Drunk Worms Wiggle Their Way to an Ig Nobel Win

The 34^th First Annual Ig Nobel Prizes were announced on September 12, 2024. Known to spotlight “research that makes people laugh…then think,” the ten accolades don’t shy away from a spectrum of unique topics—from plants imitating plastic to mammalian anus-breathing.^1,2

Daniel Bonn, a physicist, and Sander Woutersen, a physical chemist, along with their colleagues at the University of Amsterdam, were awarded the chemistry prize for racing drunk and sober worms through a chromatography maze to sort them by their wriggly activity to better understand polymer dynamics.³ “We’re very excited,” said Bonn. “We’ve had a hard time shutting up about it.”

Much of Bonn’s work encompasses the Ig Nobel spirit; he previously reported on how to build the perfect sandcastle and why quicksand cannot fully submerge its victims.^4,5 More recently, active polymers, which are capable of self-propulsion and play biological roles in cell membrane structure and sperm motility, caught his attention. As active polymers are difficult to create and observe, given their microscopic size, Bonn found a unique macro model: the thin, aquatic Tubifex tubifex worms. Their segmented bodies resemble polymers that consist of repeating units and, most importantly, display active motion. So, Bonn and his colleagues set out to explore the physics of these dynamic, polymer-like worms.

Chemists and other life science researchers often use pillar-array chromatography to separate molecules through a maze of pillars. For example, it can separate DNA strands and polymers of different lengths based on how long it takes for each one to move through the column. Woutersen thought of a unique use of this tool.

I think the best lesson from the experiment, at least for me, is that when a drunk worm is wrapped around a lamppost and a sober worm passes by, he occasionally takes the drunk worm with him.
– Daniel Bonn, University of Amsterdam

“We had the idea that we could separate worms based on length,” said Woutersen. “Obviously, the long ones get stuck more easily around pillars and at equal lengths, then you can separate them on activity.” They needed to get inactive worms. After initially toying around with the morbid idea of euthanizing the worms, the team came up with a more humane method—anesthetizing the worms with alcohol.⁶

Instead of taking the worms to a tiny tavern, the researchers intoxicated worms by temporarily placing them into a three to five percent ethanol solution, which also contained a small amount of methylene blue dye. “It worked like a charm; [the worms] get completely drunk,” said Woutersen. “But if you put them in water again, they resurrect and become sober again in 20 minutes, without any headache or other problems.”

To compare activity, they placed the worms—the naturally reddish worms were sober, while blue worms were drunk—into a maze, a hexagonal pillar assay with distilled water flowing along its length, and measured the time spent by the worm in the channel. Woutersen expected the drunken worms to exit the maze faster because they would “go with the flow” and the active worms to get stuck along the pillars. To his surprise, the intoxicated worms exhibited less activity and sober worms tended to curl and knot, which helped them navigate through the pillars. Within a few minutes, it was clear that sober worms had an easier and faster time traversing across the maze to get to the finish line.

“But the sad conclusion is that the drunk worms get home very late,” said Woutersen. Bonn likened the process to the aftermath of a night of revelry at the pub, where drunk people often latched onto lampposts and said, “Our maze is actually little pillars, and so the drunk worms actually wrap themselves around the pillars and never get home.”

While the work answers some questions, it also raises new ones about using these wriggling worms as a model for studying the separation of active polymers. In any case, these worms resonate with the human perspective.

“I think the best lesson from the experiment, at least for me, is that when a drunk worm is wrapped around a lamppost and a sober worm passes by, he occasionally takes the drunk worm with him. So, the moral of the story is, if you go to the pub, somebody needs to remain sober and bring everybody home,” said Bonn.