Q: Why don’t spiders stick to their...

Q: Why don’t spiders stick to their own webs?

A: In the first place, not all spider webs are sticky, according to biologist Gary Polis of Vanderbilt University. The funnel webs commonly found in grass, as well as the webs made by trapdoor spiders and burrowing spiders like tarantulas, are not sticky at all, but serve as a remote sensing system that alerts the spider to the presence of prey.

For webs that are sticky, he said, the spiders leave a pathway of webbing that is not sticky to walk upon. The classic web of the orb spider, for instance, has radial spokes and concentric circles (actually one continuous spiral). The spider walks only on the spokes, which are not sticky, while prey is caught on the spiral. “Most webs that are sticky have safe passages for the spider,” he said.