Biotic interactions

Ecosystems are characterized by numerous players (species, individuals) interacting in complex ways. These can be described as ecological interaction networks. The networks in our studies often represent a particular function in an ecosystem, e.g. pollination or herbivory. We have contributed tools and concepts to analyse and interpret the specificity of the interactions (see Methods). 

Associations between species may be positive for both (mutualistic networks), or negative for one of them (food webs, antagonistic networks), short-term or long-term and intimate (symbiosis). 

 

Networks - mechanisms and consequences

We are trying to understand why certain pairs of species interact while others do not (niche partitioning). What are the benefits and costs of being a specialist? Why are consumers specialised on certain resources – because of nutrition, chemical signals, constraints? What are the consequences of specialisation for ecosystem functioning and functional stability? Does specialisation enhance the functional performance of the target system (functional complementarity), but represent an extinction risk? In turn, does biodiversity buffer the system against environmental disturbances (response diversity, functional redundancy)? 

Army ant colonies are host to a diverse community of arthropod symbionts. We combine diverse research approaches including taxonomic studies, molecular analysis, studies on symbionts` life histories and behavior as well as community sampling and ecological network analysis. This project aims to document the rich biodiversity of army ant symbionts and provide novel insights into co-evolutionary and ecological dynamics of these species-rich host-symbiont communities.

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Army ant colonies are host to a diverse community of arthropod symbionts. We combine diverse research approaches including taxonomic studies, molecular analysis, studies on symbionts` life histories and behavior as well as community sampling and ecological network analysis. This project aims to document the rich biodiversity of army ant symbionts and provide novel insights into co-evolutionary and ecological dynamics of these species-rich host-symbiont communities.

--> Christoph von Beeren

We study predator-prey interactions in forest microhabitats: soil, litter, dead wood, lichen, moss, tree bark. We investigate the morphological and chemical defensive mechanisms of oribatid mites as prey and the specific adaptations of the predators, e.g. gamasid mites, ants, beetles. Furthermore, the effectivity of predator-prey interactions is tested in laboratory experiments. Oribatid mites are an ideal model group for investigating the evolution of predator-prey interactions: they are among the first animals on land, ubiquitous and highly abundant in many microhabitats.

--> Katja Wehner, Micha Heethoff

We study the extent of intra- and inter-population variation in plant traits and its consequences for interactions across trophic levels in “common garden” experiments, where plants from different populations are exposed to a common environment. We currently focus on plant traits and interactions with higher trophic levels for beech (Fagus sylvatica), brown knapweed (Centaurea jacea), and apple (Malus domestica and M. sylvestris).

--> Karsten Mody

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