Tiny, Hidden Driving Forces: Conference on the Microbial Symbiont Network of Bark Beetles

On February 7-9, 2024, researchers from twelve leading institutions across nine countries gathered in Freiburg to discuss the complex relationships between bark beetles and their associated microbes. Organized by the Chair of Forest Entomology and Protection, the BBMicroNet Conference was themed “Exploring the Microbial Symbiont Network of Bark Beetles in a Changing Climate”. Participants from diverse disciplines, including microbiology, chemical ecology, entomology, tree pathology, and forestry, discussed the latest advancements in our understanding of bark beetle-microbial interactions. The discussions highlighted the critical need to deepen our understanding of the functional dynamics between bark beetles, their host trees and their respective microbial communities, setting the stage for potential collaborative research efforts.

Bark beetles are keystone species in our forests, playing critical roles in this important ecosystem. Among the >6000 species worldwide, only 25 are commonly recognized as significant disturbance agents — a number that is rising due to global change pressures. Recent climatic shifts towards warmer temperatures and decreased rainfall have rendered trees more vulnerable, enabling bark beetles to breach tree defenses more efficiently. This has led to unprecedented scales of bark beetle epidemics and extensive forest loss. Notably, the European spruce bark beetle Ips typographus, the main insect pest of Norway spruce (Picea abies (L.) Karst.), has become one of the top disturbance agents in European forests.

Despite bark beetles’ importance to our forests, there are still many gaps in our understanding of how they interact with their environment. One particular area requiring further investigation the role of symbiotic microbes in the lifecycle of bark beetles and their contribution to the beetles' ecological and evolutionary success. Previous research has shown that microbes play crucial roles in the lives of bark beetles, helping them overcome tree defenses, access nutrition, and defend against competitors and pathogens. However, due to the nature and complexity of these interactions and in light of an ever-changing climate, this topic area still lacks a comprehensive understanding.

The three-day conference provided a platform for researchers to explore these knowledge gaps and hone in on ways to fill them. “It’s always a good idea to bring experts to the same table. Joining forces, instead of competing against each other, is so much more efficient and enjoyable", noted organizer Dr. Vienna Kowallik. As part of the FRIAS Junior Researcher Conference Initiative, the event was largely organized and moderated by PhD candidates under the lead of Raluca Hedes. Featuring a forum of researchers in different career stages, the workshop fostered dialogue between emerging and established scientists.

A mix of keynote talks and flash presentations set the stage, while topic-driven discussion sessions identified opportunities for future research and established communication channels between institutions. During the discussion sessions, participants traded techniques and insights gained from years of extensive research. They developed plans for collaboration, and since the conference, participants have already started working together. This was a prime example of how collaborative efforts can enable researchers to build upon each other’s work rather than duplicating it. Near the end of the conference, a keynote speaker reflected on their experience, “There’s still a lot of work to be done, and that’s exciting."

The organizers would like to extend a heartfelt thanks to all participants for their invaluable contributions and to the Freiburg Institute for Advanced Studies (FRIAS) for their generous support in funding, hosting, and providing organizational assistance for this conference.

Organizers: Raluca Hedes, Sifat Munim Tanin, Tobias Frühbrodt, Helge Löcken, Prof. Dr. Peter Biedermann, Dr. Vienna Kowallik.