share interactive transcript request transcript/captions live captions
download
|
MyPlaylist
CHARLES JERMY: Good evening and welcome to tonight's lecture. My name is Charles Jermy, and I'm the associate dean of the School of Continuing Education and Summer Sessions. And this is our first lecture. So if that's not why you're here, you're in the wrong place.
I have to tell you that in the advent of an emergency, which we don't expect, you should exit sit quietly through the doors through which you entered or the doors here. I also want to express my gratitude to the college of agriculture and life sciences for their donation of the use of this auditorium, the David L. Call Auditorium, and we really appreciate that. And finally, our second lecture will not be Steve Squyres. Steve Squyres had to go to a meeting in Japan, and so he won't be with us. Instead, Professor Lisa Kaltenegger, the director of the Carl Sagan Institute-- and that's a brand-new new institute-- will be telling us about potentially habitable planets beyond our solar system.
But tonight's lecture-- Spider-Woman, Jessica Drew, first appeared in Marvel comics in 1977. Since then, a number of other spider women have succeeded her. Cornell was a little late to the arachnid scene with our own spider woman, but after 21 years, ours remains the one and only. Dr. Linda S. Rayor is an award-winning senior lecturer, and she has been a member of the Department of Entomology in the College of Agriculture and Life Sciences since 1994.
She is the world specialist on the 11th largest spider group, huntsman spiders, known for their sociability, size, speed, and mode of hunting. Although she won't be talking about this particular spider family tonight, if you're interested, please ask her about them in the question and answer period that will follow her lecture. Among the classes Linda has developed and teaches are two that are experiential.
One, the naturalist outreach practicum, is an innovative, interdisciplinary service learning course that provided students with opportunities to do effective scientific outreach and to organize outreach events. Research shows that training undergraduates how to do such outreach greatly enhances the probability of them going on to become STEM teachers or to continue doing informal science education that communicates the value of science to the public. In 2003, Linda was asked to conceptualize and organize an insect fair for the Department of Entomology.
Since that time, she has coordinated or co-coordinated several of the major events, called Insectapalooza, that have become important community outreach events for the department that appeal to both children and adults. Linda is also actively involved with the New York State 4-H programming through the development of naturalist outreach STEM videos on YouTube and through her participation in 4-H events and the New York State Fair's 4-H Youth Bureau-- Linda S. Rayor, A Romance with Spiders, 50 Shades of Arachnids.
LINDA RAYOR: Thank you very much. That's very nice. Thank you. I'm really pleased to be here. Bud and I were just talking. I think I gave a similar talk, like, 2000 or 2001, and I'm delighted to be back. So I get asked many questions. But the question I get asked the most often essentially comes down to, how did a nice girl like you get interested in spiders? Well, let me tell you.
I always wanted to be a scientist. I was really encouraged to be a scientist from early on. I loved animals. This is me at-- wow, I can't turn. This is me at three petting a cat, and it was just ecstatic. And these are the different animals that I've worked with in my research career.
But I'm from Denver, Colorado. How many of you are from the West? OK, a few of you. So I'm from Denver. Denver is really high. It's really dry. I literally don't remember seeing spiders until I was an adult. I literally have no recollection of seeing anything of any importance. I wasn't necessarily scared of spiders, but they weren't part of my life.
And coming from Colorado, I saw big animals up in the mountains. This was very cool, but that's the kind of animals that I was familiar with. I finished grad school studying the social behavior of the Gunnison's prairie dog. But my first semester in Kansas was really kind of interesting. I had kind of a silly job where I was walking around in fields and finding markers in the experimental station.
So I was outside a lot, and you've got to understand-- you have no idea what a rich habitat this is. So I went from Colorado to Eastern Kansas, and it was like I'd moved to the rain forest. It was my first real experience with the eastern deciduous forest. And I was ecstatic, and I was seeing all these cool insects. But especially what I was seeing were spiders.
And like I said, spiders were really new to me. Just a minor detour-- I got an undergraduate degree in molecular biology. And before my senior year, I did an internship studying primates at the Brookfield Zoo. And after that, there was no going back. It was clear animal behavior was the field for me.
So I didn't even know that spiders weren't insects when I started grad school. I'm embarrassed to admit. So I started bringing back these totally cool spiders like this-- I had no idea what they were-- and was bringing them to entomology and grad students and showing them, going, look at this jumping spider. This is so cool. What is it?
And the entomology, or the study of insect, students would look at me and say, these are spiders. They're not insects. They don't matter. I encountered uniform snootiness, except for one really cute guy who was also interested in spiders. Literally, our first date was keying these spiders up.
Students in my spider biology class would've known this within the first week and a half. But we took a very long evening, and I think, oh, my God, this guy's just gorgeous. Anyway, so we decided to study spiders together to see if we were scientifically compatible. And so eventually I fell in love with this guy, and we studied spiders together. And eventually, I married him.
And so this is Dr. Cole Gilbert, my husband. Would you raise your hand, or you're not going to admit it?
[APPLAUSE]
So as of today, Cole is the new endowed director of undergraduate biology at Cornell. So anyway, basically for me, spiders have been fun times. They've been wrapped up in romance and interesting biology from the very beginning. I have really liked spiders, and they are my romance. This is the thank you note on my wedding invitations, just to show you how nerdy we were because I look back and go, did I really do that? We really did that.
OK, so you've already got an introduction. Basically, a teach spider biology. I teach insect behavior. I teach a course, Naturalist Outreach, on how to do effective scientific outreach. I was in two seasons of the Discovery Science show, Monster Bug Wars. And if you get a chance-- how many of you actually have seen Monster Bug Wars? How many of you have seen it?
OK, relatively few-- I'm going to hype it because monster bug wars is, if you're interested in insects and spiders, it's a remarkably good show. It's got a really stupid name, but the photography is just marvelous. And they were really good about responding to comments about how to improve the biology-- so nice show.
OK, last end of hyping me up-- 4-H and now UNICEF has been supporting the production of YouTube videos that have a combination [AUDIO OUT] content and are just largely very appealing. Or we hope they're very appealing. They are 6 to 10 minutes long. We've just been in a series of film festivals. Pollination and Winter Adaptations have just come out. There are about 23 videos. It's on YouTube, naturalistoutreach channel, and I hope you'll go back and look at it. I think they're fun.
OK, so the second question that I get asked the most essentially comes down to, are daddy-long legs the most poisonous spiders in the world? And the short answer is, no. There are two spiders that are known as being daddy-long legs. The first one are the cellar spiders, in the family Pholcidae.
And I don't like to name daddy-long legs because it's a really vague name. So these cellar spiders in fact have venom, but it's really weak. Not only do they have weak jaws, but they've got venom that just isn't important at all, certainly not to humans. It might be to insects, but not to us. The other one are not spiders but are other types of arachnids.
And these are the harvestmen. Harvestmen don't produce venom at all, so they're not venomous in any measure. So this is a total falsehood.
This is a really interesting urban myth that I would like to talk about because it's an odd one. Basically, I forgot to look up when this happened, maybe six years ago or so. And what happened was an Australian photographer took a picture of the Australian black widow, the redback widow, being killed by a cellar spider. And from this, they concluded that it must be more venomous than the black widow, or the redback widow.
And they showed it to an arachnologist, a friend of mine, and he said, please, please do not tell this story. This is incorrect. This is not so. But the photo was a good one. It got published, and almost immediately it went around the world with people saying, well, it must be that this cellar spider or this daddy-long legs is more venomous. That's not it at all. What it is is when these spiders encounter one another, the cellar spider has really, really long legs and is able to wrap up the black widow, or the redback widow, before it is able to bite it. So in this case, long legs win out over venom.
OK, what I'm going to be doing today is talking to you about spiders. And spiders really are the dominant terrestrial predators on earth. You know, if you were to come up with other predators-- wolves, there aren't that many wolves. But there are spiders all over the world, and they're eating lots and lots of insects and are terrifically important ecologically. And with this photo, what I hope you get out of it is that they're beautiful. Not all spiders are beautiful, but there are a lot of really beautiful and very diverse spiders.
OK, how many mammal species are there? Anybody? Raise a hand. You can only be wrong.
SPEAKER 1: 500.
LINDA RAYOR: 500, higher than that, but not that much higher-- how many?
SPEAKER 2: 600.
LINDA RAYOR: 600, a little higher-- Howie, how many? 5,000? OK, on the order of 5,000, a little bit higher than that but not much, right around 5,000 mammal species-- and if you look at the mammals, basically what you have is you have rodents and bats and then the other mammals. And my last count was 5,490 mammals.
But in contrast, if you look at the jumping spiders alone, there are-- I need to look at my number-- there are 5,818 species as of yesterday, jumping spider species that have been identified. Of the spiders, there are 45,500-plus spider species that have been identified. And it's estimated that there's probably on the order of 170,000 if all spiders were identified. So there's a lot of spiders out there. There's a lot more spiders than there are mammals out there.
This is a beautiful painting by Francie Fawcett. It's old now, so the numbers aren't right. But what I want you to see is this is a homunculus, or basically it shows the relative size relative to the number of species out there. And what you can see is insects dominate, no question about it.
And here she used a mite to represent the arachnids. This is how many arachnids, and then you can see how many mammals there are. So put it all in perspective. There are a lot of spiders-- not as many as insects, but they're important, regardless of what those entomologists told me many years ago.
OK, so spiders are found essentially everywhere on Earth. There are two places where spiders are not found. They are not found in the ocean, and they're not found in Antarctica. They're found in the Arctic. They're found on the top of Mount Everest. And what's interesting about spiders on Mount Everest is-- you know, this is really high and cold-- where they seem to differ is that they've got anti-freeze in their blood but are basically the same spiders that you find elsewhere.
There are millions of spiders, especially in the tropics. So this is a picture that I took I think in Panama. And in a tropical rain forest, there are an enormous number of spiders. But if we were to go-- let's say, the ag quad was an old-growth field late in the summer when the baby spiders have been born. It's estimated that an area that size would have 2.25 million spiders in it. There are lots of spiders out there.
OK, so this is a picture from the Galapagos. Darwin reports being on the HMS Beagle and suddenly having thousands of spiders drop onto the deck of his ship. What happened? Does anybody know?
SPEAKER 3: Parachuting?
LINDA RAYOR: Parachuting, not quite.
SPEAKER 4: Eggs carried in a storm?
LINDA RAYOR: Eggs carried in the storm-- actually, no, anybody? Yes?
SPEAKER 5: [INAUDIBLE].
OK, right, so what you've got is this is what's known as ballooning, where basically what happens, the spider puts its abdomen up in the air. On a warm day, you know how heat rises? They're releasing silk, and the silk gets caught in this warm air. And it acts like the tail of a kite and wafts the spiders into the atmosphere.
Now, this is a good way of dispersing. They're able to move at relatively low levels, but they also go up into the highest reaches of the atmosphere. And a friend of mine has done some really interesting work where he has shown that the spiders that are ballooning-- I mean, they don't want to stay up in the earth forever-- the spiders are able to curl in different ways so that they're able to come down to the ground.
What this means in practical terms is that spiders are some of the first animals that move into really disturbed habitats, like, say, a volcanic eruption. It's the spiders that are some of the first animals to arrive there. So they are able to disperse relatively easily.
Now, I need to be clear. These are small spiders that are dispersing. You don't have tarantulas that are ballooning through here. It's a great image, though, isn't it?
This spider is the diving bell spider. It's found in Europe, a fairly large spider that literally lives underwater. And when it's living underwater, what it does is it builds a silk web. Evidently, their bellies are quite hairy. And they will come up to the surface of the water, get oxygen-- kind of a bubble on its belly-- come down, release it under the diving bell, and hunt and raise its young and do everything underwater. And they're found in ponds all over Europe, and evidently they've got a pretty nasty bite. I've never seen them, but would love to.
OK, so what traits are characteristic of spiders? Yell it out. Eight legs, absolutely-- what else? Eight eyes? I heard eight eyes. What else did I hear? Two segments, so two body parts, what else? Venom, silk, absolutely, silk matters. Hair, but that's not what makes a spider a spider. Anything else? Book lungs-- all right, you guys are good.
OK, so here are the main body parts of a spider. There's the cephalothorax and the abdomen. The cephalothorax is a combination of the head and the thorax. Most spiders have eight eyes. A relatively small number have reduced the number of eyes to six eyes, but basically spiders have eight eyes.
They have leg-like structures on either side of their mouths that are known as pedipalps or palps, and these palps are terrifically important and have been modified in interesting ways, both in the spiders and in other arachnids. In addition, at the back end of the abdomen, they've got long, muscular spinnerets. Not all of them are long, but they've got these muscular spinnerets. And this is what the silk comes out of. I'll talk about that in a moment.
So all spiders and the other arachnids have chelicerae mouth parts. And basically in the spiders what this is is the base of the fang and the fang itself with the mouth behind it. So they don't have jaws as such. What they've got are these chelicerae mouth parts, and the details are less important. This is one of my spiders. This is one of these guys, a social huntsman spider, and this is a face anyone could love.
And what you can see here are eight eyes, often in two rows, and then this is the base of the chelicerae. And the fangs, if you could see them, are underneath the base. OK, you've mentioned silk, and silk is absolutely key to spiders. All spiders produce silk. They don't all produce capture webs, but all spiders produce silk.
In the ones that use fancier silk, like your orb weavers, they have as many as seven different kinds of silk. And what's interesting about silk is that they're found in a gland in their abdomen. And the silk is liquid in these glands, so, you know, amorphous liquid. As it comes out through the spinnerets, there's some sort of a reorientation that happens so that the silk ends up in a highly structured form that has alternating, exceedingly, exceedingly strong sections, alternated by very amorphous, stretchy sections.
So the thing about silk, the thing that makes silk so awesome, is that it's this combination of incredible strength and stretchability. Just let me clarify. This is an orb web, and here you see the silk coming out of the spinnerets. And I should add that the spinnerets are covered with spigots so that spigots come into each of the up to seven different glands. And they're able to mix and match the silk for many different functions.
Even if they don't build a web, silk is absolutely key to the lives of spiders. It's used in drag lines. It's used in covering the egg sac. It's used as a mat that the spiders may molt on. It's used in a huge range, in all aspects of spider's lives.
I'm not going to talk a great deal about webs this evening, but what I want you to know is that spiderwebs are essentially a way for-- you know, the spider might be big. It might be the size of my thumbnail, but it can have a web this large. And so instead of the spider just knowing what's touching its body, it's able to hold onto its web and find prey over a much larger range. Its information about its world comes through the webs.
I was talking to my 4-H students today, and one of the things about webs is, what makes a good web? Well, you don't want prey bashing through the web. You also don't want prey that hits the web, and the web is so strong that they bounce out of the web. So it's this combination of strength and flexibility. Stickiness helps hold on to the prey and helps the prey get entangled in the webs. So webs are really important for spiders.
This is a gorgeous picture of a golden orb weaver, or Nephila. And these spiders, body like this, a big female has a leg span as big as the palm of my hand. And I have seen webs as big as two meters across-- very, very long, very, very strong webs. I once wasn't paying attention and walked into one of these webs and literally bounced off like I'd hit a trampoline. They are so incredibly strong.
OK, so this is a Sydney funnel spider. Any Aussies in here? The Australians think this is the most poisonous spider in the world. It isn't. It isn't. It's the second most poisonous spider. Anyway, what I want you to see with this picture is you've got-- funnel webs are related to tarantulas. It's rearing up, and [AUDIO OUT] see is they can choose to move their fangs.
So it's got its fangs up. All spiders have a very narrow esophagus, and so they're not eating solid food. What they're doing is they have hollow fangs and they attack their prey, inject venom of some sort, and then they will regurgitate digestive enzymes out through their mouth and liquefy the prey and often crunch it up with its chelicerae and then essentially be sucking up a protein milkshake. So they have external digestion.
I just wanted to show you this. The Sydney funnel web is a totally cranky spider. I cannot come up with an equivalently cranky spider. But what you can see here is these guys will rear up so that they're ready to strike. And if they strike, they strike repeatedly. And they literally drip venom out of their fangs and will stay there for a long time. What I want you to see with this image-- do you see those red hairs? These are the hairs that are found on all spiders that are essentially acting as a filter as a spider is liquefying and sucking up its prey.
What do spiders eat? All spiders, with very, very few exceptions, are eating living prey. They're going after small invertebrates, especially insects. But a number of them specialize on killing other spiders or eating spiders, other invertebrates.
There are a few-- and this is a big deal when it happens-- where some of the large spiders with super strong webs, like the Nephila, are able to capture vertebrate prey. So small birds or bats get stuck in their web, and they'll eat these. But this is exciting because it's so rare. It's a man bites dog sort of thing.
There is one spider that has been found in southern Mexico, found on various acacia-like trees, that produced-- do you see these little globules? These are Beltian bodies that are really high in lipids and are obviously plant material. This one jumping spider, about 80% of its food is this nutritious plant material. And then they hunt a little bit. And this is so exciting because it's so different. Essentially, all spiders are predators, and they're eating living prey.
OK, I just wanted to give you an idea of the relative size of prey. Basically, they can go as adults from microscopic sizes all the way up to dinner-plate sized tarantulas, quite a huge range. Predation matters to spiders. When I started studying spiders, I was absolutely convinced that spiders were these amazing predators and all they did was prey on things and they were totally tough and all this. Not actually so-- they're all of that, but there's more.
Basically, there is a number of animals that specialize or happily eat spiders. None of the spiders are chemically defended in any way. Some of them have spines and various other features, but basically spiders are juicy bits of protein. Birds eat them. Monkeys eat them. Coatimundis eat spiders. But really the toughest predator on spiders are the spider wasps.
And what these spider wasps do is they will paralyze the prey. There are two different kinds of spider wasps-- Pompillid and Sphecid wasps. They are all over here in Ithaca. I see them at main garden all the time. Very distinctive, often very shiny wasps, on the Pompillids, they've got long legs, and they're kind of twitchy wasps as they're looking around for these spiders. And then what they do is paralyze them.
So let me tell you about one of the coolest things I ever saw in terms of spider predation. I was in Costa Rica. I was doing research on cellar spiders, and there was this rustling on the ground. And it's a snake. It wasn't a snake. What it was was it was a young female tarantula who had her legs up, and she was defending herself. Her fangs were up, and she was defending herself.
And there on the other side was a Pompillid wasp who had her abdomen between her legs, stinger out, trying to sting this tarantula. If she had done it, what she would have done is stung in between the cephalothorax and the abdomen, in the pedicel. She would have paralyzed the spider, dragged the spider back to a hole in the ground, and there she would have laid one egg on this living tarantula. And the larva of this wasp would have eaten the spider alive, saving the vital organs for last.
And not a nice way to go-- so the spider is fighting for its life. And when I knew that predation really mattered-- so the tarantula is doing this, and the wasp is trying to get in. And this is going on for 15 minutes or something. And off to the side is an Anolis lizard, literally just waiting to grab either the wasp or the spider.
And people often ask me. The spider lived. I think I was too much in the way, but it was an amazing sight. And while I saw this in Costa Rica, again, you could see this anywhere in Ithaca, with large spiders, not with tarantulas.
Spider systematics aren't very important, but it helps if I point this out. So there are three main groups of spiders. The Liphistiidae are Southeast-Asian, very primitive spiders with a segmented abdomen. They don't matter, 1% of the spiders. 4% of the spiders are the Mygalomorphs. These are tarantulas and their kin, so trapdoor spiders and purseweb spiders and things like that.
The other 95% are the Araneomorphs. So any other spider you can think of are these Araneomorphs, and they differ in a number of key ways that are awfully helpful if you're identifying them. Just to give you a sense of this, the Mygalomorphs, from my experience, they're living anywhere from about 12 years to 25 years. I'm going to show you this female in an image that I took, I believe, in 2000, and this is the same spider.
I gave my husband a tarantula that I captured in Mexico as a wedding gift. And we finally moved her out of the guest room through objections. But anyway, she lived to 16 years, and she was not a baby when I captured her. So the Mygalomorphs generally can live very, very long periods.
The Araneomorphs, all these other spiders, are basically living a year, occasionally two years. My big huntsman spiders live two and a half years across the board, and that's the end. I don't even know of any other Araneomorphs that live for three years. So it's incredibly different biology for these animals.
The other difference that I want to point out is that the Mygalomorphs have fangs that are essentially parallel, and they're striking downwards, whereas the Araneomorphs have fangs that cross. Why? Well, the Mygalomorphs mostly are terrestrial. And if you're capturing prey on the ground, striking and hitting it toward the ground is great. It works just fine.
The big advance in the Araneomorphs, or one of the big advances, is that they've got silk that sticks together and can be put together into complicated webs. It's not that the Mygalomorphs don't use webs, but they basically build kind of uncomplicated sheets that aren't sticky, that can't do fancy things. With the Araneomorphs, they've got kinds of silk that can be attached to one another and make complicated webs.
What this means in practical terms is that the Araneomorphs were able to build wells out into the open that the Mygalomorphs were not able to do. If you're in the air, and you're striking prey like this, you're going to lose it. So they have evolved to have fangs that cross and catch prey much more effectively in the air.
When spiders are born, come out of the egg sac-- they molt once in the egg sac. They come out of the sac, molt a second time to the second instar. And you can see here spiders that have just come out. Mama's just let them out, and then they molt one more time, get much longer legs. But what do they look like? They look like adult spiders. For all intents and purposes, young baby spiders look like adult spiders.
They differ in the number of sensory hairs. They're not reproductive. But basically, all spiders look like spiders. They're not metamorphosing. In order to grow, because spiders have an exoskeleton, they need to shed or molt their exoskeleton because they've got a hard exoskeleton. There are two ways that spiders do this.
The first way that any light spider does is the easiest. They attach silk, attached to the back of their abdomen. They use the force of gravity. 60% of the hemolymph that is in there abdomen pushes in to the cephalothorax, and it pops the top off the back of your cephalothrax. And then they wiggle their legs out, come out, and then start pumping.
They increase dramatically in size. I forgot something. The tarantulas are too heavy to do this, and so what they do is they lay down a silken mat. And as it turns out, she's starting to lay down a silken mat to molt. So come up and look at it in a minute.
And the tarantulas will lay on their backs. So I get a lot of calls, people saying, I've got a spider on her back. Is it dead? No, it's not dead. It's getting ready to molt. It's when a spider's on its belly with its legs crossed that it's dead.
Spiders increase dramatically with each molt, and the way they do it is really cool. So everybody knows Shar Peis? Imagine that this is the exoskeleton underneath. If they're going to shed, they need an exoskeleton. Imagine if you had a bicycle pump and pumped up these Shar Pei puppies. How big would they be to fit that skin?
This is what's happening with the spiders, essentially. So they've shifted the hemolymph into the cephalothorax. They've popped the top off. Here, let me just show you this. This is my girl. From 2000 is when I believe this photo was taken. She's popped the top off of her cephalothorax. Now, they need to wiggle their legs out, their chelicerae out.
They need to get out. They tend to fold up the skin, pushing it away. And then what they do is they kind of move the hemolymph around. And they exercise, pumping up so that they pump up to the full size, to their full potential. Clear? OK.
And like I said, she is at least 20 years old. I bought her when she was the size of my thumbnail for $25 and still have her.
SPEAKER 6: Could you point where the spider was and where the new spider was?
LINDA RAYOR: Oh, sure. This is the spider that shed her skin. I took her skin out and used a little alcohol to pin it out. And what you can see here is here is her exoskeleton. She's gotten her legs out. Here are the holes that the legs came out of. This is a little support. It separates the heart and the sucking stomach so the sucking stomach doesn't affect the motion of the heart.
Here are two book lungs, openings to the book lungs. And this is the opening to her genitalia. And think of book lungs as terrestrial gills, where you've got sheets of tissue that oxygen exchange goes through. And having four of these is typical of the Mygalomorphs. So it's all the same animal, but she's gotten rid of this. And I should say that she has gotten rid of something like that for the last 20 years, about once a year. Yeah?
SPEAKER 6: The legs are still part of the--
LINDA RAYOR: Absolutely, so she's got to get out of the former exoskeleton and pull it out. And you know, you'll see on my baby scorpions here, you'll see some shed skins. You see it in insects, especially the shells of cicadas and stuff like that. But insects tend not to be as totally cool as shed spider molts. They're just more-- they're better. What can I say?
You in back, OK. All spiders are generalist predators. I've already told you that they mostly eat small invertebrates. And by generalist predators, basically, they'll pretty much eat anything small enough for them to handle, which is mostly invertebrates.
And the way to think about venom is that it's a cocktail. So as the dragonfly hits the web, its physiology isn't the same as the butterfly that hits a web. And so they've got this mix-and-match combo of toxins designed to affect nervous systems of lots of different animals. So that's what venom is.
And venom is endogenously produced. And what this means is that it's not that spiders are eating toxic animals and sequestering the toxins, not at all. What's actually happening is they generate these venoms on their own. And there's a lot of interest in spider venoms that might be used for various human purposes.
So some of them are being used as beta blockers, possibly saving stroke victims from brain damage, blocking neurotransmitters. So there's some interest for the most poisonous spider in terms of dealing with erectile dysfunction. There was a science article, and one that I read in the Wall Street Journal on the 15th of April this year where Australian researchers had looked at the venoms of, what is it, 206 different spider species.
And they were interested in whether some of these venoms might be used to block human pain. And the results were pretty cool. So 40% of these spiders, of a wide range of different things, had one or more compounds that blocked human pain. Seven compounds were really effective in blocking human pain. One of them was very potent that had the combination of chemical, thermal, and biological stability, which is evidently needed when developing a new drug.
And this Borneo orange-fringed tarantula was the one that had the coolest combo of different things. So there's a lot of interest in what might be done with spider venoms because they're affecting so many different areas of the physiology of insects. And then, incidentally, it had effects on humans some of the time.
I very briefly want to talk about some of the poisonous spiders, mostly because I suspect a number of you are interested in them. So worldwide, the most important poisonous spiders are the black widow family, Latrodectus. And that's largely because black widows are found all over the place, and they affect human physiology. They're found worldwide, and they have a neurotoxic effect. They have a systemic effect.
And so the people who tend to die from these are either very young or very old, and it affects the function of the diaphragm. It stops working, and so people suffocate. And by all accounts, it's a really painful bite to get.
I see somebody in the audience who tells me that the black widows are found in the Adirondacks. I have never seen one from anywhere close to here. They are clearly not common in New York. Do you know otherwise, Caroline?
CAROLINE: No.
LINDA RAYOR: OK, but she told me they're in the Adirondacks, so I believe it. So these guys are important, but not something that affects us. The brown recluse is an interesting one. The recluses here in America are clearly nasty. They have a necrotic bite that essentially causes local tissue death, which can be blistery and very painful. Usually what happens is that the bite is incised and taken out.
And this is something that people tell me all the time that they have been bitten by recluses. And probably not so from around here. The recluses are not found in New York unless they have been brought in. If you live in Kansas and you travel with stuff, you might be bringing in a recluse. But they clearly are not native to New York.
These are shy spiders. When we lived in Kansas, we saw them all the time. But they're really shy, meek spiders that tend to be found under clothes. We didn't put on shoes without shaking out the shoes. Where people tend to get bitten is that they have, say, clothing on the floor. They pick up clothing. They put on a pair of jeans. And the spider is getting squished, and so they bite on the legs.
And because this venom moves around more, it seems to be more effective in fatty tissue, people tend to get more damage in the thighs and the buttocks. I can't imagine why, but anyway this is where they suffer damage. But we really don't have it here.
What I think is more important is there is an enormous amount of evidence, increasing evidence, that so many things are blamed on spiders, and especially the brown recluses, that just aren't spider bites. And often they are way worse than the bite of a spider. And so people need to really be aware of what the alternatives are. And briefly, medical condition--
Help. Did I just turn that off? Oh, sorry, OK, bacterial, fungal, gangrene, herpes, vascular venous disease, diabetic ulcers, lymphomas, leukemia, poison ivy, guys-- poison ivy is pretty nasty-- all sorts of plant-based things, mosquito bites tend to get blamed on spiders. And so spiders aren't the first go-to agent. This is why people really get bitten. Excuse me, but the others sent me up here to ask you not to roll around so much.
OK, I'm going to talk a little about spider sex now because spider sex is cool. Spiders have got a problem. Or let me say this differently. Terrestrial animals kind of have a problem in that they need to keep their eggs and their sperm from desiccating.
Aquatic animals in many ways have it really easy. So a frog is in the water. She drops her eggs. The male swims over and fertilizes the eggs. All right, they don't desiccate. This all is good. If you're a terrestrial animal, you need to have some sort of internal fertilisation or things aren't going to work out. This is great if you've got some sort of intermittent organ, or effectively a penis, that can transfer the sperm into the female directly. And that works great.
Many insects have the equivalent of a penis, but many don't. Many, many don't. So things like these orthopterins or katydids will produce spermatophores. And these are actually totally cool. These are sperm packages encased in protein that have a pumping device. And so the male or the female inserts this into her genitalia, internal fertilisation.
In these katydids, they have added on a nutritious substance so that the female doesn't pull out and eat it, but is eating this nutritious substance on the outside while the sperm is pumping into her. So spermatophores are really cool, but that's not what spiders have. Here are Amblypygids. And just so you know and are ready to come up and look, here are the Amblypygids.
This is a male and female pair, and these guys have a spermatophore stock that you can see on the bottom that they lay this pumping spermatophore in. The male spends weeks vibrating and stroking the female, and then he'll put down one of these spermatophore stocks. And I made a point of bringing a male and a female that I put together about two months ago, and you can count. I think they have 10 or 11 stocks, so I know that they've actively mated this many times. That's neat, but actually isn't all that effective.
Spiders have come up with something very different. So here I wanted to show you mature male and female palps. Female palps look like legs, nothing particularly different. Male palps are really fancy. Male palps start to look like boxing gloves or drum sticks, but they've got something different at the end, much more complex.
Basically, what male spiders have done, unique in the animal kingdom, is they have developed their palps into hypodermic syringes for all intents and purposes. So pay attention to this little, curly, corkscrew-like thing. What the males do is they put down a sperm web. They ejaculate onto the sperm web. Their sperm are not mobile. They're in packages, essentially.
He sucks up this package of sperm into his palp, and he's got kind of a bulb here-- and I don't want to show that yet-- and then uses this corkscrew-like structure, puts this into the female's genitalia, and transfers the sperm directly. So essentially, he has indirect sperm transfer through his palps, and it works really well. The spiders have been very, very successful compared to the other arachnids. They make up 49% of all the arachnids.
This is the most erotic picture that I could come up with. And it's a hot one, basically. What you see here is this is a long-jawed spider. Walk out on any of the bridges on campus, especially the bridge between west campus and the rest of campus. These spiders build their webs on bridges a lot, and these are easy to see.
So this is a long-jawed spider. The male has courted the female, probably with vibrations. She is leaning back and is receptive. The male has inserted one of his palps. And I should say, females have two openings, and so he has inserted one palp on one side. He has his other palp held aside.
Not only this, and they're long-jawed spiders for a reason, do you see that he's got his fangs around the female? And in fact he has what I would call a hookie, where he is holding her chelicerae apart so that she can not attack him. OK, so a lot's going on.
He will pull this other palp out and then insert the second palp on the other side. There's handedness in this. So sexual conflict is really a big deal for spiders. How do porcupines have sex?
AUDIENCE: Very carefully.
LINDA RAYOR: Yes, very carefully-- sexual conflict in the spiders very often leads to sexual cannabilism. A huge number of spiders have sexual cannibalism. Here's the female. Here's the male, and he's courting her using vibrational cues.
So let me quickly go through some of these. So this is the golden orb weaver, Nephila. You've seen them before. I've talked about them before. Again, these are big spiders, easily could be the size of my hand, and big orb webs.
What do you see here? That's the male. The males are literally thousands of times smaller than the female. The males are littler than the size of female prey. There's been a lot of debate about what's happening here, but it's believed that maybe the female is aware of him mating. Maybe she isn't. But he's smaller than prey, and it's generally believed that the females are so big so that they can lay many, many eggs. And the males have simply shrunk in size so they're less likely to be eaten.
This is a common web builder around here. This is the black-and-yellow garden spider. It's found in edge habitats, kind of at the edge of the woods. And basically what happens is the male courts the female. He inserts one palp. He pulls out. He vibrates to her again.
He inserts his second palp, promptly has a heart attack, and dies on the female. And when he does this, he is essentially acting as a copulatory plug. So she can't mate again. Not only can she not mate again, at least for a while until she gets rid of him, it tends to increase her latency. She's not anxious, with this male hanging from her, to mate again very soon.
Crab spiders-- crab spiders are everywhere. And we were looking for them today in main garden. Crab spiders are beautiful. I've got to say, this picture on the cactus, my career would be made if I had taken this picture, which I did not.
The crab spiders are really masters of disguise. They're often on flowers, and they're often catching pollinators. So if you see a butterfly hanging at an odd angle off a flower, look closely, and you may see a crab spider.
There are a couple of species that do something very differently. And what they do is they court the female. And then, as they are about to copulate with her, they very rapidly wrap her up in silk-- not so tightly that she can't escape, but enough to slow her down-- and then mate with her. And she is not able to attack him as easily.
What's going on folks? Bondage-- so you've got bondage happening here. And I've got to say, I worked for a long time. Is this the right font for bondage font? I don't know.
One of my last sex stories. This is an Australian black widow, the redback widow. This is my abdomen, and this is the chelicerae. What is happening is the male courts. He inserts one palp, and he promptly flips over into the female's mouth. And she chews on [AUDIO OUT] while they're mating.
The male has a sphincter so that he does not bleed to death. He pulls out. He courts her again, and my colleague who studies these goes crazy. It takes him, like, eight hours to get back there. Inserts the second palp, flips over into her mouth, and she finishes eating them. It's not just sexual cannibalism because he couldn't get away fast enough. This is sexual cannibalism that he has set up and is absolutely key. They never not somersault.
So why are they doing it? Help me out. ideas?
SPEAKER 7: For the eggs.
LINDA RAYOR: For the eggs, how so?
SPEAKER 7: It gives nutrients to the mom.
LINDA RAYOR: OK, good, good, hi. It gives nutrients to the mom. He's hundreds of times smaller than her. That would be the obvious thing to think, and it may, in fact, be so. But my colleague, Maydianne Andrade-- who did her PhD here-- can't find evidence of it. They're just too small. They're not giving enough nutrients to the female to be making a big difference. What else? What other rational for this? Yeah?
SPEAKER 8: It means the male can only mate once, and that would decrease the likelihood of genetic repetition.
LINDA RAYOR: His suggestion is they can just make once, and more variety in the genes inserted. That's true, but why should he care, really, is the truth. So any other ideas? Yeah?
SPEAKER 7: Whatever he has made will promote ovulation or something.
Interesting, so her suggestion is chemicals in his body promote ovulation or something. Right track, not quite the story-- basically, what's happening is when the male gets consumed-- I mean, Maydianne is able to block these guys from being consumed. When the male gets eaten, the female has much longer latency before mating again. But morning importantly, as she is eating, she allows the male to continue to deliver sperm for a much longer time than if she's not mating him.
So essentially, he transfers far more sperm by being eaten than he would if he was not eaten. I would also like to say that the really little spiders are turning out to be very interesting. There's been some recent research that's showing that little spiders like this small redback widow, it turns out that instead of producing sperm all the way through their lives, as most spiders do, as most animals do, these guys come with a limited amount of sperm.
And he essentially has to matings to him. He mates once with this palp, and the tip of his corkscrew-like structure, the embolus, breaks off. He mates with the second palp. He has finished all the sperm he has. The tip of his palp breaks off. He couldn't mate again if he wanted to. Or even if he could, he doesn't have any more sperm. There is absolutely no payoff for him living.
What's interesting is that not all the black widows do this. Almost all the black widows around the world will happily eat the male if given the opportunity, but the males escape. And yet they're in the same dilemma, but are not adapted to turn them into a sexual sacrifice-- so really interesting animals.
Let me finish with the jumping spiders. Jumping spiders are bloody amazing. They are just really interesting and beautiful animals. I hope all of you have seen jumping spiders, but they're really beautiful and diverse. These guys have the largest eyes of all of the spiders, with one exception. They have very large eyes. They see exceedingly well.
Think of jumping spiders as the primates of the spider world. And they're alert. They can follow you over surprising distances. These guys jump. They are easily the smartest of all the spiders, and many of them hunt other spiders as part of their living.
How many of you have been to Arizona? Oh, OK. So Arizona is interesting because it's this combination of very mountainous and desert around it. At one point during the glacial age, it was much, much cooler, and the spiders that were lower did not differ particularly from spiders that were on mountain peaks. Now, with climate change, it's so much hotter in the desert than it is on mountain peaks.
And what you've got are essentially sky islands, where the jumping spiders and other animals on these peaks throughout Arizona have been separated for a relatively short time, but long enough that they have started to evolve big differences. And so you've got different Habronattus species-- these are all the same genus-- different Habronattus species on different mountains. And what I want you to notice is look at the differences in coloration, in eyebrows, in lips.
Palps are different colors. Often their legs have different colors. And these guys, not surprisingly, have a visual courtship-- I can't do it justice-- where they will be moving their legs and their abdomen. They might be wiggling their abdomen, the whole business. I really do not do it justice, sorry.
What is very interesting about these Habronattus is that not only are they doing visual displays, but relatively recently it's been discovered that they are also making noises. And so they move their legs up and make clicks. They move the abdomen, and there's burrs and roars and buzzes.
Interesting work has shown out of these 100 different species from Arizona that the spiders that are visually fancier actually have much simpler sounds associated with the courtship. And the ones that are plainer have fancier sounds. And this is used in sexual selection-- so totally cool animals.
I largely want to close with the peacock spiders. How many of you have seen peacock spiders? I was showing videos kind of right at the front as I was looking for one. So peacock spiders are ridiculously small jumping spiders that are found in Australia, particularly Western Australia. And in 2001, when we spent sabbatic in Australia, we were going to study them because there were rumors that they were going to glide.
But they're only there in the spring. We weren't there in the spring. It turns out, these guys are doing amazing things. These males have flaps, will flick their abdomen up, open it up, they've got these bright colors, and will do incredible dances. And it's the same basic story that I've been telling you, but they are all really very, very nice. So let me just randomly play a YouTube. This is a good one.
[VIDEO PLAYBACK]
[MUSIC PLAYING]
So that's the male courting the female, plain female. I'd go for him, wouldn't you? OK, I will leave you to this.
[END PLAYBACK]
There are lots of peacock spider videos online these days. Just in closing, I want to mention, these are my huntsman spiders, what I've got here. And here, the males are equivalent in size to the females. The females are very tolerant, almost never kill the males. A lot of spiders do this, but it's clear that spider sex is a really interesting area that an awful lot of research is going into.
So let me close that with just a little about my own work. The Ethiopians have a proverb. When spiders unite, they can tie down a lion. And in many ways, this is true. Spiders that live in groups for any amount of time are exceedingly rare-- less than 1% of all the arachnids, and, folks, we're talking less than 90 species of spiders live in groups beyond early maternal care.
The payoff for spiders of living in group seems to be that they're able to catch more prey. It's not group breeding, like a bee colony, but they're able to catch more prey. And I have been really interested, basically, in how animals that are cannibalistic and intolerant predators, what sort of concessions they make to live in groups. And this has been what my research has been on, and I'll leave it here.
My work has been on the Australian huntsman spiders that are very unusual because they don't live in webs but are obviously sharing prey and are very congenial. So I'm going to end it there. I'm happy to answer questions. Thank you very much.
[APPLAUSE]
Yes?
SPEAKER 9: Why are such an overwhelming amount of species [INAUDIBLE]?
LINDA RAYOR: The question is, why are there so many spiders that have evolved. I don't know, because they do a lot of different things. I think I don't have a simple answer for that.
SPEAKER 9: Such an invisible creature, and there's so many of them.
LINDA RAYOR: The question is, for such an invisible creature, and there's so many of them, why is it? I think because they do a lot of different things. They're very successful predators all over the world. And these are right at the end of the big ones, so we don't notice them. But they're certainly taking down enormous numbers of insects around the world. Ecosystem-wise, they're hugely important. Anybody else, yeah?
SPEAKER 10: You said a while back, spiders make up to seven different kinds of silk. Is that your average spider that would make that many types?
LINDA RAYOR: Your average web-building spider, like an orb weaver, has seven different kinds of silk. Tarantulas have, like, four different kinds of silk. I don't even know how many different kinds my huntsmen have. So if you're doing fancier things with silk, there are more different kinds of silk that are being used. But all of them have a minimum of four different kinds of silk that they're able to mix and match for different purposes. That answer your question?
SPEAKER 10: Yeah.
LINDA RAYOR: I saw another hand up over here. No? Yes?
SPEAKER 11: So you said that there are spiders in Mount Everest. Why aren't there many spiders in, like, the Denver, Rocky Mountain area?
LINDA RAYOR: Darned if I know. The question is, why aren't there many spiders in the Rocky Mountain area? You know, a friend of mine has been doing collections of spiders through the Denver Museum of Nature and Science, and they're finding a lot. They're just not really flashy spiders in Colorado, and I suspect it's simply that it's so dry, although desert spiders are fairly rich.
I don't have a simple answer, but they like the tropics. They like trees. They like woodlands. Yeah?
SPEAKER 12: You said that there are, like, the population islands in the Arizona mountaintops. So they can live in altitude, so are those kind of where they get flashier, kind of like birds of paradise? Do they have fewer predators?
LINDA RAYOR: Oh, so the question is, these peacock spiders are found in the sky islands of Arizona. And can they be so flashy because there's fewer predators on the mountaintops? And the answer is, no.
These guys are tiny. These guys are so small that I can't imagine what's eating them. I suspect what's eating them are other spiders that they're competing with. So they're diversifying because they're not in the same gene pool and because females are picking and choosing males that are flashier and have cooler sounds as part of them, I think is the real answer. Yes?
SPEAKER 13: What's the best evidence of the intelligence of the jumping spider? What's the smartest thing they do?
LINDA RAYOR: What's the smartest thing that jumping spiders do? I feel like I should let my husband come down and talk about this. But basically, what jumping spiders do is they're able to climb mazes. And they may start here, and you can have two different towers, one of which has prey on it.
They can see the prey. And they can go, you know, I really can't get there from here, track it, and go around to where they can catch prey or where they can jump on it more effectively. What's reputed to be the smartest of all the jumping spiders is, um--
SPEAKER 14: Porsche.
LINDA RAYOR: Porsche, thank you, Porsche, which is found in the Southeast Asia, Australia area-- this is a spider that looks like a piece of debris. It's a jumping spider. And they will see prey below them. They can't get to them easily. They will lose track of where the prey is but remember where it is, which is exceedingly unusual, get into a better position, and then attack them.
They will also mimic vibration, so that they're mimicking vibrations of prey in the web, so the spider comes toward it. And they attack. And they will also mimic vibrations that might be related to courtship of, say, a web builder-- so totally, totally cool stuff. And my husband is just now starting up with a student of his a bunch of maze-following stuff. Do you want to say something, hon?
COLE GILBERT: No.
LINDA RAYOR: Yeah?
SPEAKER 15: You said that spiders make a variety of mechanical sounds. So how well do other spiders hear?
LINDA RAYOR: Spiders don't hear very well. So the question is, spiders make a variety of mechanical sounds. How well do they hear? And the short answer is, spiders don't hear very well, but they feel vibrations exceedingly well. And so vibrations in the substrate, whether it's webs or the ground, they're very responsive to, and so they hear well.
SPEAKER 15: The sounds are incidental to the vibration?
LINDA RAYOR: It's the vibration that matters, not the air-born sound, largely. Yes?
SPEAKER 16: I'm aware that tarantulas can release tiny hairs in self defense to irritate the eyes of an attacker. How many other spiders have unusual defenses like this?
LINDA RAYOR: So what he's mentioning is many of the tarantulas have urticating hairs which are hairs that are chemically defended, and these are hollow hairs that have a variety of shapes. But especially think of an arrowhead that goes in but does not pull out easily. Plus, it's got chemistry associated with it. They hurt.
And this is found in New World tarantulas which, when disturbed, will kick. One of the tarantulas I have here is a Mexican flameleg tarantula. This is-- my God-- this is an absolutely beautiful tarantula, but, man, she is a kicker. This species is a kicker, and you've got to be really, really careful not to-- you know, I do not open her cage and take a deep breath with it because she's shedding such nasty hairs. So this is really good.
Other anti-predator defenses that spiders have are-- some of the spiders, especially diurnal orb weavers, have spines and hard spines such that a bird bites it and gets a spine in the roof of its mouth. It's less likely to come back. Oh, good heavens. [INAUDIBLE] Cole, help me out. I'm just blanking on other good anti-predator defense.
The most obvious spider anti-predator defense is that they're camouflaged, and they blend in with the background. Can you guys think of anything else, yeah?
COLE GILBERT: They also do the vibrational--
Oh, thank you. So the cellar spiders twirl, literally, but their legs are longer than mine. And so they will literally twirl and disappear. You try marking the legs of one of these guys. But they will twirl when threatened by a predator. Other things are more behavioral, where a bunch of the orb weavers will shake their web and kind of blur, and this is especially effective against wasps. Yeah?
SPEAKER 17: When a female consumes its mate, how does she deal with the neurotoxins that are in?
LINDA RAYOR: They don't seem to be an issue at all.
SPEAKER 17: Is that where they derive antivenoms from?
LINDA RAYOR: No, no, it seems to be digested. Go ahead. Am I going the right way? It just gets digested. It's not like it's injected into their bloodstream effectively. It just gets digested and isn't a big deal for them. And let's be clear. The male would rather have youngsters than fight to the death with the female anyway. And so many of the males don't seem to put up a whole lot of a fight, either. Yes?
SPEAKER 18: Is there a way to train spiders, maybe with vibrations?
LINDA RAYOR: Is there a way to train spiders, maybe with vibrations? Spiders certainly learn. Vibrations would be the way to do it. I am not coming up with a whole lot of-- you know, they learn, yes.
COLE GILBERT: [INAUDIBLE] uses electroshock.
LINDA RAYOR: Does she?
COLE GILBERT: Yeah.
LINDA RAYOR: On what?
COLE GILBERT: For negative reinforcement on [INAUDIBLE].
LINDA RAYOR: Why?
COLE GILBERT: To train them to recognize visual cues and see what they can learn about visual cues.
LINDA RAYOR: That seems harsh, doesn't it? Yeah?
SPEAKER 19: Do you think there could be a purpose to training spiders?
LINDA RAYOR: Oh, there's plenty of purpose for training spiders if you're interested in learning. And so these are the people who are looking at it. I haven't. Yes?
SPEAKER 20: When spiders shed their skeleton, how much of their body weight do they lose and how do they regain that nutritional loss? Do they eat up in advance? Do they eat extra after?
LINDA RAYOR: Oh, that's a super question. The short answer is, I don't know how much they lose with a molt, but it's substantial. It's a real solid thing. What most spiders do is they eat up and they reach a certain mass or maybe a combination of mass and time. And then they get ready to molt, and then they just stop eating. And I've got to say, it's like these spiders have PMS.
I mean, they just get cranky. They hide themselves. The spiders are very, very vulnerable to predation during the period where they're molting. They're lying on their backs. They can get eaten very readily. And so they'll typically seal their borrows or they'll hide in leaves to protect themselves.
And that's basically it. And it's an awesome question. I don't know the answer. If I was smart, I would weigh her now and then weigh her post molt, because she's clearly getting ready to do it. Yeah, you in back?
SPEAKER 21: So you mentioned that spiders have this [INAUDIBLE]?
LINDA RAYOR: So her question is, how do they keep the eggs and sperm from dehydrating? Essentially, they've got internal fertilisation, so the same way everything else does it with internal fertilisation, through the palp. Many spiders do not have parental care. They build an egg sac. They leave the egg sac. Mom dies, and the youngsters come out in the spring.
However, maternal care isn't uncommon throughout the arachnids, and the mom will take care of the young for some period. She may open the egg sac. In some groups, she regurgitates to very young. In others, she may simply build a web and remain in the web, a nursery web, like the fishing spiders in the fall.
So she provides some level of care. It's really not until you get to the social spiders where you've got mom providing food and sharing it with the young. And that certainly happens, but only with the social ones. Yes?
SPEAKER 22: I have two questions. Do you have a favorite spider? And if you do, what is it? What kind is it?
LINDA RAYOR: I do. I have two favorite spiders. I'm going to go with groups. I love my huntsmen spiders. I think my huntsmen are awesome. So I like these guys. The other spiders that I'm particularly fond of are the ornamental tarantulas, which I think are just beautiful. Is she down? She's not.
Did she come down? No, I'll do something bad, but essentially the ornamental tarantulas are arboreal tarantulas that I really, really like. I was at a talk in Australia, and it came up, what's the prettiest spider? And I vote for ornamentals, but other people voted for the peacock spiders. And what's your other question?
SPEAKER 22: I'll let him--
LINDA RAYOR: OK, yeah?
SPEAKER 23: One more, just about the drugs and medications that are developed from venom-- is it that the dose is controlled, or is it certain toxins are selected? Does that make sense?
LINDA RAYOR: It makes sense, and unfortunately this is totally out of my range of knowledge. There's enough large molecules that have different effects on various receptors, and I need a chemist. I read it and translate it. Yeah, one last.
SPEAKER 24: Have you read about the man-made web? People are making web material [INAUDIBLE].
LINDA RAYOR: So there's a lot of interest in using silk in biotechnology. Silk is strong. It's stronger than steel, but it's got enormous flexibility. Imagine parachutes that were awesomely lightweight but never tore. Imagine police vests, instead of Kevlar, that aren't super heavy, that are lightweight but prevent bullets from going through. Obviously, you don't want a bullet going through and coming back because it's so stretchy, but something that emphasizes the strength of it.
There's a lot of interest in silk biotechnology. The last thing I've heard is that they have successfully-- but spiders are hard. Spiders are solitary, largely. You can't keep them and keep pulling silk out. So there's a lot of interest in using biotechnology to insert silk genes in other animals, like bacteria, that can produce massive amounts and then organize it.
The most successful one has been inserting the silk gene in goat's milk. And I have no idea why goat's milk, but she produces a lot of it, I gather. But what I am not aware of is that to the best of my knowledge there has not been a lot of success in translating all this silk being produced in this milk into something actually usable. But there's a ton of interest in it.
So thank you very, very much. I enjoyed this.
[APPLAUSE]
I've got spiders up here, and I hope you're going to come up and look close, OK? So come on up.
Spiders are the dominant terrestrial predators on earth, and their biology and behavior are fascinating. Learn all about them from Cornell's spider expert, Dr. Linda Rayor, star of Monster Bug Wars and award-winning senior lecturer in the Department of Entomology. Find out how these little cannibals work out conflicts between the sexes, what happens when spiders live together in groups, which animals find them tasty, and interesting details about the most poisonous spider in the world. Recorded July 1, 2015 as part of the School of Continuing Education and Summer Sessions summer lecture series.
