Here, we will bring together three very active but largely independent research areas: host-microbiota-interactions, innate immunity and bacterial resistance evolution against innate immune effectors. Our overall goal is to understand the impacts of the host immune system and the resident microbiota on pathogen virulence and resistance evolution. Our study systems are insects because of their high biodiversity and importance for ecosystems and human health. Insects are also highly amenable to experiments and represent excellent models.Our unit comprises six empirical projects in combination with one integrative theoretical and one bioinformatics project. We will use six different insect species including representatives of the four most speciose groups. This combination provides a powerful comparative approach, allowing for robust general insights, and providing a means of identifying key differences. All projects will add individual components of unique added value. Project 1 will investigate how the immune system of the insect model Tenebrio molitor and the presence of antibiotics affect virulence evolution of the bacterial pathogen Staphylococcus aureus. Project 2 will examine wild flies, and ask how immune defences of wild- and lab-bred Drosophila melanogaster and their microbiota affect bacterial virulence evolution using experimental evolution. Project 3 will study the honeybee and Paenibacillus larvae as its natural pathogen. It will focus on the evolution of virulence in P. larvae under the influence of the larval immune defense and microbiota. Project 4 asks how immune effectors are used to control microbiota during metamorphosis without compromising their utility as canonical immune defences. Project 5 studies the alliance between beewolves and antibiotic-producing Streptomyces, and will assess the impact of host- and symbiont-level selection on the composition of the symbionts’ antimicrobial cocktail and its efficacy against pathogens and competitors. Project 6 examines how systemic immunity and resistance of a cockroach are influenced by the diversity and physiological age of host-microbiota interactions, and they impact virulence evolution in a bacteria. Project 7 will provide a theoretical underpinning for all the empirical projects. By acknowledging that bacterial population size, resistance, virulence and their evolution are interrelated in a complex fashion, this project will integrate the formal tools of population dynamics to tackle this complexity. All empirical projects will partially rely on next generation sequencing that will be performed at a genomics facility in Berlin (BeGenDiv). A scientist will be employed to lead the bioinformatics.Our overall aim is to combine the three research fields of insect immunity, host-microbe interactions and bacterial evolution. We argue that this synergy is essential for generating new insight into infection dynamics in vivo and the evolution of pathogen virulence and resistance.

Further information on DFG websites: DFG - GEPRIS - FOR 5026: Integrating insect immunity, microbiota and pathogens