A newly discovered species of spider in Madagascar spins the world’s longest web, report scientists writing in PLoS ONE.
Darwin’s bark spider (Caerostris darwini), a type of orb spider, weaves webs that span rivers and lakes to capture up to 30 insects at a time. One web reached 82 feet (25 meters) in length, giving the species the title of the world’s largest web spinner. The length of the webs allow the Darwin’s bark spider to capture insects in a niche otherwise unexploited by spiders.
 A, several C. darwini webs over river in Ranomafana. Individual web area (the extent of the sticky spiral) was about 0.5–1 m2, the longest bridgelines exceeded 10 m. B, a web across a small stream in Andasibe-Mantadia NP illustrating architecture. Images courtesy of the authors. |
The silk of the species is also the strongest ever encountered. Ingi Agnarsson, the director of the Museum of Zoology at the University of Puerto Rico and lead author of the research, says the web is twice as resilient as the next strongest silk and 10 times tougher than the material used in bulletproof vests.
“The toughness of forcibly silked fibers averages 350 MJ/m3, with some samples reaching 520 MJ/m3,” write the authors. “Thus, C. darwini silk is more than twice tougher than any previously described silk, and over 10 times better than Kevlar®.”
The giant webs are generally created by female spiders—males devote themselves to mating. Webs are thought to take multiple days to create.
Scientists have documented larger webs before but these have always been created by groups of colonies of spiders, rather than an individual.
Citation: Agnarsson I, Kuntner M, Blackledge TA (2010) Bioprospecting Finds the Toughest Biological Material: Extraordinary Silk from a Giant Riverine Orb Spider. PLoS ONE 5(9): e11234. doi:10.1371/journal.pone.0011234