Spider silk is one of the toughest materials produced by living organisms, yet its tensile performance varies greatly between species. Despite an extensive sampling of dragline silk material properties and compositions, the reasons why some silks perform better than others are still limited. Here, we employ a phylogenetic comparative approach to clarify the Silcom The researchers compared their database of 164 spider silks with the literature, aiming to (a) provide an extended model of silk property evolution, (b) test correlations between structural and mechanical properties, and (c) test whether silk tensile performance differs between web-weaving and non-web-weaving species. Contrary to the common belief that circular-web-weaving spiders have evolved the best silks, superior tensile properties were found both within and across spider species of the Araneae order. Phylogenetic linear models showed that the mechanical and structural properties of spider draglines were poorly correlated, but silk strength and toughness were more highly correlated with birefringence (an indicator of material anisotropy) than with crystallinity. Moreover, in contrast to previous beliefs, silk tensile performance did not differ between ecological guilds. These findings indicate that there are multiple unknown pathways towards the evolution of superperformance in spider silk tensile performance, and call for further inclusion of non-circular-web-weaving spiders in spider silk research.
Jonas Owolf, Spider silk tensile performance does not correlate with web use, evolution2024;, qpae135, https://doi.org/10.1093/evolut/qpae135
