Science Friday - HIV Remission, Bones, Jumping Spiders. March 8, 2019, Part 2

Episode Date: March 8, 2019

Nearly twelve years ago, a cancer patient infected with HIV received two bone marrow transplants to wipe out his leukemia. Now, researchers in the United Kingdom reported in Nature earlier this week that their patient, a man known only as “the London patient,” had been in remission and off anti-retroviral therapy for 18 months after undergoing a similar bone marrow transplant, with the same gene mutation involved, to treat leukemia. While the team is hesitant to call their patient cured, he is the first adult in twelve years to remain in remission for more than a year after stopping medication. But what do these two patients’ recoveries, requiring risky and painful transplants, mean for the millions of others with HIV around the world? Two HIV researchers not involved in this research, Katharine Bar of the University of Pennsylvania and Paula Cannon of the University of Southern California, tell us about the latest treatments that could someday be more broadly accessible, including gene therapies and immunotherapy, and what hurdles clinical studies still face. Plus: Over 500 million years of evolution has resulted in the same bony framework underlying all mammal species today. But why is the leg bone connected to the ankle bone, as the song goes? And what can the skeletons of our ancestors tell us about how humans became the walking, talking bag o’ bones we are today? Science writer Brian Switek, author of the new book Skeleton Keys, joins Ira to explain why our skeletons evolved to look the way they do. And jumping spiders are crafty hunters, but sometimes they need their own disguise to avoid their own predators. The Crematogaster jumping spider, for example, avoids detection by mimicking ants, and go as far as losing their ability to jump to look more ant-like. Sometimes, predators can be your own mates—male jumping spiders becoming a female’s meal if their courtship displays don’t impress. Biologist Alexis Dodson and  Entomologist Lisa Taylor talk about what jumping spiders can tell us about tell us about the evolution of coloration and communication in the natural world. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. Later in the hour, unlocking the mysteries of our skeletons. But first, hopeful news this week for people living with HIV. A couple of drug trials have shown that a monthly, long-acting injection is as effective as daily dosing of pills in keeping HIV in check. This news comes just days after researchers reported that a second man has been cured of infection from HIV, a man known only as, the London patient. This comes 12 years after the cure of the world's first person. Now, why? Why a cure for these two? Well, both men, in addition to HIV, had cancer requiring bone marrow transplants, and both received transplants of cells with one very particular genetic twist, HIV resistance.

If the London patient remains off drugs and HIV-free, as he has for 18 months, then that would make two people in the whole world who have been cured of the virus, and only after risky procedures meant to save them from advanced cancer. So, what does research hold for the other 37 million people hoping to live the best lives they can with a virus that was once a death sentence? Here to talk about the future of HIV research, our two HIV researchers, working on different kinds of treatments. Dr. Paula Cannon is professor of molecular microbiology and

immunology at the Keck School of Medicine, University of Southern California in Los Angeles. Welcome, Dr. Cannon. Hello, Aura. Hi. Nice to have you. Dr. Catherine Barr, Assistant Professor of Medicine in the Infectious Disease Division, University of Pennsylvania and Philadelphia. Welcome, Dr. Barr. Hello, nice to be here.

You're welcome. Thanks for joining us. Dr. Cannon, as I just said, this patient's cure, required that you have a bone marrow transplant from a donor who happened to have this rare genetic mutation that makes people resistant to HIV infection. He is, as I say now, the second person to ever achieve remission for more than a year.

There may be another patient in Dusseldorf, right, on the way to the same thing. But is this a practical cure for the other 37 million people? No, not at all. But that doesn't mean this is not incredibly exciting and

of great value. And what researchers are focused on doing now is saying can we understand why this, you know, very specialized and boutique treatment worked for these patients? And can we recapitulate the elements of that and find a way to do it that's, you know, safer and applicable to, you know, people who don't have an underlying cancer that would make them undergo a bone marrow transplant? Dr. Barr, what about other things like vaccines or other work that isn't getting as much

attention. There was a case of a potential cure that got a lot of press coverage earlier this week. One publication actually leaked the news earlier than they were supposed to. What are you excited about? Yeah, that's a great question. I mean, it is hard not to be excited about the second example of a possible cure, but you're right, and Dr. Cannon is right. This is not directly translatable to a large number of people. So when we think about the 37 million people, as you mentioned, who are infected with HIV right now in the world, we want to think about things that are a little more simple and a little bit more broadly applicable. And honestly, the HIV cure research field for those approaches is a little bit earlier on. So we're looking at strategies to reduce the size of the virus population that is infected and remains in the body,

despite long periods of HIV medicine. And then we're looking at novel immunotherapy mechanisms, so a way to train the immune system or enhance the immune system to identify those cells and then clear those cells. So you're right. There are things like vaccines. There are things like antibodies.

There's many strategies that have been used in other types of cancer approaches that we're looking to apply to the situation of HIV. But I will say that many of these stages are in the very beginning of development and though there are positive and really exciting developments, we are not at the stage of being able to even do large-stage clinical trials or implement them broadly to all the people who could benefit ultimately.

Dr. Cannon, what about gene therapy? We hear so much about that. Is that a useful and applicable line of work here? Oh, absolutely, yes. And indeed, as we are trying to figure out how to sort of recreate what happened with these transplant patients, gene therapy is, is, you know, really playing a starring role. We have two challenges.

You know, first of all, we have to figure out a way to sort of debulk the reservoir of HIV that exists in patients. And that's kind of one of the things that happens when somebody gets chemotherapy for their cancer. We don't want to have to do that. We don't want to have to give people chemotherapy. So instead, we're trying to sort of figure out kind of gentle, more sort of targeted ways that could specifically remove HIV-infected cells.

But then that's not going to be enough because we'll never be able to get rid of all of the HIV. And so what we want to do then is use gene therapy to take some of the patient's own cells and make them resistant to HIV to sort of mimic what happened with these donors of the bone marrow transplants. And in 2019, and it sounds crazy to me that I can even say this, but doing gene therapy to, you know, recreate the genetic quirk that these HIV-resistant donors had is almost becoming routine.

You know, we have amazing tools like CRISPR, for example, that allow us to go in and target the specific gene that can make people's cells resistant to HIV, a gene called CCR-5. And so that part of the treatment, that part that gene therapy can do, I kind of feel like, you know, we can do that already. But what we don't know is if that's going to be enough. And instead, you know, what do we combine that with to kind of, if you like, debulk people's HIV reservoir? If you can, you think, do gene therapy, that kind of work already, are there trials with gene therapy? Yes, indeed. And there's actually trials going on already. work, people's own bone marrow stem cells have been taken out and with reagents that are a bit

like CRISPR-cars called zinc finger nucleases. They act like genetic scissors and they are mutating this gene, this CCR-5 gene, in the patient's own stem cells, which are then kind of returned to them. So there are ongoing trials in Los Angeles looking at whether or not that can help patients, if not completely cure them, at least give them some benefit in some way of controlling their virus. Catherine, let me ask you, what makes HIV such a hard disease to research? Is it just that the virus is a complicated problem? Yeah, the virus is a very tricky adversary. You know, it's a small virus, but it's very flexible, and it changes quickly to sort of fight off whatever strategy we use.

So it can quickly develop resistance to HIV medicines. And that's why we have to use multiple medicines at the same time in order to even suppress it effectively, not eradicate the reservoir for cure, but just to maintain suppression. But the other thing that makes it really tricky is that it's a type of virus called a retrovirus, which means it takes a copy of its DNA or its genetic material and puts it into the host cell. And so shortly after infection, just a very short period of time, the virus embeds itself permanently in an HIV-positive person's body. And so that window to prevent the seeding of HIV is very, very narrow. And so basically every person who becomes infected with HIV has these permanent copies within their own cells.

And that's this major barrier for HIV cure that all the research is sort of trying to reduce. and hopefully completely clear. More and more we're seeing the overlap between cancer research and HIV. As you point out, both of these men involved in this cure had cancer, and treating the cancer also got rid of the virus. Doesn't mean there are still other things from cancer treatments that we could apply to HIV. Yeah, I think that's actually a very exciting area of research. We are borrowing a lot of immunotherapeutic strategies, as well as a lot of the knowledge

that cancer researchers have gained from exciting new and really groundbreaking treatments in cancer. But one of the problems is, you know, when you think about someone who has a life-threatening cancer that may be caused their death in three to six months, you're really willing to take a lot of risks in order to try to extend that person's life. So side effects or toxicities for very exciting therapies are tolerated in that situation. But when we talk about a HIV-positive of individual who's doing well on HIV medicine and really living a very functional life, we're not willing to entertain serious toxicities. And so that margin or that window of what we're able to tolerate in order to see the effects

of these exciting immunotherapy strategies is much smaller. And so that's one of the limitations of applying many of these exciting immunotherapy strategies that are currently being so successfully employed in cancer. Are you limited by the number of candidates who have both cancer? and HIV, finding them? If you want to test out something? Paula, what do you think? Oh, yeah, no, absolutely.

I mean, you know, really, if you have a blood cancer and you fail the initial treatment so that you then become a candidate for a bone marrow transplant, it's almost like, you know, the planets have to be aligned and, you know, you have to have HIV, have a blood cancer, need a bone marrow transplantation and then find a donor who is not just what we call a tissue match, somebody who can serve as your bone marrow donor, but who also has this rare genetic mutation, this CCR5 mutation that only about 1% of the population do.

So it's always going to be a very, very unusual circumstance. But one of the things that I think is quite exciting is increasingly, you know, cancer doctors know, about this. There's a large consortium in Europe called ICR stem, which is, actually, it's funded by the American Foundation for AIDS Research, which is the charity that Elizabeth Taylor set up. And they are putting together a database of potential bone marrow donors who are carrying this CCR5 mutation. You know, they've got more than 20,000 people on their books, if you like, ready to go. So although it's always going to be a very unusual and only be possible in a small, group of patients. I think what's exciting is that, you know, that's going to be made available

to people who, you know, who qualify for that and who want to undergo that treatment. All right. Well, thank you both for taking time to be with us today. Dr. Paula Cannon, Professor of Molecular Microbiology and Immunology at the Keck School of Medicine at the University of Southern California, L.A. Dr. Catherine Barr, Assistant Professor of Medicine in the Infectious Disease Division at the University of Pennsylvania in Philadelphia. Thanks again for taking time to do this today. Thank you. We're going to come back and we're going to unlock the mysteries of the human skeleton.

You wonder about your bones? Give us a call 844-724-8255 and also tweet us at Cy Fry. We're going to talk to Brian Sweetek, author of the new book, Skeleton Keys. It's going to be fun. 844-724-8255. We'll be right back after this break. This is Science Friday. I'm Ira Flato, a musk ox, an armadillo, and your uncle Earl.

They're about as different as three mammals can be. But underneath that fur, armor, and skin lies something that connects us to a common ancestor, our skeletons. One skull, two arms, two legs, and a spine. Muscox, armored dillo, Uncle Earl, we all have that. That's the bony framework underlying all mammal species today. But how do we end up this way? That is, why is the leg bone connected to the hip bone? I almost sang it.

As the song goes. Give us a call. Our number of 844-724-8255. If you want to talk about that, we're going to be talking about the skeleton or tweet us at Cy Fry. We're going to find out joining us now to take us through the evolution of our skeleton and the mystery of our bones is Brian Sweetek, author of the new book, Skeleton Keys. Out now. Welcome back to Science Friday. Thanks for having me back on. You're welcome. I think the most interesting thing about the human skeleton to me is that our bones, I think people don't realize they are alive. They have blood vessels. They do more than just hold up a lot of weight, right? Absolutely.

Our skeletons are incredibly active. I mean, even as you and I are talking, as our listeners are hearing us, you know, our bones are being incredibly busy. Their bone cells are laying down new bone material. There are cells called osteoclasts that are eating up old bone material, that our bones are constantly shifting, responding, you know, to everything from gravity to the hormones in our systems, that they are not this dead static tissue, but they're incredibly dynamic. And the marrow puts out products, right? Absolutely, as we were just talking about, too, blood cells come from our bone marrow held

inside of our bones. So what keeps our bones alive? How is our circulation connected to our bones? So as you mentioned, you know, in our lead-up, that bones are fed by blood-werews. vessels and you can see some of these are bones are porous. It's not just, you know, the cement type structure that if you were to look into it through the science called the histology, that you just see something that's flat, that there are all sorts of nerves and blood vessels that are constantly feeding into the bone, that there's a

give and take between our skeletons and the rest of our bodies. Let's take. So take us back to the time before bones. When did we first see the first signs of something bone-like in our history of the earth? Right. So we might think that skeletons and bones would be synonymous, that they would go together because that's the way it is in our own bodies. But we know that this isn't entirely true because we have things like sharks and rays, you know, even alive today that have skeletons, but those are made of cartilage, not bone tissue. So the skeleton came before bone.

The first thing that bone basically looked like when it showed up was about 455 million years ago as this thing called a spidden. And it didn't have cells in it yet. It wasn't as reactive as our current bone tissue is. it was much more like teeth, but it was this precursor to real bone tissue that evolved as armor outside these fish. They will look like a biological broombow almost, these sort of roundish fossil fish with these tails sticking out the back. And that was basically the beginning of mineralization of this external skeleton. Once that happened, the internal skeleton that already existed that was made of a more flexible material could start to become mineralized or ossified. So bones started out on the outside, then it was able to form on the inside.

inside and eventually when, you know, fishes, when our ancestors lost that outside armor, you're still left with the internal bony skeleton inside. Why did that change? Why did it go from outside to inside? So bone initially evolved as a kind of armor and protection against, you know, many of the invertebrates that were the dominant form of life in the oceans. I mean, they still are, you know, on our planet. But, you know, the things that we're catching and eating are our ancestors.

They need some form of protection, you know, against all those, you know, rasping and gnashing mouth parts. Eventually, as vertebrates started to come into their own, when vertebrates evolved their own jaws, when they were able to swim a bit faster, thanks in part to the push and pull of muscles against that hardened internal skeleton, that armor on the outside ended up weighing them down. They're investing a lot of energy basing into protection. So it's almost like a tradeoff in these great evolutionary arms races between, are you going to invest in a lot of armor and be relatively slow, or are you going to lose all that weight and be relatively quick and nimble and live in a different way.

So that probably has something to do why that external skeleton was eventually lost. At some point, reading in your book, ancient fish developed this new structure, a jawbone. But you say there's some debate over how they actually did that. That's right. So the earliest jaws that we know of date back to around 420 million years ago. It's this really basic anatomical hinge.

Prior to this, you had these armored fish that was basically just this whole. that was at the front of their skulls, and they didn't really have very much control about what went into their mouths. They also couldn't really breathe very efficiently because a jaw, as it opens and closes, helps pump water, you know, back then over the gills and make them more efficient breathers. But how that jaw formed is still debated. One of the front-running hypotheses is that the gill arches, the bony sort of struts that underlied the gills in these fish, that they were made of two parts and it basically had the precursor. to that hinge so that the frontmost gill arch ended up becoming the support that eventually became the jaw.

Now there are other methods by which this could have happened, perhaps through a developmental route. But how exactly we got the jaw is still being discussed in debate amongst paleontologists, but we know, at least from the fossil record, that does show up about 420 million years ago. So, you know, if you have a jaw, that means you got to have teeth, right? Why would you have a jaw if you don't get teeth? So do we find evidence of teeth? That's right. Teeth show up at about the same time. So teeth and the precursor of bone that we mentioned before is spidden show up around the same time as a kind of external armor. And teeth basically got carried along. It's not as if these fish evolved a jaw and then there's a sudden need for teeth or anything like that. That's not how evolution works. Instead, the teeth or the precursors of teeth were already on the outside of the body around the area of the mouth as a form of armor, as a form of protection.

So when that jaw evolved, now there's something extra to grip with. There's something that literally gives a little bit more bite to when these fish would chomp down on something. And that variation allowed teeth become locked in as these new sorts of structures that we still have. How different are teeth from bone? Right. So bone is made of principally two different components. A mineral component called hydroxyapitite and a protein component called collagen. And these are basically the hard parts and the flexible parts of bone.

that make them so useful to us that, you know, bone has a bit of give to it. It can bend and flex. It was just the mineral part. It would shatter very easily. Teeth have an outer coating of enamel, and that's a very hard substance. It doesn't respond the way bone does. Basically, you know, you get your two sets of teeth. You have your milk teeth when you're, you know, little, and then you get your adult set of teeth.

But that's it. Your teeth aren't continuing to grow on the outside or change. You can wear them down, but they don't repair themselves the way that bone does. So it's almost a much more like cement-like structure, but it's also a lot harder, and that's what makes it so great for biting and just constantly literally chewing through our lives. Let's go to San Antonio to Lupe. Hi, welcome to Science Friday. Hi, dear. I have a two-part question.

This is mostly for the older person. Everybody has bones. Why don't we have an efficient and safe way to strengthen our bones? and what is your recommendation for strengthening our bones if you can't do weight-bearing exercise or strength training? Thank you very much. All right. Well, I don't know if you qualified to answer those, Brian, but give it a shot. Well, I'm not going to answer the medical question just because I'm not a doctor.

But I will say, like, there's the point to that, that exercise and what we go through, it strengthens our bones. It's important to the health of our bones, for example, people who go up, you know, into space and zero-g environment. for months at a time lose about 1% of their bone mass per month because there's not that push and pull and that exercise that they're normally down here on earth to keep bones strong. So they lose some of their bone density. Their bones become more fragile. Why we don't have a system that keeps our bones, you know, healthy as we age, I would say, I mean, this is something where we might be living longer than we ever expected to or that evolution, you know, might have not that evolution plans, but that it's something that, you know, just hasn't been an adaptation. Yet that our bones actually do a lot of work repairing themselves and constantly putting down new tissue and things like osteoporosis, loss of bone density that many of us unfortunately experience, that has to do with the bone cells that are laying down new bone material that aren't doing so as well. Or the bone cells are eating old bone tissue being a little bit too active or possibly both. So it's really a matter of the basic maintenance crew that's always acting in our bones starting to get a little bit out of whack and how that might change. Yeah, that's more of a medical question, but it has to do with just the basic day-to-day, you know, life of our skeletons. And, you know, it's strange to think that we could have anything other than two arms and two legs.

But how did we wind up with a number like this? How did we get the two arms and two legs? You're right, it was a weird genetic quirk in ancient fish? That's right. So, I mean, we could have wound up with just, you know, all the things being equal with just two limbs, or we could have wound up with extra limbs. This is just really a historical accident so that the beginnings of limbs

were pectoral fins, so basically fins on fish that are in the equivalent of their chest area. And it seems to be this genetic mutation, this duplication event, that create another set of limbs, like something happened, a mutation occurred, that during development, fish started to get the second set of limbs.

And we know that this happened, aside from tracing back through some DNA comparisons, matching those against the fossil record. But the fact that if you think about your arms and you think about your legs, they're laid out in the exact same way, that there's a single upper arm bone, just like there's a single upper leg bone, your femur. There are two lower arm bones just so you have your fibula and tibia in your lower leg. And then the mess of all those hand and foot bones and your finger bones and your toe bones, they're laid out in exactly the same pattern.

It's what researchers call homologous, that these are basically the same structures just expressed slightly differently. So if that mutation hadn't happened, if that duplication event never happened, vertebrates might have very different body plans and something that is humanoid may never have evolved at all. That's why, you know, when we think of aliens, they can have any amount of limbs, right? Right. And that's an easy way to kind of make something look a little bit sci-fi, is just stick an extra pair of limbs on there and you get an alien. Speaking of aliens, let's go to Cincinnati. No, that was a joke.

Let's go to Adrian and Cincinnati. Hi, welcome to Science Friday. Well, thank you so much. Thanks for taking my call. I was just wondering, as someone who has a lot of neck troubles, I was told that that top vertebrae, the Atlas, I believe, is sort of key to, you know, the passing of the information to their brain. And from a design standpoint, it seems really sort of flawed. I'm wondering if that's common in other animals and this kind of skeleton structure.

And I'll take my answer off the mind. Yeah, design flaw up there? I mean, really, human skeletons are really unusual. They're really kind of weird. There's no other animal that walks like we do or stands upright like we do. And a lot of these balancing issues, like the skull being balanced on the Atlas or a lot of the back problems that we have are the fact that our shoulders are relatively easy to dislocate. Comes from our human ancestry of basically moving out of the trees, you know, around four million years ago or so, and starting to spend more and more time on the ground in this upright posture

that we didn't end up knuckle walking like chimpanzees and gorillas do and having this more horizontal posture where there's not as much pressure and not as much weight being stacked up, you know, on our spines in some of these ways. But we had a different way of moving. And to go back, you know, for example, to our shoulders dislocating, part of the reason that that can happen is because our shoulders aren't really connected to the rest of our body very firmly.

You might think that, you know, it has a solid connection because we use our arms for just about everything. But if you follow your shoulder blade is just floating over the back of your rib cage, it connects to your upper arm bone, you're humorous, and that all connects by way of your collarbone to the top of your rib cage. So this is really this tiny connection for this critical appendage that's really just held in the soft tissues. So, of course, if you whack that too hard or you do something, you know, pull it, is going to get pulled out because there's nothing really anchoring it there other than the muscles and the soft tissues.

So this is all basically, we can thank our ancestors of millions and millions of years ago as they moved onto the ground. for some of these problems that we now experience. This is Science Friday from WNYC Studios. I'm Ira Plato, talking with Brian Sweetek, author of Skeleton Keyes, a great book about bones and things you never really realized. And our spines, are we just talking about our shoulders and up there, our spines? What changed about our spine that made it possible for our ancestors to stand up? Right.

So there are a couple of changes. And if you look at Lucy, the famous skeleton of Australopithecus aphyrensis, I lived about 3.5 million years ago, you know, a prehistoric human. The skeleton of Lucy, in terms of, you know, the arms, those have to relatively long, the fingers are relatively curved. This is still a human that's spending a lot of time, you know, climbing around in the trees. But the spine and the lower body are all about upright movement on the ground. In terms of the spine, you see a phenomenon called lumbar low doses. So basically in the lumbar section of the back, low down in your back, the very back, the vertebrae become wedge-shaped where they're a little bit narrower towards one side than the other.

And that's because the way that these things stack, basically that S-curve of our spine, that it's not a straight rod, but there's a curve to it where it's out at your shoulders and then it goes in towards your stomach and then back out again towards your hip. And this is part of the balancing act for being able to stand upright. Changes in the hip are also related to this, where we have bowl-shaped hips that basically hold the weight of our viscera and our internal organs in our upright posture, where if you look at the skeletons of, for example, a gorilla or a chimpanzee, that they have these hips that, you know, flare out in a different way, but they aren't really holding in the organs in the same way because they spend a lot more time on all fours.

So these are some of the changes that just came with that balancing act. Adam on Twitter shouts out, hey, the hyoid bone. What's the story there? Yeah, so this is a bone that, you know, we often forget about because it's another one that's not anchored directly to the skeleton. So the hyoid bone, it's hidden bone. behind your lower jaw. It's a bone in your throat.

And it's an anchor point for the musculature of your tongue. And it's thought to be very important to the evolution of speech. So sometimes when paleoanthropologists in particular want to figure out whether a prehistoric human had basically the mobility to make certain sounds, they'll look for the hyoid bone to see what its shape is and if it relates to what we see in ourselves to get an idea of what sort of sounds may they have been capable of making. So this is one of the sort of secret bones in our skeletons that isn't always obvious, but it's certainly critical to our day-to-day life.

Last question for you. You say if things had gone a bit differently, we might still have an eye bone. What is an eye bone? Right. So our distant ancestors, our proto-mammal ancestors, going back to things like Demetrodon, so that sailbacked lizard-looking creature that, you know, looks kind of like a dinosaur, but it's much more closely related to us. They had bones in their eyes called scleral rings.

And you can see this today in reptiles and some fish and some other organisms. You know, dinosaurs have them as well. And no one entirely knows what the function of these arts thought to be, you know, supporting the eye shape specifically in creatures that might have eyes that aren't totally round or creatures that live in high pressure environments like the deep sea like ecteosaurs in the past. So we're not entirely sure what it does. But around 200 million years ago or so, when our weasel-like proto-mammal ancestors, these things called Sined Adon started to get smaller.

When dinosaurs were getting big and mammals were getting small, something changed and we lost those eyebones. And I'm for when I'm thankful for that. I'm glad I've never had to go to the emergency room with a broken eyebone. That would probably be terrible. It's a great book. Brian Sweetek's author of Skeleton Keys. He's also a writer for Laylapse blog for Scientific American. You answered a lot of questions in the book.

Thank you. Thank you for taking time to be with us today. Oh, it's been a pleasure. Thank you so much. We're going to take a break. And when we come back, we're going to talk some more about. unlocking, you know, mysteries of other kinds of stuff. Think spiders.

This is really interesting about how spiders behave as ants. I mean, why would a spider want to look like an ant? So we'll have the answers when we come back. Stay with us. This is Science Friday. Am I Refleto? Why would a spider try to imitate an ant? I mean contort its body.

It's Santone. Slouch down. Do its best be something than it's not. Well, that's what certain types of jumping spiders do. Here to answer that question is Alexis Dodson, Ph.D. candidate in Biological Sciences at University of Cincinnati, and Dr. Lisa Taylor, research scientist in entomology and nematology, University of Florida in Gainesville.

Welcome to Science Friday. Hi, thank you. Thanks for having us. Dr. Taylor, there are 6,000 species of jumping spiders. Obviously, they jump, but do they build webs? And what makes them the distinct group of spiders? Yeah, so jumping spiders are really common. Like you said, there is more than 6,000 species.

They're found on every continent except Antarctica. So all of your listeners have these guys in their backyards. They're really interesting because they jump. And they're also really interesting because they have these really big eyes that make them pretty adorable as well. They don't build webs. They don't build the typical orb web that most people are familiar with. They do have silk, so they use silk to build little retreats,

a little nest that they lay their eggs in and that they kind of hang out in at night. But, yeah, they're kind of everywhere, and they're really interesting, and most people have them in their yards. All right, let's get into how interesting they are. Alexis, you studied a jumping spider that is such a good mimic, that it looks more like an ant than the actual ant does. Yes, so what we actually found is that the, so there are adults and juveniles of the species that we looked at, and we have found that the adults more closely resembled their model ant species, which is in Campanotus, than they did juveniles of their same spider species. And the same was true for the juveniles who mimic an ant in the genus Chromaticaster.

So it's pretty crazy. They look more like ants than each other. Okay, so why do they want to do that? Well, so Murmachomorphy, aside from being one of the more fun words to say in the English language, is a really widespread strategy. And the reason the animals do this, why they want to mimic ants, is that ants are, they're not great to eat. They bite, they sting, they come in numbers so they can swarm you. And when it comes down to it, they're quite small and not very nutritious, so it's often not worth the effort.

So it makes sense that an animal that's small and maybe nutritious and not as formidable might want to mimic that to get. the protection from predation. Another reason could be that they want to eat ants themselves and maybe not reveal themselves to their prey. Speaking of interesting stuff, our number 844-724-8255. You can get in on the conversation about jumping spiders, 844-8255, or you can tweet us at SciFri. This is, they have also, Lisa, they have all sorts of predators, and sometimes the predators can be its own mate, as we just heard? Females eat males?

Yeah, yeah. So jumping spiders have two challenges. So one is to avoid getting eaten by bigger things like birds and just other large animals. And then if you're a male jumping spider, you have an additional challenge, and that's to not get eaten by the female who you're trying to court. So females are all jumping spiders are voracious predators. And so if you're a male jumping spider, you have to very carefully approach a female and put on a good show, impress the female, let it.

or know that you're the right species and you're willing to mate and also that you're not going to be a very appealing meal. So it's a pretty big challenge. A lot of other animals don't have to face when they're courting. After their courting is finished, does the female eat the male? So sometimes she'll attack and eat the male before he's done courting. Sometimes she'll attack and eat the male after he's already mated. It just kind of, yeah, things play out differently almost every time.

So one thing that I didn't mention that's really unique about jumping spiders is they have a lot of really bright colors. So they're the really interesting ant mimics like the ones at Alexis studies that look like ants. And then there are also a lot of other jumping spiders that look more like spiders except they have really elaborate colors that kind of rave the color patterns of some of the more elaborate birds. So they're actually jumping spiders called peacock spiders that have really bright coloration on their abdomens. and they actually wave their abdomens around at females. There's a lot of, yeah, basically males put a lot of effort into their courtship displays. Some of them, so they're really colorful. Some of them also sing and dance, actually produce sounds that travel through the substrate for the female.

Now, I know, Lisa, because you study this, you study very carefully. You actually dress up termites in different colors, coats to test this? That's true. Yeah. Yeah, so one of the main hypotheses that we're testing is this idea that males, that perhaps maybe some of these colors that males put into their display. So one of the species we spend a lot of time studying is very common for species males to have really bright red faces and other closely related species. The males have black and white, these bold black and white stripes on their faces. And so one of the ideas that we're trying to test is that perhaps these colors have evolved on the males in order to avoid getting eaten by the females.

And so one way we can test this is we can ask females what kinds of things they like to eat. So that's where the termites come in. So we've given females lots of choices between different termites that have been painted different colors, who have little capes with different patterns on them. And so what we know in general from a bunch of different species is that in general, the species that can see red don't like to eat the color red. So they'll choose a lot of other colors over red. And they'll also choose a lot of other colors over black and white stripes.

So that kind of lends some initial to support to the idea that maybe these colors have evolved on male faces to help them avoid getting eaten by females. Yeah. 8447248255. Let's go to the phones to Kate in Owensboro, Kentucky. Hi, Kate. Hey, how are you guys? Hey there. I have a question about sort of jumping spider ownership.

I was wondering if it was ethical or not. My daughter is really into spiders. She's three. And so I was wanting to get her into, you know, spider husbandry and ethical spiders. ownership. And we were thinking about maybe starting with a small native jumping spider that's native to this part of Kentucky in case it gets out. Is it ethical or, you know, would we be able to keep it in an enclosure or would it be better to kind of catch and release? Yeah. So I have a four-year-old also who loves watching jumping spiders. And I mean, we, so we have a lot of them in the lab that we

observe and, you know, collect data on. But I think as a, you know, just a, you know, just a, a normal citizen who's maybe not doing research on them. I think it's, I would say to me it seems ethical to take them into captivity for short periods of time as long as you're taking good care of them and giving them all the resources that they would have in the wild. So pay attention to or learn a little bit about the species before you take it in and start taking care of it, provide it with food. So they only like to eat live prey.

So it's a bit of a commitment. Then you have to go out and catch stuff to feed them. And, you know, you have to give the spider water occasionally. and I think it's probably a good idea to not keep them in captivity forever, but maybe just keep them watch them a little while, give them a little bit of extra food, maybe even more than they would get normally, and then send them on their way,

and they'll go back out into your garden and help eat some of your pests. Did I leave anything out, Alexis, about things that spiders might need? Oh, no, I actually absolutely agree with you. I would add to that that just the idea of sort of doing the research to figure out what the animal needs and how to best take care of it is just a really great way to learn about their natural history and to get your child engaged in, you know, the ecology of these animals and what they do need

and what they hunt and how they live. And so it's sort of a fun exercise in and of itself. But yeah, I think absolutely short periods of time is great. Katie, do you think you're going to do it? Katie, you're there. Oh, Kate's gone. I'm right here. Are you going to go ahead and try this?

Yeah, I mean, we're really into, I mean, she's really into the Pidipis. I can't remember. remember what the second word was, but it's like the Royal Jumping Spider, the Regal Jumping Spider. They get Phidipus for Gallus. Yeah, Phidipis Regis. Which is native to this area. And it's a pretty decent-sized spider, so she'll be able to, you know, see it better.

But, yeah, I mean, we might, if we come across one in our garden, this year, we might bring in, spoil it for a little bit and then let her go. Yeah, I mean, back to the question of ethics, I think if you're raising a three-year-old to appreciate nature and appreciate that these are, and take a closer look at these little creatures, I think she'll probably grow up to be. an adult who cares about nature and science. Absolutely. So I'd say go for it. Good thing there. Let me go to the phone. So Rick and Charlotte from Bridgeport, Connecticut.

Hi, Rick. Charlotte. Hi, Ira. How you doing? Hey there. Go ahead. So I have Charlotte in the car with me. We're driving home.

And I really appreciate that last caller. I hadn't even thought about that. I think we might do that too. Of course, my daughter loves spiders. And one of the questions that she always asks about whenever we talk about a new spider is, how much does the spider bite hurt humans? So in terms of jumping spiders,

because I know that most spiders don't bite, but if they did, how bad is the bite? Hmm. Do they bite? So they're capable of biting, so they do have fangs. Most of them won't bite you. I've never been bitten by a jumping spider,

and I've handled thousands of them. I mean, usually they don't bite you to kind of go after you. They just might bite you if you squeeze them in, you know, squeeze one in your hand and it has nothing else to do but bite. So I can't comment on how much it actually hurts, but it's not, they don't have a venom that interacts with our system in a negative way. So it wouldn't, you know, it wouldn't be kind of like a big systemic effect or a lesion or anything. It probably would just feel like getting pinched by something pointy. I don't know, Alexis, have you ever been bitten by a jumping spider? No.

No, I've been working with spiders for over four years now and I've not met anybody that I've worked with that's been bitten by spiders, nor have I been bitten by myself. by myself. Yeah, same human. Yeah, and so, and I think the interesting thing about a lot of spider venom, and this isn't true for all spider venom, so you should do your research, but that a lot of it doesn't impact vertebrates. So it's meant for invertebrates, yeah. So there are some spiders that are dangerous to humans, you know, the black widows and

your brown recluse and things like that, but many spiders, you know, the puncture will probably hurt if they can break skin, but some of them can't even do that. Is it surprising, too? You just had two callers on with kids who certainly don't have arachnophobia. I mean, they are not scared of spiders. Not at all. That doesn't surprise me a bit. You know, children are amazing in that way.

They really enjoy the natural world, and they haven't yet, many of them haven't yet learned some of those fears that we get of, you know, strange-looking animals or animals that might be spooky, like spiders. I told someone what I did on sitting next to someone on an airplane, and they said, oh, you study spiders all day. You'd get along really well with my son. He's three. And I thought. Yeah, actually, I probably would. Yeah, we hear that a lot.

Oh, my kid loves spiders, yeah. Let's go back to the ant-looking spider. Okay. How did the ant-looking jumping spiders communicate to the other spiders? They say, I'm really a spider. So, yeah, they whisper. No. They do this.

So these animals exist in these three-dimensional environments. And so we were kind of actually trying to figure out. So if these guys are looking so much like ants, how are they then doing this essential thing, which is communicating to cons specifics that they're there and they're ready to mate? And one of the things that we found when we were doing this morphological analysis of these animals, so they look a lot like ants from up above. But then when you look at them from the side perspective, so a lateral perspective, you find that the adults actually adopt a more spider-like profile and move away from that very ant-like profile. This doesn't happen for the juveniles. So what you're seeing here is just sort of a change in the ratio of selective pressures, where a lateral selective pressure is saying, you know, I need to be recognized by cons specifics.

And, you know, there are predators and they are going to try to eat me, but this is important, too. So I need to communicate in some way. I'm Ira Flato. This is Science Friday from WNIC Studios. Talking about that. Jumping spiders. Let's go to Santa Fe, New Mexico. Gail, hi.

You're here on Science Friday. Hi. Hi there. I lived in Costa Rica for many years, and one of the most amazing sites I ever saw in terms of predator prey observations was when I was sitting with friends at about 6,000 feet elevation in a rancho-style, you know, open-sided restaurant. We're watching a beautiful morpho butterfly flying by just admiring the gorgeous blue colors of the morpho. and suddenly it smashed to the ground. It just fell to the ground like a torpedo had hit it, and I ran over to see what had happened, and it was a jumping spider about the size of a large chocolate-chip cookie

that just landed on the spider. It came out of the rafters of the restaurant, and attacked it and proceeded to eat the morpho. I bet it did. It's really amazing. Yeah, they're amazing. Wow. They're like cats in that way.

Yeah, they hunt and they stalk and they pounce. And you can find them anywhere. Anybody can find them in their backyard? Yep. You can find them at the top of the Himalayas. They are everywhere. Wow. Yep, I find them in my office all the time, just kind of like free range,

not because they escaped from the lab, but just because they came in through the windows. Lisa, you talk about the psychology of spiders. Do you mean in the same way we talk about it for humans? The spider's plan? Try to trick each. other? Yeah, well, so they, in a sense, yes.

So when we think about, so one of the things we've been thinking about a lot in terms of trying to understand why males have all these really elaborate displays is we think that what they're actually trying to do is exploit the female psychology. So females are predators. And so they are always kind of searching for prey. And so they're kind of like, their prey searching intersects with their mate searching. And so they're kind of like always, basically they're always in predator mode. And so we think that males maybe by putting some of these colors on their faces are kind of like taking advantage and tapping into that psychology and trying to deceive females a little bit because if they know that females might hesitate a little bit before attacking something that's red or striped, then it's not necessarily that the male is trying to look like, you know, a red, something that's red and toxic or something that's striped and toxic, but it might just kind of trick the female a little bit so she pauses a little more before attacking.

It sounds to me like a spider is a lot smarter then if it's able to be. To be cunning and think of tricks that we give it credit for. Oh, yeah, definitely. So part of our research involves actually training spiders. So to test some of these ideas about how females respond to colors on males, we also have to train them to have particular preferences and aversions to color. And so we can actually train them in the lab. We give them red food that's really tastes really great,

and we give another group red food that tastes bad. We can actually train one group to prefer red and the other group to avoid red. And so we can actually kind of take advantage of their smarts to learn a little bit about why they do. what they do. You know, we talk about cephalopods all the time and how smart they are, and we think of the octopus as being really smart, but this is like the land-based octopus brain. Yeah, yeah, they are. They're like tiny octopi, and they have eight legs, too. Eight legs, no, yep. I think we made a match. Well, I want to thank you both for taking a happy to be with us today.

Alexis Dodson is a Ph.D. candidate in Biological Sciences at the University of Cincinnati. Dr. Lisa Taylor is a research scientist in entomology and nematology. Yes. Yeah, thanks for having us. It was fun. Thank you so much. It was great. We learned a lot. We connected with a lot of people on their spiders. Dr. Taylor is at the University of Florida in Gainesville. And you can see photos of these spiders. We have them there.

The spiders we talked about, they're up on our website at ScienceFriday.com slash Jumping Spider. Thank you. Thank you for taking time to be with us today. Yeah, thanks. B.J. Leiterman, compose our theme music. And if you missed any part of our program, would like to hear it again. Subscribe to our podcast. If you have a smart speaker, you can ask it to play Science Friday whenever you want.

If you want to see, if you'd like to read an excerpt from the book we talked about, Skeleton Keys, it's out now. You can read an excerpt from the book. Check it out on our website. It's sciencefriety.com slash skeleton. And, of course, if you want to see the pictures of the spiders, are up there on our website also. So a lot of stuff, a lot of fun stuff to do for this weekend. Everett weekend.

Safe weekend. We'll see you next week. Plato in New York.