November 25, 2011
Shichang Zhang and colleagues have found that at least one orb weaver, Nephila antipodiana, deposits a substance on its web threads that deters ants. Ants prey on spiders, but ants have not often been seen preying on orb weaving spiders. Zhang et al. may have discovered why.
Alex Wild, over at Myrmecos, has a good summary of the study as well as an interesting quibble about the range of ants tested.
June 9, 2011
People and other animals have always adapted spider silk to their own purposes. Here's a spectacular piece of footage from Jeremy Wade's Animal Planet "River Monsters" series showing a skillful South Pacific fisherman using Nephila, or golden orb weaver, silk as an all-in-one tool. Notice the golden hue of the silk, and just how stuck into the tangled silk the fish gets. I wonder whether the aggregate silk protein glue that lies along the web's capture spiral survives its swish through the salt water and that's what the fish sticks to, or whether the fish simply gets major ampullate and flagelliform silk wound around its teeth. Thanks to Green Matter for the tip.
April 22, 2011
Nephila spiders are big, they're bold (in terms of web coloration, that is), and now we know they're old, too--more than 165 million years old, the approximate age of a fossil just described as a Nephila by veteran spider fossil researcher Paul Selden and colleagues ChungKun Shih and Dong Ren. These gorgeous spiders are also known as the golden orb weavers because their huge webs range in color from pale yellow to vibrant gold. We write about why spiders would have evolved to construct such obvious webs--and why insects still fly into them--in Spider Silk's tenth chapter, "Now You See It, Now You Don't."
Named Nephila jurassica in honor of its age, this fossil is the oldest Nephila fossil yet found and hails from a site in present-day Inner Mongolia that has already yielded exciting numbers of arthropod fossils and may contain more spider bounty. It's startling to consider that, as far as spiders have been concerned, the dinosaurs were interlopers who showed up and then disappeared rather quickly.
Here's how to think about N. jurassica in the history of spiders: The oldest spider fossil (a mesothele) yet found is 290 million years old, or 130 million years older than N. jurassica. The oldest araneomorph fossils are 225 million years old, or 60 million years older. And the oldest known fossil of an araneoid--the group containing all vertical-orb weavers, including Nephila, and spiders evolved from vertical-orb weavers--is about 175 million years old, or about 10 million years older. We can't tell from this fossil whether Nephila jurassica wove golden webs, but its size certainly indicates that, like today's Nephila, it wove giant webs and could wrangle with large insects. Arthropods don't fossilize easily. So every new spider fossil is a treasured key to the distant past.
July 6, 2010
We stopped in at the American Museum of Natural History in New York over the weekend to see the one-of-a-kind tapestry woven in Madagascar from the silk of Nephila madagascariensis, one of the golden orb weavers. Weaving was a highly developed art in Madagascar through the middle of the 20th century, and Europeans marveled at Malagasy creations in raffia, silk, and cotton, but especially silk. Malagasy royalty gave silk textiles to foreign leaders as they tried to establish or cement strategic alliances.
But that was silkworm silk. Weaving textiles from spider silk has never been practical, even in Madagascar, where giant golden orb weavers abound. When the tapestry was unveiled last autumn, The New York Times explained how Simon Peers, who has partnered with Malagasy weavers over the last two decades to revive their traditional art, put into play a plan to create the world's largest--and certainly most beautiful--piece of spider silk cloth. And the AMNH made a film, which you can see here. But if you can, get to the AMNH yourself to see this almost incredible piece of work. I dare you to keep your fingers off the case--they'll want to reach in and feel those wandering fringes where the silk looks still untamed.