I have yet to ever find a credible answer to how spiders set the top line of a web that often spans a considerable distance. I have read they hang off a line down from high a high branch or point, then let the wind swing them until they eventually reach the other side…another saying they can jump respectively vast distances. Yet neither can explain, when I frequently walk a bush trail aprox 2-3 meters wide and bushes either side up to 3 meters tall, I see many new webs started over night at the top level, spanning the trail …and with no wind, and a jump out of the question.
How can they possibly do that without crawling down to ground level …along the ground to other side, clamber up to highest point, all the while trailing a line of web…then tighten it up. Which just isn’t an option either of course!
Sometimes they move the thread rather than themselves, i.e., spin out a very light “streamer thread” from a high perch and let the air carry the end of it till it catches on something. It doesn’t take much wind to carry a couple/few feet of spider thread.
No wind ? There’s always wind. They sit and wait for a suitable gust,
land launch a web into it.
Baby/small spiders parachute with it, but the big ones will have to hope the end of the web will get tangled on the other side and then its got a bridge. Thats why the spiders built the web across the path… its a narrow gap to span … more chance the first bridge can be made… and cheaper to make it.
I watched a spider working on its web once that was doing something I thought was strange: it was on the top of an entryway, and it would attach a line to the ceiling, drop itself down almost to floor level, climb up the line it had just created back to the ceiling, and then sort of “reel in” all the line it had just let out using its legs. I’m not entirely sure what it was doing with that line, because at that time I was too spider-phobic to get that close. But I imagine it would be a piece of cake for the spider to walk to another location and set the line for use as an anchor line for a new web.
Also, be warned: there is evidence of spiders using tools to anchor their webs. Tell me that ain’t scary.