Transcripts
I was just sitting in front of my computer trying
Amy Martin:to figure out how to start this episode, which is all about
Amy Martin:plants and pollinators and sound, and I heard this noise
Amy Martin:across the room, and it made me wonder, wait, did I leave my
Amy Martin:phone on vibrate? And then I walk over to track down the
Amy Martin:sound, and then I see it's an enormous bee just outside my
Amy Martin:window, moving from flower to flower on my snapdragons, which
Amy Martin:are in full bloom right now. Nice!
Amy Martin:I grabbed my sound gear and walked out into my yard and
Amy Martin:everywhere I looked and listened, the bees were on a
Amy Martin:bender. They were drinking nectar with so much gusto, they
Amy Martin:made me want to try some. They disappeared into the blossoms
Amy Martin:and lost themselves there, then stumbled out later with pollen
Amy Martin:all over their legs and wings and flew off into the morning
Amy Martin:sun. This is pollination in action. Plants can't pick
Amy Martin:themselves up and move toward potential mates. They need to
Amy Martin:attract helpers to move the sperm from the male plants to
Amy Martin:the ovaries of the females. So the flowers have essentially
Amy Martin:thrown a nectar drinking party because they want to have sex.
Amy Martin:And it works. Animals like these insects pollinate around three
Amy Martin:quarters of all flowering plants. Without them, a lot of
Amy Martin:plants would die, including many of the foods we depend on daily.
Amy Martin:The amorous intentions of plants are the hidden force behind a
Amy Martin:lot of activity on our planet. Take the sound I heard earlier-
Amy Martin:on the surface, this seems like an interaction between two
Amy Martin:animals, a human and a buzzing bee, but the flowers are
Amy Martin:actually driving all the action. They produced the nectar which
Amy Martin:attracted the bee that then attracted me, all of which is to
Amy Martin:say, plants can do things. They are doing things, making things
Amy Martin:happen around them. Like all living things, they're using
Amy Martin:whatever resources are available to get their needs met. And one
Amy Martin:of the things that's available in abundance around them is
Amy Martin:sound. So what, if anything, are they doing with all that
Amy Martin:acoustic information? Welcome to Threshold, I'm Amy Martin, and
Amy Martin:we are living through a botanical paradigm shift. A
Amy Martin:growing body of research is disrupting and reorganizing what
Amy Martin:scientists thought they knew about trees, flowers and all
Amy Martin:things vegetal. In our last episode, we met Heidi Appel and
Amy Martin:Rex Cocroft, the two researchers who proved that plants can tune
Amy Martin:into vibrations made by insects doing unfriendly things to them,
Amy Martin:like caterpillars biting into their leaves. But what about all
Amy Martin:of these sounds made by friendly visitors? Is it possible the
Amy Martin:plants can sort of hear these pollinators happily buzzing
Amy Martin:among the blossoms? While I'm wandering around in my yard
Amy Martin:listening to bees, are the flowers listening too?
Amy Martin:Dr. Lilach Hadany: I wondered about this question.
Amy Martin:Dr. Lilach Hadany didn't only wonder about this
Amy Martin:question, she decided to try to answer it, and in this episode,
Amy Martin:we're going to follow her down that primrose path into a whole
Amy Martin:new world of planty possibilities.
Amy Martin:Flowers are a time honored part of human courtship rituals. I
Amy Martin:mean, just try to imagine a wedding with no flowers. And Dr.
Amy Martin:Lilach Hadany says this is no accident. Attracting suitors is
Amy Martin:exactly what flowers were designed to do. It's just that
Amy Martin:plants use them to attract creatures with six legs.
Amy Martin:Dr. Lilach Hadany: It is actually well known that the
Amy Martin:plant signals to the pollinator. It is large and colorful and
Amy Martin:emits smells.
Amy Martin:Lilach is an evolutionary theoretician at Tel
Amy Martin:Aviv University, and she says scientists have studied how
Amy Martin:plants send pollinators these kindsof visual and chemical
Amy Martin:signals through their flowers for a long time, but the
Amy Martin:assumption has been that sound wasn't really a factor, that
Amy Martin:there was no acoustic communication going on between
Amy Martin:the plants and the pollinators. And this seemed odd to her.
Amy Martin:Dr. Lilach Hadany: Plants are communicating all the time. Why
Amy Martin:wouldn't they use sound?
Amy Martin:Almost all flowering plants need to attract
Amy Martin:pollinators, and a lot of those pollinators make a fair amount
Amy Martin:of noise. Was all of that sound really just wasted on the
Amy Martin:plants?
Amy Martin:Dr. Lilach Hadany: Pollination seemed to me like one of the
Amy Martin:cases where responding to sounds would be immediately beneficial
Amy Martin:for the plant. So there was an evolutionary puzzle here.
Amy Martin:It was a puzzle she wanted to solve. So she designed
Amy Martin:an experiment focused on nectar, the sweet liquid plants make as
Amy Martin:a reward for animals that visit their flowers. Producing nectar
Amy Martin:is costly for plants, so it's to their advantage to time the
Amy Martin:production of it really precisely, right when they're
Amy Martin:most likely to be visited by the birds and beesthey most want to
Amy Martin:attract. And breezing by isn't enough. Ideally, the pollinators
Amy Martin:will get very interested and hang out a while and then spread
Amy Martin:the love around.
Amy Martin:Dr. Lilach Hadany: If a flower is pollinated by an animal that
Amy Martin:makes sounds, then it is possible to prepare pollination
Amy Martin:at exactly the time that the pollinators are likely to be
Amy Martin:around. So it is not necessarily responding to a single
Amy Martin:pollinator, but a single pollinator is a good indication
Amy Martin:that other pollinators may be around.
Amy Martin:So the plant might be kind of, in very metaphorical
Amy Martin:terms, the plant might be thinking in quotes, there's the
Amy Martin:sound of one pollinator, so there's probably going to be
Amy Martin:others around. So maybe it would help me to produce more nectar.
Amy Martin:Dr. Lilach Hadany: So I would put it that, natural selection
Amy Martin:could act on the plants to produce improve the reward in
Amy Martin:times where pollinators are likely to be around.
Amy Martin:So this was what Lilach decided to test. When
Amy Martin:plants are exposed to sounds made by pollinators, do they
Amy Martin:change something about their nectar production?
Amy Martin:Dr. Lilach Hadany: If you hear a pollinator nearby, would the
Amy Martin:plant say, me, me, me! Sort of.
Amy Martin:Because if they did, that could be a sign that they
Amy Martin:were hearing the pollinators somehow.
Amy Martin:Dr. Lilach Hadany: And it might be preparing for fertilization.
Amy Martin:Lilach and her team drained the nectar from a bunch
Amy Martin:of beach evening primroses, tough little plants with big
Amy Martin:yellow blossoms. Then they played the kinds of buzzes that
Amy Martin:pollinators, like bees, might make.
Amy Martin:Did you have like a little portable speaker? I'm trying to
Amy Martin:picture what it looked like.
Amy Martin:Dr. Lilach Hadany: So the speaker is portable. We were
Amy Martin:trying to mimic a bee going around the bush rather than
Amy Martin:standing in front of the flower and the buzzing.
Amy Martin:I didn't ask Lilach if costumes were involved, but I
Amy Martin:really hope so. They also played other sounds to the plants,
Amy Martin:sounds that had nothing to do with pollination. And sometimes
Amy Martin:they played them no sounds at all.
Amy Martin:Dr. Lilach Hadany: And after three minutes, we test the newly
Amy Martin:produced nectar, and we discovered that indeed, the
Amy Martin:flowers that were exposed to the sound of a bee had a higher
Amy Martin:concentration of sugar than the ones that were not exposed to
Amy Martin:these sounds or that were exposed to irrelevant sounds.
Amy Martin:Lilach was shocked. There was a measurable change.
Amy Martin:When the plants were exposed to the sounds of bees, they
Amy Martin:appeared to sweeten their nectar.
Amy Martin:Dr. Lilach Hadany: It was like, no, this cannot be true. And
Amy Martin:then we redid the whole experiment.
Amy Martin:They actually redid it multiple times, inside and
Amy Martin:outside.
Amy Martin:Dr. Lilach Hadany: Eventually, it was done several times by
Amy Martin:different people in different contexts. So we were convinced.
Amy Martin:Heidi Appel and Rex Cocroft had shown that some
Amy Martin:plants respond to an acoustic stimulus by sending out a
Amy Martin:chemical weapon. Lilach and her team demonstrated that they can
Amy Martin:also respond by making a love potion, sweetening themselves
Amy Martin:up, maybe so pollinators will linger longer on their flowers
Amy Martin:and come back again later. And while Heidi and Rex were focused
Amy Martin:on the vibroscape, acoustic waves moving through the body of
Amy Martin:the plant, Lilach's work was about airborne sound, bee
Amy Martin:buzzes, just like the ones I heard through my window.
Amy Martin:One of the sentences I loved from the paper was this one, "we
Amy Martin:found that the flowers vibrated mechanically in response to
Amy Martin:these sounds, suggesting a plausible mechanism where the
Amy Martin:flower serves as an auditory, sensory organ." So in
Amy Martin:non-science speak, it's almost like you're hinting that flowers
Amy Martin:are kind of ears. Is that right?
Amy Martin:Dr. Lilach Hadany: So I think it is something like the external
Amy Martin:ear. It's an amplifier of the sound. And then we can think,
Amy Martin:when we think of flowers as they selected to be visible to the
Amy Martin:pollinator or to hear the pollinators better.
Amy Martin:Wow, I love that. That's so cool.
Amy Martin:Dr. Lilach Hadany: It really converted my view of walking in
Amy Martin:fields with flowers. Suddenly I find myself... little small
Amy Martin:ears, and who would be a good ear?
Amy Martin:Everyone agrees we need more studies on more
Amy Martin:species to figure out what's really going on here. But when
Amy Martin:this research was published in 2019, it catapulted Lilach into
Amy Martin:the global spotlight. You may have read about it in National
Amy Martin:Geographic, or The Atlantic, or any number of other places.
Amy Martin:There's just something thrilling about western science validating
Amy Martin:the very ancient idea that plants are not passive set
Amy Martin:pieces. They are main characters. They're doing things
Amy Martin:and they're highly relational. They're in constant
Amy Martin:communication with their surroundings and with other
Amy Martin:living things, especially insects. And that led Lilach to
Amy Martin:ask another daring question, if plants can detect sound, could
Amy Martin:they also be producing it? We'll have more after this short
Amy Martin:break.
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Amy Martin:Hi Threshold listeners, do you ever find
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Amy Martin:Welcome back to Threshold, I'm Amy Martin, and I'm going to ask
Amy Martin:that question from before the break again using terms that
Amy Martin:plant scientists would definitely not use. Now that we
Amy Martin:know that plants can hear, can they also talk, or at least make
Amy Martin:sounds of some sort? The answer is yes, and this is what it
Amy Martin:sounds like. This is the sound of a stressed out tomato plant.
Amy Martin:It's making these sounds as it's drying out, most likely as
Amy Martin:little air bubbles pop inside its planty veins. These noises
Amy Martin:were recorded by Lilach Hadany and her team at Tel Aviv
Amy Martin:University.
Amy Martin:Dr. Lilach Hadany: We used most of the time tomato and tobacco,
Amy Martin:but we recorded several other plants also, and we directed two
Amy Martin:sensitive ultrasonic microphones at the plant.
Amy Martin:I'm picturing a plant almost like it's being
Amy Martin:interviewed. It has microphones set up around it.
Amy Martin:Dr. Lilach Hadany: And then we heard these clicks.
Amy Martin:They're happening in ultrasonic range, too high for
Amy Martin:us to hear, but they've been converted into our audible range
Amy Martin:and condensed in time. When Lilach and her team first heard
Amy Martin:them, they were skeptical. They thought,
Amy Martin:Dr. Lilach Hadany: Perhaps it's not a plant, perhaps it's an
Amy Martin:insect or other sounds.
Amy Martin:So they repeated the experiment over and over and
Amy Martin:over, including in a soundproofed box in the basement
Amy Martin:of a building where no other sounds could intrude.
Amy Martin:Dr. Lilach Hadany: Then we recorded them also in the
Amy Martin:greenhouse and in the botanical garden. And then we tried like
Amy Martin:wheat and corn and grapevine. So basically, we had to be ultra
Amy Martin:careful, perhaps more than in different areas, and we were
Amy Martin:sure that the sounds are emitted by the plants themselves.
Amy Martin:Lilach was surprised to find herself in the spotlight
Amy Martin:again after this research was published in March of 2023. News
Amy Martin:outlets around the world covered the story.
Amy Martin:News Person 1: Researchers have found that plants can make
Amy Martin:noise.
Amy Martin:News Person 2: There is an actual sound that tomato plants
Amy Martin:make when they're thirsty, a whimper or scream, if you will.
Amy Martin:News Person 3: But this discovery here is probably one
Amy Martin:of the biggest in the last few years.
Amy Martin:News Person 4: I wonder if our dogs can hear them. Our dogs
Amy Martin:often bark at something random, probably like, hey, the plants
Amy Martin:are hungry. Feed them.
Amy Martin:We've actually known that plants make ultrasonic
Amy Martin:clicks and pops since at least 1966 when they were documented
Amy Martin:by a botanist named John Milburn, but those sounds were
Amy Martin:detected by sticking wires inside plants. So it wasn't
Amy Martin:clear if the vibrations stayed trapped inside the stems and
Amy Martin:leaves or if they made it out into the surrounding ecosystem.
Amy Martin:Lilach's research showed that the noises are indeed audible
Amy Martin:outside of the plant, and that plants make more of them when
Amy Martin:they're stressed, like when they need water or after they've been
Amy Martin:cut. And together, those two facts point to something
Amy Martin:important and pretty exciting. The sounds plants make have the
Amy Martin:potential to shape the behavior of other living things. For
Amy Martin:example, picture a field full of tomato plants drying up on a hot
Amy Martin:summer afternoon, each of them popping away. It might make
Amy Martin:quite a racket in the ultrasonic range, and those sounds might be
Amy Martin:meaningful to the right kinds of listeners.
Amy Martin:Dr. Lilach Hadany: For an organism with the relevant
Amy Martin:hearing ability, like a moth flying through the field, maybe
Amy Martin:hearing plenty of sounds and also getting a lot of
Amy Martin:Maybe all those little popping sounds cause the
Amy Martin:information.
Amy Martin:moth to avoid those plants or to feed more heavily on them, or to
Amy Martin:respond in some other way. And maybe that affects other
Amy Martin:animals, like bats. Lilach's study didn't test all that, she
Amy Martin:had to answer the most basic questions first, but now we know
Amy Martin:that the sounds plants produce at least have the potential to
Amy Martin:influence all sorts of other living things. In short, plants
Amy Martin:are talking, so now we can ask who's listening.
Amy Martin:I'm curious how you see the future of this field of plant
Amy Martin:bioacoustics. What are you hoping for?
Amy Martin:Dr. Lilach Hadany: So I really think we are just seeing the
Amy Martin:edge of the iceberg at the moment, and I expect that we
Amy Martin:would record plenty of sounds from different plants under
Amy Martin:different circumstances, and we might be able to understand the
Amy Martin:acoustic interactions of plants with their environment, which is
Amy Martin:the most exciting part for me. I'm hoping that within a few
Amy Martin:years, we will be somewhere completely different, because
Amy Martin:now we know that there is this layer of acoustic information
Amy Martin:that we can investigate.
Amy Martin:Okay, I'm wandering around in a Swedish forest
Amy Martin:looking for people who might be attaching microphones to trees.
Amy Martin:I'm in northern Sweden now, walking through a dense and
Amy Martin:fairly dark woods. It's kind of story bookish, with lots of
Amy Martin:lichen hanging off with branches. But instead of forest
Amy Martin:gnomes, there are mysterious pieces of scientific equipment
Amy Martin:tucked among the mossy rocks.
Amy Martin:Signs of research projects around, but no signs of
Amy Martin:researchers.
Amy Martin:This is an experimental forest where scientists from area
Amy Martin:universities come to do research on one of Sweden's most valuable
Amy Martin:and plentiful natural resources: trees.
Amy Martin:Hey! Hi!
Amy Martin:I've spotted the scientists I'm looking for: Dr. Jonatan
Amy Martin:Klaminder and his three person crew who are here to set up an
Amy Martin:experiment that will run throughout the summer.
Amy Martin:Dr. Jonatan Klaminder: My name is Jonatan Klaminder. I'm a
Amy Martin:professor at Swedish University of Agriculture Sciences in Umea.
Amy Martin:I'm totally driven by curiosity, so you can't say a field that
Amy Martin:I'm really interested in. I've been interested in so many
Amy Martin:things.
Amy Martin:One of those things is soil bioacoustics. Jonatan
Amy Martin:has done some really interesting studies on the sounds that ants
Amy Martin:and earthworms make underground. But lately he's turned his
Amy Martin:attention to trees.
Amy Martin:Dr. Jonatan Klaminder: Well, trees is a soil organism, if you
Amy Martin:think about it. The root system is underground, and it's
Amy Martin:difficult to not think about trees if you're in Sweden.
Amy Martin:Forestry is an important part of our economy. And then, of
Amy Martin:course, I like being out among trees. So trees, there's many
Amy Martin:reasons why we should keep track of the trees. Trees are
Amy Martin:important.
Amy Martin:The person that I talked to that maybe had the
Amy Martin:closest connection to your work was Lilach Hadany in Tel Aviv.
Amy Martin:Is what you're doing a continuation of her work?
Amy Martin:Dr. Jonatan Klaminder: Yeah, absolutely. I mean, her work is
Amy Martin:really important because they show that it worked for tomato
Amy Martin:but they don't have bark. Trees in Sweden have bark.
Amy Martin:All trees have some kind of bark, actually, or at
Amy Martin:least a protective bark, like layer. Jonatan wanted to know if
Amy Martin:these ultrasonic pops were loud enough to make it through that
Amy Martin:layer of soundproofing where they could be heard in the open
Amy Martin:air. And he also wanted to know if they could be heard in a real
Amy Martin:world setting.
Amy Martin:Dr. Jonatan Klaminder: When you have rain, when you have wind,
Amy Martin:when you have cars, that's what we're testing. So if we can hear
Amy Martin:them,, well, that is the million dollar question. We're the first
Amy Martin:to try this. So we'll see. We'll see.
Amy Martin:I'm joining this team on their very first day in
Amy Martin:the field as they figure out where to set up their equipment
Amy Martin:and how to keep it running outdoors all summer long. The
Amy Martin:first order of business is to set up a tent. It's big and
Amy Martin:green and wedged somewhat awkwardly into a bumpy little
Amy Martin:spot, but it's not meant for sleeping in.
Amy Martin:Dr. Jonatan Klaminder: So this is our lab. We're actually
Amy Martin:building our outdoor lab. We have some electronics with us
Amy Martin:that can't handle rain. The field workers, they can handle
Amy Martin:rain, right? It's just electronics.
Amy Martin:The field workers, Lena, Matthias, and Sebastian,
Amy Martin:look vaguely skeptical, but choose not to comment, maybe,
Amy Martin:because what they're really wondering is if they're going to
Amy Martin:be able to handle the clouds of blood thirsty mosquitoes
Amy Martin:tracking our every move.
Amy Martin:Dr. Jonatan Klaminder: I mean, the mosquitoes love you the
Amy Martin:most, Matthias. Sebastian, you have been drinking bear blood.
Amy Martin:So they won't touch him.
Amy Martin:I don't know. I've been seeing a lot of them on
Amy Martin:him.
Amy Martin:Dr. Jonatan Klaminder: Yeah, put on a jacket, maybe.
Amy Martin:Jonatan is pursuing this question of whether trees
Amy Martin:make sounds that can be heard in the open air, in part, for a
Amy Martin:very simple reason, because we don't know the answer.
Amy Martin:Dr. Jonatan Klaminder: So, I mean, we're exploring the
Amy Martin:unknown, and I think that's the driver.
Amy Martin:But he's also interested in potentially
Amy Martin:applying what he learns. After decades of steady increases,
Amy Martin:forests in Sweden have started growing more slowly, possibly
Amy Martin:because of drought. That's a problem for the forestry
Amy Martin:industry, but also, for all of us. Trees are one of nature's
Amy Martin:best carbon capture and sequestration systems. Every
Amy Martin:ring on a tree represents more planet warming gasses sucked out
Amy Martin:of the atmosphere and locked away, potentially for hundreds
Amy Martin:of years. But when trees slow their growth, they draw less
Amy Martin:carbon out of the air.
Amy Martin:Dr. Jonatan Klaminder: Our forests have lost productivity,
Amy Martin:and we don't really know why. There's different theories, and
Amy Martin:one of the theories is that if you have a really, really dry
Amy Martin:year, the trees suffer from cavitation, which is bubbles
Amy Martin:that forms inside the xylem.
Amy Martin:Sai-lem, or zai-lem, is spelled, X, Y, L, E, M.
Amy Martin:Remember that scrabble players. It's the part of the tree
Amy Martin:responsible for water transport. Trees take in water through
Amy Martin:their roots and pump it up through the xylem to their
Amy Martin:needles or leaves high above.
Amy Martin:Dr. Jonatan Klaminder: The basic is that a tree pumps up water
Amy Martin:through the xylem and downwards it pumps sugar through the
Amy Martin:phloem.
Amy Martin:It's quite remarkable that they can do this
Amy Martin:when you think about it, every tree is a carbon eating, gravity
Amy Martin:defying water pump, but an essential part of that process
Amy Martin:is keeping the pump primed. Water molecules want to hang
Amy Martin:together. They kind of pull each other along in a little train,
Amy Martin:if there's enough of them present. But if the roots can't
Amy Martin:find enough water, and that train of molecules is broken.
Amy Martin:Dr. Jonatan Klaminder: The water transport is going to cease. And
Amy Martin:not all trees can just get rid of these bubbles.
Amy Martin:Once that link in the water train is broken, it's
Amy Martin:really hard for the tree to reconnect it. So these bubbles,
Amy Martin:or dry patches in the xylem can stay dry even after the water
Amy Martin:returns.
Amy Martin:Dr. Jonatan Klaminder: You might knock out the water transport
Amy Martin:for several years, so that bubble could be fatal for that
Amy Martin:part of the xylem. And if you have many bubbles, of course,
Amy Martin:then you shut off the water transport. And worst case
Amy Martin:scenario is that the trees die.
Amy Martin:The process of these bubbles forming in the water
Amy Martin:transport shutting down, that's what makes these pops and
Amy Martin:clicks. That's cavitation.
Amy Martin:Dr. Jonatan Klaminder: But so far, no one has managed to hear
Amy Martin:those cavitations explosions in an outdoor setting through bark.
Amy Martin:So it's a challenge.
Amy Martin:If Jonatan is able to detect these sounds in the
Amy Martin:open air through the bark, the next logical question would be
Amy Martin:the same one Lilach Hadany is asking- who or what might be
Amy Martin:listening.
Amy Martin:Do you suspect that the trees are producing sound that is
Amy Martin:ecologically relevant?
Amy Martin:Dr. Jonatan Klaminder: So now we're definitely speculating.
Amy Martin:Maybe, just as a thought experiment, a bark
Amy Martin:beetle might be able to hear the pops of a tree under stress.
Amy Martin:That's an insect that kills a lot of trees in Sweden, the US
Amy Martin:and other countries.
Amy Martin:Dr. Jonatan Klaminder: So if that information is around, why
Amy Martin:should the beetle not use it? That's not far fetched, I think.
Amy Martin:I mean, it can be something mind blowing there, but could also be
Amy Martin:the dead end. I mean, that's kind of exciting.
Amy Martin:Yeah. It is.
Amy Martin:Maybe in the future, foresters might be able to listen to trees
Amy Martin:the way doctors listen to our hearts and lungs to keep tabs on
Amy Martin:our health. Maybe the sounds trees make can serve as a kind
Amy Martin:of early warning system, letting us know when they're suffering
Amy Martin:from drought before it becomes acute. And maybe we can figure
Amy Martin:out which species of trees or varieties within species can
Amy Martin:handle dry conditions better, so we can grow more climate
Amy Martin:resilient forests, not just in Sweden, but everywhere.
Amy Martin:Dr. Jonatan Klaminder: Maybe you can put the drone with a
Amy Martin:microphone and fly over the forest and sort of get an
Amy Martin:overview how many trees in your forest that suffers from, from
Amy Martin:this. We aim for something applied, but we need to do some
Amy Martin:basic research before we can actually do something. Yeah, it
Amy Martin:could be a total failure.
Amy Martin:That's science, right?
Amy Martin:All of the things that Jonatan hopes to learn start with that
Amy Martin:embrace of uncertainty, that willingness to do bold science.
Amy Martin:You seem like you enjoy this.
Amy Martin:Dr. Jonatan Klaminder: Yes.
Amy Martin:Dr. Jonatan Klaminder: I mean, because it's unknown. And I
Amy Martin:Why?
Amy Martin:mean, when I was younger, I was a junkie for adrenaline. I can't
Amy Martin:do that now, because I should be old and smart and wise. So I do
Amy Martin:this is like academic bunjee jumping. I mean, it's high risk.
Amy Martin:I like that. It's a high risk, high reward, but it could be
Amy Martin:high risk, low reward also, but I mean, our community are
Amy Martin:steered towards, the research community steered towards
Amy Martin:getting a number what goes up and what goes down. But the
Amy Martin:processes behind them are, I think, more interesting than
Amy Martin:just getting the numbers. I want to understand how soils and
Amy Martin:forests functions.
Amy Martin:A couple of months later, I checked in with Jonatan
Amy Martin:to see how things went. He assured me that the field
Amy Martin:workers had not been carried off by mosquitos, and he also sent
this:These are the sounds of cavitation happening inside a
this:birch tree. Jonatan's team captured them in the open air.
this:As with the plants that Lilach Hadany recorded, these are
this:ultrasonic sounds that have been converted into our hearing
this:range. So Jonatan's gamble paid off. He now has documentation
this:that when trees dry out, or at least when some trees dry out,
this:the sounds they make are loud enough to push through the bark,
this:and could at least theoretically be detected by other organisms,
this:including humans, if we have the right equipment, and if we
this:decide we want to listen.
this:I'm on a hiking trail in western Montana, looking up at
this:beautiful, rugged mountain peaks, and there are wild
this:flowers all around me, purple, yellow, red, violet, blue. And
this:there are also tons and tons of bees right here, moving from
this:flower to flower to flower.
this:There's a bee with its entire head stuck into a like trumpety
this:flower of a larkspur, just going for it. And I wonder if it's
this:possible that that flower heard that bee and maybe sweetened its
this:nectar just a little bit.
this:I really like plants. I like to look at them, smell them, eat
this:them, and just be around them. But even as I appreciate plants,
this:I've always positioned myself as the perceiver and them as the
this:perceived. I've assumed I was the subject and they were the
this:object, but now I realize that's just scientifically inaccurate.
this:Plants are perceivers as well. They are listening, possibly
this:even tuning into some of the same sounds I am, and they're
this:also talking in their way. They're in a sort of
this:conversation with the life around them. There is acoustic
this:information getting passed between pests and pollinators
this:and plants that has the potential to affect all the
this:participants. And if we start tuning in, that conversation
this:could shape our behavior too, and it's hard to imagine how
this:that could be anything but good for us.
this:This episode of Threshold was written, reported and produced
this:by me, Amy Martin, with help from Erika Janik and Sam Moore.
this:Music by Todd Sickafoose. Post production by Alan Douches. Fact
this:checking by Sam Moore. Special thanks to Lilach Hadany, her
this:collaborator Yossi Yovel and Jonatan Klaminder for sharing
this:their plant recordings. Threshold is made by Auricle
this:Productions, a non profit organization powered by listener
this:donations. Deneen Weiske is our executive director. You can find
this:out more about our show at thresholdpodcast.org.
