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 spiderweb unique?
00:06Spiderwebs are delicate, but also amazingly complex.
00:10Even if webs don't literally spell out the words terrific and radiant like in Charlotte's Web,
00:15each is still an intricate engineering marvel.
00:18But a web wouldn't be much use to a spider if it were just pretty to look at.
00:23Webs also trap insects and other prey long enough for a spider to immobilize them with venom or silk wrappings.
00:30Building these delicate traps is a process that follows patterns shared among spider species.
00:37But is there room for individual variation that makes one species' web, or one individual's spiders,
00:42recognizably different from another's?
00:46Are all webs identical, or is every spiderweb unique?
00:50There are about 48,000 known spider species worldwide.
00:54And while all spiders have silk-producing organs, known as spinnerets, and can produce several varieties of silk,
01:00not all spiders spin webs and lie in wait for their prey.
01:05The web is only affected by the kind of prey the spiders can expect,
01:10and by the kind of support spiders have to build their webs.
01:15Picture a spiderweb, and you might imagine a wheel-like structure with 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 because it covers a wide area for prey capture and is nearly invisible.
01:37Spiders that build orb webs typically begin with a few threads that center on a single point, in a Y shape.
01:43The 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.
01:57But this is a non-sticky placeholder.
02:00The real spiral, made of sticky silk, comes last.
02:04Once 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 trashline orb weavers,
02:22install a decoration in the middle of their webs made of prey leftovers and bits of leaves, which the spider may use as camouflage.
02:30Some time ago, I observed a web in Switzerland, and at that time there was just one Cyclosa species known in Switzerland.
02:39And I knew, well, it's not the Cyclosa species I know.
02:43So it must be another one which hasn't been documented to occur in Switzerland.
02:48Other orb weavers incorporate a zigzag structure into the web center, known 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, 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, or spin its web in a tree.
03:14So if you think of a spider building a web in a forest with strong wood, it has very good support, sturdy support.
03:24Spider building a web in grassland has to, well, it's a bit more difficult,
03:30because the grasses tend to be soft and they move around, so it has to give additional flexibility to the web.
03:38Even though the webs follow the same basic construction plan, they won't look exactly the same.
03:44Spiders make a fresh web every night or so, which means that a spider can produce about 100 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 a human to detect.
04:00And each web, if you look close enough, each web will be somewhat different.
04:07Intricate spider webs. Just one of life's little mysteries.