Ed Yong in The Atlantic:
Most web-spinning spiders line their silken threads with droplets of glue, which snag blundering insects. But one group—the cribellate spiders—does something different. Their threads are surrounded by clouds of even more silk—extremely fine filaments, each a hundred times thinner than regular spider silk. These nanofibers give the silk a fuzzy, woolly texture, and since they have no glue, they’re completely dry. And yet they’re clearly sticky. Insects that stumble into the webs of cribellate spiders don’t stumble out again.
Raya Bott and colleagues at Aachen University in Germany have now shown that cribellate silk adheres to insects in a previously unknown and unsettlingly macabre way. When an insect touches the strands, waxy chemicals in its outer surface get sucked into the woolly nanofibers and reinforce them, turning the tangled mass of delicate threads into a solid, sturdy rope. The victim literally becomes a part of the web, inadvertently strengthening the instrument of its own capture.