The diversity of spiders never ceases to amaze even their best specialists. Raphaël Jeanson, a research director (and member of the CNRS, France’s state research organization) at the Research Center on Animal Cognition in Toulouse, recently dedicated a fascinating book to them, Dans la Tête d’une Araignée (Inside the Mind of a Spider, HumenSciences, 208 pages, €19) presenting the wide range of talents of these small eight-legged beasts. Still, he confessed that he was “astounded to discover the sophistication of the hunting technique” of the Theridiosoma gemmosum species. To capture its prey, this millimeter-sized critter unfurls and stretches its web like a bow before throwing it like a gladiator. In an article published on Thursday, December 5, in the Journal of Experimental Biology, Sarah Han and Todd Blackledge, from the University of Akron, Ohio, just revealed that the animal activates the operation when it hears the presence of its prey, in other words even before it touches its web. In truth, however, the entire process, studied over the last ten years by Saad Bhamla’s team at the Georgia Institute of Technology, is truly remarkable.
Like many other spiders – but not all – species of the Theridiosoma genus weave circular webs known as orbe-weavers. But where most of their cousins wait passively for their prey to become entangled in their trap, they use their wits. In this case, they weave an additional silk thread that starts from the center of the web and runs perpendicular to it, which they hook onto any object. They then return to the web, clinch it with their four hind legs, and move along the thread with their four front legs. This way, the web is lifted in the middle and stretched. You can imagine what happens next: Once the tension is right, our miniature Hercules awaits the arrival of its flying prey and releases its thread as it passes. The accumulated tension propels the web and the spider toward the target like a slingshot. The sticky silk then traps the insect. Dinner is ready.
You have 54.5% of this article left to read. The rest is for subscribers only.
