Spider Silk Grabs Electrically Charged Insects in Midair
Like socks on carpet, insects build up static electricity as they fly. And that can be a bad thing when it comes to spider webs. Certain strands of spider silk are attracted to statically charged objects, according to a new study, enhancing an arachnid’s ability to catch prey. In lab tests conducted in an environment isolated from electrical fields, researchers dropped a variety of freshly killed insects down through a spider web that had been recently collected near the lab. High-speed video revealed that individual strands of spider silk, especially those flexible filaments running in spirals around the center of the web (a cross spider, Araneus diadematus, shown), flexed as much as 2 millimeters toward a statically charged insect, but wern’t influenced at all by uncharged insects passing near the strands. The silk flexed quickly, too, at an average speed sometimes approaching 2 meters per second, the researchers report today in Scientific Reports. Static electricity isn’t all bad for insects, however. Studies published earlier this year reveal that bugs can use the electrical fields that build up on their bodies to communicate with each other and identify flowers that might have been recently visited by another insect .
| image by V.M. Ortega