The almost unknown scorpion fauna (Arachnida: Scorpiones) of El Salvador, Central America

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  The almost unknown scorpion fauna (Arachnida: Scorpiones) of El Salvador, Central America Abstract (EN) The scorpions from Republic of El Salvador, Central America, have been poorly studied. The present work confirms the presence of at least six species in this country: Didymocentrus krausi Francke, 1978 (Diplocentridae), and five species belonging to the genus Centruroides Marx, 1899 (Buthidae), including the first records for Centruroides koesteri Kraepelin, 1911, Centruroides tapachulaensis Hoffmann, 1932, and an unidentified species of the thorellii species-group. Centruroides tapachulaensis had been confused with Centruroides edwardsii (Gervais, 1843), Centruroides gracilis (Latreille, 1804) and Centruroides margaritatus (Gervais, 1841). None of five nominal identified species are Salvadoran endemism. A taxonomical key is included for the identification of these six scorpion species. Most of the new records were made based on available data on the iNaturalist citizen science...

Riparian spiders make pyriform silk attachment discs that stick better when wet

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Riparian spiders make pyriform silk attachment discs that stick better when wet

Adhesion in wet conditions presents significant challenges due to the disruptive effects of water on interfacial bonding, spreading, and curing. Many organisms have evolved adhesives that adhere strongly in damp or submerged environments. However, the pyriform silk attachment discs of the western black widow spider lose ∼8x of their adhesive strength when wet. Here, we test the hypothesis that riparian species of spiders have evolved attachment discs that are resistant to water's adverse effects on adhesion. We compare adhesion of attachment discs from three terrestrial, relatively dry habitats to three riparian spider species when discs are loaded under both dry and wet conditions. Failure modes shifted from dragline breakage in dry conditions to adhesive failure in wet conditions across all species, highlighting water's impact on interfacial bonding. However, riparian species attachment discs maintained adhesive force when wet while terrestrial species experienced ∼50% reductions in peak force and work of adhesion in wet conditions. These findings suggest that riparian spider silks have evolved specializations that maintain adhesive performance of pyriform attachment disks in wet environments, offering insights into bioinspired design for water-resistant adhesives.

Bernd F. Steklis, Todd A. Blackledge; Riparian spiders make pyriform silk attachment discs that stick better when wet. J Exp Biol 2025; jeb.250902. doi: https://doi.org/10.1242/jeb.250902