Fixing a Hole: Better (Spider) Web Design
⎈ From tiny webs like the one “repairing” a hole in a leaf seen in the image, to giant orbs spanning 25 meters across rivers and lakes, the architecture of spider webs can teach us a thing or two about engineering. After all, spiders have been spinning silk for 400 milion years and now number at least 41,000 species spread out over every continent, including Antarctica. Each spider produces many different types of silk covering a range of mechanical properties: from the steely dragline silk in the radial strands to sticky capture silk that forms concentric circles in the web. Yet, only few spider silks have been studied, mostly at random, sometimes simply from the researcher’s own backyard!
⎈ Bioprospecting: By combining fields as diverse as natural history, ecology, taxonomy, behavior and biomaterial science, researchers found that the Darwin’s Bark Spider (Caerostris darwini), a giant Malagasy riverine orb-weaving spider, produces the toughest silk discovered to date. Outperforming steel and Kevlar, the radial web threads of this spider have unusual elasticity, absorbing more kinetic energy upon prey impact so that they stretch, instead of fracturing. This allows the spiders to occupy a new ecological niche- the flyways above rivers where they can catch unsuspecting insects and even small birds and bats. Don’t you agree that scientists should get out of their labs and explore new habitats as well?!
⎈ Biomimicry: In nature, tiny amounts of metals penetrate protein structures to change their properties. These “impurities” are found in jaws, claws and cuticles where they impart additional toughness to biological material. Inspired by nature, scientists purposefully introduced zinc, titanium or aluminum into spider dragline silks by using a multiple pulsed vapor-phase infiltration method. The resulting material was tougher and more stable to environmental damage. Now this is the stuff of Spider Man!
Free Reads: New Opportunities for an Ancient Material (2010) Ometto and Kaplan. Science. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136811/
Bioprospecting Finds the Toughest Biological Material: Extraordinary Silk from a Giant Riverine Orb Spider (2010). Agnarsson et al. PLOS ONE http://goo.gl/CcSMTd
The Beatles-Fixing a Hole: https://www.youtube.com/watch?v=j0I2ZrBuFdQ
Photo Credit: Bertrand Kulik