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

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.

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.

Pyriform silk glands make the attachment cement that's the silk that's used to adhere silk lines to a substrate.

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

This is a picture of the spinnerets coming out of a spider and the silk being formed from a spider. Isn't that beautiful?

Cheryl Hayashi The magnificence of spider silk

There are many kinds of spider silk.

We think that's because the dragline silk, which is used to make the frame and radii for a web, needs to be very strong.

I used a money spider's web to actually attach certain things, which sent me insane.

These are spinneret glands on the abdomen of a spider.

And the spider's web is for the reins on the horse.

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

In addition to these biomimetic applications of spider silks, personally, I find studying spider silks just fascinating in and of itself.

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

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

Spider silk is almost entirely protein.

And the most studied silk line of them all major ampullate silk.

This is the comparison of the toughness of the dragline spilk spun by 21 species of spiders.

Each of these silk fibers exits from the spigot, and if you were to trace the fiber back into the spider, what you would find is that each spigot connects to its own individual silk gland. A silk gland kind of looks like a sac with a lot of silk proteins stuck inside.

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

Minor ampullate silk is used in web construction.

But what, exactly, is spider silk?

There are several features that all these silks have in common. They all have a common design, such as they're all very long they're sort of outlandishly long compared to other proteins.

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

This is the silk that's used to make the frame and radii of an orb web, and also the safety trailing dragline.

And I normally rig it with the web of a money spider.

These are the two species of spiders for which the vast majority of time and money on synthetic spider silk research has been to replicate their dragline silk proteins.

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 the aggregate and flagelliform silk glands which combine to make the sticky capture spiral of an orb web.

It's short. And on the bottom, this is the repeat sequence for the egg case, or tubuliform silk protein, for the exact same spider. And you can see how dramatically different these silk proteins are so this is sort of the beauty of the diversification of the spider silk gene family.

This makes testing spider silk really, really easy to do in the laboratory, because we're actually, you know, testing it in air that's exactly the environment that spiders are using their silk proteins.

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

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.

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

We spend long days and nights staring at this part of the spider.

Spider silks also have a lot of potential for their anti ballistic capabilities.

I love when I'm in the laboratory, a new spider silk sequence comes in.

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

It's like the spiders are sharing an ancient secret with me, and that's why I'm going to spend the rest of my life studying spider silk.

So silk fibers vary in their strength and also their extensibility.

Because the web of the spider, it was sending me insane, because I couldn't get the web to move off.

Nearly all of these proteins can be explained by a single gene family, so this means that the diversity of silk types we see today is encoded by one gene family, so presumably the original spider ancestor made one kind of silk, and over the last 380 million years, that one silk gene has duplicated and then diverged, specialized, over and over and over again, to get the large variety of flavors of spider silks that we have today.