Year: 2022

SILK INNOVATIONS. "The evolutionary diversification of spiders is attributed to spectacular innovations in silk. Spiders are unique in synthesizing many different kinds of silk, and using silk for a variety of ecological functions throughout their lives, particularly to make prey-catching webs." http://www.pnas.org/content/106/13/5229.full View in LinkedIn

DIVERSIFIED BY SILK. "In contrast to megadiverse orders of insects, evolutionary diversification of spiders is not coupled with major trophic shifts. Spider diversification is instead linked to key innovations in silk use." http://www.pnas.org/content/106/13/5229.full View in LinkedIn

ORB WEB GEOMETRY. "Our analysis shows that orb webs arose a single time. The orb appears to be derived from a substrate-bound web, likely an irregular ground web or brushed sheet web. The evolution of orb webs was marked by a dramatic increase in geometric regularity, resulting from increased behavioral stereotypy of spinning." http://www.pnas.org/content/106/13/5229.full View in LinkedIn

SPIDER WEB EVOLUTION. "Subsequent to the orb's origin, aqueous viscid silk replaced cribellate silk and the orb was transformed at least 3 times into less regular appearing aerial sheet webs. Moreover, the orb web has been highly reduced independently in tetragnathoids and Araneidae." http://www.pnas.org/content/106/13/5229.full View in LinkedIn

WEB LOSS. "Although the orb has been lost independently at least 3 times within the context of our current taxon sampling, it has likely been lost even more frequently among all orb-weavers." http://www.pnas.org/content/106/13/5229.full View in LinkedIn

FIRST EVOLUTION. "Instead of cribellate and ecribellate orb webs evolving in parallel, orb monophyly explicitly implies that dry cribellate capture spirals were replaced by ecribellate gluey spirals. This involves 2 major changes. First, a shift in the silk used to produce the core fibers of capture threads, resulting in novel tensile properties." http://www.pnas.org/content/106/13/5229.full View in LinkedIn

SECOND EVOLUTION. "The second major shift involves the mechanism of adhesion, from dry cribellate fibrils that adhere through van der Waals forces and hygroscopic interactions to chemically adhesive viscid glue in ecribellate spiders. This results in webs with greater adhesion per surface area and may have facilitated the transition from horizontal to vertical web orientation in modern orb spiders, which is associated with increased prey interception rates." http://www.pnas.org/content/106/13/5229.full View in LinkedIn

SPIDER FAMILIES. "Most of the current diversity of spiders results from 2 major radiations −RTA clade (>21,000 spp.) and Orbiculariae (>11,000 spp.). The putative sister group of Orbiculariae in our hypothesis, the RTA clade, is even more diverse (>21,000). Hence, we cannot, by sister group comparison alone, claim that the invention of the orb web per se dramatically affected diversification rates. Notably, the most diverse families of spiders within the RTA clade are largely, or entirely webless, and have secondarily lost cribellate silk." http://www.pnas.org/content/106/13/5229.full View in LinkedIn

STEREOTYPICAL WEBS. "The most species-rich families within Orbiculariae are the linyphiids and the theridiids. Each has independently transformed the orb into different aerial sheets. In both cases, these webs are distinguished from ancestral sheets not only in being aerial but also in the overall stereotypy of their architectures, a characteristic inherited from orb weaving ancestors." http://www.pnas.org/content/106/13/5229.full View in LinkedIn

STRUCTURE AND FUNCTION. "A better understanding of how silks interact with web structures during prey capture, how and why silk properties vary at individual and interspecific levels, and what selective pressures drive the evolution of silk properties will reveal new possibilities for the application of silk analogues." https://lnkd.in/dHWBg9g View in LinkedIn