Evolutionary Insect-Microbe Ecology

Microbial activity shapes insect evolutionary success in both positive and negative directions. We investigate experimentally the mechanisms underlying direct and evolutionary change in insect-microbe interactions. For this we combine experimental ecology/evolution with molecular genetic and genomic approaches.

Contact Marko Rohlfs for more information (mrohlfs@uni-goettingen.de) on potential BSc or MSc projects.

  • 1. Functional Drosophila-microbe symbiosis

  • By manipulating microbial consortia associated with Drosophila we determine the metabolic processes performed by microbes to support insect fitness in different breeding habitats. Currently, we establish a unique collection of yeast and bacteria derived from field-caught flies and maintained by the insects by between-generation transmission on a natural fruit substrate. Plasticity in Drosophila-microbe symbiosis is analyzed in the context of following system properties:
    a. Plant substrate breakdown and insect nutrition
    b. Larval and adult insect fitness (e.g. immune responses, life-history traits)
    c. Resistance of insect-microbe symbioses to invasion by noxious microbes

  • 2. Experimental evolution of insect adaptation to habitat invasion by toxic fungi

  • In the decomposer food web, invasion of ephemeral habitats by filamentous mold fungi pose an inherent threat to insect-microbe symbioses. By means of evolution experiments we explore the trajectories underlying Drosophila adaptation to chronic invasion by toxin-producing mold. We focus on:
    a. Heritable changes in protection against mold and fitness trade-offs
    b. Identification of alleles underlying the adaptation process

  • 3. Chemical ecology of invasion success of insect-microbe symbiosis by toxin-producing fungi

  • Mycotoxin production is assumed to be a major determinant of resistance against antagonistic insects. We use a combination of experimental ecology, molecular genetic techniques, and secondary metabolite (SM) profiling to explore the ecological determinants of adaptive changes in fungal chemical defense. We are interested in the:
    a. Lag between insect attack and onset of differential SM expression
    b. Threshold responses in differential SM expression
    c. Effects of insect symbiotic microbes on fungal SM expression
    d. Insect behavioral counter-adaptations to fungal chemical defense

Representative publications (full publication list)

  • Yin W, Amaike S, Wohlbach DJ, Gasch AP, Chiang Y-M, Wang CC, Bok JW, Rohlfs M, Keller NP (2012) An Aspergillus nidulans bZIP response pathway hardwired for defensive secondary metabolism operates through aflR. Molecular Microbiology [doi:10.1111/j.1365-2958.2012.07986.x]

  • Trienens M, Rohlfs M (2011) Experimental evolution of defense against a competitive mold confers reduced sensitivity to fungal toxins but no increased resistance in Drosophila larvae. BMC Evolutionary Biology 11: 206

  • Rohlfs M, Churchill, ACL (2011) Fungal secondary metabolites as modulators of interactions with insects and other arthropods. Fungal Genetics and Biology 48: 32-34

  • Anagnostou C, LeGrand E, Rohlfs M (2010) Friendly food for fitter flies? – Influence of the microbial food composition on diet choice and parasitoid resistance in Drosophila. Oikos 119: 533-541