Short Wave - Butterflies Have Hearts In Their Wings. You Won't Believe Where They Have Eyes

Episode Date: October 12, 2020

Adriana Briscoe, a professor of biology and ecology at UC Irvine, studies vision in butterflies. As part of her research, she's trained them to detect light of a certain color. She also explains why they bask in the sunlight, and why some of them have 'hearts' in their wings. Plus, you'll never guess where their photoreceptors are.She's written about the importance of teachers and mentors in diversifying the STEM fields. Email the show at [e-mail]. 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

Hey, everybody, Maddie Safaya here. And Emily Kwong. Wishing you a happy Indigenous People's Day. To Native American, Alaska Native, and Indigenous people in STEM, we see you, and we appreciate you. The Shortwave team is off for today. So we're encoring one of our favorite conversations from the summer. You will never see butterflies the same way. Thanks for listening. Enjoy.

You're listening to Shortwave from NPR. Adriana Briscoe has probably forgotten more about butterflies than you or I will ever know. Probably, yes. That's a fair assessment. She's a professor of biology and ecology at the University of California Irvine. And my lab studies the evolution of coloration and vision in butterflies. Now, you can probably guess that butterflies see with their eyes, thanks to the to these little light-detecting cells called photoreceptors.

But they also have those photoreceptors in interesting places. They have photoreceptors in their genitalia. Yeah, genitals. You can imagine how that might be beneficial to them because... Dear listeners, I could not imagine how. But it turns out that females use these special cells that detect light on their genitals, to figure out where to lay an egg. They need to do this kind of quickly to avoid it being eaten by a bird.

So we think that it's probably evolutionarily advantageous for them because they can very quickly point and shoot and lay an egg. I mean, that's as good as reason as any other to have, you know, photoreceptors in your genitals, I think. Yeah. Yeah. And males also have photoreceptors in their genitalia. and they need them in order to mate.

So if you paint those general photoreceptors over with black paint, the males try to court and try to mate, and they just can't complete it. They can't do it. First of all, I have a lot of questions for whoever designed that experiment. And second of all, wow. It's like, yeah, it's like, who thought to look there for this? This summer, this year, it is especially important to a pre-examination.

the little things, like a walk in the fresh air peepin some butterflies. Adriana Brisco is going to help us make sure the next time you do that, you will know a little bit more about how they do their peepin right back at you. I'm Maddie Safaya, and this is Shortwave, the Daily Science Podcast from NPR. Okay, yeah, so I thought the photoreceptors in the genitals thing was pretty cool. But then Adriana explained to me what she does with butterflies in her life. lab at UC Irvine. Oh my gosh, it is so fun to train butterflies.

It is so cool. To learn more about how butterflies seek color, Adriana trains them to fly towards, let's say, a certain type of red light. And so what we do is we train them to associate a colored light of a particular wavelength with something they really want. Butterflies always want nectar. And so we feed them by just placing them on the colored light, unrolling a proboscis, and letting them sip. I mean, if the biggest question of your butterfly day is who's going to unroll your proboscis and stick you next to a yummy pile of laboratory-grade nectar, that's pretty good, right?

And after about a week, Adriana introduces a second colored light, one they haven't been trained to detect. You're given this choice, and if they correctly choose the trained color, you know that they can distinguish between those two colored lights. Now, there's a little twist to this, which is that you have to test them over a series of relative brightnesses of the two lights, because some insects are positively phototactic, meaning that they love flying toward bright light. Aside from understanding butterfly vision better, knowing what kind of light and colors butterflies see could help us better understand how not to interfere with their environment. If we want to design buildings and unnatural objects that are sustainable, that don't adversely affect our animal and insect populations, we need to know something about what their sensory world is like. So we mentioned that Adriana has to make sure that the little butterfly isn't just flying towards the brightest light in her experiments.

A lot of insects do that. And that's because scientists think it's part of a survival strategy. You can imagine that if you're a butterfly flying in a forest under the canopy, that it's a little bit darker under the canopy than if you're flying above the treetops. And butterflies are constantly. trying to avoid being eaten by lizards and birds. And one of the things that they do is they have an escape response, which is to fly towards the brightest patch of light they can find in their visual field. Yeah, and that's often a gap in the canopy of the forest.

On the subject of flying, it's actually something butterflies can't always do at the drop of a hat. They need to be warm to fly, but they're cold-blooded. So Adriana says if you've ever seen a butterfly hanging out, slowly opening and closing its wings, that's called basking. Where they can open their wings and the wings pick up sunlight and that helps warm them up. Right. But they also have to be very careful. Opening their wings is risky because it also means that you, Usually their more colorful parts are now visible to potential predators.

On the flip side, their wings can also keep butterflies from getting too warm. We used to think most of the butterfly wing was composed of more or less like dead cellular material. But it turns out that there are parts of the butterfly wing that are very much alive. Their wings actually circulate hemolymph, which is kind of like butterfly blood, to help regulate their temperature, kind of like the ears of an elephant. And incredibly, some butterflies, some male butterflies in their wings, have incredibly physiologically active tissues, and they have little winged hearts. What?

There are little structures, little structures which are pumping hemolum in the wings. Little butterfly hearts in their wings. Which is, like, to me, like, totally amazing. So, yeah, warm, but not too warm. And once they're in the air, Adriana helped discover that some butterflies see in a way you or I can't. For example, monarch butterflies can see what's known as polarized light. The light that you see in the blue sky is partially polarized by the atmosphere.

That means that the orientation of the photonic waves is kind of filtered in one direction. Right. And we can't really see that. So we lose that directional information. But butterflies have the ability to detect polarized light. And so one of the things I've contributed to is the discovery that monarch butterflies use ultraviolet polarized light when they navigate.

That means they can see ultraviolet polarized light from the sun, which helps them know where the sun is, even if it's cloudy. And butterflies navigate by adjusting their flight pattern relative to the sun while they're migrating. And so it gives them this extra ability to continue their migration, even if the weather isn't good. Got it, got it. Awesome. Awesome. So cool. Adriano wasn't always interested in butterflies. But as an undergrad in college, she knew she was interested in evolutionary biology. So she wrote to a professor in that department to ask if there was an open spot in his lab.

And there was. And so the next summer, he and his wife, who was also a biologist who studied butterflies, invited me to join their research groups to spend a summer doing field work in the Rocky Mountain Biological Lab. And I jumped at this opportunity. It was just an incredibly transformative experience for me. I ended up being surrounded by flowers, meadows, and butterflies. And that was my path to becoming a professor. That summer, she spent in the Rocky Mountains,

made Adriana realize how important teachers are in creating scientists. Not just those two professors who took her out in the university. field, but the teachers she grew up with, in her own family. My earliest role models were my mother and my grandmother, who were both bilingual elementary school teachers. So they weren't scientists, but they were role models for me in terms of educational attainment. And so I became curious, like, how many of our K-12 public school teachers in California, where I live are Latino and also teach science math or computer science.

So I Google this and I could not find this information anywhere. And yet I thought, God, this is like such an important question. Naturally, she and a graduate student wrote code to analyze more than one million California Department of Education records looking at the demographics of K through 12 public school teachers. When we dug into the data to look at what percentage of teachers are Latino and also teach science math or computer science, the number was 3%. Oh, wow. Yeah. Wow. And it's just shocking to me. So what that means is that if you're a Latino student in California, there's a pretty good chance that you will never have a Latino teacher who teaches science math or computer science. And yet, teachers for sure are the

reason why I became a scientist. Right. Yeah, I mean, I think you're right. We focus so much on, you know, the percentage of college professors or high school teachers. But a lot of those decisions about who you are and who you can see yourself as happen way earlier than that. You know, like teachers create scientists, right? We know this. Yeah, absolutely. There have been studies which have shown that girls who participate in summer science camp are much more likely to actually major in science when they're in college. And the hands-on experiences and having role models absolutely crucial, both in terms of that early experience when I was in middle school and in terms of the college experience, it gave me a sense that this was something I could do

because there were, for example, there were women, which opened up my eyes to the possibility that I could also become a scientist. And it helped me on my journey. Adriana Briscoe. This episode was produced by Brett Bachman and Rebecca Ramirez, edited by Debra George and fact-checked by Rebecca Ramirez. I'm Maddie Safaya. Thanks for listening to Shortwave from NPR.