Some of them are orb weaving spiders and some of them are non orb weaving spiders.

When you look at this orb web, you're actually seeing many types of silk fibers.

In fact, the toughest dragline in this survey is this one right here in this white region, a non orb web weaving spider.

If you look right here at the two red arrows, they point to the toughness values for the draglines of nephila clavipes and araneus diadematus.

It's been hypothesized that orb weaving spiders, like this argiope here, should have the toughest dragline silks because they must intercept flying prey.

The 21 species are indicated here by this phylogeny, this evolutionary tree, that shows their genetic relationships, and I've colored in yellow the orb web weaving spiders.

What silk biologists do is we try to relate these sequences, these amino acid sequences, to the mechanical properties of the silk fibers.

Perhaps some circular pieces of metal.

This is the dragline spun by scytodes, the spitting spider.

Like the spider who eats her mate when he is no longer a necessity?

Most spiders use copious amounts of silk, and silk is essential to their survival and reproduction.

Even fossil spiders can make silk, as we can see from this impression of a spinneret on this fossil spider.

But how about variation among spider species, so looking at one type of silk and looking at different species of spiders?

The frame and radii of this web is made up of one type of silk, while the capture spiral is a composite of two different silks the filament and the sticky droplet.

How does an individual spider make so many kinds of silk?

Spider

You Spider!

It's a spider.

Spiders?

Spiders use silk for many purposes, including the trailing safety dragline, wrapping eggs for reproduction, protective retreats and catching prey.

Some of them are orb weaving spiders and some of them are non orb weaving spiders.

I have had many meetings with strangers.

Scytodes doesn't use a web at all to catch prey.

Spider

A cobweb.

These are spinneret glands on the abdomen of a spider.

For example, this garden spider can make seven different kinds of silks.

Most spiders use copious amounts of silk, and silk is essential to their survival and reproduction.

It doesn't take long from working with spiders to start noticing how essential silk is to just about every aspect of their life.

There's quite a bit of variation within the fibers that an individual spider can make.

Spider

The Spider of Finance

I'm afraid of spiders.

For example, this garden spider can make seven different kinds of silks.

So this means that both spiders and spider silk have been around for 380 million years.

Tom hates spiders.

I'm really scared of spiders.

I hate cobwebs.

Means spider !

How does an individual spider make so many kinds of silk?

To borrow from the writings of a spider named Charlotte, silk is terrific.

There are two orders of magnitude more spiders than primates.

It doesn't take long from working with spiders to start noticing how essential silk is to just about every aspect of their life.

So silk comes out of the spinnerets, and for those of us spider silk biologists, this is what we call the business end of the spider.

So if you ever have the opportunity to dissect an orb web weaving spider, and I hope you do, what you would find is a bounty of beautiful, translucent silk glands.