Vibrating earthworms pick up an Ig Nobel

When you think of award-winning scientific research, you might think of determining the structure of DNA, or Marie Curie’s work on radioactivity. You might not think of vibrating drunken earthworms with a subwoofer in a garden shed. And yet, here we are.

Two Australian scientists have taken home a 2020 Ig Nobel Prize for exactly that. Swinburne University’s Ivan Maksymov and Andrey Pototsky, a physicist and mathematician, were intrigued about the shape of a worm as it vibrates. More specifically – would standing Faraday-like waves form the way they did when Pototsky vibrated liquid droplets.

Maksymov says the project began when one day, while gardening, he found several earthworms and decided to vibrate them. “When this experiment was conducted, we did not think of any specific research question. It was just a ‘what-if?’ moment.”

And sure enough, he found standing Faraday waves form in the earthworm itself. The results were published earlier this year in the journal Scientific Reports.

“The experiment demonstrated that a vibrated earthworm behaves similar to a water drop,” he says. “When anaesthetised, earthworms are essentially a liquid drop wrapped in an elastic membrane. As a result, Faraday ripples on them are not so different from those on a drop, which is held together by surface tension.”

Most of the research occurred not in their laboratory, but in Maksymov’s garden shed. He set up a subwoofer with a Teflon plate resting on top. Onto the plate a “lightly sedated” earthworm was placed, with a laser diode to illuminate the waves and a camera recording what happened next.

How do you lightly sedate an earthworm? Vodka. Turns out earthworms love it.

Getting the ground spaghetti drunk has a couple of advantages. Usually an earthworm’s muscles help maintain a high internal pressure that holds the cylindrical shape of the worm. Get a few drinks into them and their muscles completely relax, making them even more like thin tubes of water. Also, it just helps stop them from escaping, a problem Maksymov had during the experiment.

“However, whereas this result indicates that the results presented in our work should also apply to non-anaesthetised worms, it is very challenging to keep the worms in the focus of the laser beam,” he writes.

And while the researchers may have preferred to do the experiments in their lab, there were some advantages of doing it at home.

“Sometimes it is beneficial to go straight to the lab to test a ‘wild idea’ – which was in many cases possible when the experimental setup was located in the shed. Also, some experiments were conducted after 9pm, when kids were asleep. So, it seems that the pandemic slightly helped us.”

While it all sounds a little like a feverdream, there is actual use to this research. Some of Maksymov’s previous research was aimed at verifying a hypothesis that additional to the electric components, nerve pulses moving in our brain are also sound waves called acousto-mechanical waves-solitons.

Maksymov and Pototsky found that the waves in living earthworms have a frequency of between 20–300Hz, which they say coincides with those of natural nerve impulses.

Therefore, they suggest mechanical vibrations could be used to amplify or suppress the worm’s nerve signalling through constructive or destructive interference. And that could open up novel opportunities to control nerve signals.

“There is an opportunity to use vibrations to create a safe non-invasive link with the nervous system,” says Maksymov. They proposed the idea to neurobiologists based on their findings, and the researchers say they got positive feedback.

There are obvious neurobiology applications, helping scientists understand neuron signalling and functions, and ultimately help explore animal behaviour. Alternatively, vibrations could also potentially be used to control worms to modify soil structure and increase crop yields, say the researchers.

The IgNobel Prizes are presented each year to studies that “first make people laugh, and then make them think”.

Usually the 10 winners are celebrated in an unapologetically weird ceremony at Harvard University, but with travel restrictions thanks to the pandemic, this year’s ceremony happened entirely online.

“It was a big surprise. We never thought that our work would make somebody laugh and then think. We only wanted people to think,” says Maksymov.

“We recorded an interesting acceptance speech video, where we had just one minute to explain our work. Of course, there were many weird things… Unfortunately, we cannot give you more details – you’ll just have to watch the ceremony to find out.”