High school students explore genes, behavior, and the future of biological robots.

Why does a tiny nematode follow the smell of buttered popcorn? How can a single genetic mutation change its behavior? And how could organisms like these one day contribute to medicine, agriculture, or environmental protection?

These were just some of the questions explored by students from CJD Königswinter during a five-day project week at the Max Planck Institute for Neurobiology of Behavior. Working in our Public Lab, they used the model organism Caenorhabditis elegans to carry out their own experiments on mechanosensation and chemosensation while gaining first-hand insights into modern neuroscience research, from behavioral tracking and high-performance computing to electron microscopy.

A particular focus of the week was the BABOTS research project, which investigates how the behavior of living organisms could one day be harnessed for biohybrid robotic systems. Alongside the scientific aspects, the students also discussed the ethical opportunities and challenges associated with emerging technologies like these.

Rather than telling the story ourselves, we would like to hand over to one of the participants. In the following report, Anna G. describes one of the experiments she carried out during the project week.

Please note: Anna originally wrote the following report in German. The English version below has been translated by the institute for publication on our website.

During our project week at the Max Planck Institute for Neurobiology of Behavior, we gained exciting insights into neuroscience research. We worked with the model organism Caenorhabditis elegans (C.elegans), learned a variety of experimental techniques, and explored how genes can influence behavior. Among other experiments, we investigated how animals respond to touch (mechanosensation) and smell (chemosensation). One of my favourite activities was an experiment on chemotaxis—the ability of organisms to move towards or away from specific chemical substances.

To prepare for the experiment, we first divided Petri dishes into four quadrants and drew a small starting circle in the centre. This layout made it easier to systematically analyse the worms' distribution later on. We then pipetted diacetyl into two opposite quadrants and ethanol, which served as the control, into the other two. Diacetyl is an aroma compound that is naturally produced during baking and butter production. To us, it has a sweet, buttery smell—personally, it reminded me of freshly made buttered popcorn. For C.elegans, however, diacetyl is an attractive odour that often signals the presence of food.

Next, worms from two different Petri dishes (A and B) were washed onto separate assay plates, making sure the two populations did not mix. After one hour, we observed that the worms from dish B had moved predominantly into the areas containing diacetyl, showing a clear preference for the attractive odour. In contrast, most of the worms from dish A either remained close to the starting point or were distributed across the plate without any obvious direction.

Afterwards, we calculated the chemotaxis index, which indicates how strongly organisms are attracted to or repelled by a particular substance. The worms from dish B showed a much higher chemotaxis index than those from dish A. From these results, we concluded that the worms in dish A carried a mutation that impaired their ability to detect diacetyl. As a result, they could no longer orient themselves towards the odour and instead moved across the plate in a largely random manner.

This experiment clearly demonstrated how a change in a single gene can influence the behavior of an organism. Working with the model organism C.elegans allowed us to experience first-hand how scientists investigate genetic differences and answer biological research questions through experiments. At the same time, we gained valuable practical laboratory skills and an authentic insight into everyday research at the Max Planck Institute.

- Anna G.