Short Wave - Clownfish Might Be Counting Their Potential Enemies' Stripes

Episode Date: February 9, 2024

At least, that's what a group of researchers at the Okinawa Institute of Science and Technology Graduate University thinks. The team recently published a study in the journal Experimental Biology suggesting that Amphiphrion ocellaris, or clown anemonefish, may be counting. Specifically, the authors think the fish may be looking at the number of vertical white stripes on each other as well as other anemonefish as a way to identify their own species. Not only that — the researchers think that the fish are noticing the minutiae of other anemonefish's looks because of some fishy marine geopolitics. Questions, comments or thoughts on another marine sea creature you want to hear us cover? Email us at [e-mail] and we might feature it on a future episode!See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, Shortwavers, Regina Barber here. And this time I've got two of our favorites for a regular roundup of science news. Ari Shapiro. Oh, you're one of my favorites too. Oh, thank you. And Margaret Serino. Hey, Marge.

Hey, Gina. Much love. As always, we're going to share three science stories in the news that have caught our attention recently. Moths with an anti-bat signal built into their wing. Clownfish could be counting up to three. Also, tomatoes that are purple and potentially better for you. All that on this episode of Shortwave, the science podcast from NPR. All right, Ari, as our guest, which topic do you want to start with?

I know what a bat signal is, but I'm super curious about an anti-bat signal. What is that? These maas don't want to be eaten by bats, so they make this clicking sound with their wings that can disrupt the bats echo location. Yeah, so the real sound is out of human hearing range, but if it's slowed down enough, it sounds like... Yeah, if I were a bat, I'd stay away from that. Yeah, it's wild. They evolved to make the sound with their wings every time they fly as a way to compensate for being deaf because they can't hear when predators like bats are around.

And this warning system, we've actually known about it for a while now, but exactly how they make these sounds was the mystery until this week. A new study in the journal Proceedings of the National Academy of Sciences details how these ermine moths are able to do this with their wings. And what's the answer to the question? So I talked to a researcher on the study, Mark Holarede, and he mentioned that the wings that he and his team collected, like, in Bristol, UK, actually buckle and unbuckle. Huh. Yeah, Ari, think of a plastic bottle that deforms and makes a little click,

and then deforms back, it makes another click. That's what's happening here, but much more elegantly, a part of the moths, hind wings, buckle, and then unbuckled sequentially along the ridges there. And it's completely reversible. happening hundreds, thousands of times in flight without damaging the wing. Wow, is that unique to this kind of moth? No, actually it's not.

But Mark says that they haven't seen this particular mechanism before. That it's a sound production mechanism. That's completely novel. It doesn't require any muscles. Just the physics and the mechanics of the sound production is baffling. But now that they know what it is, they're seen it in other insects. And one last thing to say about this. Nature is showing scientists how this kind of buckling process can be beneficial, which is the opposite of how it's viewed in engineering.

You know, in engineering, buckling is generally associated with failures and damaged building material. So maybe engineers can take note. Cool. All right. Let's pivot to the second story. Take us underwater into new research about clownfish. They can count. Well, maybe.

A team at Okinawa Institute of Science and Technology is saying clown anemone fish. That's what Nemo is. Could be counting the numbers of white stripes on each other. But why would they want to do that? Yeah, well, so you need to know two things about these fish, Ari. First, adult clown anemone fish have three stripes. And second, they're much more aggressive and territorial than the fish in Finding Nemo. Oh, so I'm not going to watch the movie the same way again after this, is what you're telling me.

Yes, absolutely. And here's the thing. Clown anemone fish are most aggressive toward their own species because they want to protect their cute anemone king. them from being taken over from within. Sorry to burst your bubble, Ari. No, actually, I kind of like the idea of these really cute fish actually being total jerks to each other in real life. Right. Vincent Loda, a researcher on the study, told me that the alpha female seems to be most aggressive toward other anemone fish also with three stripes, because they look most like herself. So the scientists think the fish are counting.

We love a diva. So how do they find out that the fish are counting stripes? Right. So researchers did these two experiments led by Kina Hayashi. And first they placed different species of anemone fish with different numbers of white stripes inside the tank and observe how often and for how long the clownfish would behave aggressively by either circling or charging towards the others. And then in the second set, the researchers painted little plastic like orange discs with zero, one, two, or three stripes. And again, measured aggressive behaviors. And the more stripes on the fish or the disc, the more they were circled or charged. Wow. So the fish are actually counting stripes? Yeah, I mean, I will know one expert I talked to, Karen Carlton, a biologist not affiliated with this study,

she was a bit skeptical. She pointed out to me that this might just as well be clown anemone fish picking up on other visual cues, you know, different coloration on the fins across species, for example. Right. And so as it often is the case in science, more experiments need to be done to know for sure if the fish are actually counting stripes. But Vincent says either way, we need to give these fish more credit. People think fish are dumb because fish have no facial expression that we can read. But in fact, fish are extremely clever. Individuals have their own personality.

And we see that very clearly with an emone fish. Honestly, I could listen to a weekly segment from that man. But let's pivot to the third scientific discovery you have brought us, just in time for seedlings sprouting in the greenhouse as we approach spring. So what have you learned about purple tomatoes? Right. So the color is kind of like a Concord grape. And last year, the Food and Drug Administration gave the go-ahead for some small farmers to grow and sell this purple tomato.

But now gardeners can buy the seeds to grow them at home. Yeah, they just went on sale this past weekend. And this is the first time transgenic seeds. So they contain genetic material from two different organisms. have been sold directly to customers in the U.S. Sasha Woodruff with Boise State Public Radio wrote about it for NPR. Okay, not to brag, but I grow a lot of different colored tomatoes in my garden. What makes this one so special?

I mean, love that, but there's a reason behind the purple. Norfolk plant sciences, the company that created this tomato, hacked the color genes from a snapdragon flower into the plant. But those genes not only give the tomato its purple color, they boost its levels of anthocyanin. So anthocyanins are antioxidants. And these compounds have been shown to have anti-cancer and anti-inflammatory effects. So think blueberries, blackberries, eggplants.

They mostly get their color from anthocyanins. I love a purple fruit. And yes, eggplants and tomatoes are fruits. You're right. You tell them, Ari. Thank you. Okay, so these purple tomatoes are genetically modified. And, look, GMOs have had a perception problem in the U.S., right?

Very true. A 2020 Pew Research study showed that most Americans see, GMOs as worse for their health than foods with no genetic modification. But since GMOs were introduced three decades ago, studies don't actually show any harm. And the FDA has concluded that there isn't a health risk to eating genetically modified foods currently on the market. And some of this negative perception can be traced back to the first wave of genetically modified crops that were developed to be resistant to herbicides. Yeah, it brings to mind like agribusiness and huge corporations that are kind of biohacking crops, right? Right. Yeah. It was all about

making crops easier to grow, but the purple tomato could be considered part of a new wave in GMO foods, with the goal to increase nutritional value. So the GMO industry is hoping the purple tomato could help change the conversation. I want an orange tomato with three white stripes like a clownfish. Cannot wait. Make the clownfish angry. Ari, thank you so much for hanging out with us. Delight as always. You can also catch Ari on Consider This, NPR's afternoon news podcast. Before we head out, a quick shout out to our Shortwave Plus listeners. We appreciate you and we thank you for being a subscriber.

ShoreWave Plus helps support our show and if you're a regular listener, we'd love for you to join so you can enjoy the show without sponsor interruptions. Find out more at plus.npr.org slash shortwave. This episode was produced by Kai McNamee and our showrunner Rebecca Ramirez. She also helped edit it along with Viet Le and Catherine Fox. Britt Hansen checked the facts and the audio engineer was Patrick Murray. I'm Regina Barber. I'm Margaret Serino.

Thanks for listening to Shortwave from NPR. This was a good one. I agree. Good stories. Okay. I'm going to check out and have fun saying anemone. And NEM. It literally is like the movie where he can't say it.

Have fun. NEM. Yeah. Wait, how am I saying it wrong? Oh, enemy. An Annamy.