Speaker
Description
Predation shapes biological evolution at multiple scales, from genomes and organisms to entire ecosystems. Albeit traditionally studied in larger organisms, predation also pervades the microbial world: nematodes and protists ingest prey whole via phagocytosis; many Bdellovibrio-and-like organisms (BALOs) invade their prey and reproduce in a virus-like fashion; and group-hunting myxobacteria deploy a whole arsenal of diffusible and contact-dependent mechanisms to kill and lyse their prey. Despite their expected great impact, little is known about how such deeply divergent predators affect the composition and dynamics of microbial communities over extended evolutionary times. Moreover, it remains unclear how predators adapt to their prey, and whether predator-prey coevolution leads to Red Queen dynamics at the community level. After a short primer on predation in the microbial world, I will present the design of – and ongoing work leading up to – a large-scale evolution experiment that should shed light on these issues. In this experiment, we will use three species each of five divergent classes of predators – myxobacteria, BALOs, dictyostelids, cercozoa, and nematodes – and coevolve each of them with a defined community of 20 soil bacteria. By comparing the effects of each predator species and class on prey community evolution, we will gain systematic insights into how distinct major predators of microbes shape the evolution of species-rich communities. Metagenomic sequencing will moreover allow us to test how different predators and their prey (co-)evolve. Overall, our comparative approach will foster a more comprehensive understanding of the evolutionary ecology of microbial predation.
