New locality records and future habitat suitability of Sassanidotus gracilis (Birula, 1900) (Scorpiones: Buthidae) in the Iran–Afghanistan–Pakistan arid belt

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  New locality records and future habitat suitability of Sassanidotus gracilis (Birula, 1900) (Scorpiones: Buthidae) in the Iran–Afghanistan–Pakistan arid belt Abstract This study reports new locality records from Iran and a climate-based habitat suitability assessment for Sassanidotus gracilis (Birula, 1900) (Scorpiones: Buthidae) in the Iran–Afghanistan–Pakistan arid belt. We document new specimens from Sistan and Baluchestan Province, Iran, with an updated distribution map and illustrations, and we model the species' potential distribution across south-eastern Iran and adjacent parts of Afghanistan and Pakistan. Habitat suitability was associated mainly with precipitation seasonality, precipitation of the wettest month, precipitation of the driest month, and slope. In an arid setting these rainfall variables are unlikely to indicate a need for moist habitat; they more plausibly track seasonal productivity and the terrain features that provide shelter. Present-day suitable areas...

A comparison of adhesive performance among six cursorial spider species

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A comparison of adhesive performance among six cursorial spider species

Abstract

The ability to adhere to surfaces is particularly relevant for cursorial predatory arthropods like hunting spiders, which often traverse relatively complex environments characterized by large variation in substrate properties. Here, we evaluated the adhesive performance of six hunting spider species that are common in eastern temperate North America and lack specialized tarsi for climbing smooth or inclined surfaces [Lycosidae: Pardosa lapidicina Emerton, 1885 and Rabidosa rabida (Walckenaer, 1837); Oxyopidae: Oxyopes salticus Hentz, 1845; Pisauridae: Pisaurina mira (Walckenaer, 1837); Dolomedidae: Dolomedes triton (Walckenaer, 1837), and Dolomedes scriptus Hentz, 1845]. We tested adhesion performance as shear load resistance (g) on a glass plate, and as the angle of failure (°) when the plate was gradually inclined relative to horizontal. Average angle of failure and shear resistance differed among species, and shear resistance increased interspecifically with mass. Rabidosa rabida had the highest average angle of failure and shear resistance. Adhesive performance was not related to tarsal index (tarsal contact area per unit mass) for most species, but shear resistance declined with increasing tarsal index in Pardosa lapidicina and Rabidosa rabida. Collectively, these results suggest that, for spiders lacking specialized adhesive tarsi, adhesive performance is largely a function of basic physics, i.e., the interaction of mass and contact area with a substrate.

E. J. Schleff, M. W. Chmielewski, A. Y. Stark, S. P. Yanoviak "A comparison of adhesive performance among six cursorial spider species," The Journal of Arachnology, 53(3), 203-207, (8 June 2026) https://doi.org/10.1636/JoA-S-24-046