Year: 2022

SPIDER BODY SIZE. "While past research suggested that small spiders producing thin diameter silks should compensate evolutionarily by producing tougher fibres, recent research instead reveals that evolutionary increases in orb spider body sizes are accompanied by concerted improvements in many different silk properties and web architectures." https://lnkd.in/dHWBg9g View in LinkedIn

SILK PROPERTIES. "In addition to high levels of structural diversity among webs, the biomechanical properties of silks are also highly variable. This variation may be due to a range of physiological and abiotic mechanisms, such as the rate of spinning, pH levels in the silk glands, humidity and temperature. Diet may also influence availability of silk proteins, which will in turn affect silk properties." https://lnkd.in/dHWBg9g View in LinkedIn

DIVERSE TOOLKIT. "Our study quantifies the mechanical and material properties of the fibrous silks spun by Argiope argentata. As a whole, the silks possess extraordinary properties, but are also strikingly diverse. These silks provide orb-weaving spiders with diverse toolkits of fibers that seem fine-tuned for particular ecological functions. This variety is reflected in not just the distinctive mechanical properties of each silk, but also in the underlying molecular structures and amino acid sequences of the fibroins." https://lnkd.in/dHR5T8n View in LinkedIn

SILK STRENGTH BIOCHEMISTRY. "The incredible strength of spider dragline silk is attributable to the formation of β-sheet crystals during fibre extrusion. The β-sheet crystals predominately consist of poly-alanine and poly-(glycine–alanine) repeats that are found in two types of fibroin proteins known as MA spidroins 1 and 2 (MaSp1 and MaSp2)." https://lnkd.in/dHWBg9g View in LinkedIn

SILK ELASTICITY BIOCHEMISTRY. "In addition to its strength, dragline silk is highly elastic when compared with synthetic fibres. Elasticity of dragline silk is determined largely by the semi-amorphous regions interconnecting the β-sheet crystals. These regions include helix-like structures and β-turns that are rich in glycine. When a silk fibre is subjected to tensile loading, the semi-amorphous regions unravel first owing to breaking of hydrogen bonds, which accounts for the high level of extensibility observed in silk." https://lnkd.in/dHWBg9g View in LinkedIn

DIVERSITY AT ALL SCALES. "Some nanoscale structures within dragline silk (e.g. β-sheet crystals, β-turns) are found in most spider species. However, variation in biomechanical function can arise owing to diversity in silks at all structural scales." https://lnkd.in/dHWBg9g View in LinkedIn

AERIAL WEB EVOLUTION. "The Orbiculariae, so named for the classic orb-web they build, account for more than 25 per cent of spider diversity (11 880 + species). The evolution of the orb-web meant that spiders could build aerial webs suspended in space, freeing them from the limitations in web shape imposed by the substrate. The move to building aerial webs may represent the beginnings of an evolutionary arms race with flying insects that co-radiated alongside the spiders." https://lnkd.in/dHWBg9g View in LinkedIn

STRESSES ON AERIAL WEBS. "As spiders began to build aerial orb-webs, their silks faced new selective pressures. For example, insects in mid-flight strike webs with greater kinetic energy than experienced by ancestral substrate-bound webs (and derived sheet- and cobwebs) that intercept ambulatory prey, or prey attempting to land. Additionally, webs suspended in space are subjected to much greater wind stress, even more so if anchored to flexible substrates such as grasses." https://lnkd.in/dqTjK77 View in LinkedIn

SO ENDS this part of the contemplation of the biology of the spider web. The lasting poignancy of early morning walks in English dew or frost to see spider webs in the grass and bushes outlined like pear necklaces, or to see them on a Spanish veranda railing surviving high winds, is embedded in my mind forever. Each an image seared. View in LinkedIn

THE ONLY SPECIES where the individual has the power to change ecosystems are humans. In nature, species are the agents of change, not individuals. But because of the structure of human societies, power is concentrated in a few individuals, whose decisions can have sweeping impacts on large numbers of issues. Problematic evolution. View in LinkedIn