This is the story of a love  triangle between a plant,   a striking butterfly and an  intrepid – though unlucky – gnat.

Like every good love story … it has plant  sex, deceit, and even an attempted poisoning.

At the center of this triangle  is the California pipevine.

Its supple vines wind around other  plants or structures, like this arbor.

It’s also known as the California Dutchman’s pipe   because its flowers are curved  in the shape of a tobacco pipe.

And then there’s these “lips.” Oh hello, gorgeous!

The vine grows heart-shaped  leaves, but don’t be fooled.

The plant produces poisonous compounds that  could cause kidney cancer if you ate it.

But the California pipevine swallowtail  butterfly loves it, even though the   vine is trying to poison the butterfly’s  babies.

Talk about a toxic relationship!

The caterpillars have evolved  to depend on the vine.

It’s their only food.

And they turn its poison  into their own weapon.

As they chomp away,   they accumulate the toxins in their bodies  and make themselves noxious to predators.

The bright orange screams “I can make you sick!” Even the butterfly’s eggs are crusted with toxins.

After hatching, the caterpillars feast side   by side.

Scientists call this gregarious  behavior.

They’re not just being social.

Feeding together helps them get bigger faster,  though scientists don’t know exactly why.

And the faster they grow, the sooner they’ll  stock up on those defensive compounds.

So does the pipevine get anything out of this  deal?

Pollination by the butterflies, maybe?

Nope.

They drink nectar from other flowers.

So when the pipevine’s flowers  come out in early spring,   they lure in and trap tiny  flies called fungus gnats.

The flowers entice them with a mushroomy aroma  that reminds the gnats of the fungi they feed on.

Once in there, it’s really hard to get out.

Here’s what it looks like inside the  flower, from the bottom of the pipe.

This is the actual exit ... the way it got in.

And this is where the flower keeps its pollen.

It *could* be a way out, all lit up by the sun.

So, the gnat flies up.

It gets stuck, at least for a bit.

But the flower  doesn’t eat it, like a carnivorous plant would.

The flower only needs to keep it hostage until  some pollen grains attach to the fly’s hairs.

This is called deceptive pollination.

For many gnats the ordeal is too  much.

They don’t make it out.

But some do escape.

If one falls for the  same pipevine trick again and gets caught   in another flower … boom!

Pollination.

That  flower will turn into a seed-carrying fruit   that will eventually lead to new places  for this butterfly to lay her eggs.

She’ll never know the debt of gratitude  she owes a certain disoriented gnat.