The man who walked butterflies on a leash

Static electricity plays an invisible role in the natural world, and it may even help insects pollinate plants. To understand this hidden force, scientists have jumped through some pretty weird experimental hoops — and “walked” butterflies through literal hoops. Guests: Sam England, postdoctoral researcher at Berlin's National History Museum; Benji Jones, Vox's environmental correspondent To read more about this experiment, Benji recommends this great article from Quanta Magazine, where he first encountered Sam's work. For show transcripts, go to ⁠⁠⁠⁠vox.com/unxtranscripts⁠⁠⁠⁠ For more, go to ⁠⁠⁠⁠vox.com/unexplainable⁠⁠⁠⁠ And please email us! ⁠⁠[email protected]⁠⁠ We read every email. Support Unexplainable (and get ad-free episodes) by becoming a Vox Member today: ⁠⁠⁠⁠vox.com/members⁠ Help us plan for the future of Unexplainable by filling out a brief survey: ⁠⁠⁠⁠voxmedia.com/survey⁠⁠⁠⁠. Thank you! Learn more about your ad choices. Visit podcastchoices.com/adchoices

• 0:01Speaker 00

  Support for the show comes from TikTok. If you listen to this show, you probably enjoy discovering new things. It is built into the DNA of the show that curiosity is its own reward and that there's always a deeper dive to do. And one place to explore some of the topics we've covered here is TikTok. Whether it's how to forecast volcanic eruptions, strange phenomena that the James Webb Space Telescope picked up near the beginning of time, or a literal deep dive on the ocean's deepest reefs, TikTok has a wealth of fascinating videos just waiting to be discovered. Your next discovery is waiting on TikTok. Learn more at tiktok.com/discovermore.

• 0:49Speaker 01

  Company spending is complex. Managing it should be simple. This is AMEX Corporate, a single platform connecting cards, expenses, and payments to streamline the way you work. Flexible controls for when priorities shift, support around the clock, all backed by American Express, so you can stay focused on what matters most. Built to simplify, designed to scale. This is AMEX Corporate. Get started at go.amex/ammexcorporate. Terms apply.

• 1:29Speaker 00

  All right, Benji Jones, my favorite biodiversity reporter.

• 1:33Speaker 02

  Hi, bird.

• 1:34Speaker 00

  Hello. You have a story for me.

• 1:37Speaker 02

  I do. I want to tell you about this guy I came across who has tied little leashes to butterflies and moths, like little leashes out of fishing line, and taken them for walks around his lab. And by walks, I mean little tiny flights. So like, imagine a dude with like, a real-life kite on the other end is a butterfly, and he's like, walking it around a room.

• 2:03Speaker 00

  This is so classic Benji. Um, okay. Why is he doing this, Benji?

• 2:08Speaker 02

  Yeah, I get that this research seems kind of ridiculous, but he's doing this strange, very odd research because he thinks it'll help us understand something that's actually pretty fundamental about how the insect world works. And more specifically about how insects might be interacting with a part of the world that's totally invisible to humans.

• 2:33Speaker 00

  All right, Benji. I'm hooked. I'm compelled. I will follow where you lead. Where do you want to start?

• 2:39Speaker 02

  Let's start with this guy, Sam England. He's a sensory ecologist, meaning he like, studies the way that insects sense their environment. And actually, when I-

• 2:49Speaker 00

  Cool job.

• 2:50Speaker 02

  Very cool job. And when I, when I reached him, he was working on a project where he was studying spider vision and was like putting spiders on a little treadmill in like a virtual reality environment to understand how they responded to different stimuli. So it was, yeah, crazy job.

• 3:05Speaker 00

  You're in the wrong job, Benji.

• 3:06Speaker 02

  I know, completely. Like, I want to be playing with spiders. Um, but yeah, butterflies on leashes. So for his PhD, he was studying how static electricity affects the insect world. So static electricity, this is basically the buildup of electric charges and-

• 3:28Speaker 00

  Like when I rub a balloon, right? Or like when I shuffle around on a carpet and, and get a shock because I touch something, right? That's-

• 3:35Speaker 02

  Exactly. No, that's, that's exactly right. So like, we notice static electricity in these small ways, right? Like getting shocks here and there. I also think about like when you open a package and there is a bunch of like styrofoam pellets and they like cling to your body. That's also about static electricity. And so this is what Sam is investigating just in insects.

• 3:56Speaker 03

  It's quite a funny thing to try to measure the static charge on an animal. There's not a whole load of people that want to do this.

• 4:06Speaker 00

  Why did he want to do this?

• 4:08Speaker 02

  So basically, there's been some work that suggests that insects might be using static electricity in a bunch of these invisible ways. And one way would be pollination.

• 4:20Speaker 02

  So if we go back for a second to the static electricity thing where packing peanuts are flying towards you and sticking to you and you open a package. What's happening there is that static electricity involves a buildup of charge. So like you and the packing peanuts, one of you is slightly positively charged, one is slightly negatively charged, and so the peanuts are attracted to you.

• 4:39Speaker 00

  Sure.

• 4:40Speaker 02

  And so this might actually be happening with pollination too. But instead of peanuts and people, you have pollen and insects.

• 4:48Speaker 00

  Okay.

• 4:48Speaker 02

  So pollen on flowers seems to have, at least in some cases, a slightly negative charge. And so what Sam wanted to figure out is whether butterflies and moths, these incredibly important pollinators, potentially are positively charged.

• 5:03Speaker 00

  Mm-hmm.

• 5:04Speaker 02

  And if they are, that could mean that pollen is not just like brushing up against their bodies and sticking to them, but actually like flying through the air when they get close enough to a flower, just like the tiny packing peanuts are flying towards your body as you open up whatever your exciting package is. And if he finds out that they are positively charged and this interaction is occurring, this could like open up this whole other dimension to pollination, to this thing that is really important to nature and to how we get our food. But to figure out if this is happening, Sam had to find a way to measure the charge on butterflies.

• 5:46Speaker 03

  There's not really any kind of like prepackaged equipment that you can just buy off, you know, Amazon or wherever to to measure the the static charge of an animal. So a lot of our stuff had to be built bespoke.

• 6:01Speaker 02

  Which is what led him to turning butterflies into like these little living kites in his lab. Basically, Sam thought that insects might be picking up positive charges when they're flying around, like that's how they charge up. Like the friction of their wings against the air might be like the equivalent to us scooting along the carpet and then like touching the doorknob and getting a shock. So building up charge. And so he needed to get these moths and butterflies to fly around.

• 6:27Speaker 00

  Okay.

• 6:28Speaker 02

  And then after he flew them, he also needed to find a way to measure whether they'd become charged.

• 6:34Speaker 03

  For this study, we relied really heavily on a bit of equipment called a picoameter.

• 6:40Speaker 02

  Imagine like a kind of a metal loop. And the idea is that the electrical charge of what passes through the loop can be measured. And so his task, his challenge, where the leash comes in, is that he needed to get the butterflies and the moths through that loop.

• 6:56Speaker 00

  Wait, wait, wait. So it's not just that he's walking his butterflies around his lab on a leash. He's literally having them-

• 7:04Speaker 02

  It's like an obstacle course.

• 7:05Speaker 00

  Fly through little loops, like a, like a tiny butterfly circus?

• 7:10Speaker 02

  It's very, um, dog show vibes.

• 7:14Speaker 00

  Logistically, is this like? It sounds both simple and also when I try to imagine attaching a little leash to a butterfly. Like, how?

• 7:26Speaker 02

  Okay, yeah. No, these are-

• 7:28Speaker 00

  How is he doing this?

• 7:30Speaker 02

  Okay, so basically two approaches.

• 7:32Speaker 03

  With some of the species, this was actually quite easy. What I could do was I could basically put the butterfly in a box and we lined this box with leaves so that the butterflies and moths were only making contact with a material that they would contact in their natural ecology, i.e. a leaf, you know, as they're flying around, landing on leaves, landing on flowers. So we should get an ecologically relevant measurement of their charge. So for some of the species, we basically placed the butterfly in a box and we left a tiny hole big enough for the butterfly or moth to fly out of. And a lot of butterflies and moths just like to go towards light. And essentially, when the butterfly emerged from the box, we could have this concentric

• 8:14Speaker 03

  ring sensor mounted near the hole in that box and the butterfly would fly straight through the loop and we would get a measurement of that butterfly or moth's charge.

• 8:23Speaker 02

  That's like the simple version, if you can get the butterflies to fly out of the box through this loop.

• 8:28Speaker 00

  Okay.

• 8:29Speaker 02

  A lot of butterflies and moths were not cooperative. So for the butterflies and moths that wouldn't fly out on their own, he basically had to get them to fly.

• 8:38Speaker 03

  We actually had to basically tie tiny laces made from fishing line around their abdomen. So we could tie a slip knot of fishing line around the abdomen of these butterflies and moths, um, which is completely removable afterwards. Um, and some people, not me, had a much better aptitude for doing it, I must admit. That I had this one colleague, Tom Neal, that I would come and bother every few days and say, I've got a few more moths and butterflies for you, tell a lasso for me.

• 9:09Speaker 00

  Does it hurt the butterflies?

• 9:11Speaker 02

  No, it's a good question. Like, there's really no way to know definitively, but Sam said probably not. And the butterflies seemed fine after his study and he'd often release them back into the wild. And he also mentioned that like to do this, he would knock out the butterflies using CO2. It would like temporarily like knock them out and then a few minutes later they would wake up. And then to get them to fly, he just had to like kind of pull up the leash so they were dangling. And when butterflies are dangling and don't have their feet on the ground, they just like instinctively start flapping their wings. Cause they're like, oh God, I'm in the air. I need to be flying. And so the butterflies would start flying.

• 9:49Speaker 03

  And it's quite fun because once they start flying, you're basically walking them around, like taking a dog for a walk. And it was even more, um, I don't know what the word would even be surreal, probably. Like sometimes it felt like a bit of a like fever dream, especially given that my background is in physics. And I never really imagined that I would be taking butterflies for a walk. But I used to kind of, you know, fly them around the lab on their, on their leash. And the lab that I worked in at the time had a huge glass front to one side of the, the lab. And this glass front faced straight onto the main corridor that most of the undergraduate students would walk along to get to the library.

• 10:31Speaker 03

  So very regularly that I was walking or flying these butterflies around the lab. And undergrads would stare through the window at me and probably think, what on earth is happening in there? But yeah, definitely probably came across like a bit of a mad scientist.

• 10:46Speaker 02

  The ultimate goal is to get them to go through this loop to measure their charge. But he wanted to give them enough time to fly a little bit so that they would be picking up a charge like they would in the wild. When they're flying from flower to flower. And so he flew them around the lab for a minimum of 30 seconds. And then his goal is to get them to stop flying so that he can just drop them through the loop. So in some cases they would not stop flying. They're like really like tenacious flyers, really persistent flyers. And so what he would do is he would actually play the sound, the ultrasonic sound of bats. And bats are predators for a lot of moths. And so these moths would instinctively stop flying when they heard the sound of bats. As like an, as a way to like immediately dodge an incoming bat.

• 11:31Speaker 00

  Just freeze in the air?

• 11:33Speaker 02

  Exactly. They'd freeze in the air, stop flying, and then they'd be dangling on this leash. And then he could put the leash through the loop and measure the charge of the butterflies.

• 11:42Speaker 00

  OK, so the ma's, the butterflies, they like freeze, they fall through this little loop. It measures their charge. What did he find? Like, did he find that they were charged or not?

• 11:53Speaker 02

  Oh, I will tell you all about it after the break. Break? It's gonna be after that. Here comes a break. I'll tell you after the break.

• 12:02Speaker 00

  Screaming, I'm screaming.

• 12:03Speaker 02

  Break, break, break, break, break. It's the break. Flap those wings and wait till the break is over. Was that funny?

• 12:22Speaker 00

  Support for the show comes from Shopify. Starting a business requires you to be resourceful. And the more you flex that muscle, the more you start to see opportunities for growth. For example, launching your business with Black Friday approaching means you can take advantage of the extra online traffic. And Shopify is there to help you make it all happen. Shopify says they are the platform for a record-breaking, reliable holiday selling season for businesses at every stage. They have pre-built website themes and an AI site builder, which should make it easy to launch a beautiful, professional-looking store. And you don't ever need to touch a line of code to do it. They also have a mobile app

• 13:05Speaker 00

  that lets you run your store from anywhere. And they say their AI e-commerce expert sidekick can help you manage almost any business task with a single prompt, including holiday discounts. With Shopify, you can easily sell everywhere people shop: online, in person, across social media, even in AI chats. If you are ready to launch your business before Black Friday, go to Shopify.com/unexplainable to start your free trial. That is Shopify.com/unexplainable. Go to Shopify.com/unexplainable today to hear your first.

• 13:47Speaker 00

  Support for the show comes from Quince. Fall is my absolute favorite season. I love fall colors, I love fall leather, I love the specific light you sometimes get on a fall afternoon, and I really love fall clothes, which Quince has. This fall, Quince is offering pieces with premium materials like 100% Mongolian cashmere, organic cotton, and merino wool. The styles are timeless, versatile, and designed to become the dependable pieces you reach for day after day. Their 100% Mongolian cashmere sweaters start at just $60, giving you the softness and quality you'd expect from a luxury brand without the luxury price tag.

• 14:30Speaker 00

  I think my favorite thing about Quince clothes is that they're just good wardrobe staples. I got three black shirts from them, each in a slightly different style, and they are just correct. They fit the way they are supposed to, they look nice, they feel nice, and they go well with the rest of my closet. Find your next fall favorites at Quince. Download the Quince app for app-exclusive offers or go to quince.com. Get free shipping on your order and 365-day returns, now available in Canada and the UK, too. And when Quince asks you where you heard about them, please let them know it was unexplainable. It's a great way to support the show.

• 15:12Speaker 04

  Support for the show comes from Fetch Pet Insurance. If you have a dog or cat, here's something you need to know. According to Forbes, 1 in 3 pets will need emergency treatment this year. And every 6 seconds, a pet parent gets hit with a vet bill over $1,000. Vet bills don't have to hit that hard. Fetch is pet insurance that covers accidents, illnesses, and emergency visits, and pays back up to 90% of eligible vet bills. No wonder pet parents give Fetch an excellent rating on TrustPilot. Get a free quote in minutes at fetchpet.com/save. That's fetchpet.com/save.

• 15:56Speaker 00

  All right. So before the break, Sam was flying butterflies around and pulling them through hoops to see if they were charged up. What did he find?

• 16:04Speaker 02

  The short answer is that they, on average, were positively charged. So like, what he was hypothesizing that these are positively charged turned out to be true on the whole. Like, some, there was a lot of variation. He said some were like, a little bit negative. But in general, he saw positive charges. To be clear, these are not like massive charges that like, if you touched the butterfly, you're gonna get a shock. These are like, very, very subtle positive charges. But the key here is that the difference between the butterfly and the pollen, according to these models that he made, is enough to cause pollen to be attracted to their bodies and jump through space.

• 16:46Speaker 03

  Of course, often, when insects visit flowers, they will actually just make contact with the pollen. So probably that's still the main mechanism by which pollen is attached onto pollinators, is through physical contact. But what our study shows is that it's not necessary. And even animals that only very briefly hover by a flower may still be able to attract pollen onto their bodies and then subsequently take that pollen to another flower and pollinate that flower.

• 17:19Speaker 00

  Wow. So are they, does that mean that the butterflies and moths and maybe other insects are like, potentially experiencing like, tiny electric shocks, like, every time they interact with pollen?

• 17:33Speaker 02

  Yeah, I asked him that question, and he said no.

• 17:36Speaker 03

  It's not high enough for that. It really, it's quite a small charge.

• 17:41Speaker 02

  He said like, they're not getting shocked every time they get near a flower. Because if they, if they were, it's likely that like, this would not be beneficial and like, would be evolved out, or like, adapted away, or whatever. But he said that it's likely that pollen can jump like, several millimeters, if not like, a centimeter or more, depending on how positively charged the butterfly is. So like, if you did look really closely at the interaction between a butterfly and the flower, you might see pollen move through space, almost like a magnet that you throw on to a fridge or something like that.

• 18:19Speaker 00

  I'm tossing my magnets.

• 18:26Speaker 02

  I know. When I wrote that, I'm like, oh, that's a great analogy. And I'm like, in what situation are you like, do you have a centimeter between you and the magnet and the fridge? But it's like you casually walked by your refrigerator about a millimeter away and had a magnet and it flung to the fridge. Okay, we're canceling the magnet analogy.

• 18:46Speaker 00

  Okay, so it seems like these insects are lightly positively charged.

• 18:52Speaker 00

  Are they just pulling up pollen? Or are there other kind of electrostatic things out in the world that insects might be interacting with, I guess? Or are there other things that these insects could be doing with this electrostatic energy?

• 19:05Speaker 02

  Yes, there are so many cool ways that electrostatic energy is like shaping the insect world.

• 19:13Speaker 02

  Like when I was reading about this, it was really, there were some mind blowing examples. So like bees, for example, can sense if a flower has been visited by another bee before.

• 19:24Speaker 00

  Because like the charge has changed?

• 19:26Speaker 02

  Yes, because the charge is different. And so they might avoid a flower because it has a charge that indicates that it was just visited.

• 19:34Speaker 00

  Okay.

• 19:34Speaker 02

  And then the other thing, and this came from, from Sam's research, his research suggests that some caterpillars that get preyed on or eaten by wasps are like able to detect if a wasp is approaching by sensing their positive or negative charge. And when the wasp approaches, the caterpillar like will curl up in anticipation of an attack. And so it like, does this defensive posturing because it senses the electrostatic energy of the approaching wasp.

• 20:04Speaker 00

  Did he just like, put wasps on a string and like dangle the caterpillars?

• 20:11Speaker 02

  He actually recreated like the electrostatic charge of a wasp, of a predatory wasp, and looked at what happened to the caterpillar.

• 20:19Speaker 00

  Oh, wow.

• 20:20Speaker 02

  And the caterpillar responded as if there was a real wasp there.

• 20:23Speaker 00

  So he knew it was just like it literally, it couldn't have been the smell of the wasp or like infrasonic wasp sounds or something. It literally must have been the charge.

• 20:35Speaker 02

  Yeah, and I think like it's probably worth saying here that like this is a lot of this work is really new. And so there aren't like tons of studies showing this over and over again. And so like, everything should be taken with like a little bit of a grain of salt. But yeah, that is what his paper showed.

• 20:53Speaker 00

  I sort of thought you were you were overselling it, maybe when you were saying that there's like, you know, a whole invisible force or whatever happening out here, but it does, it really does sound like potentially there's this electrostatic world that insects are interacting with on a fairly regular basis that we're we're not really aware of.

• 21:16Speaker 02

  Yeah, and like, that is what I love so much about this kind of research. And like, I have chills right now just thinking about it, because it's like, yeah, it's it's like a different sense. It's like a sense that we don't use, don't need, but that doesn't mean that like, it's not really important to other creatures. And I find it like, pretty humbling to just think that like, we are only able to observe a sliver of like, the reality that we live in. And there's all this other stuff going on.

• 21:45Speaker 00

  So how do we, I guess, how do researchers like Sam figure out what's going on? Like, what do they need to to figure out next to sort of explore this literal hidden world?

• 21:57Speaker 02

  Yeah, so like, part of it is designing super weird experiments, like trying to meet insects where they're at and like, develop ways to study how they experience the world. So like, that's where tying leashes to butterflies comes in. I would say like, the the, one of the frontiers of this research is trying to understand how we Humans and our infrastructure, our buildings, our power lines are affecting all these interactions.

• 22:28Speaker 00

  Oh, no.

• 22:30Speaker 03

  Yeah, as exciting and fun as these discoveries are, it may also be a little bit alarming because we're realizing that there are these hidden forces, this secret influence of static electricity that's actually maybe playing perhaps a significant role in quite a few different ecological interactions. The problem is, we as humans introduce so much static electricity into the environment. So whether this is from things like power lines or our electrical appliances,

• 23:12Speaker 03

  but also, you know, a lot of artificial materials, like a lot of our synthetic fibers that our clothes are made of, charge up a lot more than natural materials do. Or if we think about even, for example, microplastics and nanoplastics, like these materials charge up a lot. And this means that we may have been unknowingly introducing another kind of environmental pollutant into the natural ecology of these animals.

• 23:45Speaker 02

  So I think like all of the senses that animals use to like live their lives, whether it's like sight or even like sensing the earth's magnetic field or electrostatic energy, like all of those senses are disrupted in some ways by our infrastructure, by human things. When I was talking to Sam, he was saying that like even just trying to do these experiments in the confines of his lab were difficult because there were so much interference from like the building itself, like the plugs on the wall, whatever. And when you're trying to measure really small changes in charge, it's like you have to like get rid of that noise. And that's what Sam is super interested in understanding next.

• 24:25Speaker 03

  It's something that I'm very passionate about now trying to pursue is this is super cool, this is super exciting, but we really need to quickly gain an understanding of how we as humans might be interfering with this electrostatic ecology.

• 24:42Speaker 00

  Man, I have to admit, Benji. I really, when you led with like, I'm, I spoke to a researcher who tied butterflies to leashes. I really did not think that you were going to sell me on it to this degree, like to the point where I'm like, give Sam more funding for research, tie more butterflies to leashes. I want more answers here.

• 25:10Speaker 02

  Dude, well, first of all, like, what did you expect? I'm not going to bring you trash.

• 25:15Speaker 02

  But yeah, I don't know. I guess like it is, it's, it's another reminder that like, it often takes a lot of creativity and like these bespoke experiments to, to answer important questions. Like, the methods might be dumb sounding. The methods might be goofy. They might sound kind of dumb, but like ultimately they're chipping away at something very important to all of us.

• 25:44Speaker 00

  Benji Jones, folks, our biodiversity reporter. He's literally constantly writing pieces like this on our website. So you should read his work.

• 25:56Speaker 00

  This episode was produced by me, Byrd Pinkerton. It was edited by Jorge Just. Meredith Hadnot runs our show. Noam Hassenfeld made the music for this episode. Christian Ayala did the mixing and the sound design. Melissa Hirsch checked the facts. Julia Longoria is the fact that frogs have been making sounds for 180 million years. And I'm always grateful to Brian Resnick for co-creating the show. Meanwhile, Benji and I are always, always, always on the lookout for weird science that actually serves really interesting purposes, like this leech butterfly experiment. So if you know of weird science like this, or if you're doing weird science like this, even better,

• 26:39Speaker 00

  write in at [email protected]. You could also leave us a nice review or a rating, if you're so inclined, or join our membership program. That helps immensely. vox.com/members. That is vox.com/members. But either way, thanks for listening. And Unexplainable is part of the Vox Media Podcast Network. And we will be back on Wednesday.

• 27:14Speaker 05

  Running a business shouldn't feel like surviving a software group project. One app for accounting, another for inventory, another for sales, and somehow, none of them talk to each other. That's where Odoo comes in, an all-in-one business management software that brings every part of your business together. From sales and accounting to inventory and marketing, all in one powerful platform. No messy integrations, no bouncing between tabs, and best of all, no spreadsheets. Stop managing software and start managing your business with one unified system. Try for free today at Odoo.com/vox. That's O-D-O-O dot com slash vox.

• 27:51Speaker 06

  Support for today's episode comes from Delta, official airline of the National Women's Soccer League. Traveling is basically magic. It creates opportunities, it fosters understanding, it expands horizons, it connects people and communities to each other and to their own potential. Those are the values that drive Delta. With up to 5,500 daily Delta and Delta Connection flights to more than 300 destinations on six continents, Delta is committed to helping you explore your world. Whatever gives you the travel bug, Delta is here to help you get there. Visit delta.com for more info. Delta, wherever the journey takes you.