These orchids are made from real and artificial parts—the only all-natural orchid is in the bottom left.

These orchids are made from real and artificial parts—the only all-natural orchid is in the bottom left.

Aleah Davis, from New Phytologist (2016)

How 3D printing unraveled the Dracula orchid’s disguise

Orchids are a family full of con artists. Instead of enticing their pollinators with nectar like other flowering plants, many attract them with masterful disguises that mimic food, rivals, or even mates. The misled insects then carry pollen from one flower to another, unintentionally helping the orchids reproduce. Now—using models from a 3D printer—researchers have shown how one such orchid tricks fungus-loving flies by mimicking the sight and smell of their favorite mushrooms.

Flowers come in a dizzying array of colors, shapes, and smells. With these multifaceted advertisements, it’s hard to pin down exactly what parts of a flower are actually attracting pollinators. One way scientists break down this complexity into more manageable pieces is by using artificial flowers: By adding different odors to artificial flowers that look and feel the same, for example, scientists can see how a pollinator reacts to smell alone. Such fake flowers are usually made of simple materials such as construction paper, cotton balls, or test tubes with cotton wicks. “We’d just walk through a dollar store and see what we could use,” says Tobias Policha, a plant ecologist at the University of Oregon, Eugene, and lead author of the study.

But for Dracula lafleuri, a complex, showy flower found in the cloud forest of Ecuador, Policha needed something more durable, and more realistic. These orchids—which have a single petal that resembles the fungi that live nearby—attract flies that typically congregate around, and sometimes breed on, the mushrooms. It’s hard to mimic that look with construction paper, which would disintegrate quickly in the wet forest anyway. So Policha and colleagues worked with artist Melinda Barnadas to develop a technique for creating artificial Dracula orchids. After a long process of casting, 3D-scanning, and digitally refining, Barnadas and the team 3D printed gypsum molds from which they could create silicone orchids in whatever color patterns they wanted. This gave them unparalleled flexibility in making their counterfeit flowers. 

The team hung the artificial flowers next to actual Dracula orchids in the cloud forest. They modified both the fakes and the real flowers, changing the colors and patterns, and adding or removing scents. They even made several “Frankenstein” flowers, pieced together from artificial and natural flower parts (pictured). Then they watched to see which blossoms got more attention from the flies.

It turns out that the orchids need both the right look and the right smell to pull off their swindle. The artificial flowers—even those that were perfect mimics—attracted fewer flies than the real blooms. Only when the researchers applied scents from natural orchids were just as many flies attracted to the mimics as to the real flowers, the team reports this month in New Phytologist. Still, the fakes aren’t perfect, Policha says. Flies landed less often on these printed blossoms than on real flowers—they’d fly close, but veer away at the last second.

The orchid’s labellum—the center petal that looks conspicuously like a mushroom—is key to its disguise. A real flower with a fake labellum attracted flies no better than an orchid made entirely of silicone. This petal is also where the orchid’s mushroom smell is concentrated, a scent the researchers attribute mostly to a type of alcohol that can also be found in 80% of mushrooms living nearby.

<i>Mycena</i> mushrooms, one of several species the <i>Dracula</i> orchids mimic.

Mycena mushrooms, one of several species the Dracula orchids mimic.

Tobias Policha

But the showy, white-and-maroon-speckled sepal plays a role, too. Researchers tested different color patterns, and found that flies were convinced only by orchids with spots. These flies tend to hang out on mushrooms in huge numbers—so Policha says that these flies might see the maroon dots as a fly party.

Capturing all of these details in one experiment would never have been possible without the lifelike silicone flowers. “It’s a really important contribution to the field,” says Florian Schiestl, an evolutionary ecologist at the University of Zurich in Switzerland who wasn’t involved with the study. “I think it’s going to be an important technique for pollination ecology in general.”

And 3D printing technology is rapidly becoming cheaper and more sophisticated. Octavio Campos, a pollination biologist at the University of Washington, Seattle, was the lead author on a study last year that used 3D printed flowers to study how flower curvature affects pollination. He’s excited about the technique’s promise: “In the future, you can imagine the possibility of designing your artificial flower,” he says. “You’re not only specifying the shape of it, but also the texture, the color patterning, whether parts are harder or softer, [and] their flexibility.”

So what’s standing between us and the perfect artificial flower? Policha says one key might be texture, and what lies on the flower’s surface. “As we learn what’s naturally growing on these flowers, we could culture certain yeasts from those habitats,” he says. “Then a really elegant experiment would be to cover the artificial flowers with these yeast cells.” After that, who knows?

Follow News from Science

dancing shoes