This Beetle's Strong, But Fleixible Penis Could Inspire a Better Catheter

Yoko Matsumura, Alexander Kovalev, Stanislav N. Gorb/Science Advances

The natural world is a constant source of inspiration for innovation and sometimes that inspiration comes from the unexpected. Take, for example, the beetle penis. New research into the long, smooth and flexible penises of thistle tortoise beetles is sparking new ideas into how to make better catheters.

Thistle tortoise beetle penises are rigid enough that they don't get kinks like a garden hose, which would prevent the necessary flow. The insect's long shaft is designed to navigate the coils of the complicated female beetle's reproductive system, yet it doesn't seem to have the problems that catheters sometimes present as they're inserted into a patient.

Could catheter-designers make their products more like this penis? New research published in the journal Science Advances, explored that possibility.

Researchers at Kiel University wanted to find out the secrets of ideal penetration, so they tested outpenises of thistle tortoise beetles that they had sacrificed for the experiment. They applied pressure along the shaft and documented when it would bend. They found that it's strong at the base, but becomesmore flexible closer to the tip, producing a "stiffness gradient."

Additionally, the penis has a curved tip, that's stiffer on the outside of the curve than the inside, and the organ's thickness increases towards the base, so it's shaped like a long, thin cone.

"The penis looks very simple," Yoko Matsumura, who studies the reproductive systems of insects at Kiel, told NPR . "It is actually complicated."

While this hasn't yet resulted in a change to the way people make catheters, a better design is sorely needed. Catheter-related bloodstream infections are common and sometimes deadly. Catheter-insertion has also caused urinary-tract infections.

Designing devices based on nature is called "biomimicry." Insects in particular are a favorite for robot designers, who have looked to beetles to make their robots run better and turn themselves over more efficiently.

Not all beetle penises are created equal, though. Some beetle species including seed beetles and bruchid beetles have penises covered in sharp spikes that intentionally injure the female. Catheter-makers would probably be best off disregarding those forms.