Short Wave - Lightning Bugs, Fireflies - Call Them What You Will, They're Awesome

Episode Date: July 30, 2021

There are thousands of species of lightning bug and they live all over the world except in Antarctica. Maddie and Emily discuss lots of other amazing tidbits about the family Lampyridae and talk about what humans can do to preserve the bugs, which are facing widespread habitat disruption.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 everyone, Emily Kwong here with my co-hostess with the mostus, Maddie Sophia. Hello, Critter. Hello, what you got for us, Sophia? So, Emily, I've got a little episode about a beetle that is very popular this time of year in the States. We're talking lightning bugs, fireflies, twinkle butts, whatever you want to call them. Yeah, I remember catching them in the backyard as a kid. I don't think all of them survived that experience, but they're so cool.

And I absolutely did not know they were Beatles. I just knew that I loved them. Well, did you know that they eat snails? Because that's one of your favorite animals. How do you feel about them now? Conflicting. Just you wait, Emily Kwong. I've got a whole list of little twinklebutt facts that will delight you, disarm you, inspire you to make change, Emily.

If anyone can do it in 10 minutes, it's you. So today on the show, we are talking about the incredible world of lightning bugs and what we need to do to keep these critters around. I'm Maddie Safaya. And I'm Emily Kwok. This is Shortwave, the Daily Science podcast from NPR. All right, Maddie, you are here to talk about lightning bugs or, as you point out, beetles with flashlight butts. Yes, the family of beetles we call fireflies, Lampurity, are extremely diverse. There are more than 2,000 species in that family, and they live on every continent except Antarctica.

So, Emily, they can look and behave very differently. One type can grow to be the length of your palm. There are fireflies that live most of their lives in water. Emily, some fireflies don't even fly, and some don't flash, for that matter. So, you know, not everything we'll be talking about today holds true for every species. So what you're saying is you couldn't just stick to one. species because you got excited and distracted by all the facts about all the species. Is that right? Maybe I did. Maybe I didn't. You'll be happy for it. I'll say that. Uh-huh, uh-huh.

So who did you talk to about this constellation of creatures? I called up Stephanie Weiss, a PhD student in Rio de Janeiro. She's an entomologist who studies fireflies. And just like us, her love of fireflies started in childhood. I have a great memory of my childhood and summer children. trips with my family, and also I love to see the shining in the forest when I do my field works. She says that there's one thing that applies to all fireflies, and that's that fireflies have different life stages, and the larval stage, in my opinion, is by far the coolest. Fireflies spend most of their life in the larval stage. And when she says most, she means like almost all of their lives are spent as larvae. I mean,

And some spend one to two years just being voracious little babies. So the adult fireflies that I see flying around on the East Coast trying to flash and find a mate, that's like a short period of their lives. Yeah, yeah. I mean, some only live as adults for like a few weeks total. They're just out here trying to find a mate, fertilize some eggs, and die. But can we circle back to you calling larvae voracious little babies? Yeah, yeah, yeah. No, this is some of my favorite stuff. Okay. Babies, maybe not the best term. But I said that because the larvae feed on animals like snails and slugs by injecting paralyzing neurotoxins into their prey and then sending in some little digestive fluids that kind of liquefies it.

And then they suck up that partially digestive goo for a snack. Delicious. Movie monster stuff out here. Yeah. And I mean, these larvae quang, they just have so much going on as far as I could find out. Not all adult fireflies glow, but it seems like all larva glow. And unlike adult glowing, which is used for activities like mating or hunting, Stephanie says glowing mostly serves a different purpose for the larvae, protection.

Out in the field, she even saw a bunch of larvae like glowing in coordination. All larvae glow together, even if just one larvae is disturbed. So we believe that it's a way to protect each other. In other words, they are saying, don't eat me. If you do that, you're going to die. I'd like to think that we glow together when threatened. Bing, Bing. I think we already do.

I think we've proven that. Can we talk a little more about the glow, actually? What is going on there with it? I would love to talk about that. Okay, okay. So the first thing that I did not know is that there's kind of a lot of lighten bug colors out here. We have already found a yellow, red, orange, green, and blue coloration. That's so impressive.

Right? I didn't know. I did not know. And all fireflies, regardless of color, glow or flash using bioluminescence. And we're not going to get all the way into this, Emily, because I want to do an entire episode about it. But basically, bioluminescence is when living things turn chemical energy into radiant energy we see as light. And the coolest thing about this, I think, is that this form of light, is extremely efficient. Almost 100% of chemical energy is converted into light. If you compare that to like an old-timey incandescent light bulb,

that's only about 10% efficient because 90% of that energy is lost as heat. Fireflies aren't out here producing heat. Just sweet, sweet light. So nature came up with this very efficient and literally cool way to light stuff up. Absolutely, absolutely. And because bioluminescence plays a huge part in the lives, of most fireflies, they are particularly threatened by light pollution. Yeah, I'm familiar with this.

Human-made light messes with the fireflies' ability to see each other and to know where they can find a mate. Exactly. And while scientists have been rightly very focused on habitat loss and urbanization, as far as what threatens fireflies, more and more are looking into light pollution as well. And that actually includes our scientist Stephanie. She was part of this big multi-year study in Brazil.

in the Atlantic Forest, looking at the interplay between habitat change and light pollution in an area home to a firefly species called the tracker ghost. Basically, they wanted to see whether light pollution, urbanization, and deforestation are increasing over time in this area. That's an interesting study premise, because I feel like maybe the damage from deforestation and urbanization would be more obvious, like easier to study than light pollution. Right. In the paper, they call light pollution a more.

silent threat. And we saw that the light pollution is the fastest growing potential threats to fireflies. Oh, wow. So even though the threat from deforestation might be more devastating, light pollution is the fastest growing threat. Got it. Okay. And even more interestingly, and to be honest, more sad, there are protected areas in Brazil that kind of buffer the impact of deforestation, urbanization, and even climate change. But Stephanie's group found that light pollution from humans is making its way into those protected areas. The most surprising thing I learned is that the light pollution is growing not only over fields or rural areas and towns, but also within protected areas on the Atlantic Forest.

In other words, the protected areas are not able to buffer these light's intensities. Now, those areas are still darker, of course, and they are still havens for biodiversity, but scientists are concerned that artificial nightlight from neighboring lit areas can disrupt some of those conservation efforts. So, Maddie, I know that an alarming amount of insects are in decline, some species of fireflies included. So what needs to happen that we get to continue to see them? Well, it won't really surprise you. So habitat loss is considered the most serious threat to fireflies. Another problem, pesticides.

In one study, pesticides were rated as the third most serious threat to fireflies globally. So, you know, reducing pesticides in residential gardens, lawns, public parks, those are things you could do to help or advocate for. From a light pollution perspective, a big one is trying to maintain some of those protected dark areas. Also, artificial lights have gotten more abundant and brighter over time. So there's a couple things there. designing these lights so that they point down to the ground can help, and also just decreasing the intensity is going to help too. All right. Well, Maddie, thank you so much for bringing this episode, lighting up our lives with some Firefly Science. Very cool. You got it, M.

This episode was produced by Britt Hansen, edited by Gizal Grayson, and fact-checked by Indy Kara. I'm Maddie Safaya. And I'm Emily Kwong. Thanks for listening to Shortwave, the Daily Science podcast from NPR.