Year: 2022

FALSE PREMISE 4. "Fourth, and perhaps most importantly, it is difficult and may be impossible to eliminate eukaryocentric bias from the measures by which eukaryotes as a whole are judged to have achieved greater success than prokaryotes as a whole." http://www.pnas.org/content/112/33/10278.full View in LinkedIn

HYDROGEN POWERED train in Germany. https://lnkd.in/dXv_6qC View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend with a consideration of the biology of spider webs, how they arose, and how and why they function as they do. It is a lovely story of inventiveness at many scales: the molecular design of the material with sliding hydrogen bonds giving it toughness; the various positioning of the webs giving rise to substrate freedom; and the web geometry that exploits efficiency of an expensive material with high functionality for a powerful prey. View in LinkedIn

AERIAL WEB SILK EVOLUTION. "Spiders also responded to greater web stresses by evolving silks with enhanced mechanical properties. Dragline silk evolved early in the evolutionary history of spiders, long before the origin of orb-webs." https://lnkd.in/dqTjK77 View in LinkedIn

NEW SILK. "While dragline silk in both orb-web spiders and less-derived (non-orb) spiders is impressively strong and tough, there is a significant increase in material properties associated with the origin of orb-web spiders. Spiders within the Orbiculariae also evolved a new type of capture silk (viscid silk) that is currently considered to play an important role in stopping large, fast-flying prey." https://lnkd.in/dqTjK77 View in LinkedIn

SHIFT TO VERTICAL WEBS. "Vertical orientation not only helps araneoid orb-webs intercept more prey but also to retain them for longer, as escaping prey are more likely to fall into lower parts and become re-entangled. A vertical web may intercept more prey; however, such prey are typically larger, faster flying insects that impact the web with greater energy. This shift to a vertical web orientation was facilitated by a major shift in the type of capture silk used in the web." https://lnkd.in/dqTjK77 View in LinkedIn

CRIBELLATE SILK. "Deinopoids, like most other web-building non-araneoid spiders, use cribellate capture silk. It is comparatively more expensive than araneoid capture silk, as it requires both a greater volume of material and takes more time to produce." https://lnkd.in/dqTjK77 View in LinkedIn

CRIBELLATE STRUCTURE. "Cribellate silk is composed of a pair of axial fibres (produced by the pseudo-flagelliform glands) surrounded by a sheath of microscopic fibrils that are brushed onto the axial fibres from a specialized plate called a cribellum. This silk is dry and achieves its stickiness via hygroscopic and van der Waals forces." https://lnkd.in/dqTjK77 View in LinkedIn

SPIDER VISCID SILK. "Araneoid capture silk, often referred to as viscid or sticky silk, is more economical to produce because of an alternative mechanism of adhesion. As the axial fibres are extruded from the flagelliform glands, an aqueous glue coating is simultaneously deposited from the aggregate glands onto the axial fibres and coalesces into microscopic droplets along the fibre's length." https://lnkd.in/dqTjK77 View in LinkedIn

CAPTURE VISCID SILK. "The glue droplets are composed of about 80 per cent water as well as glycoproteins that adhere to prey and small hygroscopic molecules. Viscid silk is stickier per volume when compared with cribellate silk, which increases prey capture potential and ultimately spider fitness." https://lnkd.in/dqTjK77 View in LinkedIn