Hidden diversity in plain sight: four new species of Nemesia (Araneae: Mygalomorphae) from the Córdoba Province of Spain

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  Hidden diversity in plain sight: four new species of Nemesia (Araneae: Mygalomorphae) from the Córdoba Province of Spain Abstract A taxonomic revision of the species of Nemesia Audouin, 1826, distributed in the vicinity of Córdoba City, southern Spain, is presented. Four new species are described: Nemesia morana sp. nov. (female), N. kodama sp. nov. (male and female), N. rosae sp. nov. (male and female), and N. tamajoni sp. nov. (male and female). These species are distinguished by distinct morphological characters, including the shape of the spermathecae, palpal bulbs, and spinnerets, as well as by burrow architecture. Fieldwork was conducted across two of the three major habitat types in the region—the humid, forested mountains of Sierra Morena and the croplands and riparian forests of the Guadalquivir Valley—while the third, the “campiña”, which is mainly composed of agricultural landscapes, remains poorly explored. Sampling methods included pitfall trapping and the direct e...

Acetylcholine-binding protein 5 regulates extracellular apoptosis in the wolf spider as a sacrificial ROS scavenger

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Acetylcholine-binding protein 5 regulates extracellular apoptosis in the wolf spider as a sacrificial ROS scavenger

Abstract

Apoptosis is regulated by a conserved gene network across species for maintaining homeostasis and stress response. While intracellular apoptotic pathways are well characterized, the extracellular mechanisms governing apoptosis remain largely unexplored, probably due to divergence in species-specific gene sets involved in extracellular regulation. Here, we uncover a novel extracellular apoptotic mechanism mediated by acetylcholine-binding protein 5 (AChBP5) in the wolf spider Pardosa pseudoannulata. AChBP5 is highly expressed in the spider fat-body (midgut diverticula), while other four AChBP genes are abundantly expressed in the tissue brain. Among five AChBP genes, only AChBP5 exhibited broad transcriptional induction upon exposure to various insecticides, including neonicotinoids and other classes. AChBP5 expression was also upregulated by reactive oxygen species (ROS) including H2O2, key triggers of apoptosis. Functional assays demonstrated that, in cultured cells, AChBP5 acted as an extracellular sacrifice buffer against oxidative stress to maintain cell viability, becoming progressively inactivated by ROS in a concentration-dependent manner. RNAi-mediated silencing of AChBP5 significantly increased spider susceptibility to both-induced and direct oxidative stress, underscoring its critical protective function. Collectively, these findings support a model in which lineage-specific genes, AChBP5 may contribute to extracellular modulation of apoptosis and provide a mechanism by which spiders could respond to chemical stressors.
Zhang, H., Wang, J., Tan, Y., Zhang, J., Shi, C., Hu, T., Wang, K., & Liu, Z. (2026). Acetylcholine-binding protein 5 regulates extracellular apoptosis in the wolf spider as a sacrificial ROS scavenger. Pesticide Biochemistry and Physiology, 219, 107001. https://doi.org/10.1016/j.pestbp.2026.107001