Farewell to…
from Tübingen to the Tropics - and beyond

A farewell conversation with Hassan Salem, Max Planck Research Group Leader, reflecting on his time at the Max Planck Institute for Biology and the next chapter of his research.

As part of our farewell series, in which we speak with researchers departing the institute about their time at the Max Planck Institute for Biology, we caught up with Hassan Salem, who concluded his tenure as a Max Planck Research Group Leader at the end of 2025 to join the John Innes Centre in the United Kingdom to lead an independent research group on plant-insect interactions.

Shortly before his departure from Tübingen, we took the opportunity to look back on the scientific milestones, research culture, and memorable moments that shaped his time at the Max Planck Institute - from open yellow office doors to fieldwork in tropical forests. In this interview, Hassan also reflects on how the foundations laid at the institute continue to inspire the lab’s future research directions.

What drew you to the Institute, and how did your time in Tübingen shape your research?

I started at the Max Planck Institute for Biology Tübingen in 2020. Moving to Tübingen was a wonderful opportunity to build a research program in an environment that values curiosity-driven biology, irrespective of the study system. The breadth of models we rely on at the institute is remarkable. From plants and mice, to nematodes, algae, fungi, and insects. The institute’s strength in evolutionary and developmental biology, combined with the openness of some outstanding core facilities, made it a very attractive fit for me and the group.

What were the key ideas and achievements that defined your work here?

My hope is we have furthered the study of symbiosis not as a niche phenomenon, but as a central driver of biological diversity and adaptation.

Bringing mechanistic and evolutionary perspectives together was something we actively strived for and was made possible by mentees balancing projects in the lab with experimentation in the field. The latter came through our long-term collaboration with the Smithsonian Tropical Research Institute. That synergy led to studies that opened new directions for the lab and initiated collaborations beyond our immediate field, including behavioral ecology, structural biology, and natural product chemistry.

How did collaboration and institute culture influence your day-to-day science?

The research culture at the institute is both open and rigorous. There is a strong expectation of thoroughness, but also a genuine willingness to help each other succeed. Folks aren’t only generous with their resources and expertise, but also with their time.

I love our institute’s yellow office doors. Whenever we host visitors or collaborators, it’s one of the most commonly commented on aspects of our building. But beyond their inviting color, what I will remember most is how often they were, quite literally, open for the random chat or discussion.

What comes next for the lab after leaving the Max Planck Institute?

The lab has just relocated to the John Innes Centre in the United Kingdom. We plan to continue working on the intimate symbioses that insects form with microbes and the adaptations that arise because of these interactions. Some of this work will be part of a recently funded project from the European Research Council on herbivorous beetles and their digestive symbionts. Other studies will look at how infection by a beneficial symbiont shapes herbivore behavior. These projects, and others, are directly connected to much of the groundwork that was laid in Tübingen.

Which moments—from fieldwork to campus corners—will stay with you the longest?

Our field trips have always been rewarding to take part in as a group leader. It’s where we validated many of our hypotheses and laboratory findings under natural context. But it’s also where you pack a substantial portion of the lab onto a plane for weeks at a time, which can be challenging logistically, but rewarding in almost every other metric. These trips will always stay with me from our time at the MPI. One such memory of our time sampling beetles in the tropical forests of Panama is when we encountered howling monkeys for the first time. Nothing prepares you for the intensity of their roar. It stopped us at our feet.

And finally: what fun facts, favorite habits (coffee or tea while writing papers), and quiet places helped fuel the research along the way?

Fun fact: Some beetle pupae are coated in a dense white material once assumed to be wax. In 2022, we showed it is in fact not wax but a fungal symbiont that protects the pupa against insect predators such as ants.

Coffee or tea: Given where we’re moving to, I won’t say too much against tea. But it’s coffee.

Favourite spot on campus: It’s the small park by Robert-Gradmann-Weg. That strip of green is only a five-minute walk from the institute, but its benches are perfect for a quiet moment. Many grant ideas (and reviewer rebuttals) were mulled over by that leafy spot.