The role of microbiota in plasticity of fat synthesis

Symbiotic interactions between bacteria and animals are widespread in nature and bacterial symbionts can have a major impact on the fitness of their host. While the role of gut microbiota in affecting fat metabolism has now been found in the highly complex human system, next to nothing is known about the part microbes play in fat metabolism of insects. Recently, an important and exceptional finding was done with regard to fat synthesis in parasitic wasps: these insects were shown capable of switching fat synthesis completely off or on, depending on environmental conditions. These insects, that feed on other insects during development, can acquire more or less fat from their host, leading to a complete switch off in fat synthesis when a sufficient amount of fat can be obtained from the host. These parasitic wasps thus show extreme phenotypic plasticity in fat synthesis. The question is how symbiotic microorganisms affect fat synthesis in these insects. Similar to findings in humans, I hypothesize that microorganisms indeed affect fat metabolism in my model parasitic wasp. Using natural, field-collected populations, I will test this hypothesis with the following work packages :WP1: Characterize gut microbiota diversity and the effect of the microbiome on fat synthesis and fitness of natural waspsWP2: Identify key bacterial strains involved in wasp fat metabolismWP3: Determine which bacterial and host genes affect wasp fat metabolismIn WP1, I will determine the gut microbial composition and the level of variation in plasticity of fat synthesis in populations sampled during different seasons. By removing the microbiome, I will then be able to estimate the effect of the entire microbiome on wasp fat synthesis and fitness (survival and reproduction; WP2). I can then perform transplant experiments to determine the role played by the microbiome on fat synthesis and fitness. Using the transplants obtained under WP2, I will use metagenomics on the microbiome and transcriptomics on the wasp gut to determine which microbial and wasp genes contribute to the observed wasp fat synthesis and fitness phenotypes.

Keywords:Insects, Gut microbiota, Fat metabolism, Plasticity, Fitness

Disciplines:Animal ecology, Invertebrate biology, Biology of adaptation, Animal morphology, anatomy and physiology, Microbiomes

Project type:PhD project