Sergio Rasmann: changing chemistry

Sergio Rasmann

Sergio Rasmann is a researcher at the University of Neuchâtel. In this post, he talks about his recent paper, Plant adaptation to different climates shapes the strengths of chemically mediated tritrophic interactions, and why he became an ecologist.

What’s your paper about?

This paper is about chemically-mediated plant-herbivore-predator interactions, and how such interactions are shaped by plants’ adaptation to different climatic (temperature and precipitation) regimes.

What is the background behind your paper?

A current major challenge in ecological research is to understand how variation in plant chemistry, and subsequent chemically-mediated plant animal interaction, is driven by variation in biotic and abiotic conditions in different habitats. Here, we combined natural history data, with field common garden experiments, behavioural assays and metabolomics analyses to address the effect of plant adaptation to different habitats along temperature by precipitation gradients and how plant adaptation, in turn, influences the strength of belowground tritrophic interactions between plants, herbivores and their predators. We found that plants originating from different climatic conditions produce a different blend of volatile organic compounds in their roots, and this differentially attracts predatory nematodes. Moreover, we highlighted the existence of plants’ growth-defence syndromes related to different climatic niches.

How did you come up with the idea for it?

I was invited to give a talk at the University of Prague by my colleague Zuzana Münzbergová, and during our conversations, I found out about this amazing experimental design in the fjords of Norway, in which a grid of 16 sites are arranged along the two axes of precipitation and temperature. As soon as I heard about this, I immediately thought of exploiting this natural temperature by precipitation grid for measuring the independent and interactive effect of temperature and precipitation adaptation on plant-herbivore-predator interaction.

What are the key messages of your article?

First, this work shows that plant adaptation to specific climatic conditions influences how plants relate with the other members of the community. In this case, plants living in more humid environments were more capable of attracting predatory nematodes when damaged by root herbivores than other plant ecotypes. Secondly, it confirmed that large-scale ecological gradients are highly useful tools for dissecting the importance of climatic factors in driving variation in the interactions between plants and their environment.

About the Author

How did you get involved in ecology?

I grew up on the mountain slopes of the Alps. I spent my free days hiking in the forests, along Alpine meadows and streams, and climbing trees. Naturally, I only had one option, continuing to study nature in its myriad facets.

What are you currently working on?

I am a chemical ecologist by training, majorly working on chemically-mediated plant-herbivore-predator interactions. My initial motivation for doing research was to develop ecologically-sound ways of reducing the impact of insect pests on crop plants. Recently, my centre of interest has been shifting toward trying to understand the ecological causes that drive the incredible variation of how plants interact with their environment, mainly through chemistry, and secondly, how chemistry is shaping the functions of the ecosystems in which the plants are imbedded.

What is the best thing about being an ecologist?

I always say that being an ecologist is the best work you can have. You get to travel and discover pristine and wildly interesting ecosystems or species, uncover patterns that make up nature’s incredible complexity. In addition, at the same time you can teach the beauty of nature to students, and promote awareness for biodiversity to the public.

What do you do in your spare time?

If not occupied taking my kids to soccer or gymnastics, I’ll devote most of my free time to climbing mountains or enjoy walks in nature.

One piece of advice for someone in your field…

Be curious for novel and bold ideas, and persistent if your experiments do not work straightaway. 

Read the paper in full here or the free plain language summary here.

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