Science Friday - Fighting Banana Blight | Do Birds Sing In Their Dreams?

Episode Date: April 25, 2024

America’s most-consumed fruit is at risk from a fungal disease. Researchers in North Carolina are on a mission to save Cavendish bananas. Also, birds move their vocal organs while they sleep, mimicking how they sing. Scientists have translated those movements into synthetic birdsong.Fighting Banana Blight In A North Carolina GreenhouseBananas are the world’s most popular fruit. Americans eat nearly 27 pounds per person every year, according to the U.S. Department of Agriculture. A deadly fungus could destroy most of the world’s crops, but a company in Research Triangle Park is trying to save the banana through gene editing.When it comes to growing bananas, RTP may not be the first place that pops in your head. But Matt DiLeo has a greenhouse full of them.DiLeo is Vice President of Research and Development at Elo Life Systems, a biotechnology firm that’s exploring how gene editing can improve fruits and vegetables.On a cloudy afternoon in early April, DiLeo opened the greenhouse door and stepped into a steamy atmosphere with a slightly floral odor. This greenhouse is packed floor to ceiling with banana trees. You’ve got to duck to keep the giant leaves from hitting your face. Some of the bananas are yellow, some are green, some are tiny and pink. DiLeo says they all share an important trait.“Many of these are naturally resistant to the TR-4 fungus,” DiLeo said.Read the rest of the article at sciencefriday.com.Do Birds Sing In Their Dreams?When birds sleep, what are they dreaming about? Researchers from the University of Buenos Aires have figured out a way to tap into bird dreams. When a bird slumbers, its voice box, called the syrinx, can move in ways that are similar to when they sing while they’re awake. Essentially, birds are silently singing in their dreams.Now, researchers have figured out how to translate that vocal muscle movement into a synthetic bird song, meaning you can listen to how birds sing in their dreams.Guest host Maggie Koerth talks with Dr. Gabriel Mindlin, professor of physics at the University of Buenos Aires about his latest bird dream research, published in the journal Chaos.Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

America's favorite fruit is in big trouble. Consumers have an expectation for how bananas look and taste, right? And farmers are accustomed to growing this variety. It's Thursday, April 26th, and it's also Science Friday. I'm SciFri producer Kathleen Davis. Even though there's just about a thousand different types of bananas, American consumers are used to eating just one, the Cavendish. There's bad news, though. A fungal disease is putting them at risk of extinction.

We'll talk about that story in just a little bit, but first, let's find out what bird dreams sound like. Yep, you heard that right. Here's guest host Maggie Kurt. Bird sleep perchance to dream. But what about? We've got more insight into this now, thanks to researchers from the University of Buenos Aires. turns out the cyrinks, a bird's voice box, silently moves as it slumbers, kind of like the way your sleeping dog might move its paws to run. And these scientists have figured out a way to translate that movement into song. We can now effectively listen to birds talk in their sleep, and that gives us some clues about what's going on in their heads.

This is all published in an amazingly titled journal called Chaos, And joining me now to talk more about his fascinating work is my guest, Dr. Gabriel Mindlin, professor of physics at the University of Buenos Aires in Buenos Aires, Argentina. So animals sleep, animals dream, or at least they have brain activity that would mean dreaming if we saw it in humans, and that includes birds. Your team found that birds are moving the syrinx in their sleep. So tell me how you found this. and what you saw.

We have been studying the physics of birds and for many years and the framework of those studies who had to measure the physiological instructions that are changing the configuration of the vocal organ while the sleep, also the respiratory activity when they are producing their sounds. Typically, we were interested in measuring that during the day when the bird was vocalizing. But one time, one of those birds stayed connected. and my colleague we realized that there were those patterns of activity that were happening at night as well. What you just said, it sounds like you're saying that measuring the dreams was actually an accident?

Yes. Oh, that's so cool. Yeah, for us it was an accident. So my other colleague, Dan Margulius, at the University of Chicago, he's a neuroscientist. Then we became collaborators, but he's the one who first recorded the neural activity at night. So in a way, we're now trying to work together, linking the neural part and the periphery part, and designing new cool experiments, like, for example, having a butt sleeping, listening to actually what is dreaming and see what impact it has in the behavior of the next day.

What are you using to kind of measure these movements? So what we do is we do some dedicated surgeries where some electrodes are implanted in those tiny muscles. Those surgeries are very delicate. they have to be performed well enough so that the bird when wakes up is in the mood of singing to the female, right? So those are delicate surgeries where tiny electrodes are implanted in the muscles. You're then kind of taking this data of the muscle movements and you're turning it into song. You're using a computer model to translate those muscle twitches into music. So how do you train that model? Are you starting with a bunch of different measurements?

data from awake birds? Yes. Basically, that's research that we've been doing for several years now. It consists in writing the actual physical equations that rule the behavior of the labia. The labia in the avian vocal organ are very similar to the vocal faults in humans. So when the bird is singing, it's changed in the configuration of the vocal organ, and they can stretch or release those labia, and that will affect the frequency of which they oscillate, therefore, the frequency of the sound that is produced. But basically, you start with

physics, which is very simple, like Newton's equations for the motion of those labia, and you try to find which are all the forces that are acting there, and how the activity of the muscles would affect those forces. In that way, you can reproduce the motion of the labia, and therefore, the modulations of the airflow, and that is what generates the sound. That sounds fascinating. So, I want to listen to what a bird dream sounds like. This one is from the bird you've been using for research, the great kiskitty. So now let's listen to what that same song sounds like when the bird is awake. So those sound a little bit different. Can you tell from the synthesized song what this bird was dreaming about, does it really translate easily between awake and asleep?

So the first thing is that the sound that you play at the beginning is a call from a different bird, okay? So probably if you would be playing the C-level corresponding to the actual bird that we're measuring, you would find it more similar. But still there are differences in between what the bird dreams and what the bird sinks. In these bird species, what they do is they use two sound sources, and the muscles control how the tune the two sound sources are. They try to sound intimidating by generating these rough sounds, and they do that by changing slightly the frequency of the vocalizations that they produce with the two sides of the settings. When they dream, the difference between that frequency is a little bit larger,

therefore the syllable sounds rougher. That's the main difference in between the actual song and they dream the replayed son. Are you able to figure out what the dream is about and correlate that to awake behavior? Yeah, in this species in particular, it's possible because they have basically two sets of vocalizations. One are these calls, these very simple goals, then they have another vocal behavior,

which is called the trid, when they produce several syllables in a very rapid sequence, and they usually do that when they are having a territorial dispute. And it's very interesting because when they are actually having this dispute on top of singing and performing this intimidating trill, they also have these feathers in the head that come up, right? It's very intimidating. So when we recorded for the first time, the muscle activity, when the bird was producing this kind of vocalizations,

the bird was completely asleep, silent, with the eyes closed, but still the feathers of the head will come up. Oh, that's great. Yeah, so you could figure out that really this guy was experiencing a nightmare, probably, okay, recreating the whole experience of having a fight in his lips. That reminds me of my toddler having a nightmare about sharing. So how did you feel getting this window into a bird's mind? It's really exciting.

The first time I did a synthesis for dreams, I was laughing the whole morning. I couldn't stop laughing. I was very happy. I thought it was very cool. That was my first impression. Then the second time I synthesized this vocal behavior, which was this nightmare,

what I felt actually was a lot of empathy, because I thought, well, this guy belongs to species that is so distant from us, but probably they are all alone, at night in a tree with his fears. And I felt that there were more similarities between them and us that we usually acknowledge. Bird on we.

Are other bird species doing the same thing? Yes. So we also work with songbirds, which are birds that are a little bit more interesting in a way because they share with us they need to be exposed to a tutor in order to learn their vocalizations. Like, for example, the canary,

Cibra Finch, a cardinal, those are songbirds. There are 4,000 species of those words, and they need to be exposed to a tutor. They learn to vocalize. The kiss cadid in the study you are mentioning is not a songman. But with sunbirds, it's very interesting because since they need to learn to vocalize, their behavior is a little bit more complex. I call them crazy dreams. What we're working now is in a precise way to introduce those muscle patterns into sounds to listen to more complex dreams. You've been studying the physics of Birdsong for 20 years now. What drew you to this field? Well, it's interesting. I was working on the physics of human voice production back then when I started, and I visited some colleagues at Rockefeller University in New York, and they asked me about birdsong.

And I thought it was such an exotic question because I didn't know it was such an active field of research, particularly in neuroscience. So at the beginning, it started like a side project. But then what happens is that you have these 10,000 species. And the kind of physics that is involved, the kind of dynamics is fascinating and very diverse and changes from species to species. So whenever I thought I had figured it out, there was some weird vocalization that implied new physics, new behavior. And I just couldn't stop it.

Basically, that was it. It was just too interesting. That's fascinating. So you ended up a bird guy from physics. Right. So humans and birds and all these other animals are having similar brain activity while they're asleep. Does that all represent dreams the way we think of them, you know, playing out these scenarios that help form memories, help us learn? Are dreams the same thing everywhere?

Well, that's actually, it's a very interesting question. So far, there are many conjectures, but we don't have an experiment that is supporting one or the other. In general, there are behavior experiments that say that the activity that the burst display at night plays a role in the process of learning, but obviously there is more because non-learning species display these activity patterns too. The idea of replaying, you know, playing these dreams back to birds is such an interesting idea. Is that the next step for your research? You know, what are you hoping it's going to teach you? One of the things I'm very interested in is in the relationship between the learning capability and the flexibility, the vocal flexibility that the species has with the kind of dreams and replace that it can exhibit. Because one of the fascinating issues with birds is, as I said before, we had 10,000 species. 4,000 of them learn, but even among the ones that learn, there is a wide variety of behavior. For example, the zebra finch needs to learn the song,

and we'll learn only one song, and it will sing it all the time during all his life. But the canary has a larger variability, has a larger repertoire, and then you have other species which are stellar vocal performance, like, you know, I don't know, stalling. Therefore, even in the songbirds, you have birds with different complexity

in terms of their repertoires, how they use their vocalizations, how they combine them, how they use it to express what they need to express. And therefore, the comparative study between that complexity and what they dream is to me a very fascinating subject. Thank you again for joining us. This has been amazing. Thank you for your interest. Dr. Gabriel Mindlin, professor of physics at the University of Buenos Aires in Buenos Aires, Argentina. Want to guess what America's most popular fruit is? Well, I'd have guessed apples, but it's actually bananas.

Yes, Americans eat, on average, 27 pounds of bananas each year. But a fungus is putting the bananas we eat in deep trouble, and scientists worry they could be wiped out. Luckily for us, there's a massive effort to protect our beloved bananas, and it's happening in a state we don't normally associate with the fruit, North Carolina. Here to tell me about it is my guest, Bradley George, reporter at WUNC in Chapel Hill. Bradley, welcome to Science Friday. Thanks, John. Glad to be here.

So let's talk about these bananas. we're all familiar with, the ones that are local grocery stores. What's exactly the deal with this species? Well, actually, there are more than a thousand species of bananas in the world, but the one that we all know best that we see in our supermarkets and eat every day, that's the Cavendish banana. This is one that's grown in countries in Central and South America, like Columbia and Costa Rica, Honduras.

And it became the dominant type of banana in the global markets around the 1950s, early 60s, after another species of banana, the gromish shell, was wiped out by a fungal disease of its own. Oh, boy. So a fungus took that one out, and now there's a fungus that's putting this monoculture at risk, too. Tell me about it. Yeah, this is called, it has a couple of different names. The one that you'll hear the most in biotech or banana circles is Tropical Race 4 or TR4. Now, this was first discovered in Australia in the 1990s, but it really became a concern in the last decade or so when it was found in some of these last Latin American countries where the majority of the banana supply is grown. It lives in the soil. Fungicides can't kill it.

And so there are a few options for growers when this spreads into their crops in terms of controlling it or killing it. So you went to a banana research greenhouse in North Carolina to learn more about this. And maybe you can tell us what kind of research is going on there. Yeah, this is a company called L-O-Life Systems. That's spelled E-L-O. And they're a biotech company that's focused on using some genetic engineering. They call it molecular farming techniques to improve foods and deal with some of these issues that the different fruits and vegetables are facing. And I spoke with Matt DeLeo, who's the VP of Research and Development in L.O.

And as part of my tour of their corporate campus, they have this greenhouse that's full of banana plants of all kinds. And so one of the challenges about plants is that they grow very slow. It takes a long time to work with them. And so we look for every opportunity we can to compress timelines so that we can make better plants in the shortest time as possible. So these bananas in this greenhouse, they're relatives of the cabin dish. These are bananas. Some of them are small and pink. Some of them look like the ones that we see in our supermarkets. Some of them are green. But they all have a natural resistance to TR4. And in 2020, L.O. entered a new. into a partnership with Dole, which is one of the largest banana growers, to develop a TR4-resistant banana. So what L.O. is doing is they're basically, they're looking in the family tree of bananas, as it were, from these other varieties and taking some of the genetic information out of them and putting them into a Cavendish banana that hopefully will be resistant to TR4. Okay, so you mentioned that there are all these different types of bananas, unestimated, 1,000 different types. So why have we've been committed so hard to these Cabandish bananas.

I mean, we know there's a risk of them being wiped out if they're a monoculture. Why not just plant and eat some of these other types of bananas? Well, some of these bananas just don't yield as much fruit as the Cabin dish. And the other thing is, you know, the Cabinish Banana has been the dominant banana variety in global markets for so long. Consumers have an expectation for how bananas look and taste, right? It's a pretty complex plant to kind of unlock the genetic structure up. Bananas contain 30,000 different genes. And each one of these genes helps the banana to do one thing that it needs to grow and survive in the environment.

And what we do is we find those single genes that are broken that make the banana susceptible to this disease, and we go in and we fix that single gene. So they're using these other banana varieties to find the genes that will help make the Cavendish resistant to TR4 and still make still maintain its dominance as the banana we all know and love. So what's it going to take for a TR4 resistant banana to actually be the norm, to be something that we can find in our grocery stores? Well, L.O. says that they're ready to start testing this in the field. Literally, they're going to start shipping these out, the plants out to some Dole banana farms in Honduras

to see how they do in the wild. But we should mention this is a global issue. It's not just about this one company here in North Carolina. Dole's main rival, Chiquita, is also working on a resistance banana. The United Nations is involved. Their food and agriculture organization recently convened a World Banana Forum in Rome to come up with a global strategy to fight TR4 because ultimately this isn't just about the palettes of consumers in wealthy countries like the U.S.

It's also about the farmers in these countries where the banana is grown in terms of maintaining their livelihood because they depend on the world's appetite. for bananas to keep their farms and crops going. It's so interesting. It's all the time we have right now. I'd like to thank Bradley George, a reporter at WUNC in Chapel Hill, for bringing us this story.

Thanks so much, Bradley. Yeah, thank you, John. You can read more about Bradley's story on our website. It's science friday.com slash banana. And that's all the time that we have for now. A lot of folks help make the show happen, including Emma Gomez,

Sandy Roberts, Robin Casmer, and many more. Tomorrow, we'll take a lot of, a look at the biggest science stories of the week. But for now, I'm SciFRI producer Kathleen Davis. Have a great rest of your day.