00:00Is every spider web unique?
00:05Spider webs are delicate, but also amazingly complex.
00:09Even if webs don't literally spell out the words terrific
00:12and radiant like in Charlotte's Web,
00:14each is still an intricate engineering marvel.
00:17But a web wouldn't be much use to a spider
00:19if it were just pretty to look at.
00:22Webs also trap insects and other prey
00:24long enough for a spider to immobilize them
00:27with venom or silk wrappings.
00:29Building these delicate traps is a process
00:32that follows patterns shared among spider species.
00:36But is there room for individual variation
00:38that makes one species' web, or one individual's spiders,
00:42recognizably different from another's?
00:45Are all webs identical, or is every spider web unique?
00:49There are about 48,000 known spider species worldwide,
00:53and while all spiders have silk-producing organs,
00:56known as spinnerets, and can produce several varieties of silk.
01:00Not all spiders spin webs and lie in wait for their prey.
01:04The web is only affected by the kind of prey
01:07that spiders can expect,
01:09and by the kind of support spiders have to build their webs.
01:15Picture a spider web, and you might imagine a wheel-like structure
01:18with a spiral and spokes radiating outward from the center.
01:22These are known as orb webs, and they're made by fewer than 10% of known spider species.
01:28This type of web is ideal for catching flying insects
01:31because it covers a wide area for prey capture and is nearly invisible.
01:37Spiders that build orb webs typically begin with a few threads
01:40that center on a single point, in a Y shape.
01:42The spider then establishes a frame around the Y, connecting a few more threads in the middle.
01:48Next come the spokes in the wheel, extending from the middle to the frame.
01:53Then the spider builds a spiral starting from the center.
01:56But this is a non-sticky placeholder.
01:59The real spiral, made of sticky silk, comes last.
02:03Once the spider removes the first non-sticky spiral, the web is ready to catch its first victim.
02:10To some extent, all orb webs resemble each other, but there are details that differ between species.
02:17For example, spiders in the Cyclosa genus, also known as trash line orb weavers,
02:22install a decoration in the middle of their webs made of prey leftovers and bits of leaves,
02:27which the spider may use as camouflage.
02:29Some time ago, I observed a web in Switzerland.
02:34And at that time, there was just one Cyclosa species known in Switzerland.
02:38And I knew, well, it's not the Cyclosa species I know.
02:43So it must be another one which can be documented to occur in Switzerland.
02:48Other orb weavers incorporate a zigzag structure into the web center, known as a stabilimentum.
02:54And while most orb weavers produce webs that are perpendicular to the ground, some, such
03:00as the silver orb spider, spin webs that are oriented horizontally.
03:04A web's physical location can also influence what it looks like.
03:08An orb web spider might build its web in flexible grass.
03:12Or spin its web in a tree.
03:14So if you think of a spider building a web in a forest with a strong wood, it has very
03:21good support, sturdy support.
03:23Spider building a web in grassland has to, well, it's a bit more difficult because the
03:31grasses tend to be soft and they move around, so it has to get additional flexibility to the
03:37web.
03:38Even though the webs follow the same basic construction plan, they won't look exactly the
03:42same.
03:43Spiders make a fresh web every night or so, which means that a spider can produce about
03:48100 to 200 webs over the course of its lifetime.
03:52Each web is likely just a little different from the other, though it might be tricky for
03:57a human to detect.
03:59And each web, if you look close enough, each web will be somewhat different.
04:07Intricate spiderwebs.
04:08Just one of life's little mysteries.
04:12Bye.
04:12Bye.
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