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Small grass yellow butterflies feed on fresh elephant dung in Kenya’s Tsavo West National Park. Photograph by Nigel Pavitt, Getty

Butterflies Behaving Badly: What They Don’t Want You to Know

Butterflies have had us fooled for centuries. They bobble around our gardens, all flappy and floppy, looking so pretty with their shimmering colors. We even write odes to them:

Thou spark of life that wavest wings of gold,
Thou songless wanderer mid the songful birds,
With Nature’s secrets in thy tints unrolled
Through gorgeous cipher, past the reach of words,
Yet dear to every child
In glad pursuit beguiled,
Living his unspoiled days mid flowers and flocks and herds!
Ode To A Butterfly, by Thomas Wentworth Higginson

But butterflies have a dark side. For one thing, those gorgeous colors: They’re often a warning. And that’s just the beginning. All this time, butterflies been living secret lives that most of us never notice.

Take this zebra longwing, Heliconius charithonia. It looks innocent enough. 

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The zebra longwing butterfly was made Florida’s state butterfly in 1996. Pixabay, CC0

But it’s also famously poisonous, and its caterpillars are cannibals that eat their siblings. And that’s hardly shocking compared with its propensity for something called pupal rape.

Once you know that a pupa is the butterfly in its chrysalis—in between being a larva and an adult—then pupal rape is pretty much what it sounds like. As a female gets ready to emerge from her chrysalis, a gang of males swarms around her, jostling and flapping wings to push each other aside. The winner of this tussle mates with the female, but he’s often so eager to do so that he uses his sharp claspers to rip into the chrysalis and mate with her before she even emerges.

Since the female is trapped in the chrysalis and has no choice in the matter, the term pupal rape came about, though some biologists refer to it more charitably as “forced copulation” or simply pupal mating. Whatever you call it, it’s hardly the stuff of children’s books.

The zebra longwing is certainly pretty, though. Maybe that’s how it got to be Florida’s state butterfly.

And don’t think for a minute that zebra longwings are an anomaly—plenty of their kin are bad boys, too.

One day in Kenya’s North Nandi forest, Dino Martins, an entomologist, watched a spectacular battle between two white-barred Charaxes. A fallen log was oozing fermenting sap, and while a fluffy pile of butterflies was sipping and slowly getting drunk, the two white-barred butterflies showed up and started a bar fight. Spiraling and slicing at one another with serrated wings, the fight ended with the loser’s shredded wings fluttering gently to the forest floor.

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A green-veined Charaxes dines on animal poop. Photograph by Dino Martins

Martins, a former National Geographic Emerging Explorer, wrote about Charaxes, or emperor butterflies, in Swara magazine, published in East Africa where he is now Director of Kenya’s Mpala Research Centre.

“They are fast and powerful,” he writes. “And their tastes run to stronger stuff than nectar: fermenting sap, fresh dung and rotting carrion are all particular favourites.”

That’s right; don’t get between a butterfly and a freshly dropped pile of dung. It drives them wild. They uncoil their probosces and slurp away, lapping up the salts and amino acids they can’t get from plants.

It’s called mud-puddling, and it’s very common butterfly behavior. It doesn’t have to be dung, although that’s always nice; you may see flocks of butterflies having a nip of a dead animal (as depicted in this diorama of butterflies eating a piranha), drinking sweat or tears, or just enjoying a plain old mud puddle.

(VIDEO: Did You Know Butterflies Drink Turtle Tears? Watch to find out why.)

But still, butterflies are harmless, right?

Sorry, kids—not always. Butterflies start life as caterpillars, which are far from harmless if you’re a tasty plant, and can be carnivorous. Some are even parasites: Maculinea rebeli butterflies trick ants into raising their young. The caterpillars make sounds that mimic queen ants, which pick them up and carry them into their colonies like the well-to-do being toted in sedan chairs. Inside, they are literally treated as royalty, with worker ants regurgitating meals to them and nurse ants occasionally sacrificing ant babies to feed them when food is scarce. Butterflies invented the ultimate babysitting con.

So, let’s review. Here are seven not-so-nice things butterflies are into:

  • Getting drunk
  • Fighting
  • Eating meat
  • Eating poop
  • Drinking tears
  • Tricking ants
  • Raping pupae

Don’t get me wrong—I like butterflies. In fact, I like them more knowing that they have a dark side. They’re far more interesting, more weird, than any ode to pretty colors could convey.

Dino Martins. Flitting Emperors – and Forest Queens. SWARA Vol. 27 No. 2 / April–June 2004; pp. 52-55. No link available.

Dino Martins. ‘Mud-Puddle’ — or Be Damned. SWARA January—March 2006; pp. 66-68.

Queen Ants Make Distinctive Sounds That Are Mimicked by a Butterfly Social Parasite. Science: Vol. 323, Issue 5915, pp. 782-785. 2009.