparia (C. L. Koch 1833) along three elevation transects in central Norway. We tested whether population differences are consistent among the three transects, respectively along the elevational gradient. We assumed that the harsh environments of alpine areas would lead to adaptations in reproductive traits resulting in larger eggs but smaller clutches at higher elevations. The results show that female size and egg number were positively correlated among all species. However, no clear elevation-related trend was found. Other traits did not change consistently between species and along the elevational gradient. We assume that local microclim...