Science Vs - Butterflies Are Secret Monsters

Episode Date: January 28, 2021

Butterflies flit through life as the pride and joy of the insect world. But when we saw photos of butterflies swarming the eyes of turtles, we wondered if there was a dark side lurking behind all those flashy colors. Assistant Professor of Biology Chandreyee Mitra lets us in on these butterfly secrets. Here’s a link to our transcript: https://bit.ly/36osuwx  This episode was produced by Nick DelRose with help from Wendy Zukerman, Meryl Horn, Michelle Dang, Rose Rimler, and Taylor White. We’re edited by Blythe Terrell. Mix and sound design by Peter Leonard. Music written by Peter Leonard. And special thanks to the Zukerman family and Joseph Lavelle Wilson. Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hi, I'm Wendy Zuckerman and you're listening to Science Versus from Gimlet. On today's show, butterflies that seem to be sucking on eyeballs. We heard about it and wanted to tell you all about it. Okay, so this all started the other day when I hopped on the phone with Chandra Mitra. She's an assistant professor of biology at North Central College in Illinois. And Chandra told me that she'd seen these pictures where it looked like butterflies were feeding on the eyes of other animals. Animals like turtles. Yeah, you usually see them sort of like mobbing the turtle's head and it's like, poor turtle. Oh my God. Looking it up right now.

Oh, there we go. Oh, poor turtle. Because it's really getting mobbed by the butterflies. I mean, the first time I saw those pictures, I was like, wow, this is incredible. And I was like, why? Why are they going after the eyes? Well, we think it's the tears, right, coming from the eyes. Wait, so they're like sucking the tears from the turtle? Uh-huh. Studies have found that butterflies want all these tears for one main reason.

They're full of salt. And butterflies need that salt to help their nerves and muscles work. Butterflies also slurp up salt from mud puddles, which is why this is known as puddling. It's called puddling because quite often if you're out on a hike, you'll see butterflies that have landed around water bodies or around puddles, and they seem to be drinking something from the mud.

Okay, so butterflies aren't actually sucking on eyeballs. They're slurping up tears to get salt. But this mystery, it has another twist. Because when you take a close look at who shows up around the watering hole, it's kind of a sausage fest. It's mostly the blokes doing all this puddling. And Chandra wondered, why? Like, why are the males mostly scrounging around for salt? She figured that maybe this is about butterfly bonking. Like, it's all for the nookie.

So to test this, she got a bunch of male butterflies, specifically pipeline swallowtails. This absolutely gorgeous blue and black butterfly with these beautiful tails. They look dull when you see them in the shade, but then they move into the sun and suddenly they flash these crazy bright colors. She took these sexy pipevine swallowtail dudes and used them to find out if she was right. Did having salt up their game?

So, she fed some male butterflies salt and gave others just water, popped them in a cage with some females... And then watched. With a notepad and pen. Exactly. For a while, my Twitter handle was Butterfly Voyeur. After watching more than 100 butterfly bonking sessions, she ran the numbers.

And what we found was males who've had salt actually mate more frequently than males who were given water. So it looks like salt was affecting their... How lucky they got. Yes, exactly. And what's particularly cool is that Chandra even noticed that the male butterflies seemed to be showing off the fact that they had salt through the way that they flirted. So in this species, the courtship is really beautiful. So the male flies around the female. He basically making these vertical swoops around the female. He basically making these vertical swoops around the female. If you're

a human female walking and there's a male sort of running in circles around you to be like, look how beautiful I am. Look how beautiful I am. Scrubbing through video recordings of these butterfly circles, Chandra saw that the salty fellas had the fancier footwork, or wingwork. These little magic mics took longer and more showy swoops. It was like in butterfly language. They were saying, look, I have salt because I can fly in this way. Other researchers found that after all this dancing, during the old rumpy pumpy,

the male injects the female with a little package of salt and sperm, which she can then pass on to her future babies, perhaps helping them survive. So next time a photo swarms around the internet of a butterfly seeming to suck an eyeball out of a turtle, you'll know that they're doing it for a pretty good cause, to make more butterfly babies. And by the way, some butterflies will go to even

more desperate measures to get their salt. They'll suck it off poo or dead animals. I know that there is one species of butterflies that I've read about that will drink blood. They're weird, weird little creatures. We imagine them with like rainbows and unicorns. It's like, yeah, the butterflies are drinking tears and blood and poop. That's Science Versus. We'll be back with regular episodes in March. And if you want to see what we're up to in the meantime,

you can follow us on Instagram. We're at science underscore VS or on Twitter at science VS. This episode was produced by Nick Delrose with help from the Science Versus team. Peter Leonard is our sound engineer. And if you want to swoop into the world of butterflies, there's a new book by Wendy Williams called The Language of Butterflies. It's really delightful.

Check it out. I'm Wendy Zuckerman. Back to you in March.