What Is A Spider Web Made Out Of?

Curious Kids: What are spider webs made from and how strong are they?

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Postdoctoral Research Fellow, The University of Queensland

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This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!

My name is Leo. I am 5 years old and I live in Sydney. My question is: what are spider webs made from and how strong are they? – Leo, 5, Sydney.

Spider webs are made from silk. And silk is made from something scientists call “proteins”.

Proteins are special chemicals made by a living thing — like an animal or a plant. You have lots of them in your body. Proteins usually have a certain job to do.

Some join together to make something bigger. Your hair and your nails are made of proteins (they are both made by a protein called “keratin”).

Insects and spiders make silk in a special part of their body called a gland, and use their legs to pull it out of their bodies. This is called spinning.

Most species of spider have more than one kind of silk gland. Each one has different strength and stretchiness and is used for a specific purpose such as web frame, sticky strands, or covering eggs. The strength and stretchiness of silk depends on the way the spider’s body arranges the silk proteins.

Spiders have evolved to spin very strong silk webs so they can catch insects to eat. This means that long ago, spiders that made stronger webs caught more insects to eat and had more babies, but spiders that made weaker webs caught fewer insects and had fewer babies.

After millions of years of this process, some spiders today make silk that is very strong. We don’t usually notice just how strong they can be because they are amazingly thin. But the strongest silk, such as silk from a golden orb spider, is actually stronger than steel. Even more amazing, it is about 50 times as light.

Actually, spider silk is a bit like a cross between steel and rubber. Even with the help of complicated machines and chemicals, humans still don’t know how to make a material this strong, stretchy, and light. Spiders are still the champions at this.

Amazing facts about silk

Most people know that spiders and silkworms make silk, but did you know there are more than 20 different groups of animals that make silk?

Silk-making animals include crickets, silverfish, glow-worms, ants, bees, wasps, flies, caterpillars, lacewings, and sawfly larvae.

Some of these make silk to protect themselves. Crickets, for example, use silk to sew leaves together to build a nest. Others use silk in mating, such as dance-flies, in which the male impresses the female with a gift of food wrapped in silk. Some use silk for hunting, such as spiders and even glow-worms, which use sticky silk to capture flying animals they’d like to eat.

Scientists are closer than ever to producing artificial silk. For example, Dr Tara Sutherland at CSIRO Ecosystem Sciences can make bee silk proteins using bacteria, and then spin them into solid strings similar to those made by bees.

Maybe one day, if you become a scientist, you might be able to make something as strong, as light and as special as spiders’ silk.

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theconversation.com

What are spider webs made of? And how do they spin them?

Find out how web-spinning spiders do what they do and learn about the impressive, multipurpose material they use to catch their dinner.

Spiders make their webs from silk, a natural fibre made of protein.

Not only does spider silk combine the useful properties of high tensile strength and extensibility, it can be beautiful in its own right.

Jan says, ‘Silk is an amazing material. Golden silk orb-weavers, which are found in warm regions around the world — but not the UK, unfortunately — spin webs with a lovely golden sheen. Their silk has even been used to create a shimmering golden cape that was exhibited at the Victoria and Albert Museum in 2012.’В

UK spiders tend to produce silk that is white or has a bluish hue.

There are seven different silk glands, which produce silk with different characteristics and uses.В For example cribellate silk is very woolly.

Jan Beccaloni, the Museum’s arachnid curator, adds, ‘Cribellate silk acts like Velcro, sticking to the legs and bristles of captured insects.’

See also:  Types Of Spider Bites And What They Look Like?

Each type of silk gland is associated with a particular spinneret. No species has all seven, but orb-web weavers have five.

Golden silk orb-weavers (Nephila species) spin silk with a brilliant yellow colour

В© Claire E Carter/Shutterstock.com

A golden cape woven from spider silk, which was exhibited at the Victoria and Albert Museum in 2012

How do spiders make their webs?

A spider spinning silk to make its web, pulling the thread out with its hind leg

В© Ian Fletcher/Shutterstock.com

Spiders have structures called spinnerets on their abdomen, usually on the underside to the rear. These are the silk-spinning organs. Different species have different numbers of spinnerets, but most have a cluster.

At the end of each spinneret is a collection of spigots, nozzle-like structures. A single silk thread comes out of each.

Jan explains, ‘Although it looks a bit like an icing nozzle, the silk is pulled out by gravity or the spider’s hind leg. The silk is liquid when it’s inside the spider.’

Before it is extruded out of the spinneret, cribellate silk first passes through a sieve-like structure called the cribellum. Spiders that make this type of silk also have a row of specialised leg bristles called the calamistrum, which combs the silk out and gives it the different, woolly texture.

Spiders then follow various patterns of activity to construct their webs, depending on what species it is. It’s fascinating to watch.

Do all spiders make webs?

Although webs are the most well-known use for spider silk, not all spiders make webs to catch their prey. In fact, less than half of the 37 spider families in Britain do.

Other spiders, such as crab spiders in the family Thomisidae, are ‘sit and wait’ predators — for example Misumena vatia lurks on flower heads, waiting to ambushing visiting insects. Others, such as jumping spiders in the family Saltidae, actively follow their prey and catch it by leaping on it.

A crab spider,В Misumena vatia,В ambushing prey from its flower vantage point

Courtesy of Pixabay (CC0)

A jumping spider,В Salticus scenicus, attacking a fly

Some spiders even invade other webs to find their food. The pirate spiders, of which there are four UK species in the genusВ Ero, go onto another spider’s web and mimic the behaviour of its prey to lure the spider closer. When the web’s owner investigates, the pirate spider attacks.

Silk: a multipurpose material

A jumping spider peers out of its silk cell hiding place

В© Judy Gallagher (CC BY 2.0), via Flickr

However, even spiders that don’t make webs have uses for silk, including creating moulting platforms, sperm webs for males, and retreats.

Jan adds, ‘Jumping spiders, for example, make little silken cells in which to hide in during the day — a bit like a sleeping bag.’

Most spiders use silk to wrap their eggs.

Another common use for silk is as a drag line. Every so often a spider attaches a thread of silk to something, like an anchor, so that if it falls, it won’t fall too far and can drag itself back up to the previous position.

Ballooning is another spectacular use for silk, allowing the mass dispersal of spiderlings and small adults.

After climbing to a relatively high point, the spider points its abdomen skywards and pulls out one to several threads. When air or electrostatic currents carry the threads upwards, the spider follows. They can be carried many thousands of metres.

A field coated in silk after a mass dispersal of spiders by ballooning

В© Stephen Michael Barnett (CC BY 2.0), via Flickr

Money spider mass dispersals in particular make quite a sight. Sometimes the numbers involved can leave an entire field coated in gossamer threads.

Jan says, ‘Not all spiders disperse this way, but it’s the reason spiders are some of the first creatures to colonise new islands.’

More spider web facts

Now that you know how spiders make their webs, discover their impressive variety. British spider webs can be grouped into seven broad types based on their architecture: orb, sheet, tangle, funnel, lace, radial and purse. But even within each group, different species put their own spin on the style.

The diving bell spider (Argyroneta aquatica) probably has the most unusual use for its web, which enables it to spend most of its life underwater — a unique ability among spiders.В It constructs a net of silk between submerged vegetation and uses it to gather a bubble of air — its very own diving bell.

View the common styles of web and the spiders that make them >

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Spider webs: not just for Halloween

Explore seven common styles of spider web and discover the arachnids that make them.

Finding love on the web

Spiders may seem scary, but most of them are just looking for love. Read some dating profiles of spiders searching for the perfect mate.

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Join the team from BBC TV programme The British Garden: Life and Death on Your Lawn to uncover some of the hidden wildlife you could spot throughout the year.

How dangerous are false widow spiders?

Every autumn there are reports of false widow spiders becoming uninvited eight-legged houseguests across the UK.

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What is a spider’s silk made of?

Spider’s silk is made up of chains of amino acids. In other words, it is simply a protein (see How Food Works for details on amino acids and proteins). The two primary amino acids are glycine and alanine.

See also:  What Do Wolf Spiders Like To Eat?

Spider silk is extremely strong — it is about five times stronger than steel and twice as strong as Kevlar of the same weight. Spider silk also has the ability to stretch about 30-percent longer than its original length without breaking, which makes it very resilient.

Check out the next page for some great related links and more.

Related Articles

  • How Spiders Work
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  • What’s the world’s deadliest spider?

More Great Links

  • Fiber Engineers, Meet Thy Master
  • The study of arachnids: Silk & Webs
  • Bioengineered Spider Silk
  • Biomolecular Self-Assembling Materials — Pretty deep article; figure 6 shows the structure of glycine and alanine in spider’s silk.
  • Kevlar

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How spider silk is one of the most versatile materials on Earth

Spiders spin webs out of silk, but they also use their threads as slingshots, submarines, and hang-gliders.

PUBLISHED September 12, 2019

Spider silk is one of the most versatile materials on Earth. Actually a protein created by special organs known as spinnerets, spider silk can be used for transportation, shelter, courtship, and all kinds of creative ways to trap prey.

Some spiders can produce more than one type of silk. A common orb-web, for example, may contain at least four different kinds, each adding a different component, such as strength, flexibility, and stickiness.

Equipped with such a versatile material, spiders have evolved to create a wondrous assortment of webs. There are horizontal sheet webs that catch falling prey and vertical latticework webs that intercept flying prey. Black widow webs are messy affairs, while funnel webs and lampshade webs can resemble three-dimensional sculptures. Spiders in the Theridiosomatidae family build conical webs that can fire a spider at nearby prey like a slingshot, while ogre-faced spiders nab their meals with hand-held nets. (Read about the spider that uses its web to shoot itself faster than a rocket.)

The redback spider of Australia spins a tangled web with sticky, “gum-footed” lines that stretch straight down to the ground like a beaded curtain. When ants or crickets brush up against one of these tendrils, the line snags the prey and then snaps, drawing the helpless creature up into the air where it will dangle until the redback decides to eat it.

“Some spiders produce a silk that is low in UV reflection and is also translucent, so insects can’t see it,” says Catherine Craig, an evolutionary biologist and author of Spider Silk: Evolution and 400 Million Years of Spinning, Waiting, Snagging, and Mating.

On the other side of the spectrum, there are spider silks that reflect ultraviolet light and appear blue at certain angles. In the tropics, there are even spiders in the Nephila genus that infuse their silks with carotenoids, which, when the sun hits them, makes the webs seem as if they were dipped in liquid gold.

Bolas spiders skip web-building altogether. These clever creatures lure moths in close with pheromones and then swat the insects out of midair with a single piece of sticky, weighted silk that they swing around like a mace. Gnaphosids shoot silk at their prey like Spiderman.

And they’re not alone.

Of the close to 50,000 spider species known to science, most do not produce webs at all, says Craig. But all spiders produce silk. The ways in which they use this material are as varied as they are fascinating.

Home is where the silk is

For hundreds of millions of years, before the evolution of webs, and even before there were flies to catch in them, spiders used their silk glands for shelter.

“Spider silk is incredibly strong and flexible,” says Catherine Scott, an arachnologist at the University of Toronto Scarborough. “It also tends to be very clean and have anti-microbial properties, because spiders don’t want molds and microbes growing on their webs.”

Spider silk is one of the strongest and most versatile materials in the world. Skilled architects and engineers, spiders use silk for shelter, for transportation, and for catching prey. This is a small sample of the different types of webs that the more than 48,000 species are able to create.

This family has more than 3,100 species, known for their “orbs,” or circular webs, commonly found in gardens and forests. Many build a new web every day.

This family of very small spiders is the second largest, with over 4,600 species, named for their flat, sheetlike webs. The spiders average less than 5 mm long.

Theridiidae spiders, such as black widows, create dimensional, irregular webs, also known as cobwebs. Sticky silk traps in the web are used to catch prey.

These aggressive spiders lie in wait for victims inside their dense, silk-lined burrows. The species found in Australia are the world’s most deadly spiders.

These spiders stretch the web’s anchor line, pulling it taut. When prey enters a web, the spider releases the line, launching itself toward it at high speed.

Spiders of this unique genus create a small, rectangular web that they hold and then drop onto passing prey like a net.

Trapdoor spiders are named for their silk-lined, underground burrows with camouflaged trapdoors that allow them to attack victims from below.

Purseweb spiders build camouflaged silk tubes up the sides of trees. They bite prey through the silk, envenomate it, and pull it inside.

Diving bell spider

The only spider species that lives entirely underwater, the diving bell spider stores a large air bubble in its web, which serves as both home and oxygen tank.

Taylor Maggiacomo, NGM STAFF. SOURCES: World Spider Catalog; Australian Museum

Spider silk is one of the strongest and most versatile materials in the world. Skilled architects and engineers, spiders use silk for shelter, for transportation, and for catching prey. This is a small sample of the different types of webs that the more than 48,000 species are able to create.

This family has more than 3,100 species, known for their “orbs,” or circular webs, commonly found in gardens and forests. Many build a new web every day.

See also:  When Spider Webs Unite They Can Tie Up A Lion Meaning?

Theridiidae spiders, such as black widows, create dimensional, irregular webs, also known as cobwebs. Sticky silk traps in the web are used to catch prey.

This family of very small spiders is the second largest, with over 4,600 species, named for their flat, sheetlike webs. The spiders average less than 5 mm long.

These aggressive spiders lie in wait for victims inside their dense, silk-lined burrows. The species found in Australia are the world’s most deadly spiders.

These spiders stretch the web’s anchor line, pulling it taut. When prey enters a web, the spider releases the line, launching itself toward it at high speed.

Spiders of this unique genus create a small, rectangular web that they hold and then drop onto passing prey like a net.

Diving bell spider

Trapdoor spiders are named for their silk-lined, underground burrows with camouflaged trapdoors that allow them to attack victims from below.

Purseweb spiders build camouflaged silk tubes up the sides of trees. They bite prey through the silk, envenomate it, and pull it inside.

The only spider species that lives entirely underwater, the diving bell spider stores a large air bubble in its web, which serves as both home and oxygen tank.

Taylor Maggiacomo, NGM STAFF. SOURCES: World Spider Catalog; Australian Museum

Some spiders, like those on the 300-million-year-old Mesothelae branch of the spider family tree, dig burrows on slopes and banks and line them with layers of gauze-like silk. Next, these spiders construct circular, hobbit-hole doors complete with a silk-bound hinge. Not only does this hide the spiders from predators and enable them to pounce on unsuspecting prey, but the doors seal the predators off from the world and allow the spiders to regulate the burrow’s temperature and humidity—and even protect them against flooding.

Purseweb spiders build silken tunnels that slink up the sides of trees. Most people never notice them, though, because the structures are covered in dirt and other bits of debris.

“You will almost never see the spider, because it is inside of that tunnel and it extends into the ground,” says Sebastian Echeverri, an arachnologist and science educator at the University of Pittsburgh. “And when prey walks along the tunnel, the spider feels the vibrations, and it will actually run up on the inside and bite through the silk and grab the prey with its fangs, envenomate it, and drag it back inside.”

And then there’s the diving bell spider.

“So, this is a spider that lives its entire life underwater by tying together some vegetation with its silken web,” says Echeverri.

These spiders can’t breathe underwater, though, so they make repeated trips to the surface to capture air bubbles with specially adapted hairs. Once back in their underwater vegetation dens, they then wipe these bubbles off and bring them into the web to form a tiny, oxygen-rich sanctuary where they can hide from predators and lay eggs.

“That’s a spider that just defies most spider-like things,” says Echeverri.

Getting around

While silk is an excellent building material, it can also be used for transportation.

Jumping spiders are constantly leaping across chasms, for instance. They protect themselves against falls by anchoring a silk safety line to their perch. This allows jumping spiders to crawl back to where they started if they miss their mark. It even allows change directions once they’re airborne with a quick tug of the drag-line.

Most spiders are tiny, but they can travel between trees or across enormous gaps through a process known as “bridging.” All the spider needs to do is let out a line of silk into the wind and then pull it taut once it connects to something out in the world. The arachnid doesn’t really know where it’s going, of course, but it beats crawling.

“And then I’d be remiss not to mention how spiders can fly,” says Echeverri.

Similar to bridging, numerous spider species are able to “balloon” up into the sky by releasing strands of silk that get picked up by the wind and Earth’s electrical fields. Ballooning spiders have been found floating more than two miles high and thousands of miles out at sea.

Watch a crab spider is survey the wind condition with its leg hairs and take flight.

Can you smell me now?

Spider silk isn’t just strong, stretchy, and sticky—it can be stinky, too.

“We know that female spiders have pheromones on their silk,” says Scott.

In a recent study published in Proceedings of the Royal Society B: Biological Sciences, Scott showed that male black widows can detect these come-hither scents from nearly 200 feet away and use them as a compass to find a female.

What’s more, Scott’s research showed that some males can make their way to a female even faster by following the drag-lines left by the males that have come before them. The males were even able to sniff out the difference between silk left by their rivals and strands laid down by males of another closely-related species, the false widow.

Getting it on

“Silk is a communication method,” says Scott. “It works chemically, using pheromones, but then for web-building spiders, it is also a dance floor used for male courtship displays.”

Partly to woo the female and partly to convince her he is a suitor rather than dinner, males of many species will tap, pluck, and otherwise send vibrations throughout the female’s web. Males may also remodel the female’s web by laying down silk of his own or destroy whole sections of it, perhaps in an attempt to hide the female from other males in the area.

Elsewhere in the mating and reproduction game, spiders use silk to safeguard their eggs and build nursery webs to protect their spiderlings. Males of some species use silk to gift-wrap food items, which they then give to females in an attempt to woo their favor, though sometimes a spider will try to cheat the female by wrapping up a rock or seed instead.

“By the time she gets to what’s inside and realizes it’s not food, he might have gotten away with a copulation,” says Scott.

Silk can also be used to tie a female up during courtship. This is called “mate binding” or the “bridal veil.” And while it may sound strange, this behavior may make the female more receptive to mating by bringing her sensory hairs into contact with the male’s pheromone-laden silk. (See a video of spider mate binding.)

Of course, the silk binding may serve a more straight forward purpose.

“Physically restraining her can also prevent cannibalism,” says Scott.

www.nationalgeographic.com

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