10/25/2019

The Tangled Lives Of Your Friendly Neighborhood Spider

33:23 minutes

Untangle the mysteries behind spider silk genetics in the latest video in our series, The Macroscope. This story is available in Spanish.


a camera slowly pans across a spider clinging to a web
Credit: Luke Groskin © Science Friday

Spiders were one of the first animals to evolve on land. And over the span of 400 million years of speciation and evolution, they’ve learned some amazing tricks. One of their trademarks? The strong, sticky substance that we call silk—every spider produces it, whether for weaving webs, wrapping prey, or even leaving trails on the ground for potential mates. 

But every silk is unique, each with different chemistry and different physical properties. Even a single spider web may use multiple kinds of silk. So how did spiders develop these wondrous fibers?

Cheryl Hayashi at the American Museum of Natural History shares her research into the variety of spider silks and the genomic clues to their origins. 

a black and white scene of a web woven between two twigs. a fly gets caught in the web and a spider in the left corner of the web unleashes a coil and the web releases around the fly, capturing it
A fly hits the web of the triangle weaver spider (Hyptiotes cavatus), and the spider releases the coil of slack silk and the web. Credit: Sarah Han

Spiders are also masters at manipulating their silk into high-energy weapons. Sarah Han at the University of Akron spins a tale about the triangle weaver spider, which can use its web as a catapult to effectively entangle prey.

two photos. on the left is a a mass of tan spiders. they are a colony together, with a larger spider on the left and a bunch of smaller baby spiders to the right. the second photo is of spiders cluster together feeding on prey. a larger spider lingers on the left
Two snapshots of family life in the huntsman spider household (Delena cancerides). Credit: Linda Rayor

Plus, while most spiders are solitary predators who will eat other spiders, a small number of species are social, living in colonies with siblings and parents. Linda Rayor at Cornell University peers into the lives of giant huntsman spiders and asks why some are so uncharacteristically cuddly. 

We asked you to show us the friendly spiders that have taken up residence in your homes and gardens. Here are a few of your crafty cobweb companions below!

See the full thread of spider buddies on Twitter!


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Segment Guests

Cheryl Hayashi

Cheryl Hayashi is a curator and professor of Comparative Biology at the American Museum of Natural History in New York, New York.

Sarah Han

Sarah Han is a PhD candidate in Integrative Biology and Biomimicry at the University of Akron in Akron, Ohio.

Linda Rayor

Linda Rayor is a Senior Lecturer and Senior Research Assistant in Entomology at Cornell University in Ithaca, New York.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. You ever look at a spider web? I mean really look at it. Whether it’s a beautifully organized orb weaver web, it could be a funnel or messy, fluffy cobweb, there’s a lot that goes into making that web. Right, there’s the design and shape, of course.

But then there’s the material. Spider silk is amazing stuff. It’s stronger than steel, but also, stretchy, sticky, and a deadly weapon for catching prey. And even more importantly, there is no one recipe for spider silk. Many spiders actually have several kinds of silk that they make, both for web building purposes, but also signaling to mates or even just hanging out, in case they fall from their perch.

How do they do it? It’s all really, really interesting. And here to spin the tale about the wonders of spider silk, Dr. Cheryl Hayashi, curator and professor of Comparative Biology at the American Museum of Natural History here in New York. Hi there.

CHERYL HAYASHI: Hey, there. Hi.

IRA FLATOW: Let me give out our phone number, 844-724-8255, if you want to talk about spiders and their webs. In just reading the kind of work that you’re doing, I had no idea about the spider silk and that there’s different kinds of it. Let’s talk about what it is first. What is spider silk, on a material level?

CHERYL HAYASHI: Well, if you look at spider silk, really zero in on it, it’s almost entirely protein. So we’re talking many, many, many, many individual protein molecules knitted together to make a silk fiber.

IRA FLATOW: Wow, and the spiders that don’t just use it for spinning webs, right?

CHERYL HAYASHI: Oh, no, no, no. That’s just one of the functions they have for spider silk. Depending on the spider, they use it to make homes, drag lines. Females wrap up their eggs in it. As you mentioned earlier, they make these silk lines that they put pheromones, so they put sense on it. They also use it to sail through the air.

IRA FLATOW: Wow. And silk is one of the prerequisites of a spider being a spider, right?

CHERYL HAYASHI: Oh, yes, definitely. You can’t be a spider without making silk.

IRA FLATOW: Does this mean that they all evolved from one silk spinning arachnid, perhaps?

CHERYL HAYASHI: Yes, that’s what we believe based on the fossil record. And when we look at all living spiders today, they all have the ability to make at least one kind of silk.

IRA FLATOW: Now when you say one kind of silk, that implies there are lots of different kinds of silk for use in different sections of the web?

CHERYL HAYASHI: Oh, yes. So there’s so many different kinds of silk. So first of all, most species make multiple kinds of silks. Many species make up to seven different kinds of silks. And when you look at, let’s say, a typical orb web, that’s the Charlotte’s Web type spider, the wagon wheel shaped web, when you look at that spider, there’s usually five kinds of silks went into making that web, sometimes six.

IRA FLATOW: And how does the spider produce all those silks from its one body?

CHERYL HAYASHI: Well, what I work on is, yeah, exactly that. How are they able to do that? Well, if you look inside a spider, there’s many, many, many silk glands, sometimes dozens, usually hundreds, in some cases, thousands. And each silk gland looks like– mm, picture a balloon. And so a silk gland would start off kind of looking like a deflated balloon. And the wall of the balloon would be the cells that can make silk protein. And those cells make silk protein, and the silk collects inside the balloon. And they just absolutely fill it up, and you get a nice, big, puffy silk gland inside a spider.

And remember now, there’s hundreds of these in a spider. And that’s where they get the silk from. And then the neck of the balloon– make that really long, and that becomes like a little channel, a duct, that leads to the outside of the spider. And that’s how the liquid silk from inside ends up on the outside of the spider, spun into a fiber.

IRA FLATOW: And when you have all that different kind of silk, what are their specific purposes in the web?

CHERYL HAYASHI: Well, there’s going to be one kind of silk that’ll be making the frame and the radii of an orb web. So that’s one kind. There’s another two silks that are used to make the sticky capture spiral, so one silk makes the thread and the other one makes a wet glue that goes on top of the thread. And there’s another silk that’s used just to stitch pieces of silk together. We call that attachment silk. And there’s another silk that’s used as a construction scaffold. The spider puts it out when it’s time to build the web and actually removes it while they build the web. And when spiders remove silk, they actually eat it.

IRA FLATOW: Wow. They recycle.

CHERYL HAYASHI: Oh, yes.

IRA FLATOW: Our number, 844-724-8255. We had a question from Ingrid on our Science Friday VoxPop app.

INGRID: Why do some spiders, like widows, make messy webs that are bad for catching bugs, while others, like orb spiders, make beautiful, elaborate webs that only last one night?

IRA FLATOW: What about–

CHERYL HAYASHI: Oh, OK. Well, I think, first of all, beauty is in the eye of the beholder. And I actually think black widow webs are quite beautiful. So actually, black widows are descended from orb web weaving spiders. So black widows actually can make all the same kinds of silks as an orb web weaving spider. They’ve just sort of changed the architecture of their web. And black widow webs are actually very, very good at catching prey. It’s the sticky part of their web is actually at the very, very bottom of the web. And they remake that bottom part every single night, actually, multiple times during the night.

And the question about why do some spiders have to remake their web, well, when insects hit the web, it damages part of the web. And if a web gets too damaged, then it’s not a good net anymore. So it’s just like if you repair a fishing net. So some spiders will repair their webs. Others will just say, ah, time to make a new one. And they’ll take the web down and eat the silk, and then they’ll spin a new web.

IRA FLATOW: They’re really busy all the time. I mean–

CHERYL HAYASHI: Well, they’re busy when they’re making the web, but these web-weaving spiders are sit and wait predators. So when they’re waiting, they’re actually quite still and just hanging out.

IRA FLATOW: You said one part of the silk was used for capturing their prey. What’s different about that part of the silk, or that kind of silk?

CHERYL HAYASHI: Capture silk is different from, let’s say, the frame of a web because capture silk is very stretchy and sticky. So the capture silk on a web, it allows the fibers– the silk fiber actually stretches. So rather than break like a more stiff fiber would, it actually stretches, which allows the web to absorb the energy of a flying insect. And also, insects literally stick to the glue that’s on the capture spiral.

IRA FLATOW: Wow. I want to see if I can get a quick call in before the bottom of the hour. Dory in Swampscott, Massachusetts, hi.

DORY: Hi, how are you?

IRA FLATOW: Hi, there. Go ahead.

DORY: So I was just calling because my daughter is a nature lover, and she actually inspired her entire family to fall in love with this giant spider that lived in a window frame and built a sort of tubular web. And eventually, we all fell in love with Shelob. We named her after Lord of the Rings. And we would check it daily to make sure she was getting fed.

And essentially, over a couple of years, we noticed she was still there, but we don’t know– we have, actually, one comment was the sad part was the landscapers accidentally killed her, and we were all very sad. But the other part was, was this the same spider living there year after year, or was it another spider that adopted this long tubular web and made it their own home?

IRA FLATOW: Great question. Thank you.

CHERYL HAYASHI: From what you’re describing, I think it was the same spider. So spiders, depending on the species, they can live year after year. In fact, some spiders can live over 20 years. And there are other spiders that will live less than a year. But from what you’re describing, I think it was one of the more long-lived species, and that probably was her web.

IRA FLATOW: 20 years. Which spider in particular?

CHERYL HAYASHI: Oh, yeah.

IRA FLATOW: Stuff that we would see around our house?

CHERYL HAYASHI: Well, spiders that would live multiple years, really long, they tend to be these trapdoor spiders and also tarantulas.

IRA FLATOW: Wow. Let me go to Erie, Colorado. George, hi, welcome.

GEORGE: Oh, hi, yeah. You often see a horizontal strand that a web is suspended from. And it’s several feet apart, and I do not understand how a spider can do that.

CHERYL HAYASHI: Yeah, that’s amazing. So spiders actually are able to– they’re actually able to release silk into air currents. And these air currents are often much more subtle than we might be able to detect. And the air current will actually– a little waft of a breeze will take a fiber from the spider to a distant branch. And when that silk line hits the branch, the spider can give a few tugs and can actually walk across. And then the spider will walk back and forth and kind of strengthen the line.

IRA FLATOW: Wow, that’s just amazing. Thank you, Dr. Hayashi, for taking the time to be with us today.

CHERYL HAYASHI: Oh, sure, thank you.

IRA FLATOW: Dr. Cheryl Hayashi, curator and professor of Comparative Biology at the famous American Museum of Natural History here in New York. And you can learn more and see our new video about her work from producer Luke Groskin. This is an amazing– Luke does great work. I’m telling you, this is at the top of the list. Go to our website, ScienceFriday.com/spidersilk. Slash spider silk on our website, ScienceFriday.com.

Now I want to bring in another researcher to fill us in on the spidey engineering of one very special spider web. Normally, when an insect hits a spider web, those strong, stretchy, silk fibers give and give and give until the insect is slowed to a stop, begins to get tangled. But the triangle weaver spider has a slightly different tactic. Here to explain more is Sarah Han. She’s a PhD candidate in Integrated Bioscience and Biomimicry at the University of Akron in Akron, Ohio. Welcome to Science Friday.

SARAH HAN: Hi, Ira. Thanks for having me.

IRA FLATOW: Tell me about the triangle weaver spider. What’s so special about its web?

SARAH HAN: OK, so the triangle weaver spider is this little spider that lives out in the forest, often in pine forests, and you can find it here in Ohio. So instead of the orb web that Cheryl was just talking about, it makes a triangle-shaped web. And what’s cool about it is that it stores energy in this web, kind of like a slingshot or a bow and arrow, and it uses the stored energy to help catch insects.

IRA FLATOW: And how does it do that?

SARAH HAN: OK, so what the spider does, if you picture a triangle-shaped web, the spider goes to one corner of the web, and its head is facing towards the triangle part. And it walks backwards with its back legs, and it pulls the web tighter and tighter. Just imagine pulling a slingshot back further and further. And this loads the web with elastic energies. The web is pulled taut, and the spider’s holding it under all this tension. When an insect hits the web, the spider senses that and it releases the web. The web springs forward, all that released energy, and the web sort of moves across the insect, entangling it in the sticky capture strand silk.

IRA FLATOW: Wow. So what keeps the spider itself from not flying off on the air when this happens?

SARAH HAN: So the spider does move forward with the web, but it is attached. It’s attached a line of silk to its spinner at the back near its back legs. It’s usually attached to a twig or a branch. So even though it is moving forward with the web, it’s not being flung off into space.

IRA FLATOW: Wow. So how quickly does this happen? And can you give us some idea on a human scale what it would be like for a person?

SARAH HAN: Sure. So the spider is accelerating at around– well, the max we found is 770 meters per second squared. So one way to think about this, if you think about in car ads, they say 0 to 60 in five seconds. Here, this would be 0 to 8,600 miles per hour in five seconds.

IRA FLATOW: Wow.

SARAH HAN: That’s a pretty fast acceleration.

IRA FLATOW: So why would this be more effective than just letting the insect get tangled the traditional way?

SARAH HAN: So the traditional way the insect is tangled, the spider has to get that insect really quickly, usually in just a few seconds, where the insect may struggle free, because it doesn’t want be eaten. With this process, the spider senses the insect, and it often reacts in just fractions of a second. And that lets the web go and starts the tangling process. So it’s like the capture process has been started very quickly and without the spider having to actually cross the web and physically grab the insect.

IRA FLATOW: So it’s safer, then, for the spider.

SARAH HAN: It is safer. And what’s interesting is this family of spiders does not have venom, so maybe that’s another reason that they might have evolved it.

IRA FLATOW: Wow. Let me just say I’m Ira Flatow, and this is Science Friday from WNYC Studios, talking with Sarah Han from University of Akron. What got you interested– this is so fascinating. How do you discover these things?

SARAH HAN: The spider itself?

IRA FLATOW: Yeah, and how it acts and catapults and all that kind of stuff. You have to do a lot of spider observation?

SARAH HAN: It is a lot of spider observation. So this was actually my first project when I first started the program in Dr. [INAUDIBLE] lab. And I was just starting because I have a background in entomology, which is insects. So I didn’t know that much about spiders. So he was like, just go out into the woods. Observe spiders just start doing things. So I found these little spiders in these triangle webs, and I was like, what are these? And he was like, oh, these are triangle weavers. They do something, and they have an unusual prey capture strategy. Why don’t you just start looking more into them?

So I started doing some experiments, and we noticed this– I mean, the cool behavior had been observed before, but not really quantified. And then one of my professors, and I guess, colleagues now at Dr. Henry Astley was like, hey, that’s an example of external power amplication. It’s storing energy in the web, and that sort of brought us further and further.

IRA FLATOW: Well, then if you’re talking about power amplification, whatever, could you look at a spider web as actually a tool? We talk about animals using tools and using their intelligence to build tools. Is the web a tool that the spider has learned how to use?

SARAH HAN: I would personally count the web as a tool because a tool in animals is classically defined as something external to your body that you’re refusing to effect a change on the environment. And even though the spider is creating the web, it’s still using it external to its body, much as we would maybe braid a rope out of our hair. So that we would still count as a tool.

IRA FLATOW: Let me see if I can get a call in before we have to go. Jonathan in Minneapolis, hi, Jonathan.

JONATHAN: Hello.

IRA FLATOW: Hey, there. Quickly.

JONATHAN: All right. I work for 3M and all sorts of sticky stuff there. And I was curious, what is the glue or the adhesive on the spider webs made of?

SARAH HAN: So in spiders that use liquid glue, it’s made of salts and low molecular weight compounds, and just a bunch of other things, and a lot of water also. For the triangle spiders, they actually use a dry adhesive called [INAUDIBLE] silk, which is just like little, very fine, puffed silk that mechanically entangle the insect. So different spiders use different kinds of adhesive.

IRA FLATOW: 3M invented Post-It notes. So maybe they’re taking notes from you about the next kind of glue they would learn to– can a spider tell us about making glue? You think we can learn something?

SARAH HAN: Oh, yes. A lot of people, even in the lab that I’m in, are always looking to glue for a better adhesive that responds well in different humidities, which spiders do really well.

IRA FLATOW: Yeah. Well, it sounds like you have an exciting job, an exciting–

SARAH HAN: [INAUDIBLE]

IRA FLATOW: –exciting career ahead of you.

SARAH HAN: I hope so.

IRA FLATOW: Are you going to concentrate on spiders as you–

SARAH HAN: I would like to, but we’ll see how it goes. There’s so much in the national world that’s exciting to study.

IRA FLATOW: Could not say it any better. And I want to thank you for taking the time to be with us today.

SARAH HAN: Thanks for having me, and thanks for all the hard work you and your team do.

IRA FLATOW: Thank you. Sarah Han, who soon will have her PhD, we hope. She’s a PhD candidate in Integrated Bioscience and Biomimicry at the University of Akron in Ohio. We’re going to take a break in our spiderbration. See what I did there? It’s not over. We’ll talk about social spiders– yes, they exist– answer your questions, have lots more dad jokes. So stay with us. We’ll be right back after this break.

This is Science Friday. I’m Ira Flatow. I want you to picture a spider now, any spider. Maybe she’s hanging out on a web, waiting for dinner to land there. Or maybe he’s prowling the ground, hunting a mate. But chances are you’re not thinking about a colony, right? You see in your mind just one spider alone, like we usually do, on a web. There’s a reason for this picture of the solitary spider. Most of them are loners. It makes sense. They’re predators, and they’re more likely to eat a fellow spider than to cuddle with one.

But my next guest researcher says there are rare exceptions– spiders that live in colonies of siblings. And she says the family that stays together seems to eat better together. Here to tell the story and answer some more of your spider questions is Dr. Linda Rayor, senior lecturer and research associate in Entomology at Cornell in Ithaca. Welcome to Science Friday.

LINDA RAYOR: Oh, thank you so much. That was a great intro.

IRA FLATOW: Was it? Did I get it right?

LINDA RAYOR: I would say the family that stays together preys together.

IRA FLATOW: [CHUCKLES] And you work with a group of spiders from Australia– the huntsman spiders, right? What are they like?

LINDA RAYOR: Oh, huntsman spiders are lovely spiders. Huntsman are medium to absolutely huge spiders and often very attractive spiders. And the huntsman are characterized by having legs that are called latrograde so they essentially go out to the sides, which mean that they can run forward very rapidly, but they can run as rapidly sideways. So they’re really cool spiders. No webs at all.

The spiders that I study live in a number of places, but the main group that I study that I sent you a photo of is delena cancerides, which is found in Australia under the bark of dead trees, especially Acacia and a few Eucalypts. And so they’re quite flattened, kind of dorsal ventrally flat. And they’re fast and they’re beautiful.

IRA FLATOW: And they live together in a colony?

LINDA RAYOR: Yeah, they live in a really interesting family group. So each colony is founded by an adult female, who has up to five different clutches of youngsters. And what’s really cool about these guys is that her offspring stay with her until they reach sexual maturity at about a year. But we’re talking spiders that are about the size of the palm of my hand. So they’re not dispersing until they’re absolutely marvelous predators who could easily kill one another, but don’t. And so what happens–

IRA FLATOW: And why is that? Why don’t they?

LINDA RAYOR: That is the eternal question when you’re studying social spiders. There are actually lots of benefits by living in groups for social spiders, both mine and other people who are studying even more socially complex spiders. With my spiders, they live in a protected retreat with mom defending it and with the older spiders defending it. The retreat is silked in, so big bull ants or other predators can’t easily get in to get them. And mom is actually fending off other huntsman spiders or other predators that might try to get in.

IRA FLATOW: It sounds like mom is keeping the peace there.

LINDA RAYOR: Mom is definitely keeping the peace. And also, my former grad student, Dr. [? EriC Yip, ?] did wonderful work where he found that spiders that had older siblings in the group were in far better condition than the ones that didn’t have older siblings. And it’s really obvious why. What happens with the social spiders is they’re able to catch large animals, are able to catch larger prey, which they’re willing to share with their younger siblings. So these younger animals get access to far, far bigger prey than they would on their own. So it’s a good deal for them.

And I’ve got to admit, the older siblings don’t necessarily want to share their prey. If they catch it away from the retreat, they’d rather eat it and then come home at dawn. But they’re nocturnally active. But what’s clear is that lots of food is coming into the retreat that littler animals get access to and are able to share.

IRA FLATOW: Why did these spiders adapt to be social when so many other species stayed solitary?

LINDA RAYOR: That’s one of the essential questions of what I’m asking, and I’m not sure I have an easy answer. My collaborator in Australia, Dr. Dave Roll, has suggested that with climate change in Australia, there were less and less places, these thin, protected, diurnal retreats, that they could live in. And with climate change, there are relatively few places that they could live. And so there are advantages to staying together.

IRA FLATOW: That’s interesting.

LINDA RAYOR: Eric’s dissertation showed another possibility. What we know is that for these spiders, there just aren’t enough retreats to go to. So it looks like there’s a lot of places. But what we’ve done is we’ve counted how many potential places young spiders can disperse to. And for these spiders, there’s nowhere to go. The habitat is between 100% saturated, and the absolute best site we’ve ever seen had about 82% saturated.

So what’s happening is these adolescent spiders are sticking around at home because if they disperse to found their own colony, they’ve got nowhere to go. And we’ve taken measures between 50 and 100 meters, and there’s nothing. There’s literally no place that these spiders can move to. So what they’re doing is they’re staying at home until they reach sexual maturity, until they’re larger and tougher and feistier.

And then bigger animals try to take over other animals’ colony. So Eric’s research showed– he put out nest boxes and what he showed is bigger adult females were taking it over from smaller females. So there’s a lot of competition.

IRA FLATOW: I’ll bet. Also, I hear that tarantulas are among your favorite spiders.

LINDA RAYOR: Tarantulas are among my favorites.

IRA FLATOW: Why is that? What is so– people are, I think, more scared of tarantulas than any other spider. What makes them your favorite?

LINDA RAYOR: Interesting. Huntsmen are my favorite, but tarantulas are second. I think tarantulas are really big. I had no idea. When I started teaching, I brought spiders in to my course because they are big enough that I could show things. And it turns out they’re incredibly diverse. Many are arboreal. I’m especially a sucker for arboreal tarantulas that are just gorgeous and have a very different build than the terrestrial tarantulas.

I’ve gone on a phase where I just like blue tarantulas right now. And it turns out there are a lot of gorgeous tarantulas, many of which also live in groups. I’m stuck on social behavior. So I’m particularly interested in spiders that live in family groups with their mother and with other adults in a colony. And I’m afraid a bunch of the social tarantulas or the– yeah, I’ll go with social tarantulas– don’t actually do that much that’s totally cool, but enough of them do.

Recently, I got a colony of– they’re called Socotra island blue, but monocentropus balfouri. And they’re siblings and they dig a burrow underground. And then they pile in like sardines on top of one another when they’re not out feeding and wandering around. It’s crazy.

IRA FLATOW: That’s crazy. We have some calls. Let’s see if we can get to them.

LINDA RAYOR: Sure.

IRA FLATOW: Let’s go to Linda in Portland, Oregon. Hi, Linda.

LINDA: Hi, there, Ira.

IRA FLATOW: Hi, there.

LINDA: Thanks for taking my call.

IRA FLATOW: Welcome.

LINDA: Yes, I have a question. I, for the past few weeks, have been watching this spider that’s on my back porch and on a Japanese maple that’s in a pot on my back porch. Originally, it would build its web sometime during the day, sometimes at night. And then about two weeks ago, I noticed that although it used to just roll itself up in a leaf at night I suspected to keep warm, now it is just wrapped up in that leaf, and I’m wondering is it hibernating because it hasn’t come out in a while. And I’m worried because the leaves are starting to fall off the maple tree. So what’s going to happen to this little spider?

LINDA RAYOR: Can I answer?

IRA FLATOW: Sure, please.

LINDA RAYOR: Sure, so a number of different options. It’s possible that what your spider’s done is wrapped herself in a retreat so that she can malt in it, and she’ll be protected during this risky period. And she’ll grow to another [INAUDIBLE]. The more likely option is that she has laid eggs in this leaf, and she’s about to die over the winter. And so you’ve got an egg sac in there. I think those are the main options you’ve got.

IRA FLATOW: Hm. That’s quite–

LINDA RAYOR: But the truth is, is orb weavers die this time of year. It’s sad, but they leave eggs that over winter.

IRA FLATOW: You mentioned the– I think when we began to speak, I mean talking about these social spiders, did I hear you say that they don’t build webs? They do not make webs.

LINDA RAYOR: Yeah.

IRA FLATOW: But the definition of all spiders we heard from one of our other experts is that they have the silk. So your spiders do have silk also?

LINDA RAYOR: All spiders produce silk of some sort. But a very large group of spiders, including jumping spiders, wolf spiders, huntsman spiders, and crabs spiders, have given up using a prey capture web. And so all spiders use silk to bind their egg sacs. They might use it for drag lines as safety ropes and any number of things. But they don’t all use webs to capture prey.

IRA FLATOW: That answers that question.

LINDA RAYOR: And I actually prefer animals that don’t use silk.

IRA FLATOW: OK, well, we had a message from Rod on our Science Friday VoxPop app about a cool spider living in his house.

ROD: Yes, we have these little black and white crab looking spiders that live in our house. They eat aphids and small insects and other spiders that bite us. And so we let them have the run of the house. They’re really kind of cool.

IRA FLATOW: Linda, you find that spiders are kind of cool, too, right?

LINDA RAYOR: I absolutely find spiders are cool. Once, I assigned my spider biology class to record what spiders were in their dorm rooms, identify what the spiders were in dorm rooms and apartments all over Ithaca, New York. and of course I did it myself, and when I realized we had 85 spiders, mostly baby cellar spiders in the house, I realized I needed to do something different. But largely, they’re good.

IRA FLATOW: I’m Ira Flatow. This is Science Friday from WNYC Studios, talking with Dr. Linda Rayor, a senior lecturer and research associate in Entomology at Cornell University. About spiders, let’s go to the– oh, so many people. Marty in San Jose, hi, Marty.

MARTY: Hi, good morning. I took a trip to the Amazon a few years ago, included camping, and woke up in the morning with tarantulas crawling all over the mosquito netting, which was a bit startling. The question I had was, how does spiders avoid ensnaring themselves? And the other question is, is there any difference in the web or silk between poisonous and non-poisonous spiders?

IRA FLATOW: OK.

LINDA RAYOR: As far as I know, there’s no difference in silk between poisonous and non-poisonous spiders, at least, as your previous speakers mentioned. There’s different kinds of silk that different kinds of spiders have. But if you were to look at something like cobwebs spiders, as far as I know, there are absolutely no differences between a black widow and a house spider, which is not venomous to humans.

IRA FLATOW: Do you think that most people don’t appreciate the spiders living in their garages and basements and things like that?

LINDA RAYOR: I would think that they would be less appreciative of the insects that the spiders are feeding on in their houses. So I think spiders are awesome to have in your house and certainly in your garden.

IRA FLATOW: So if this spider is there, then it may be eating predators that you don’t like and you don’t want to have around.

LINDA RAYOR: They’re certainly eating prey. People ask me why they have big [INAUDIBLE] spiders or wolf spiders in their basement, and essentially, it means that there’s cracks in the foundation that the spiders are getting through. So it’s an indication that you have other things coming in.

IRA FLATOW: We talk a lot about the black widows, the brown recluse, the spiders people are scared of. Give me an idea of some spiders that we can look for in our backyards and we might find less intimidating.

LINDA RAYOR: Well, certainly the black and yellow garden spider or [INAUDIBLE] is gorgeous. It’s a stunning orb weaver that uses stabilimenta or those zigzags in the web, possibly to attract prey, possibly not. But beautiful spider. I think jumping spiders, you could start a fan club on the Cornell campus of jumping spiders. They’re like the primates of the spider world. Really quite smart, good vision. They’ll follow you. They’ll pay attention to you and look around to see what you’re doing. So the jumping spiders are awesome. Personally, I love having– most of us are not going to find tarantulas in your backyard, but they’re awesome when you do.

IRA FLATOW: Do they make good pets?

LINDA RAYOR: They’re actually marvelous pets. They are not supremely active pets, but a number of them do really interesting things.

IRA FLATOW: All right, I’m going to leave it right there, because we’re running out of time. Thank you for your work, and thank you for all that knowledge that you gave us about spiders. Dr. Linda Rayor, senior lecturer and research associate in Entomology at Cornell, thank you for joining me today.

LINDA RAYOR: Thank you very much. It was a pleasure.

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