Managing Invasive Plants And Ticks Together | Clue Into The Evolution Of The Bird Brain

Researchers are connecting two ecological problems in the Northeast in hopes of reducing the risk of tick-borne illnesses. Also, a “one-of-a-kind” fossil of Navaornis hestiae helps fill a giant gap in scientists’ understanding of how bird brains evolved.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Flora Lichtman?

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• 0:46Speaker 01

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• 1:04Speaker 02

  Navaornis hesihi is a little bird that's about 80 million years old, and it's helping scientists piece together how bird brains evolved.

• 1:14Speaker 03

  They look very, very much like that of a modern bird. And yet, the bones that made up this skull are primitive. So in a sense, it's like if you were to be building the Empire State Building with adobe bricks.

• 1:30Speaker 02

  It's Tuesday, November 19th, and you're listening to Science Friday.

• 1:36Speaker 02

  I'm Sci-Fry producer Rasha Iridi. A little bit later, we're going to get into why we know so little about what happened to birds' brains between Archaeopteryx, which was the earliest bird-like dinosaur, to the birds we know now. But before we get to bird brains, we'll learn how black-legged tics, also called deer tics, might be hanging out with invasive plant species. Here's Sci-Fry's Kathleen Davis.

• 2:01Speaker 04

  Black-legged ticks, also known as deer ticks, are a big problem for both people and wildlife in the eastern United States. Their bites can spread bacterial infections like Lyme disease, and their populations have spread over the past few decades. Researchers in Vermont and Maine have noticed an interesting correlation between ticks and invasive plant species. A better understanding of this could have an impact on how we manage both. Here to talk about this project is my guest, Lexi Krupp, science and health reporter for Vermont Public, based in Burlington, Vermont. Lexi, welcome to Science Friday.

• 2:40Speaker 05

  Thanks for having me.

• 2:41Speaker 04

  So tell us about this project that you reported on. What exactly are these researchers in Vermont and Maine trying to figure out?

• 2:49Speaker 05

  Just backing up for a minute, there have been a couple of studies showing this link between an invasive shrub, Japanese barberry, and black-legged ticks. And if you haven't seen barberry, it's this bush that can grow over your head. It has small leaves that turn red in the fall and bright red berries. It's pretty. A lot of people will plant it in their yards. But in the forest, it can really take over the understory. A while back, researchers in Maine noticed that there were way more black-legged ticks on these plants, twice as many ticks in forests with Japanese barberry compared to nearby forests with native shrubs. Then, a few years ago in Connecticut,

• 3:34Speaker 05

  other researchers found if you cut down barberry, there's fewer ticks. So this new project that I covered is funded by the National Science Foundation. They have almost $2 million to test this idea out over a longer time period, five years. So these researchers are going to experiment with different methods of removing these plants. They're looking at whether you see a reduction in tick numbers nearby in surrounding areas. And they're looking at other invasive species, too, plants like honeysuckle and common buckthorn that also take over. Over the understory of forests to see can we find this connection between ticks and invasive plants as well.

• 4:18Speaker 05

  Associate Professor Ally Gardner is the project lead. She's a medical entomologist at the University of Maine. And she said at the end of this study, she really wants to be able to give landowners practical advice.

• 4:31Speaker 06

  The bottom line is that, you know, we can do all the ecological research we want on the problem, but if we're not actually able to translate our findings into recommendations, you know, ultimately, we're not going to make any headway on the problem.

• 4:44Speaker 04

  So what's the science behind what these researchers are saying? I mean, why do ticks seem to like these invasive plants?

• 4:52Speaker 05

  One thing that might be going on is black-legged ticks like sort of damp environments. They'll actually dry out if they get too much sun. And barberry and maybe some of these other invasives too, offers this dense shady habitat where ticks can hang out. Another piece of the story here is the other animals that are part of a tick's life cycle, which is mainly white-footed mice and whitetail deer. Mice and deer also like to hang out in these areas with plants like barberry and honeysuckle. They offer some protection from predators. And while mice and deer are seeking shelter in these areas, they're also carrying a bunch of ticks.

• 5:36Speaker 04

  Hold on, just let me get some clarity on something. Is it still tick season right now? I was always under the impression that tick season was in spring and summer.

• 5:44Speaker 05

  It is still tick season. And this is really confusing because the mosquitoes are gone. It feels like ticks should be gone too. But that's just not how their biology works. October and November is actually the peak of black-legged tick season in most of the eastern U.S. Where I live in Vermont, this is when there are the most emergency room visits because of tick bites outside of the spring. And I think this is surprising every year because you find very few ticks in August and September. And that's because ticks are around, but they're teeny tiny, basically baby ticks.

• 6:28Speaker 05

  And they don't bite people and dogs. So it's not until they get to this adult phase later in the fall that they start looking for what's called a blood meal.

• 6:40Speaker 04

  So this project that we're talking about, it seems like it could be the perfect solution for two problems, right? Like, you're getting rid of invasive plants to get rid of ticks. But is this too good to be true? I mean, are there skeptics to this idea?

• 6:55Speaker 05

  Yeah. I think one issue here is that there are just so many variables when it comes to habitats that ticks like. I spoke to Professor Thomas Mather about this. He's a tick ecologist at the University of Rhode Island and runs this program called Tick Encounter. And he said, you can certainly find ticks in places with invasive species. But there's also lots of ticks in areas without any invasive plants. And he's cautious about this connection between black-legged ticks and an invasive species like barberry.

• 7:29Speaker 07

  If you were to look at sort of people's interpretation of those studies, you would think, oh, as soon as you go over to a barberry, instead of those little red berries, they're going to be raining ticks on you. It's not that way.

• 7:41Speaker 05

  And he made this point, that if you really want to reduce your risk of tick-borne illnesses, there's probably easier ways to do it than removing a bunch of invasive plants. Tick checks are really effective, and so is spraying insecticides that are targeted at ticks.

• 7:58Speaker 04

  So what's next for this project?

• 8:01Speaker 05

  The research I talked about is starting next year. And they're still figuring out all the details, but the goal is to come out of this with best practices for how to manage invasive plants with the best shot at reducing tick numbers. And I think another goal is to spread awareness of this connection between invasive plants and black-legged ticks. That might give people another reason to manage some of these invasive species on their properties.

• 8:31Speaker 04

  Well, that's all the time that we have for now. I'd like to thank my guest, Lexi Krupp, science and health reporter for Vermont Public, based in Burlington, Vermont. Thanks so much for being here.

• 8:40Speaker 05

  It was a pleasure.

• 8:43Speaker 02

  After the break, Ira Flatow talks with a paleontologist about how an ancient bird fossil is helping unravel how bird brains evolved. Stick around.

• 8:56Speaker 01

  WNYC is supported by Bear. Every day in America, science delivers, not just in the headlines, but in the moments that matter most. Science is a journey, one of curiosity, persistence, and progress. It's about asking questions, testing, learning, and improving again and again. Science delivers harvests that feed families, tools that help farmers grow more with less, and new ways to protect land for generations to come. Let's keep asking, keep testing, keep discovering, so science can keep delivering. Learn more at sciencedelivers.com.

• 9:31Speaker 03

  I'm Kevin Ruess. And I'm Casey Newton. And together, we've been tech journalists for decades. Now, we're your hosts of Machine Gods, a new podcast from NPR that makes sense of what AI means for your work, your life, and all of our futures. Twice a week, we'll be exploring the biggest moves in tech and give you unmatched access to the real titans of industry. Listen to Machine Gods from NPR on the NPR app or wherever you get your podcasts.

• 9:59Speaker 03

  Archaeopteryx is the earliest bird-like dinosaur that we know of. It lived 150 million years ago, but from then to now, well, researchers don't know much about how the bird brain evolved. There's a gap. But now, an 80-million-year-old bird fossil from the Mesozoic era is helping fill in this gap. It has a remarkably preserved skull, which scientists use to digitally reconstruct the bird's brain. Joining me is a lead author on this study, Dr. Luis Quiape, paleontologist at the Natural History Museum of Los Angeles County in California. Welcome to Science Friday. Thank you. Pleased to be here. Nice to have you. Tell us about this ancient bird. What's its name?

• 10:44Speaker 03

  Where did it live? The name is Navornis hestia. And as you pointed out, it lived 80 million years ago in what is now southern Brazil, not far from the city of Sao Paulo. It looked very much like a plover, if you want, but it was not at all a plover. It belongs to a group of archaic birds called Enantiornitis that were widespread during the Cretaceous period. They lived all around the world. But Navaurnis, like other Enantiornitis, was a very capable flier and it had roughly the size of a plover.

• 11:26Speaker 03

  And what is surprising of this animal is how much the skull looks like a modern skull, like the skull of a plover. Wow, so, but is it a direct descendant then? It is not. I mean, all Enantiornitis died out with a mass extinction at the end of the Cretaceous, the same mass extinction that killed dinosaurs like T. rex and Triceratops 66 million years ago. So then why is this bird important for you to study? Two pieces of the story, if you want, are very important. On the one hand, as you pointed out in your introduction, the brain of this animal that we were able to reconstruct falls between archaeopteryx and that of a modern bird.

• 12:11Speaker 03

  So it really fills a very long gap that existed before. And on the other hand, what I think is really surprising and was unexpected is that the geometry of the skull of this animal, by that I mean it has a slender bill, it has big eye sockets, it has a vaulted basic cranium, that's where the part of the skull that contains the brain. They look very, very much like that of a modern bird. And yet, the bones that made up this skull are primitive. They have primitive features, they're very dinosaurian looking.

• 12:55Speaker 03

  So in a sense, it's like if you were to be building the Empire State Building with adobe bricks.

• 13:03Speaker 03

  Yeah, I mean, surprising, right, and unexpected. Yeah. This is a great example of what we call convergent evolution. So in this case, Navarre and modern birds had a common ancestor that is at least 130 million years old. So those lineages have been separated for 130 million years, and yet they converged in having the same geometry of the skull. That's interesting. As you say, that bird did not survive, but the other birds did. The modern birds did, of course. The modern birds did. And so this fossil's lineage, which is extinct, developed similar skull features to modern birds separately. Exactly.

• 13:48Speaker 03

  Wow, that is surprising. Yeah, and unexpected. And not just similar. Yeah. I mean, the similarity is remarkable, you know? I mean, when you look at, say, the skull of an animal, like, I'm using a plover because roughly that size, right? Or a pigeon. And you put that skull on one next to the other, unless you're looking into the details of the bones, those skulls look remarkably similar. Okay, so now that we've met this bird, how did you go about reconstructing its brain? The way we reconstructed the brain is you use what is called a micro CT, a micro computer tomographer.

• 14:32Speaker 03

  It's very much like an MRI, right? And, but much more precise and it's an X-ray based machine. So you have a bunch of X-ray slices that are very thin of the fossil. And then with software, you stitch them all together and you create a three-dimensional rendering, a three-dimensional image of the skull. And therefore, you could look into the internal portions of the skull without breaking it. And you could reconstruct what is the void of the brain.

• 15:13Speaker 03

  uh preserved in the fossil. The brain is not preserved anymore, but you could at least reconstruct the void. That's where, you know, you do comparative anatomy, right? And you look at the brain of modern birds and the brain of other animals to be able to identify where the optic lobes are, where the cerebellum is, and so on. Interesting. So, so what elements of this fossil then were similar to the earliest birds of those alive today? Well, what you have, for example, that's most remarkable in terms of the brain is that the brain is rotated. That means that, like in most modern birds, the connection between the brain and the spinal cord

• 15:59Speaker 03

  comes from the bottom of this, the skull, not from the back of the skull, the way it does, say, in a typical dinosaur or in archaeopteryx. So that is an advanced feature that you see, a modern feature that you see in the brain. Nonetheless, when you look at, say, the size of the cerebellum, the size of the other components of the brain, they look more primitive. We were able to reconstruct the inner ear of the, the bird. And this is important because it's a very critical sensory organ, in particularly for

• 16:37Speaker 03

  an aerial animal that has to navigate in three dimensions. And the inner ear of Navarone is, is also very modern in appearance. Wow. So there are modern elements in this bird? Yeah, there's definitely modern elements and there are also archaic elements. And that's why this is somewhat in between. You mentioned about how surprising how this bird looked so modern. Did this fossil challenge what you thought you knew about bird brain evolution? I think it challenged what we knew about the convergent evolution that we see in the, in the shape of the skull. I think that, you know, it also surprises, to me, it was surprising to have

• 17:23Speaker 03

  An inner ear that was so modern looking. I didn't expect that. But what was more unexpected was really the fact that you have this modern looking skull made up of this very primitive bones. And that was completely unexpected. And you know, it may be telling you that at the time of constructing a modern avian skull, the skull of a modern bird, you don't have too many ways of putting together a modern avian skull. In that evolution used the tools that it had at the time and built a modern one based on basic bricks. I mean, does it ever get old studying, you know,

• 18:08Speaker 03

  creatures that lived millions and millions of years ago? No, no, I have done, you know, I've worked on early bird evolution for nearly forty years. And this one was a mind blowing discovery, but I'm sure that many others are going to come in the future. I hope to see them. Where does this rank? Does this, does this make it into the top five fossils of your career? Definitely, I think so. I doubt it. What, what number would you put it? Well, you know, I have found some very cool fossils during my lifetime. And I haven't found this one, you know, was found by an amateur paleontologist in Brazil. But I think that this is really one of those remarkable fossils.

• 18:53Speaker 03

  It's the best preserved avian skull in the Mesozoic worldwide. It's just beautifully preserved. Could we actually see it ourselves at a, at a museum someplace? It's in Brazil. It's at a museum, a small museum in Brazil, in the, in the, in a city called Marília. But you can see pictures. Yeah, we have pictures. Dr. Chiapi, I want to thank you for sharing your knowledge and your discoveries. Thank you so much. Thank you for having me, Ira. You're welcome. Dr. Luis Chiapi is a paleontologist at the Natural History Museum of Los Angeles.

• 19:28Speaker 02

  County in California.

• 19:34Speaker 02

  And that wraps up today's show. Lots of folks helped make it happen, including Jordan Smudgert. Charles Burgquist.

• 19:40Speaker 03

  Shoshana Buckstown. George Harper.

• 19:43Speaker 02

  On tomorrow's episode, how bacteriophages, aka viruses that munch on bacteria, are lurking all over your bathroom. But they might be doing you a favor. Catch you then. I'm Sci-Fry producer, Rasha Aridi.