Notes on the identity of the orb-weaver spider Araneus nox Simon, 1877 (Araneae: Araneidae) from India, including its transfer to Eriovixia Archer, 1951 and one new synonymy

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  Notes on the identity of the orb-weaver spider Araneus nox Simon, 1877 (Araneae: Araneidae) from India, including its transfer to Eriovixia Archer, 1951 and one new synonymy The orb-weaver genus Araneus Clerck, 1757 has historically served as a heterogeneous assemblage for numerous araneid spiders lacking clear generic placement, and several Asian species formerly assigned to Araneus have subsequently been transferred to more narrowly defined genera. One species that still needs further investigation on its true identity is Araneus nox (Simon, 1877), originally described as Epeira nox Simon, 1877 from Basilan Island, Philippines, and later transferred to Araneus by Simon (1905). In the same year as the description of Epeira nox, Thorell (1877) described Epeira pilula from the Moluccas (Indonesia), which was subsequently synonymised under Epeira nox by Simon (1880). Despite its broad Oriental distribution, the taxonomic identity and generic placement of A. nox have remained insuff...

Intraspecific body size variation in spiders is mediated by multiple stressors in an urban area

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Intraspecific body size variation in spiders is mediated by multiple stressors in an urban area

Abstract

The urbanization process causes multiple environmental changes, encompassing habitat fragmentation, increasing temperature and variation in food availability, imposing significant challenges to living organisms. The synergistic effect of these stressors may have repercussions on species traits, especially on those strictly related to species survival, such as body size. We investigated the intraspecific body size variation along an urbanization gradient, considering multiple environmental facets in the city of Torino (NW-Italy), in three spider species: the sedentary cobweb spider Asagena italica (Araneae Theridiidae), the cursorial wolf spider Pardosa proxima (Araneae, Lycosidae) and the ballooning money spider Erigone autumnalis (Araneae, Linyphiidae). Our findings revealed distinct patterns among the examined species, probably related to the species’ intrinsic ability to deal with environmental changes occurring in the urban environment. The sedentary cobweb spider responded at the local scale, exhibiting body size reduction at increasing temperature due to increased metabolic costs, and body size increase at both increasing vegetation cover and species richness of the spider community, probably reflecting variation in food availability. Conversely, the cursorial wolf spider displayed a significant body size increase at decreasing average community body size, as a possible reduction of intraguild predation and competition for food. The highly dispersive money spider responded at landscape scale showing smaller body sizes at increasing habitat fragmentation, possibly due to the enhanced dispersal ability of smaller individuals. As spiders are predators exerting a significant top-down control on invertebrate communities, these complex findings underscore the need for further investigation into how intraspecific body size variation of spiders along urbanization gradients may affect food webs. Importantly, our results highlight that species do not respond uniformly to urban-driven environmental pressures; rather, their responses are strongly mediated by species-specific ecological traits such as mobility, dispersal strategy, and foraging behavior. Understanding these trait-based responses is crucial for predicting the broader ecological consequences of urbanization.

Piano, E., Piquet, A. & Isaia, M. Intraspecific body size variation in spiders is mediated by multiple stressors in an urban area. Urban Ecosyst 28, 165 (2025). https://doi.org/10.1007/s11252-025-01776-6