Thermal ecology of Plesiopelma longisternale: novel insights and comparative analysis with a sympatric species

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  Thermal ecology of Plesiopelma longisternale: novel insights and comparative analysis with a sympatric species Abstract Understanding thermal responses in ectotherms is key to assessing vulnerability to climate change. Tarantulas (Theraphosidae) are informative models due to their sedentary lifestyle, long life cycles, and reliance on specific microhabitats. We present the first integrative assessment of the thermal ecology of Plesiopelma longisternale , a widespread Argentine species, combining experimentally derived thermal limits and thermal preferences with species distribution models, and compare its thermal profile with the sympatric Grammostola vachoni to explore patterns of thermal niche differentiation. Plesiopelma longisternale showed a minimum thermal limit near 4 °C, a maximum near 44 °C, a thermal optimum of 29.5 °C, a narrow thermal performance breadth, and a preferred temperature of approximately 32 °C. Models integrating climatic and thermal parameters predicted...

Under pressure: mapping the distribution of medically important Tityus Koch, 1836 (Buthidae) scorpions in Brazil using a century of Instituto Butantan records

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Under pressure: mapping the distribution of medically important Tityus Koch, 1836 (Buthidae) scorpions in Brazil using a century of Instituto Butantan records

Abstract

The buthid scorpions Tityus serrulatus, T. bahiensis, T. obscurus, and T. stigmurus are considered the most medically significant species in Brazil. Since the early 1900s, their identification and distribution have been central to the zoological collections of the Instituto Butantan (IBSP). In this study, we map the distribution of these species using 7241 presence-only records from the IBSP collected since 1905. Species richness and record density were analyzed using 2° grid cells, and spatial overlap was assessed via a Jaccard similarity index. Based on our dataset of species records, Tityus serrulatus showed the broadest distribution, present in nearly all Brazilian states except Rio Grande do Norte, Maranhão, Amapá, and Roraima, with the highest densities in São Paulo and northern Paraná. Tityus bahiensis had the second widest range, with dense occurrences largely restricted to São Paulo. Mesoregions in São Paulo (Macrometropolitana Paulista, Metropolitana de São Paulo) and Paraná (Noroeste, Norte-Central) have the highest probability of encountering medically significant Tityus species, considering the density of records obtained from the IBSP collection. Also, we emphasize the importance of implementing long-term monitoring programs and conducting new species surveys, especially in high-risk areas and current species distribution gaps.
Goldoni, P. A., Brescovit, A. D., Castro-Souza, R. A., Cequinel, J., Marques-da-Silva, E., & Iniesta, L. F. (2025). Under pressure: Mapping the distribution of medically important Tityus Koch, 1836 (Buthidae) scorpions in Brazil using a century of Instituto Butantan records. Toxicon, 268, 108627. https://doi.org/10.1016/j.toxicon.2025.108627