Building these strong yet ephemeral traps is a process that follows patterns shared among spider species. But is there room for individual variation that makes one species' web — or one individual spider's — recognizably different from another's? Are all webs identical, or is every spiderweb unique? And what factors cause spiders to vary their silky webs?
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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.
00:18But a web wouldn't be much use to a spider
00:20if it were just pretty to look at.
00:22Webs also trap insects and other prey long enough
00:25for a spider to immobilize them with venom or silk wrappings.
00:30Building these delicate traps is a process
00:32that follows patterns shared among spider species.
00:36But is there room for individual variation
00:39that makes one species web, or one individual spider's,
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,
00:54and 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,
01:10and by the kind of support spiders have to build their webs.
01:15Picture a spider web, and you might imagine
01:17a wheel-like structure with a spiral and spokes
01:20radiating outward from the center.
01:22These are known as orb webs,
01:24and 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
01:34and 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.
01:43The spider then establishes a frame around the Y,
01:46connecting 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,
01:57but this is a non-sticky placeholder.
01:59The real spiral, made of sticky silk, comes last.
02:04Once the spider removes the first non-sticky spiral,
02:07the web is ready to catch its first victim.
02:10To some extent, all orb webs resemble each other,
02:13but there are details that differ between species.
02:17For example, spiders in the Cyclosa genus,
02:20also known as trash line orb weavers,
02:22install a decoration in the middle of their webs
02:24made 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 had been documented to occur in Switzerland.
02:48Other orb weavers incorporate a zigzag structure into the web center,
02:52known as a stabilimentum.
02:55And while most orb weavers produce webs that are perpendicular to the ground,
02:59some, such as the silver orb spider,
03:01spin 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,
03:20it has very good support, sturdy support.
03:23Spider building a web in grassland has to...
03:27Well, it's a bit more difficult,
03:29because the grasses tend to be soft and they move around,
03:34so it has to give additional flexibility to the web.
03:38Even though the webs follow the same basic construction plan,
03:41they won't look exactly the same.
03:43Spiders make a fresh web every night or so,
03:46which means that a spider can produce about 100 to 200 webs
03:50over the course of its lifetime.
03:52Each web is likely just a little different from the other,
03:55though it might be tricky for a human to detect.
04:00And each web, if you look close enough,
04:02each web will be somewhat different.
04:07Intricate spiderwebs.
04:08Just one of life's little mysteries.