A team of researchers from the University of Kiel has conducted an experiment using a nearly natural compost mesocosm to study the adaptation of host worms and the microorganisms associated with a novel environment. The researchers sought to understand how host organisms and their microbiomes work together to adapt to changing environmental conditions.

The study focused on the functional cooperation between hosts and microorganisms, known as a metaorganism, and aimed to determine if the microbiome plays a significant role in the overall environmental adaptation of the host organism. They developed an innovative cultivation method using the nematode Caenorhabditis elegans and a selection of microorganisms in a compost habitat.

The study revealed that both host organisms and their microbiomes jointly contribute to the optimal adaptation of the metaorganism to the new environment. The researchers found that under certain conditions, the coevolution of both hosts and microbiomes leads to better adaptation of the entire organism. This finding challenges previous studies that have focused solely on the role of the microbiome in environmental adaptation.

Caenorhabditis elegans was chosen as the study subject due to its short generation time, making it an ideal organism for studying evolutionary mechanisms. The worms were cultivated in mesocosms based on decomposing organic material to mimic a compost environment. After 100 days, the researchers analyzed both the host organisms and the microbiome to assess the changes and adaptations.

The research team discovered that a population of C. elegans in a compost box showed higher fitness values compared to other replicas. These worms exhibited a strong deviation in gene expression, indicating genetic adaptation to the environment. Furthermore, the evolved microbiome also contributed to the fitness advantages of the worms in the compost environment.

This study provides valuable insights into the coevolution of host organisms and their microbiomes in response to environmental changes. Understanding the intricate relationship between hosts and microorganisms can help researchers investigate the underlying mechanisms of adaptation and improve our understanding of metaorganisms.

– University of Kiel: “Adaptation through Symbiont-Mediated Host-Phenotype Expansion” (The ISME Journal)
– Definition of microbiome: The community of microorganisms that inhabit a specific environment, such as the human body.
– Definition of metaorganism: The functional cooperation between a host organism and its associated microorganisms.