Nature & Environment

Spider Webs Snare Honey Bees and Other Insects with Electrical Charge (Video)

Catherine Griffin
First Posted: Jul 05, 2013 09:55 AM EDT

Spider silk may be more adept at trapping insects than we thought. One scientists has discovered that insects that flap their wings build up an electrical charge that causes them to be easily snared by the webs.

The scientist at the head of this study, Victor Manuel Ortega-Jimenez, usually studies hummingbird flight as opposed to spiders. Yet an encounter with a child's toy actually inspired the current research in webs. He was playing with his four-year-old daughter when something happened that made him stop and think.

"I was playing with my daughter's magic wand, a toy that produces an electrostatic charge, and I noticed that the positive charge attracted spider webs," said Ortega-Jimenez in a news release. "I then realized that if an insect is positively charged too, it could perhaps attract an oppositely charged spider web to affect the capture success of the spider web."

In fact, he suspected that light flexible spider silk, the kind used for making the spirals on top of the stiffer silk that forms the spokes of a web, may have developed because it more easily deforms in the wind. This deformation creates an electrostatic charge that helps with capturing prey.

In order to test this theory, the scientist searched for cross-spider (Araneus diadematus) webs along streams in Berkeley. He then brought them to his lab, using an electrostatic generator to charge up dead insects. He then dropped these creatures, which included aphids, fruit flies, green-bottle flies and honey bees, into a neutral, grounded web.

Actually dropping them into the web wasn't enough, though. He then used a high speed camera to track the movement and found that the spider web was clearly deforming and touching the insect before it actually reached the web. Insects without a charge would not do this.

"Electrostatic charges are everywhere, and we propose that this may have driven the evolution of specialized webs," said Ortega-Jimenez in a news release.

Currently, the researcher is planning on seeing if this same phenomenon occurs naturally in the wild. If it does, it may show that spider webs are uniquely suited to capturing winged prey.

The findings are published in the journal Scientific Reports.

Want to see the falling insects for yourself? Check out the video below, courtesy of YouTube and UC Berkeley.

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