Why doesn’t a spider get stuck in its own sticky web? — Maxine, Toronto, Canada
Marshall Brain Answers:
Spiders are amazing creatures, and the ability to spin and navigate a web ranks up there near the top of insect capabilities. In the following video you can see a spider spinning the classic web:
The first thing to understand is that the spider’s web is not all sticky. The radial lines in this web (the lines that look like spokes coming out from the center of the web) are not sticky. The spiral that the spider is adding to the web contains the sticky lines. So the spider can navigate the web using the radials without any problems.
The second thing to understand is how the spider walks across the web. The spider is not wearing sneakers with big flat bottoms. If you look at this page, it describes a special claw, tiny in size, that lets the spider grab strands of web: “web-building spiders have a third middle claw that hooks over the silk lines of the web and holds the silk against barbed hairs.” Therefore, when a spider is touching its web, it not like a fly with a big wing stuck across a sticky strand. The spider’s contact point on the strand is extremely small. Even if a spider touches a sticky strand, the amount of adhesive it touches is very small and therefore easy to release.
The third thing to understand is that spiders have an oily protection system that makes it less likely for strands to stick to a spider.
More info: How Spiders Work